VX getting lousy FE lately, what are the causes?
 

I just can't seem to get good mileage lately with my VX. I'm ranging from 37-40(at best).

Admittedly, I haven't been able to drive more conservatively with a hospital run and higher than typical interstate speeds(65-75 instead of 60-65).

I have cruddy lower PSI in all 4 tires currently(having to run them lower)...36 max PSI(rear tires low on tread and starting to dry rot, I don't want to run them higher, and the current fronts s. u. c. k. ! )

Stop and go related, the clutch symptoms force me to use more gas; as the pressure plate/disc seem to be slipping(not sure if thats what to call it, output shaft bearing is hopefully still catching :( ), either way it forces me to "stay on it" more than I'd like during acceleration from a stop, especially in 1st/2nd gear obviously.

To top it off, the battery is showing signs of beginning to become flaky and perhaps the alternator is running at max output.

Aside from extreme hyper-miling techniques(EOC, even P&G), lately I've still driven in mostly 50/50 highway vs city-like driving, but a lot of my trips are of a short variety(10 miles or less), so it's been more of a go-kart mode of late. :D V-TEC is engaged once every trip lately, drivers are insane around here, more than usual and I'm having to aggressively merge with traffic for my area(or I'd be dead already).

Not sure what else could effect the mileage?

Fuel economy seemed to dip as soon as the hottest weather this summer kicked in. The engine, from time to time, will get a 'buckling' feel during engine braking(at the initial point that happens, especially in the lower gears), almost as if the engine 'rocking' (excessively idk?) or something? I thought of that perhaps being the motor mounts? :confused:

Now, I'm just digging, see I need some help! :p

I do notice improvement while using MMO, for what ever reason. FWIW. I've seen spikes from 37-38 without MMO, to subsequent tanks yielding 41-42 MPG. Could be coincidence. Just finished getting 38 MPG on my last tank(fail), and will be using MMO this time.

Before, when running 40 front/36 rear, and on a long interstate drive I could achieve about 50 MPG calculated(no MPGUINO etc to use), that was prior to replacing the 02 ( LAF) sensor. I had averaged lower 40s with a CEL for the 02 sensor, and then got mid-40s after installing the LAF, Standard Motor Products SG335, IIRC. I estimate initially the gains were 3-5 MPG once the sensor was replaced.

Perhaps I'm just not using lean-burn much? It just seems mileage TANKED this summer, no pun intended.:confused:

Re: VX getting lousy FE lately, what are the causes?
 

In my opinion, all of the things you described are attributing to your low numbers. Those things seem like they'd be more than enough to cause the drop. Do you have AC? Can I assume you are using it if you do?
My mileage/ Cd goes down a sizeable percentage when I have the window down. Especially if both windows are down. A hill that I normally see 65mph during EOC will only net 58 mph with just the drivers window fully down.
For that reason, I almost never have the window all the way down. Usually I leave it 2" from closed when it's hot. Otherwise, I bought a cheapo (>$10) clip on dc fan and keep the window closed. The extra alternator load is worth less than the increase in drag.

What about weight? Carrying any extra cinderblocks? Really though, my vx is super sensitive to weight. I'd be seeing 75-80mpg during summer if I didn't have to haul #300 of drums on 90% of my drives! I always keep the "stuff" light if I can.

I will say that if the motor isn't in perfect running condition, it is harder to maintain lean burn. And, as you know, without lean burn the VX uses more fuel than other civics that don't have it. (IIRC)
What about maintenance? How do you stand on that? What's the rpm at idle/how smooth is it?
B

Re: VX getting lousy FE lately, what are the causes?
 

The assumption was correct. AC use has been a must during the day and even sometimes on the humid nights, I'm in Georgia. It's been brutal this summer...

Anyhow, I did change the spark plugs recently, around the time when the mileage started dropping. I wonder if it's worth a pull to inspect them? Maybe I damaged the plug wires somehow and didn't realize it(doubt that). They were really hard to come off the plugs, though! :D

I notice the VX will get the occasional 'hiccup' *not a cough or backfire etc*, during full temp idle.

I used anti-seize for the first time during the plug replacement back around the 1st of June. Perhaps I used too much and it's affecting lean-burn/combustion chamber in general??? My cylinder #4 felt 'notchy' when inserting the new spark plug into the threads(I did not cross-thread it) and it felt different from the others, in that it took more to torque it down by feel(no torque wrench). Perhaps a couple revolutions more, it sorta scared me and made me wonder if I should plan on re-threading/tapping #4 by the next plug replacement?

I may also get the engine compression tested eventually, but we'll see. A mechanic did that back at the beginning of 2010 when the car was first purchased, and it passed compression test for a blown head-gasket, but they mentioned it was done while the engine was "only warm" and not at full temp, so 'it might make a diff' according to them if it were tested again at full temp instead. Their choice to run the test warm and not after being street driven, so I never got it done, in hindsight I probably would have asked them too. Oh well?

I "do" occasionally notice the engine, upon restart after a drive that brought vehicle to operating temp(car perhaps sits 1-2 hours?), will feel like it can't decide whether or not to sit at operating temp idle or should it run up to high-idle. Perhaps the 'in-between' idle? It tries to idle near or slightly above 1,000 RPMs, but just doesn't seem 'right', so I blip the throttle a couple of times until it settles ever so slightly and doesn't concern me. It doesn't feel like IACV issues, that was cleaned well and this symptom is different from the hunting idle problems, all together. It only has happened twice, but obviously something is affecting matters. EGR valve and ports were cleaned. My thoughts regarding this were: MAP sensor(doubt it) or Ambient Air Temp Sensor?

