Throttle Body problem?
 

I recently became the happy new owner of a gas sipping 1993 Honda Civic VX (49 state version) It has a 1.5 liter VTEC-E engine and 5 speed manual transmission. The speedo/odometer don't work all the time so it has *at least* 175,000 miles.....

There's quite a few problems with the car so far but the biggest issue is with how it drives. A few things regarding this.

First,

when shifting at lower speeds (mainly going from first gear to second and second gear to third) the tach does not drop down to 1000RPMs immediately *like it should when the clutch is depressed between shifts*. I'm at 2000RPMs, I put in the clutch, but the tach just hangs out at 2000RPM for a second or three before slowly dropping down to 1000. I usually shift at around 1800-2000RPM when in first or second gear, and 1400-1600 rpm from 3rd to 4th, and 4th to 5th. This car likes to operate at low RPMs. The problem does not go away when the car is warmed up. The problem doesn't seem as noticeable going to 4th and 5th gear (but that could just be because I shift at lower RPMs for these gears)

Second,

When cruising at highway speed (60-65mph, I'm trying to get a bazillion miles per gallon here), and the gas pedal is depressed at a steady constant to maintain a constant speed, there will be a sudden, but subtle, loss of power, and the car will start slowing down, then there will be a sudden, but subtle, surge of power and the car will start accelerating again or at least maintaining speed--the power surge and power loss are very subtle. It actually happens at just about all speeds except maybe below 25mph. It's almost as if it is slacking on the job, and then realizes it and tries to correct itself. The person who sold me the car said that that was the car entering into the lean burn mode. But I am skeptical. Especially when you consider the third part of this problem of which all three parts I'm assuming are related.

Third,

When accelerating at lower speeds, especially at low RPMs (say 1200, no really, the car likes low RPMs!) sometimes in addition to lagging, it stutters, and for a brief moment, sometimes, I think the car is going to die on me. But then it pulls itself together and pulls forward. It doesn't always do this so I don't think it is a lugging problem. When a car lugs, it makes an unhappy but fairly even noise that screams 'Up shift! Up shift! For Godsakes Up shift!". There is no noise out of the ordinary, and it seems to me the jerky stutter is too erratic to be a traditional lugging of the engine.

Might there be something wrong with the lean burn aspect of the VTEC-E engine?

Here are some of the things I've been told might correct the problem, or that I thought in my own limited understanding of cars might correct the problem: (these are quotes from car forums)

"VX and CX engines are both finely tuned engines and require valve adjustments every 15,000 miles I believe."

"the varrying throttle in my expearince is the o2 sensor, but going thru and doing a tune up might make it go away as well, make sure your EGR valve is working properly too, as I was told by the dealer mecanice that if that is not working right that it can sometimes have the same affect, to check that simply pull the vaccum hose off the EGR valve and plug it with a pencel." [sic]--dyslexia maybe, or English not his native tongue

I'm car-DIY-aphobic so I haven't messed with anything on the engine myself. I've left that to my friend who works at Jiffy Lube (who was the one to do the tune up). Oh, the guy who sold me the car said the rising RPM problem could be fixed with a throttle body cleaning? or something with the throttle body--not exactly sure, the car lingo kinda goes in one ear and then gets stuck on some ear wax before it ever gets a chance to actually penetrate any gray matter let alone make its way over to my other ear.

It did have some other throttle issues, but they *were* mostly improved by tune up. For example it stalled once on the 45 mile drive home from where I bought it but hasn't stalled since the tune up. But the engine still rises to 2000RPMs sometimes inexplicably when I put the shifter in neutral (the temperature gauge indicates the engine is warm, but this will continue to happen up to ten minutes after the temp gauge has stopped rising-or even after a long drive [not all the time, but sometimes, when it feels like it. Sometimes it'll stay motionless at 1000RPM like a good tach, and other times it will bob up and down between 500 and 1100-but then sometimes it'll sorta just wander up to 2000 and hang out there. This seems to happen more while putting along in congested traffic in town])

Just so I'm really clear. What I *want* the car to do is to idle normally . That is stay at 1000RPM at all times when not in gear (I don't really mind the bouncing tach at low RPM). If it wants to warm the engine up at 2000RPM, then it should do it for the first five minutes, not at random intervals throughout the day. And I want it to have even and smooth acceleration and to maintain even throttle response when I have the throttle depressed at an even, constant pressure.

One thing I forgot to mention that would help with the surging idle is cleaning the IACV (Intake Air Control Valve). It is on the backside of the intake manifold. It's an easy DIY.

CLICK HERE for a How-To to help you along.

