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-   -   94 Civic VX smog troubles (https://www.fuelly.com/forums/f10/94-civic-vx-smog-troubles-12807.html)

mcc6 07-27-2010 01:18 AM

94 Civic VX smog troubles
2 Attachment(s)
Hello wonderful gas savers! I just bought a 94 civic VX (federal) with 184,000 miles and it failed CA test-only smog.
I had a bad gas cap and was over 10 on the HC at 25mph. Here's a pic:
Attachment 1729
No CEL during test, but I currently have 2 codes from the ECU: 48 (O2 sensor) and 12 (EGR system). After the test, I replaced the gas cap and faulty thermostat. I have a few questions for you VX geniuses! I can't do repairs (health related problem), so I need help with how I should "manage" these mechanic repairs. (terrible scenario...I know!)

1) Should I get a valve adjustment?
2) If the CEL code is for the EGR system, do I need to have the ports cleaned AND replace the EGR box? (not sure if I'm using the right terms)
3) O2 sensor was replaced by previous owner 2 years ago. Is there a way to test if the sensor is working before biting the bullet of buying a new one?
4) How do I know if I need a new CAT?

Here's more background if you have the time/interest:
*Over the phone, smog guy from shop I like "guaranteed" I needed new CAT after hearing my numbers.
*His manager offered to "dink around" (check spark plugs, ignition timing, etc), but the VX actually performed HORRIBLY on the shop's 2 smog attempts following his efforts. It failed all over the place, not just by 10 points on the HC anymore.
*Previous owner replaced the distributor and wires, but the shop tells me it's not quite the right one (it's for VTEC, not VTEC-E). They can only get the timing to 18 (close enough to 16 to pass though), so they say it shouldn't be a problem. Are they wrong?

So I tell him, "go ahead and change the thermostat, I'll get back to you about the rest". He does so and charged $50 (for everything up to that point).

To make matters worse, today I did a little test drive, and suddenly the speedometer/odometer stopped working. I then tried going on the freeway and I couldn't get it over 2000rpm in 5th gear. (even flooring it + downhill).

About the CEL:
When I first drove the car from LA to San Diego on day of purchase 2 weeks ago, it felt pretty good. 47 mpg over the first 150 miles, (65mph on highway, plus some city driving and less than ideal 185/70/13 tires). CEL light was on in LA, but it turned off within an hour and stayed off for another hour. Drove it 30 miles next day, no light. Drove it next day, no light. Only AFTER taking it to the shop did the CEL come back. Now it's sorta intermittent.

I'm probably just being paranoid, but I feel like everything is moving in the wrong direction since I took it to the shop. I used to take my old CRX to them and they always seemed honest (many times doing small jobs for free).

Any thoughts/suggestions would be greatly appreciated!

jadziasman 07-28-2010 03:43 PM


Your VX barely missed passing the test initially - right? You didn't have driveability issues before you took it to your mechanic -correct?

And now a mechanic you "like" has managed to FUBAR your VX somehow?

It's bad enough that your car fails the smog test miserably now. Somehow your grease monkey also managed to make your car almost undriveable. That's pretty hard to do.

The symptoms you describe indicates to me that he trashed your catalytic converter while he tried to "fix" your smog test issue. How do I know this?

You have difficulty increasing rpm probably because he fried your cat and now its clogged. Exhaust gas is having trouble getting past the blockage in the cat. The O2 sensor says somethings wrong. Yeah, it will say that when the cat isn't working properly. The egr issue might also be related to the clogged cat. The exhaust gas temperature will rise with a clogged cat forcing the egr system to respond earlier than it would otherwise. That might be what triggered the code 12.

Take your car somewhere else before your "favorite" mechanic says you need a new engine.

add|ct 07-28-2010 04:23 PM

I agree with jadzia. If your sensor and cat are bad, you could try to 'unclog' the cat by running some of this in through where the PCV hose goes into the intake manifold:


You spray it in as the engine is running at full temperature(make sure you keep the RPMs up JUST enough so the engine won't die on you but dont be higher than 1000 RPMs if you can help it), yes it is a 2 person 'job.'

Kill the engine as soon as the can is empty, close the hood to keep the engine as hot as possible while off, and then proceed to wait for about an hour or more.

Then, with the PCV reconnected to the hose leading to the Intake Manifold, proceed to crank the car and once that is done successfully do the following:

Push RPMs up to 3k or so for about a minute. All the while be monitoring how the RPMs fluctuate as the engine is expelling the product, now an expanded foam that's been sitting in the engine, out of the exhaust with whatever gunk it could take with it. After it becomes easier to hold the RPMs at 3k or a minute goes by(which ever comes first) let the car idle back down on its own and then pump the throttle briefly to rev the RPMs a few times(4 or 5 is plenty).