Then again, could that all be related to the clutch somehow(?)...

I don't carry much weight, though I do have the spare tire in the hatch area and some jumper cables.

I don't think I have the underbody panel that is supposed to reduce wind drag, the one located under the back seat/fuel tank area. It's about $40-$50 to get one, worth it eventually? :confused:

PS: Maintenance...

What I thought was affecting MPG recently were 're'-worn re-man CV joints. Replaced with new ones, MPG small blip but not like I was expecting(the reman CVs went out in 12-13 months...in that symptoms appeared anyway).

Outer/inner tie rods and boots were replaced. The shop that replaced old/installed new, used the boots for the Civics that came equipped with power steering though so they couldn't 'clamp' the end of that boot over the inner(manual steering w/o PS needs a slightly longer boot), so the grease was already leaking. Its under warranty until the end of the month, worth hassling them to make it 'right'?

Timing belt/water pump/engine and WP seals replacement(@240k, currently 254k). As well as, drive belts. Alternator was checked by mechanic and was within spec, hands on. Paid the man time so...

Replaced 02 sensor, as covered. Maybe it's flaking out on me without throwing a code, the infamous grounding issue with rusting around the exhaust manifold pre-cat?

Brakes(shoes/pads) and drums/rotors serviced. MTF replaced with Amsoil MTF 5w-30 Synchromesh, this after an 18k mile run on Honda Genuine MTF.

Using Amsoil 0w-30 with half a can of Lubro Moly MoS2. Eventually plan to do extended oil changes, but working my way up there slowly. Recent UOA showed insoluble(insols) percentage was high, perhaps crud cleaning out(Ive taken such measures to 'cleanse' engine, modest ones so not surprised, I am monitoring for trending data there).

Of course, wires(Sumitomo), distributor cap/rotor, TB cleaning has been done(I used Amsoil's Power Foam twice and sprayed at the IACV while running. Currently, I have a K&N air filter, but monitoring Silicon in my UOA to see if I want to go with OEM paper filtration instead.

Valve-adjustment done, valve cover gasket replaced, leaking seals at VTEC(housing and solenoid) both replaced.

1,800 RPMs at 55* MPH(*according to the gauge anyway with 175 tires). Bled the brake fluid and clutch fluid, though didn't completely drain and replace(nervous about that). Cleaned existing engine grounds and added another for the engine. Was concerned about motor mounts but no idea of how to inspect them with the limited tools I have? Vehicle doesn't seem to run hot(nothing above norms anyway), but when I first got the car I noticed the temp gauge climbed between the mid-high mark once. This was just before the car got it's first thorough once over, tech said coolant level was down 1/2 a gallon I believe. I haven't noticed nor had confirmed coolant entry into the oil, though, so I believe it was just left too long, IMO(that is, someone didn't actually refill correctly). After the timing belt job, the replacement coolant has stayed nice and green(not perfect but good IMO) 1 1/2 years since now.

Any other questions or thoughts? :thumbup:

EDIT: Oh, idle RPM full temp is around 400-550. Varies, sometimes higher of course with AC or any headlights. Of course when the cooling fan kicks on as well...RPMs adjust 200-300 then idle back down.

Re: VX getting lousy FE lately, what are the causes?
 

Could be the car doesn't like the plugs you put in, or they weren't gapped right, or they're defective. Could be damaged wires too.

Rot of visible rubber doesn't affect pressure holding ability. Increased pressure may slow the rotting process (by reducing sidewall flex) so you may want more pressure to help them last longer. I have one rotted tire that I often run 15psi over its max.

Mounts would match that description. Also, fuel supply. Failing fuel pump, clogged fuel filter.

I'm not familiar with the part, but can it be made with standard DIY belly pan materials and techniques?

You do want to make sure grease stays there, whether by greasing often or by using the correct boots. It would be a shame to replace your brand new tie rods prematurely. It won't affect FE though.

Check for free spinning of wheels, a bad caliper or drum cylinder/hardware could mean sticking brakes.

You don't drain those systems. You remove all fluid from the reservoir, clean the reservoir, put new fluid in the reservoir, and bleed the other end (clutch slave cylinder, brakes at each wheel) until only new fluid is coming out. The clutch may move enough fluid that you don't need to bleed it, you can just empty+fill the reservoir periodically and eventually it'll be almost all new.

Re: VX getting lousy FE lately, what are the causes?
 

Thanks for the tips, HC. I believe the VX came with this belly pan, but mine doesn't seem to have it. At least, maybe I need to double-take under the vehicle, going from memory on my post last night and it sorta hit me.

I'll see about getting the boots, re-done. Lame COA as I really don't want to go back to the shop. Someone there(an "ASE" certified mechanic) was trying to take me for a ride claiming the pre-mature CVs going out was 'rod knock'(during a phone conversation after the tie rods didn't stop the noise I heard), and that my engine was just getting too many miles(worn out) and would probably need a new engine. Oh, but not to worry they can drop in a nice performance one and that they 'have other civics' lined up for a drop. Did I mention this same ASE certified mechanic did throw out 'needs a new clutch soon', while I was there in person but didn't mention my engine had rod knock? Yet, I should just throw money at this same engine?