I had a problem similar to this. I thought it was one thing it seem to fix the problem then it came back. A few things the ignition module, fuel filter, fuel pump, engine computer, spark plugs, distributor, Compressor lock up, to name a few can cause the resuting problems. With mine I had to replace just about everything for it to finally fix roughly the same problem you had. Try running the car with the A/C turn off. See if that improves the situation My car was a 94. I highly recommend before you do anything. Find a repair shop or some place that will run the codes for the car.

Try running the car with the A/C off!? Wait, do you think this is like, the Gassavers forum or something? Hah!! I'm just kidding. I haven't used the A/C since I've owned it. It goes into the shop on Thursday, and I will give the mechanic a piece of paper with all the advice I've received on what might be the causes. Oh boy, he's just gonna love me.

[QUOTE=1993CivicVX;69793].... I haven't used the A/C since I've owned it...QUOTE]

Welcome home buddy, you're right where you belong.

On another note make sure they check the timing belt. I had a car that would stall on me on the highway. No problem: just put the auto car in neutral while driving, restart the car and pop back in to drive an keep going. But it would keep doing it. Sometimes while gassing, it would just completely lose power (as if the fuel pump went) and sometimes it would die (hence, neutral and restart). Thought it was spark plugs or feul pump intul the car just died and would not restart. Luckily I was driving fast enough to coast to the next exit and roll into a sweet parking spot (LUCKY !!!)
Turned out to be the timimg belt. Auto store had one for less than $20 and a coworker install for next to nothing. Job took less than an hour. Was an older Toyota, so it was an EASY job. If you dont know how long its been since changed, you might as well install a new one if you are going to be doing ANY engine work. Plus on a 90's Honda, Im guessing its an easy and cheap job. Mechanics love working on older cars. so much faster and easier

I've noticed newer cars (mine is an '89 which I consider "newer") don't drop rpms as fast as the older ones did. I think it's the computer maintaining rpms and letting them drop gradually to avoid driveability issues and maybe to reduce emissions. In the carburetor days, they added an idle-drop limiter of some kind so the idle would reduce slowly when you took your foot off the gas.

Anyway, do look around for intake leaks. That's hoses of course. Also if you have a corrugated air intake hose downstream from the air mass meter (aka MAF), remove the hose and check for holes everywhere. Nearly impossible to see the underside of those hoses when installed.

yeah the timing belt is something to look into. The engine computer can cause problems like this as well. Its something that will fustrate even the mechanic believe me. I even thought at one point it was the throttle position sensor or whatever they call it. I almost made myself believe that the 10% ethnaol mixture made it stall because it couldnt handle the new mixture. Which wasnt true. I wish you the best of luck.

Thanks guys. Well, it only stalled once, and that was after 50 minutes of driving. But I haven't done a long trip since. But It hasn't idling real low like it used to ever since I did the tune up and the exhaust clean. I think those things really helped! A friend just installed the CD player and connected the speakers. So now I finally have something other than the rattle to listen to while driving! Actually, hardly notice it anymore--the music drowns it out nicely. Anyway, thanks guys, and I'll let you know how it goes on Thursday!

Check your throttle possition sensor for a dead spot in it's rotation, if it's good then I highly suspect that it's your O2 sensor, you can check all that other stuff on your list, but the O2 sensor on the civic vx seems to have a life span of about 15 years, some people exspect an errer code from the computer, but most of the time it will not have one, but if you replace the O2 sensor your problem will most likely go away, and if it's a choice of paying someone $300 to figure out the problem, or pay $300 to have the sensor replaced, then I say get it replaced.

There's no need to pay $300 for an O2 sensor. eBay for about 1/2 that price.
Check TomO's links, I think he has the info there.

First things first he should atleast get the codes check on the car then go from their. Being that checking the codes is probably the cheapest thing he can do right now before he starts replacing stuff. I have had allot of O2 sensors go bad normally I havent seen them act in this fassion when they go bad. The biggest thing I notice is I fail the emissions test. Which requires a new O2 sensor run it back on the dyno. Pass the emissions test. While I'm not ruling out the O2 sensor. The codes will probably reveal it. If not he can get and emissions test to see if passes.

Mechanic immediately said the throttle body had been tampered with and suggested to replace it. So I agreed. Will be $140 for parts and labour. The emergency brake fix and rear brakes will run me $475! $72 for each rear brake cable. This was not an expense I was expecting. So we'll see if the throttle body replacement will fix the idle and the hesitation upon acceleration. I forgot the to bring the list of all the advice and tips. But I owe the mechanic a deposit on the used throttle body so I'll show it to him then and see what he thinks.

400 for this 400 for that. Yeah sounds like mechanic prices. Comes to a thousand real quick before you know it. I recommend getting a haynes repair manual and fix it yourself. To many people live and die by mechanics these days.

Is this the Jiffy Lube guy? Maybe try checking with a real Honda mechanic.