Then, take it to the road for a WOT. Keep it in first until 30 MPH, and hold it there at 30 as well as you can while still in 1st gear, do that for a few moments before shifting to 2nd, then hold the speed at 50-55 while in 2nd. Be careful not do this at all until the coast is clear and you can be sure no one will be directly behind you when you first 'go for it' and dont break the speed limit.

I used some Mopar CCC(combustion chamber cleaner) on my Stratus before. Its similar stuff to what the Amsoil site is sellling, but Mopar CCC is a local Jeep/Chrysler/Dodge dealership sold product. They may no longer sell it at your dealer, but you can always call to ask. It helped my idling amongst other things and definitely would've killed any living or non-living 'things' in my exhaust while expelling the excess gunk that was finally coming free from the engine. It could clog a CAT or 02 sensor in this process(in other words destroy them), but in this case you are already at this point so for a few bucks its worth a shot, IMO.

You can pass a smog test without a working 02 sensor, I know, my VX did and it was failing really bad on HC emissions. Though, I'm not sure of CA requirements. The cat is a possibility but if that is what is gone, its worth trying to unclog it before just buying a new one. Oh, and if you decide to buy the Amsoil or try to find Mopar CCC from a local dealer, they are each about the same price after tax.

If you know the risks, its worth taking in your case IMO.

What got our vehicle to pass was running with a few gallons of premium gas instead of 87, as well as having the new distributor cap, rotor button inside, Honda spark plug wires installed new, and original NGK V-power plugs.

As for the EGR, you could always have someone ELSE clean it for you. Of course, after anything you try to do, clear the CEL codes by pulling the fuse labeled 'back up', a 7.5A rated fuse, from under the hood at the fuse box located by the battery. Pull it, wait for 15 seconds, then reinsert the 7.5A fuse. Notice the spark from the fuse as the ECU is 'jolted' ;)

IMPORTANT: Dont spray in through the throttle body, use PCV method only. It could foul your sensor that is located on top of the throttle body entrance, potentially. Also, after reading more about the Power Foam above, I would recommend trying to buy the Mopar Combustion Chamber Cleaner first by calling your local dealers. This could potentially knock over the edge a plug that is old. Your CEL is most likely the EGR or LAF(02 sensor) going off. You can find out yourself by pulling the codes yourself. Any child could do this.

add|ct 07-28-2010 04:55 PM

Wait, I just re-read your post. Is the distributor itself actually what was replaced or just the distributor cap, by the previous owner?

Either way, I've yet to hear of parts for the VX being off based on VTEC. All of them are a VTEC-E equipped engine I thought. Wouldn't that make any one specified for the VX the correct distributor or cap? It wouldn't fit in otherwise. It may be a part from a non-VX, non-VTEC engine. Perhaps just '1.5 Liter' engine was selected at a local parts store and the part wasn't for the VX itself, yet somehow still 'fit'. You'd figure the distributor cap to be worn by now after nearly 2 years either way, if that's the case.

mcc6 07-29-2010 12:35 AM

Speedometer/odometer came back. Have a feeling it will keep doing that. VX seems to be driving normal again. Mechanic said I had something blocking the throttle pedal. He drove it around with me and took it to 80 on the freeway (as I whimpered quietly).
I cleared the ECU codes, and so far the 48(o2 sensor) has come back, but not the 12 (EGR). I feel like getting the EGR cleaned anyway. I called around and one guy said $140, another said $90, and another $50. Is there such a thing as cleaning the EGR box, but not cleaning the ports? Don't want to pay $50 and then not actually have the ports cleaned.

As for the distributor...the whole thing looks new, including spark plug wires (as previous owner claimed). When I took it to my mechanic before going to smog, he said "This distributor is not for the VX. I'm guessing it is for a VTEC, but not VTEC-E, cuz it's not fitting exactly correctly, so I can only get the timing to 18 instead of 16. Not ideal, but shouldn't be a problem. Timing at 18 will probably improve your mpg, even." He was going to charge me $20, but then said "don't worry about it. I didn't really move it at all." He practically always does that. He said that if I brought him the new O2 sensor, he would put it in for free.

So should I try a valve adjustment ($50) and cleaning of the EGR system before biting the bullet and buying the $200 O2 sensor? Does a code 48 always mean that you need a new sensor? I told my mechanic I wasn't sure about buying a new O2 sensor since the previous owner just bought one 2 years ago. Mechanic says "Well, he probably bought the wrong one just like he did with the distributor."

I've been trying to get ahold of the previous owner, but he's not responding (surprise, surprise).

I can't tell you how much I appreciate these responses! Keep 'em coming!

jadziasman 07-29-2010 01:40 PM

Are you messing with us, mcc6?