Ugh, makes me not want to go back there. It sounded like the mechanic that worked on my car and not the owner, so you know who will be hearing what I have to say before they touch my car again.

Anywho, I'll pull a plug or two and check, they all looked identical before I installed them(NGK 4043/stock OEM), and the plugs come gapped to .043; what the VX calls for. Though, quite frankly I don't think it's an issue with them, as it 'feels' like something else, could be missing in one of the cylinders I suppose it's possible, #4 comes to mind. Ugh!

Re: VX getting lousy FE lately, what are the causes?
 

The missing underbody panel will help a little, but doesn't explain the problem you have now. That is to say, it wasn't there before FE dropped. Fixing would help a little. I wouldn't spend the bread on the real part. I'd get something like coroplast or plastic anything and fill it in with that. There's plenty of surfaces to hook to, with small panhead coarse thread screws or tie wraps, etc.

I run 5w30 engine oil (mobil 1) in the trans. Every person I talked to said engine oil is what it took. I suppose MTF wouldn't hurt though.

1+ for checking all wheels for easy movement. Jack a wheel at a time up and spin it. The fronts will spin somewhat less than the rears. Good rears should spin for a long time on their own after you put some spin into them. You could well have a sticking brake and that would hurt FE a lot.

The extra a/c usage is very likely a strong culprit. There aren't really any alternatives though, if your climate wont allow for driver comfort otherwise.

Replace the battery if it tests bad or failing. The alternator in the VX does turn off the field (or actually, the ECU does that...) when it reaches certain parameters. Such as: battery voltage above 12.something volts, engine above a certain rpm, below a certain mph, etc. That helps with FE a fair amount and if it's not working because the battery is tired it will hurt FE. Advance/battery places can test your battery usually for free. Worth it because you don't want to be stranded either.
Good luck!
B

Re: VX getting lousy FE lately, what are the causes?
 

I had the battery tested twice, once by a counter employee at an O'Reilly Auto parts place 1-2 months ago, and about 1 month ago by an Interstate Battery location.

O'Reilly's "test unit" resulted with the employee saying: "Bad battery".

Interstate Battery's employee said the battery(after being driven 6 miles to the location), had an estimated of 13.4volts at the battery terminals. This was also with the engine off, and re-tested with the engine on(at the bat term) to see what the alternator was keeping the voltage at(all at idle off course), and it was showing 14.2v or so. Their 'print out' from the hand-held tester said the battery was 'Marginal' and to replace it before seeing temps as low as 21 degrees F or extreme heat; otherwise difficulty starting may occur. So far, so good this summer as far as starting...

I suppose the following: The shot start and subsequent cut-off could yield the battery too low(or completely drained) before the alternator can put back enough?

I haven't checked for free wheel play, will do that, though I hate to use the bottle jacks I'm resigned to using(kidding).

When you mention the alternator in the VX turns off 'the field' what are you referring to? I'm still new to understanding how a car truly operates with the battery/alternator(I guess the field means the electrical system?), so I don't necessarily understand the term 'field'. Are you saying if it's operating at full capacity, under certain parameters, the vehicle won't use lean-burn or something along those lines; due to 02 sensor not being used while alternator is doing 'extra' re-charging?

PS: The car came with MTF, Honda Genuine(HG), and it was a slightly thick multi-grade 30. The newer Type-II HG is more like a 20 spec multi-grade engine oil, though truly a MTF.

Engine oil(10w-30 or 10w-40 as per the manual; modern 5w-30 okay) can be used instead of MTF if you can't FIND any MTF, it's better long-term to use true MTF as it has Friction Modifiers(FM) to help with shifting(sychros). Protection should be adequate with the M1 engine oil, but not "ideal" for long-term use. Just from what I gather, anyway.

Re: VX getting lousy FE lately, what are the causes?
 

Most alternators have a wire that supplies 12 volts to the alternator field when the key is ON. The field is part of the alternator windings. If the field is energized with 12 volts, the alternator will charge. If the field windings do not get 12 volts, the alternator will not produce any current.

On most hondas, under certin conditions, the ECU grounds one of the terminals on the regulator and this causes the alternator field not get get current and thus load on the engine is reduced and mpg increases.

Re: VX getting lousy FE lately, what are the causes?
 

What Erik said!
Good explanation, far better than the one I would have given.

As for your battery-
Part of the test procedure is to test performance under load, IIRC. I've had a few batteries over the years that performed well in the voltmeter test but ultimately weren't up to the task of starting/running reliably anymore. I'd say use it as long as you can/feel comfortable with but plan on replacing it before cold temps arrive.
Incidentally, my Volvo wagon would barely start (and often not start at all) during this past winter. The car only sees 3k a year, so it hardly seemed worth buying a battery for. It has started flawlessly all summer long. I will be replacing it as cold temps arrive this year when jumping it wont work anymore.

EOC shortly after starting could be problematic on a tired battery. A new battery would tolerate it much better. It would still diminish the life span of the battery to some (likely) marginal degree.

I'll have to swap to MTF on the next change. I've been doing it once a year or so, which is over 20k. The honda stuff is SO pricey. I know, I know, it's best, but I'll be scowering the internet for info on reputable alternatives.

B

Re: VX getting lousy FE lately, what are the causes?
 