Its always good to get second opinions as well. Call up a junk yard ask them what mechanic they would use. Their might even be somebody at the junk yard who might try fixing it for ya. Just throwing out past experience things that have done well for me. I would stay away from any tire name repair shops. Also dont let the guy at Jiffy lube repair it for yeah. If these guys where good at fixing things they would be a mechanic.

The rear hand brake cables on a civic vx cost $46 for one side, and $38 for the other side, the highest priced brake shoes you can get for the vx are $38 for a set, about a year ago I was quited $50 to replace one hand brake cable on my crx hf, it's a slightly shorter cable, but a simaler lay out at the vx, it required me to remove the wheel, brake drum and brake pads of the side that I was replacing the cable and took me about and hour and a half, and it wouldn't have taken any extra time to replace the brake shoes at the same time as I had to remove them to replace the cable, and I think the only tools I needed were a jack, a lug wrench, a pair of pliers and a 12mm wrench.
My mechanic charges around $50 an hour, so even if yours charged $100 an hour and was as slow as I was the total still should have come to less then $425 with the highest quality parts I could find.
I agree compleatly with staying away from the jiffylube kid, I learned how to change oil when I was 15 years old from a girl who didn't want to get her hands dirty, and after spending countless hours working on cars and reading repair manuals I still change oil the exact same way as when I was 15.

Rest assured I know better than to let the Jiffy Lube guys do actual mechanic work on my vehicle. It's a local mechanic near my house. My cousin goes to him and she has a Honda so I figured what the hell. He seems like a nice guy but he is very busy and it's hard to get an appointment with him (I saw this as a positive sign, but $475 does seem expensive!) I might have my non Jiffy Lube friend who claims to have recently learned how to do the brakes (he's changed them twice now, although I think he learned from the jiffy lube friend!) But I think I'll still let the mechanic do the e-brake. As far as part prices, I think the throttle body was $80 from the junkyard because that's how much of a deposit he wanted and said the total for installing it with the price of the part would be $140 (leads me to believe he charges $60 an hour which is pretty normal for the mechanics around here)

The only thing I perhaps would say might be to his disadvantage is he is young so not as experienced as some of the older mechanics. I'd say only a few years older than me and I'm 27. I think he got his shop maybe a year ago.

Based on your math Ryland I should be paying for the rear brakes and e-brake about: $250. The drums and the shoes need to be replaced. Everything on the back brakes he said needed to be replaced--very rusty and didn't look like they'd ever been done or at least not in a very long time.

Once the ebrake gets fixed it will be safer for me to work on my car. The same friend who might do the brakes on my car didn't put the ebrake on while jacking up his g/f's car and because the car rocks back and forth a little while its in gear it rocked off the jack before my friend had finished putting the wheel back on. I'd like to do some work on the car myself, but a little wary.... I'll look into getting a Haynes manual tho.

Just changed the spark plugs!
 

I just put in the proper spark plugs (V-Power) with the part number corresponding to what is recommended for this car written on the hood and it has made a huge difference! I barely notice the hesitation now at all when accelerating and it doesn't lose power, gain power, while cruising. I've driven 25 miles to test it. So wondering if that fixed the problem. Is any sort of hesitation normal with this engine? It doesn't seem to lag anymore, but the power delivery still isn't quite 100% uniform, but it's pretty darn close. Putting in the right spark plugs really made a difference! A whopping $10 fix. hahaha. Good times. :thumbup: :D

Congrats on getting the right plugs in there. There still will be some noticeable switching between lean burn and regular and VTECE mode, but this is normal. I can barely tell when my VX switches between those modes now, and I know what to feel for, lol.

Okay, great! I think it is working properly now. Will get the rattle fixed, and having the throttle body replaced, so hopefully that will fix the sticky idle. After those things, car should be purring like a kitten. I still haven't done all the other little tweaks, like cleaning the IACV. I prolly should have the timing belt changed as well as its been at least 30,000 miles since it has been, and probably a lot more than that. Expensive tho. maybe I will do the valve adjustment if I do. I read on another VX forum that it's something that should be done every 15,000 miles. "VX and CX engines are both finely tuned engines and require valve adjustments every 15,000 miles I believe."

From the same forum: "the varying throttle in my experience is the o2 sensor, but going thru and doing a tune up might make it go away as well, make sure your EGR valve is working properly too, as I was told by the dealer mechanic that if that is not working right that it can sometimes have the same effect. To check that simply pull the vaccum hose off the EGR valve and plug it with a pencil."

Anyway, great little car. Very happy with it so far.

I recommend getting a haynes repair manual its such a small investment that will pay for itself over and over. The manual tells you just about how to fix the whole d a m n car. Even if your not a mechanic inclined person. Haynes makes it easy to understand how to fix it. Plus you gain the knowledge of how to work on cars for yourself.