The mechanic said you had "something blocking your throttle pedal"?

That's pretty frick'n obvious, ain't it? What about his recommendation to replace the cat? Miraculously cured itself?

There are only two distributors for the 5th generation Civics - TD-41U, no VTEC and TD-42U, VTEC. You cannot mix them up because the electrical connectors are different - unless some fool cut the wires and changed the connector; which is unlikely. And what does the mechanic mean when he says the distributor is not fitting exactly correctly? Either it fits or it don't.

So should I try a valve adjustment ($50) NO and cleaning of the EGR system before biting the bullet NO and buying the $200 O2 sensor? Does a code 48 always mean that you need a new sensor? NO

My guess is your VX has a misfire to get a high HC test reading. You will need to find out what's causing that. Go to the back of your car and listen for a misfire at the tailpipe when your car is parked and idleing - it will be obvious if you have one. Start there before replacing parts that you (or Jimmy Neutron) aren't sure are causing the problem.

add|ct 07-29-2010 05:05 PM

Once again, I agree with jadzia.

If the plug wires were replaced before, it could be the wrong wires and they COULD be causing some misfiring. When I first got to work on the VX I thought I could just use aftermarket ones, but found out quickly that NO plug wires nor spark plugs period, work like the OEM wires from Honda or the original NGK V-power plugs. I paid $80 for the wires, which was definitely too much, but I had no choice at the time. Also an emissions passing problem. The VX is very picky about using original plugs and wires, especially as not many Autopart stores use the correct wires when selling you replacements, which was my predicament before doing more research on the car.

You could try popping the hood, turning the car on in a dark garage and looking at the wires for any small blue arcing. If the distributor isn't fitting right, it may be the seal hasn't been replaced and needs it, but like was mentioned its either VTEC or non-VTEC, its either fitting or its not fitting. If it was the wrong one it'd have been junk by now.

Your mechanic sounds like a regular car junkie trying to work on anyone's car that will let him. That doesn't mean he will know the specifics of your vehicle, like is so crucial with a VX more so because of how picky it can be. That sounds to be the reason he 'lets you off the hook' from paying him money for work he isn't sure of. Especially concerning is the timing issues.

Find the nearest REAL Honda super/master tech in your area. Avoid the dealer if possible, but get either of THEM to check the timing next time.

A valve adjustment and 02 sensor may not get you to pass emissions right away and if your CAT is still clogged and needs a cleaning attempt/replacement, I wouldn't put a new 02 sensor in until that is for sure not the issue.

mcc6 07-30-2010 12:19 AM

One of the selling points for me for this VX was the new distributor, and O2 sensor. I'm very disheartened to find that they might not be the correct ones, not even the wires. (At least the spark plugs, while old, were right). The seller said that it was an aftermarket distributor, so I suppose I should assume that so are the rest. Should I just unplug the O2 sensor to see if I can identify it? New O2 sensor might not solve my smog, but if I have the wrong one in there, seems like it would be a good idea no matter what.
I've been trying to get the owner to send me some paperwork on these repairs he's done, but he seems to be gone for good. Not sure how to identify what he put in there.
Tomorrow is my last day to get a free smog, so I will see if the new thermostat (which apparently was broken), oil change, and new spark plugs make any difference...or at least if I'm back to barely failing rather than being all over the place.
BTW, the recommendation to change the CAT came from the guy who answered the phone, who claimed to be the smog expert of the shop. He made it before he was aware that I was getting a code 48 and 12. Since clearing them a few days ago, I'm still only getting the 48.
How does one go about checking to see if the CAT is okay? The mechanic said that for the VX, they're not in an easy place to look at them where they are attached, but that he could remove it so as to check it's condition inside.

I've begun my search for a Honda master tech. Someday I'll be healthy enough and knowledgeable enough to do the work on the car myself. Until then, I've got to pay for it.

An OEM distributor and wires aren't exactly cheap now, are they? Is replacing the distributor just one of those things that's a matter of time (like replacing the clutch), or is it a sign of something else?

theholycow 07-30-2010 03:31 AM

I think the only way to check the cat (BTW it's not an acronym, no need to capitalize) is to remove it and look inside the pipe.

add|ct 07-30-2010 07:03 PM


Originally Posted by theholycow (Post 153527)
I think the only way to check the cat (BTW it's not an acronym, no need to capitalize) is to remove it and look inside the pipe.

Crazy Air-fixer Thingy :p

IMO, it's still worth it to throw in a few gallons of premium and try to get tested again since he only failed by such a small margin.

Since he has a FED Vx getting tested in CA, it may not ever pass...is that a true statement? I'd go to have it tested at a certain time of day, but I forget which one it is recommended for the reason.

If the sensor really is bad, it could be what puts him in the 'pass' category.

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