Thanks for the reply and believe cold weather will push this battery over the edge. If I didn't have to save to buy my tires, I'd probably throw in the battery for good measure ahead of time. Oh well. :D'

As for the MTF, I saved a site recently that sells the original Honda Genuine, but most folks have good results(it seems) with Amsoil's MTF. 1 year intervals on motor oil should be fine, otherwise. I doubt you did any real harm, if at all. I do believe I got better shift performance right away after a swap to HG a while back, it's just once the FMs were worn out the shifting got much worse(more notchy, need to rev-match a lot). The issues are worse now with a clutch that is now having slipping during WOT. The Amsoil MTF, on the other hand, has seemed to be a little more solid overall. Not sure if the dealer has the original HG MTF, but I'd try to find it instead of the newer Type-II.

Re: VX getting lousy FE lately, what are the causes?
 

I am in georgia also, I have a almost brand new set of cv axles i was saving for whenever my civic needed them. Let me know if you would be intrested in them.

Re: VX getting lousy FE lately, what are the causes?
 

If these 'new' ones I have go out short of 3-4 years, minimum, I'll be overpaying for Honda originals next time.

Re: VX getting lousy FE lately, what are the causes?
 

Update:

Yesterday, while waiting at an extreme incline(car front facing UPHILL) of at least 20-25 degrees, the car suddenly stalled upon attempt to move once the light turned green. I had the AC on, blower set to max. Maybe I should have ridden the clutch a little longer? :confused: ...but it seemed to die very easily, in any event.

My last tank yielded about 36 MPG, by the way, the vast majority of run time with the AC of course, this after about 43 on a highway trip out of town(pretty lame for mostly highway if you ask me, some stop and go). It feels like the car wants to die at slow speeds, especially with AC on...and if I press on the clutch pedal to early coming to a stop(while the engine is starting to brake itself), I feel a 'shudder', strange 'pop' like sound at the same time. This is just on occasion, though.

Suspicion: I wish I could replace both the tires and the clutch, but I may have to eat taking worse MPG on these older tires for the sake of a clutch replacement due to the need of functionality in a populated area/safety concerns with my wife needing to drive it. This should improve MPG, too, though.

I just have this strange feeling as if something fuel related is an issue, but I do believe a new clutch would fix my issue(I hope my cat isn't starting to clog?) Emissions testing is in a month or two, so I'll report back soon regarding that. I also had the car die while trying to move in reverse a few weeks ago at night, the car was facing downhill slightly(5-10 degrees). I was on the grass there, the stall yesterday was leaving a parking lot on a crazy incline. Not sure, but it could have well been closer to 30 degrees, no joking.

Re: VX getting lousy FE lately, what are the causes?
 

Hmm. Your comment about the "pop"sound and shudder sounds a bit like spark knock to me. That would account for bad FE as if it's knocking the timing isn't adjust correctly (or the advance/related systems are malfunctioning). That might also account for lower rpm reduced power/stalling. I recall a while back we discussed timing in your car... I think? What ever came of it? Have you seen the youtube video and heard the sound of knock/ping? It has a very distinct sound you wont forget. I believe Holy Cow embedded it last time.
It sounds like the timing is either set to far advanced or the timing advance isn't working right. Too far advancing timing will hurt FE just as much as too far retarded. Those marks on the plastic case are tricky to look down and get line of sight on. It's a bit like lining up the crosshairs to the circle on and old gun, then looking up down 3" to marks on the harmonic balancer.

I think replacing the clutch will only help FE if there is a significant amount of clutch slippage. If, OTOH, the associated bearings are failing and will be replaced when the clutch is replaced, FE would likely improve.

It is my understanding that extreme angles will make the engine lack lubrication because the pickup for the oil pump can become no longer submerged, if only for a brief period. That could do some funny things.

One other thing-
Pull your plugs and take photos of them. Make sure you label which one came from what cylinder while you do it. Post the photos here... if there's a major difference in plugs or they don't look just right, it may give some clues about what's going on. For several months my VX had the number one plug always much whiter than the rest.... then I cleaned the injectors in the shop... and even color across all four after that.
B

Re: VX getting lousy FE lately, what are the causes?
 

Thanks for the tips ben. The sound I was describing seems to be related to the clutch, the sound itself/feel I get. It is only occasionally and typically happens with the AC on which causes start and go drive-ability to be lugged, etc...for instance, I start moving in 1st gear with AC on and the car feels like it's either wanting more power or wants to die, so sometimes I come back onto the clutch pedal too hard or fast and the preceding symptoms/sounds etc happen at that moment.

The extreme angle makes some sense, I think it might be this clutch making it harder(slipping when I need to ride it more?)...I do plan on replacing at least the ISB, but overall I think the transmission is just fine otherwise.

I will pull the plugs soon on and see what's up, compare each one to the other. When I first pulled the plugs to 'check' them, the old ones also original NGK p/n, I noticed cylinder 1 had more carbon around the threads. I'm afraid of pulling cylinder #4 since it was being difficult compared to the other 3 cylinders when installing the new replacement plugs, back in the end of May.

I also have thought that perhaps my injectors aren't operating optimally, as the ticking from them seems noisy/sporadic. Would it be worth it to use the old screw driver or mechanics stethoscope on each injector to listen for any differences? I did use a bottle of Red Line SI-1, the full bottle, on a full tank. I realize now this was over-treatment, maybe it did 'too' well and gummed up an injector slightly? IDK.

I wish I could find out where to test the fuel pressure on the VX(fuel test port?), I'd buy a pressure gauge and do that in a heartbeat.