Till you buy a manual, you can use this link.
https://www.honda.co.uk/car/owner/workshop.html

To me, your throttle problem sounds like a sticking throttle cable. To solve this, lubricate all the friction points with some PB Blaster and clean the throttle body with some throttle body cleaner. I had the same issue with my 95 VX.

Your low RPM acceleration stutter sounds to me like the car just doesn't have enough power, and that it might simply need a tune up to accelerate a little smoother. In addition to the plugs, I would replace the distributer cap/rotor, and plug wires if the look old. It should help with making the acceleration even smoother, but I agree, the new and correct NGK v-powers ALWAYS made a difference for every Honda I used them in.

I've done all the tune up bits. You don't think the o2 sensor would make it run smoother at highway speeds and accelerating? It's just these sudden surges of power (small) but annoying--make it hard to maintain a constant speed. Losing and gaining power all the time. Especially at higher speeds. Is this just part of the behavior of the lean burn? Do you think replacing the throttle body would help? I still haven't done any of the other DYI mentioned on here by various members.

I replaced my O2 sensor last year because I didn't know how old it was. I didn't see any difference with the new one.

does your car maintain constant speed at high speed? Or do you feel it slow down, gain power, slow down, gain power at 70mph? I still haven't gotten any VX owners that say "no, this doesn't happen" or "yes, this is normal, my car does it too"

70MPH!!!!!!!!! I'm trying for 70MPG. I doubt that my VX sees 60 more that 1 mile/Month. My car has an aftermarket cruise control thats set for 49MPH on my way to & from work. I do EOC for 10 to 15% of my 30 mile trip to work & back. The few times I'm on a highway, I'm probably running 55 tops. I don't experience the up & down power you describe. I'm slowly raising tire pressures too. I also run the A/C as much as needed.

hehe, sometimes I drive with other people in the car *gasp* and if it's 80 mile interstate driving I sometimes will yield to their desire to get some place and go 75mph. Anyway, I have a feeling I'll never solve this problem on my car. :( very sad.

You might want to take off the EGR valve to clean it out. My car has a similar hesitation (though I think it might not be as drastic as yours), and everything else has been replaced tune-up wise, or cleaned out (including the IACV).

All you should need to take it off is a wrench, it could be cleaned out with some throttle body cleaner, and then it should probably be resealed with some high temp RTV when it gets put back on.

is their anybody who lives close to this guy who can help him out. Where do you live????? 1993CivicVX

Heh, I live in Western Mass. 20 minutes north of the Connecticut border and 5 minutes east of the NY border.

I've been compiling a document with all the information and tips I've collected from these forums to show to my mechanic, because I'm a complete noob when it comes to cars so I'm hesitant to try doing these things on my own. I'm also not too good with Enginese and get a little lost with some of the acronyms. ;) I made an appointment with my mechanic to go over all the issues with the car and advice I've collected on them to see what his take is. Hopefully then I will be able to make an informed decision about how to proceed. And I still need to get a manual!

the haynes manual would really help.

Western Mass. if their is anybody close to this location please pm this guy and drive to his location and help him out. I'm sure theirs got to be somebody in the Mass area that can help him.

If School hadn't started today I'd say I'd do all the work on his car for him, if he flew me down there, lol. Too bad you weren't closer to MN. I usually work for beer and pizza.

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how about it 1993CivicVX.

You could offer beer and pizza as a form of payment. SVOboy it might be worth it this guy is really up a creek with this car. 1993CivicVX you could pm your phone number to him and make arrangments.

Hah! That would be really really cool. Well, my friend and I are going to spend all weekend trying to do the brakes. And if that goes well I'll think about trying to solve the idle and hesitation problems. I'm going to the mechanic right now to talk about all the issues. I could also meet someone somewhere half way. Cheers guys!

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Svoboy that would be a good idea meeting him halfway. Maybe like a nearby auto parts store or something of sorts.

1993CivicVX try to keep us inform so that if it comes down to a meeting with svoboy the arrangement can be made.

Well, I like road trips and I like driving. :) Maybe it'd be worth the drive. Instead of this weekend attempting the daunting task of doing the rear brakes and ebrake myself with my friend (which is only half the battle) take a little road trip to check out the mini appleless mini soda. :) Come to think of it, I actually have a very hospitable friend in Minneapolis where I could maybe stay. Pizza and beer, you say? I could offer better reimbursement than that, but that is a very kind and generous offer. Especially if you could help me with the rust as well. That would be HUGE. :) I have a rough idea of how to fix it but I don't have any experience. Ideally I want to work on my car with someone who knows what they are dong and pay them to help me.

What do you think TomO? Minneapolis is only 1275 miles away. :p I suppose the same offer could extend to anyone else on the forums as well with VX knowledge and know how who isn't so far. :D

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