Back to the plugs, they seemed to be alright when pulled before. #1 seemed a little 'cruddy', with some of the carbon and all, but when I checked the other 3, they appeared 'normal'. Of course, turning white on the arm but not 'terrible', it seemed like normal wear for a lean burn chamber to me. I'll see what these 'new' ones I installed look like and take pictures if worth it. Maybe I added too much anti-seize?

Re: VX getting lousy FE lately, what are the causes?
 

You could use a long screw driver touching an injector and your ear with the car running (carefully with the pointy end on the injector) to listen for clicking. It should be nice and even, no "misses." Check each one. They should all sound similar/the same at the same RPM.
If one is particularly louder than the others, you might have an issue. It would be acute though. More likely, you'd find one that was more faint than the others.
More carbon build up could be an indication of something... could also be related to FE type driving. If pulling #4 is precarious, you may wait until you don't need the car for a weekend or something. That way if you have bad threads to deal with, you'd have some time/money to take care of it.
When you do pull them, try cleaning off the antiseize from the plugs. They'll still be some left in the head so you wont have to worry about them seizing on you.
The VX fuel test port is supposed to be on the fuel line that attaches to the fuel filter on the top. It has a larger bolt head that goes into the filter and then a much smaller bolt head on top. The smaller one threads out and you put your FPG there.
B

Re: VX getting lousy FE lately, what are the causes?
 

Similar patterns on all 4 injectors, but once warm I could tell a 'slight' dullness in cylinder 4 compared to cylinder 1, cylinder 1 sounding slightly 'raspier' and cylinder 4 being ever so slightly more faint than the other cylinders. Either way, I'll probably wipe off some of the anti-seize.

I'll probably pull #1 and then perhaps all expect #4 when I have a couple days off in a row in the event of an issue, if I decide to pull all including #4. So, we'll see.

I also noticed the wire that comes out of the VTEC solenoid lately has oil on it(it may have done this before), I had previously lost oil from either the housing or the top part, replacing both gaskets already. Maybe it's leaking internally? No codes as of yet.

The VX fuel test port location, that sounds plausible, but wouldn't that only detect pressure post-filtration, perhaps telling you if you had a clogged fuel filter or not? I have replaced my fuel filter twice, one upon getting the car and then 20,000 miles later with a Purolator. I'm considering going with a Mann, Hengst, or Wix/Napa Gold next time.

I suppose if it failed a pressure test ever so slightly and replacing the filter didn't see a spike with pressure, a fuel pump would be the suspected culprit in the end? This wouldn't test for FPR functionality, though if I'm understanding things right.

Re: VX getting lousy FE lately, what are the causes?
 

If you are hearing differences in your injector sounds, it would definitely be worth a cleaning. It isn't all that hard to do, really. You need a couple of jumper wires with gator clips, a 9v battery (or car battery), a length of hose that fits the end of injector tightly, spray throttle body cleaner, and something to block the other end of the hose with like a bolt.
I doubt oil around the vtec solenoid will have much effect on anything other than leaking oil. Besides, I suspect you rarely get above 2300 rpm anyway.
Yes, you are right, the test location is pre-filter, I think. I'll have to look at the routing on mine to confirm this. You can test there, then replace the filter... if the pressure goes down, the filter was clogged. If the pressure is then under spec/inconsistent, you can suspect FPR or pump. There's a procedure for testing the FPR, it involves pulling the vac line and inspecting for fuel (which there should be none), then providing a vacuum on the line, or not, and checking to see that pressure changes when you do so. If the pressure doesn't change at all or there is fuel in the vac line, replace the FPR. If it is functional and the pressure is still low, replace the fuel pump.
B

Re: VX getting lousy FE lately, what are the causes?
 

It sounds like you replace your fuel filter often enough. You'd have to have a severe sediment problem to clog a filter enough to cause insufficient pressure at idle...and then I imagine you would have severe lack of power, like, can't get over 2000rpm or 20mph. I wouldn't recommend worrying too much about location of the test port, as long as it's somewhere between the fuel pump and the injectors.

Re: VX getting lousy FE lately, what are the causes?
 

Yes, I do replace the fuel filter often enough(twice since owning the car in about 35,000 to avoid such a 'clogged' filter after bringing the car up on maintenance)...

I took out plugs from cylinders 1, 2, & 3 today. Here are some pictures. The one on the left, in the pictures, is from #2.

The plug on the right is from #1, and #3 looked similar to #1...(#3 not pictured)...what do you think guys? I did add lubro moly Mos2 and used a full bottle of Red Line SI-1 fuel system cleaner after these plugs were put on about 4,000 miles ago, I think I may have used too much anti-seize as well:

https://img153.imageshack.us/img153/3654/1003550.jpg

https://img854.imageshack.us/img854/8595/1003553d.jpg

https://img828.imageshack.us/img828/1763/1003554.jpg

Gap for #2 was slightly larger than the spec'd .043 gap, but #1 and #3 were just under .042 gap or so.

Re: VX getting lousy FE lately, what are the causes?
 

Great quality on the photos!

You used less anti-seize than I did. I am not qualified to comment on the actual condition of the plugs...

Re: VX getting lousy FE lately, what are the causes?
 

^I used slightly less this time on all 4 new ones just now. :D

Yeah, I went ahead and replaced all 4. :thumbup: Cylinder #4's plug removed easily, and is not degrading as I had feared. Perhaps installation this last time 'cleaned' the threads on #4, I went by feel more relaxed this time, so I only did a half turn(with 3/8s wratchet+extension+plug socket)...once hand tightening needed more than wrist/hand turning(slight forearm strength) that is.

Also, I checked the plugs in the photos above(with 4,000 miles on them) to the ones I pulled back in June which had around 20,000 miles on them. They did not have any of the scorching on the side of the 'ceramic?' part leading up to the electrode. Also, the arms didn't have 'flaky'; bake on anti-seize 'like', material as these plugs I removed today had.

I'm about to go for a test drive.

Not sure if running the Red Line SI-1 as concentrated as I did(mistakenly overdosed using the entire bottle to the 10 gallon tank) would cause that discoloration, but it worried me compared to the originals none-the-less.

So, for $8.86(total) I replaced all 4. Will report back on drive-ability and FE.

PS: Just to be clear, all 4 of the plugs I removed today had the similar discoloration on one side of the plug as shown on the right-hand plug in the pictures. I just didn't turn the left-hand plug around to display it's discoloration.

Re: VX getting lousy FE lately, what are the causes?
 

IMO the plugs look pretty dirty for only 4000miles. They should look like brand new.

I think your oil separator isn't doing its job or you have worn valve seals (real common for these engines with a few miles on them). There's a way to check this. Will explain later.

Also a great way to check to see if your plug wires are arcing at the boot is to put a single layer of masking tape around the hard part of the boot. If it arcs it will leave a burnt black mark that's really easy to see. One miss fire will leave a distinctive mark.

I would do a leak-down test and compression test to see where the engine is at health wise.

Re: VX getting lousy FE lately, what are the causes?
 

Oil separator, is that like the breather chamber or what??? I'm new, yes. :D

Worn valve seals, after the previous plugs with only 20,000 prior didn't have these marks and only had carbon on the threads? The valve seals would go up in flames in only 4,000 miles?

I do not know how to perform either test, and would have to wait to pay a shop I know to do the tests. At 232,000 it passed a compression test(now at 254,000), but the mechanic that did this(he did so in passing) only tested the engine 'while warm' and not at full temp, implying it may 'fail' a compression test if performed again under full temp.

The plug wires have 24,000 miles on them(installed January of 2010), and have been pulled 3-4 times, I suppose that's worth a look, but all 4 wires arcing doesn't seem likely to me since they were brand new so recently. (unless one arcing would cause such a drastic misfire to be a problem resulting in all plugs appearing to have that strange burned mark on them). Either way, I haven't noticed severe misfire at any time, as far as I can tell.

Also, the clutch starting to go causes me to put more load on the engine(while riding the clutch longer to 'prevent' non-slippage of the disc, if that is what is happening to the clutch?) than I would under normal acceleration with a good clutch, not sure if that would impact plug appearance?

Yes, I too thought the plugs looked terrible for such a short period of time, especially compared to the ones with more mileage that were pulled previously.

Re: VX getting lousy FE lately, what are the causes?
 

I'm interested in this too-
PGF, what is the tolerable compression for a VX? I know you're supposed to give 7 cranks or less, WOT, to test compression. Is it critical to be at full operating temp? As I recall, I tested mine on a cold engine.
Leak down I've heard of but never heard a good explanation of it.
B

Re: VX getting lousy FE lately, what are the causes?
 

Yep its the black box underneath the intake manifold that the PCV valve line connects to.

OK if the other plugs looked good after 20k then something else is causing the poor plug readings.

The engine should be at operating temp to do a compression test. Also you should have the throttle wide open with the injectors disabled.

Sorry I was referring to when you said in another post that you thought you might be having a miss-fire.

This is whats strange. Did you clean you EGR valve inlet lately. I have seen after cleaning the plugs will read dirty for a while.

Re: VX getting lousy FE lately, what are the causes?
 

I don't have my Honda service manual with me now, but going by memory I think its around 170+ The main thing when doing a compression test is to know your tester. My Snap-on compression tester makes all my friends cry when we test their engines(it reads about 20psi lower then others) So the main thing is to make sure all cylinders are with in 10% of each other.

Yes its very critical to do the test at engine operating temperature. More so on race engines with loose piston to cylinder wall clearance.

Leak down testing is wheres its at;)

Compression test are a fast reference to determine that something is wrong with the engine. Kinda like doing a blood pressure test. It tells us that your blood pressure is at a critical point but not whats causing it.

A Leak Down test tells us whats causing the low compression in a cylinder or cylinders. Kinda like the more advance medical test to pinpoint whats causing the high blood pressure.

So what I do after I know I have loss power on one of my race engines is do the compression test first. It gives me a quick reference of what cylinder is hurt.
Example: Number 4 cylinder has a compression reading of only 90psi compared to the other three that read around 165psi. So now I do the leak down test on number four only.

The Leak down process goes like this. Hook up the leak down tester to number four cylinder. This is down by threading a hose into the spark plug hole. You then put number four cylinder at TDC.

The other end of the tester is the hooked to a compressed air source via. "air compressor". The test will show you by its gauge what the leakage is in %. Anything over 3% for a stock engine is bad.

Now its time to determine where the leakage is at. If you hear air coming from the valve cover oil filling cap its rings or ring-lands. If air is coming from the exhaust pipe its a exhaust valve. If air is coming from the T/B its a intake valve. If air is coming from the adjacent cylinder spark plug hole its a head gasket etc. There's more to this but I think you get the idea.

One other thing I would like to add is this. On this site most of you aren't building race engines. But what I have found on a lot of stock engines with high mileage is the rings gum up and start sticking to the piston. This in turn will make you lose power and start consuming oil.

Engines like the VX are more prone to have this issue because of the dreaded EGR system in them. Do to lean burn they had to reduce NOX and did this by higher amounts of recirculating the exhaust gases. The EGR system of these engine was dirty and inferior to today's systems. This will cause the oil to breakdown early and loose its lubricating properties. In turn gum up the piston rings.:(

Hopefully this helps. I need to post this now before I screw up something and lose the entire post LOL;)

Re: VX getting lousy FE lately, what are the causes?
 

^So, this leak down test is done with the engine off and attempting to determine if air is 'leaking' from various sources to identify a trouble spot

...but anything under 3% on the gauge, you're saying, is considered 'within tolerance' on stock setups anyway?

Yes, I did have the EGR + ports cleaned out a while ago now(9 months?), within the past year. Is it possible it had gone so long without servicing that they are needing servicing again?

I've been posting over at the BITOG forums learning about lubrication/apps etc, trying to extend out the oil change intervals on this VX. My insols were at 0.5% recently(considered just under the 'warning' level of 0.6%); that was a spike from my first UOA of 0.4%, I ran a HDEO combo with MMO(20% of the refill capacity/volume) for about 2,750 and it seemed to generate more gunk in the oil.

Currently, I have an Amsoil oil filter on there and I'm trying to see if that will help catch more of the crud that could have stayed behind after draining that oil.

I suppose I've got some cleanup going on in the engine, still, and it's caused me to hesitate extending the interval to date(longest so far has only been 5,000). I may have some ring related issues.

I may try a piston soak eventually(though I've used Amsoil's Power Foam twice now), and I hear Mobil1 is good at 'keeping' ring packs clean(though I don't know about actual cleanup compared to other oils). I have also considered taking Pennzoil up on their 'guarantee program' under another vehicle my parents own that would qualify for their rebate going on( https://pennzoilwarranty.com/our_warranty/) ...so, that'd give me a chance to run Ultra for 5,000 or so in an attempt to clean things out more. (for basically free, I have oil filters on hand and just have to pay postage for the rebate, ...maybe $2 out of pocket after rebate)...

Currently using Amsoil 0w30, but I have some High mileage oil(Valvoline MaxLife Full Synthetic) and was going to use that next summer. I could alternative try an idle engine flush before my next oil change as well.

It's possible the breather chamber needs a good once over. Is it easy to pull that off? Any o-ring/gaskets to replace? I believe it may have an o-ring??? I was actually going to pull it off the next time I remove my oil filter from underneath the car and see how it looks. Judging by how dirty my actual PCV valve was seated into the breather chamber(oil separator), ben(IIRC) had asked me to remove it when I had the chance.

PS: Sorry for the confusion, I should watch how I say things, but it could have misfired and I didn't realize anyway knowing my level of car 'expertise'. ;)

Re: VX getting lousy FE lately, what are the causes?
 

I see your well educated in the oil testing part of the program, me not so much.:o Its something I plan on learning in the near future. I'm also very interested in a way to soak the ring pack to loosing up them. If you come across anything let me know.

The black box is very easy to remove. You will have to get to it from the bottom of the car. They do get gummed up and then they don't scrub the oil properly. I recommend letting it soak in carb cleaner for a day or to then blow it out really well.

Yes engine off with the cylinder being check set to TDC.

EDIT Yes there is a o-ring where it goes into the back of the engine block. I have seen them become very brittle and need replacing. But most of the time there re-usable.

Re: VX getting lousy FE lately, what are the causes?
 

Interesting that another plug would allow more air to pass even though it's seated into the threads?

As far as piston soaking:

Kreen is a big hit on the other forums for now. It's encouraged to order the stuff by the quart opposed to larger quantities as gallons or larger containers charge a ton more for shipping(haz. mats.)

I'd get a couple quarts of the stuff and try that for your next soaking experiments(plugs out, soak and then manual crank you know)...it's sold by KanoLabs(relatively expensive, cheaper than AutoRx).

https://www.kanolabs.com/engCle.html

PS: I'll post pics of the box when I pull it. :thumbup: ...oh and definitely some parts cleaner would be worth it as a true soaking. If the box is still in tact no cracking etc, I'll just clean it up and be done, also will check the PCV valve again. Thanks for the help! :D

Re: VX getting lousy FE lately, what are the causes?
 

Not to sure what your asking here???

Re: VX getting lousy FE lately, what are the causes?
 

I would like to give some more insight on what I have been working on lately. I have been doing some low dollar builds on a couple turbo DSM 4G63 engines. Its one of those things that in these times being frugal can also be fun.

My goal is to be able to run a stock piston, ring and produce over 500whp all awhile keeping the engine alive.

In my adventure I have been giving a ton of stock piston and rods from donor engines that the owner is going to replace with after market high performance parts.

Most of the stock piston and rings are gummed up real bad. The top compression ring is usually still loose but the second compression ring and oil rings are a mess. Literally glued to the piston.

I have tried a ton of different solvents at different temperatures to unstick the ring pack. I have had no success.:( So I have to pry the rings out of their ring lands with a small screw driver to get them to come off.

The kicker then is I do what we did in the old days and run a ring grove cleaner through the ring grooves and clean up the rest of the piston with a red scotch brite and sanding paper. I then reused the same rings that were on the piston and a assemble. I broke a few pistons based on pushing the power level on pump gas but now have came to a point of anything under 550whp on pump premium the engine will live.

This adventure all started out as joke with a friend because we are on major budgets. But now its my new way of building my DSM engines.;)

OK were I'm going with all this is I'm wondering if there is a cleaner out there that will work??? I have even considered to find a engine that the rings are gummed up after taking them out of the block. Then re-install them and then try some cleaner and see if it will un-stick the rings? Tear the engine down and see what the results are?

I'm sure there are different levels of how bad the ring pack can be and some cleaners might work. But after what I have been through I don't think any cleaner can revise them if they are extremely bad.

Re: VX getting lousy FE lately, what are the causes?
 

Oh, the leak down test, I was referring to that. Where you described having the one cylinder as the test point and another plug/cylinder is the culprit; passing too much air even though it still has the plug installed? I put it like that because it seemed odd to me, but I suppose I haven't worked with too many 'bad' HG issues, let alone perform leak down tests.

Re: VX getting lousy FE lately, what are the causes?
 

Ah, I see now what you are describing. I don't have engine tear down experience, and part of me would really like to get into that as a hobby and eventual profession over years(not necessarily for money). I can wrap my mind around something fairly easily once I get the entire concept and functionality...

I'll see what I can dig up on the other site and PM you here regarding the Kreen product. If it couldn't help you, I don't know what could safely while inside the engine without seriously attacking the seals(of course Kreen wouldn't be used for prolonged periods in an engine).
The product itself evaporates out after so many miles(1k-2k or so), while evaporating and cleaning the PCV system as well, IIRC.

Re: VX getting lousy FE lately, what are the causes?
 

Oh I see what your asking now LOL

When doing a leak down test all the spark plugs are removed. This makes it easier to get on TDC for the cylinder your testing.

What happens with a blown head gasket with a cross over is the cylinder next to it will receive the air your pumping into it and make a sound at its spark plug hole.

Re: VX getting lousy FE lately, what are the causes?
 

That would be cool. I appreciate the time and effort.:thumbup:

Re: VX getting lousy FE lately, what are the causes?
 

add|ct, it sounds like you've got a rather large budget for oils and other liquid products that exceed specification at increased cost or aren't specified for use at all. I'm curious, have you compared the sum total of all the extra oil/fluid effort to the cost of whatever service would be necessary to repair it mechanically?

:eek: I run a little increased EGR in my 1980 Buick and I was thinking of doing more. Do not want that problem.

Re: VX getting lousy FE lately, what are the causes?
 

^I have been getting the car serviced and caught up on maintenance on big jobs(tie rods, CVs...done twice long story...timing belt service etc) so oil and fluids have been among the cheapest things purchased towards this car(maybe $250 in oils, filters, and other fluids since owning the car for almost 1.75 years).

I've only started to try out Amsoil, and have made a hobby of a Used Oil Analysis, but it's in a very small sample size(as all of that is expensive compared to basic maintenance in that regard). My goal is to get the complete value of Amsoil by extending out my oil changes to 10,000 miles.

I haven't gone into very expensive solvents, etc; but I have tried some products and procedures in an effort to help the vehicle with carbon. Hey, I even threw $200 at a tech to look over the car for a rough idle last summer and they couldn't really determine anything. I suspected a bad alternator after a 'tester' from the local parts store stated the Voltage Regulator was bad, so the shop I used serviced the alternator and it was within spec. The EGR had been cleaned, IACV had been cleaned, etc.

The things I know about are clutch related now, but I don't know truly whats going on in the engine. On the other hand, I have feeling this battery I'm using won't suffice in the winter and I have a feeling the alternator is working at max output more often than it should be.

Re: VX getting lousy FE lately, what are the causes?
 

[QUOTE=theholycow;163290]add|ct, it sounds like you've got a rather large budget for oils and other liquid products that exceed specification at increased cost or aren't specified for use at all. I'm curious, have you compared the sum total of all the extra oil/fluid effort to the cost of whatever service would be necessary to repair it mechanically?



:eek: I run a little increased EGR in my 1980 Buick and I was thinking of doing more. Do not want that problem.[/QUOTE]

I have been running more EGR on my Talon and doing some testing with it. As of now I'm not seeing any increase in mileage. But I think this has to do with the fact my lean burn has increased my fuel mileage as far as it will go.

I'm sure its helping with NOx emissions but other then that its just creating a more dirty burn.

On my Honda I made a long tube (like a exhaust silencer) to try to clean up the EGR system. It work but it would become more maintenance.

Re: VX getting lousy FE lately, what are the causes?
 

Well, tonight the clutch was slipping again, but I'm not sure if it was related to being low on fuel or not?

On an incline and I come off the clutch too soon, WOT...high rev, stunted power at the wheels, etc....

This was the first cool spell down south here since the summer began. It's down in the 50s for once. I was thinking that perhaps that(thicker MTF) would have affected disk slippage/power transfer coming from a stop in first, but possibly being on that upward incline again/while also being low on fuel did me in?

Ugh, and I need tires for the winter...and a battery! :eek: I was hoping to put off the clutch until next summer. I wouldn't have gunned it then, but someone pulled up close behind me at the light.

The car definitely didn't like it. I went into 2nd and it was still busy in 'recovery' from slipping in first from the initial restart. I'm hoping it's just the clutch, I'd have if the output shaft is going, somehow.

IIRC, someone mentioned their VX had a similar issue and the ISB was needing replacement with the clutch kit as well to fix their symptoms that were similar to this?