EGR Problems and Solutions??? 97 Camaro 3.8 - Team Camaro Tech
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post #1 of 6 (permalink) Old Jun 15th, 07, 01:43 AM Thread Starter
Join Date: Jun 2007
Location: Texas
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EGR Problems and Solutions??? 97 Camaro 3.8

This has developed into a very bad situation, and financially we are unable to combat it all, concindering a Catalytic Converter is $200 installed and a new EGR Valve is $250 just for the valve, so I need to try and find out a way to make absolutely sure before spending anymore money scanning/guessing if this is what's happening.

Basically the car idles rough, but doesn't die. It has never stalled, only the hesitate and lurch (And what feels like a misfiring engine.) Acceleration is near non-existant, and reaching even 55MPH is a chore if even possible (Which it isn't at times it appears)

2 Error codes get returned on the engine, Catalytic Converter and the EGR Valve.

Now from my understanding of the EGR Valve part, it wouldn't cause the car to be unable to go over 30 or more MPH. If it is stuck open it would cause stalling or the engine to die at idle, which doesn't happen. The car doesn't stall or die, it does however idle rough. It's the lack of ability to reach speeds that bothers me most. And if the EGR was stuck closed the car should potentially run fine, correct? But would more than likely develop the knock or "ping" because of the excess heat... Which also doesn't happen. There is no knock or ping, and the car obviously won't drive fine.

Now what the Cat can contribute too I'm more sketchy on, so I don't really know there.

The other odd part is, if you disconnect the neg terminal to clear the engine codes from the computer and get the Check Engine Light off. The car will start running perfectly fine again as if nothing was wrong for a few days until the light comes on and then its a gradual return to the previous issues. (Not a sudden return, it happens over time getting worse as it lasts.)

So the main question is. Is there something else going on (That doesn't have a code) that could be taken care of cheaply that could be causing this issue and making the EGR and Cat call bad? (Although Cat probably is for sure, there is a definite rattle from the undercarriage). I've heard of carbon buildup on the EGR. How would you clean the electronic EGR Valves in the 97 3.8 Camaro?

Is there any cheap DIY method of checking the eletronic EGR Valve on the 97 Camaro's to see if it definitely bad or just blocked (Or some other issue?) I pick things up easily and retain what I hear a lot, but I freely admit I am no mechanic.

Which of these parts is the most vital to be replaced (Since we are flat broke heh) that is more than likely responcible for the more serious aspects of the issue? I can deal with the rough idle (And to some degree performance loss, as long as I'm not damaging the engine) but not the inability to reach higher speeds, or even drive the thing as it has become almost undriveable. Is it possible to leave in a bad EGR Valve for a while without damaging the engine since it is more than likely not stuck closed (Leading to detonation and engine stress), or can it be safely disconnected completely with the aformentioned detonation/knock but for all intents and purposes normal driving without severly damaging the engine. (Basically how serious a problem IS the detonation/knock that comes from no EGR Valve/Stuck EGR valve on damaging the engine?) If so, how can this be done?

Sorry, long post, I know. We are kind of desperate though. I could give you horror stories of the last 7 years heh.
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post #2 of 6 (permalink) Old Jun 15th, 07, 04:32 AM
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Re: EGR Problems and Solutions??? 97 Camaro 3.8

the knock sensor will not allow spark knock, it`ll just pull timing to accomodate...a stuck egr valve usually can be fixed by removing the valve and cleaning the pintle valve and shaft, so that they move freely...a clogged cat will choke performance, but all the time, not over a couple days...the fading performance thing is a stumper...those cars are famous for plugged cats affecting performance, though...i`d replace that, and leave the egr for now...(or clean it)...removing the batt cable doesnt clear codes on a 97...that car is obd2, so codes stay in memory...maybe you have a bad ground that you are affecting whenever you pull the batt post...i`d look into that also...jm2c...hope it helps...and also, do a fuel filter...they can cause odd problems...and they`re cheap...

sometimes you`re the windshield and sometimes you`re the bug...
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post #3 of 6 (permalink) Old Jun 15th, 07, 10:34 PM
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Re: EGR Problems and Solutions??? 97 Camaro 3.8

Faethx, I would leave the EGR alone for now. You seem to have a good understanding of the issues EGR can create. While it can cause driveability problems and codes, it won't cause the problem you describe. As I recall, your engine has a linear EGR valve which has a 5 pin electrical connector and no vacuum hose. You might remove it and check for carbon bits holding it open, but I doubt it is the biggest problem at hand.

Catalytic converters can become clogged and cause an exhaust restriction which will create exactly the problem you describe, but this is not something that comes and goes.

Disconnecting the battery will clear the codes on an OBD2 car but the battery will need to remain disconnected for a longer period of time than on an OBD1 car. The fact that clearing the computer causes the engine to run well for a while is an important clue.

You might pull a spark plug or two and check their condition. If they are black it would indicate a rich fuel mixture which is definitely hard on catalytic converters. Another test would be to unplug the mass airflow sensor (MAF) and see how it runs. This will throw a code, but if it runs better you may need a MAF. I am assuming your engine is equipped with a MAF.

Your best bang for the buck would be to have someone who knows what they are doing scan it with a full function scanner paying particular attention to fuel trim numbers, O2 sensor voltages, coolant temp, air temp, MAF values, and a number of others that a good tech will know to look at. This will cost some $, but will minimize buying unneccessary parts.

Some of the worst running problems I have encountered on modern vehicles have been caused by sensors that have not completely failed but are ouputting a value that is incorrect but is close enough to be believable by the computer.
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post #4 of 6 (permalink) Old Jun 16th, 07, 06:13 PM
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Re: EGR Problems and Solutions??? 97 Camaro 3.8

Faethx..I would address the cat rattle first before writing off the egr valve.Anytime you have restricted exhaust,egr and maf codes creep in.Failed cats can show up after extending driving or in your case a seperation internally..hence the rattle.You know you have a fail in the convertor..correct this issue first.When you have a functional cat in place..take the additional step and scan the long term averages so as to prevent further catalyst failure.Hope this assists you.

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post #5 of 6 (permalink) Old Jun 16th, 07, 08:18 PM
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Re: EGR Problems and Solutions??? 97 Camaro 3.8

yes just as fat said i rattle in your cat will cause a alot of miss lead codes. put a new cat on and clear codes. if light comes back on than that is problem of why cat went bad.
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post #6 of 6 (permalink) Old Jun 18th, 07, 09:50 AM Thread Starter
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Re: EGR Problems and Solutions??? 97 Camaro 3.8

Okay, taking the advice here. Will be taking it in to get Cat done today, since it definitely needs to be done.

I did check the MAF while I was messing around and no change at all, MAF appears to be working fine.

Wires, Plugs, and Air Filter were done less than a month ago, btw. Probaby should have mentioned that. We also replaced a faulty ignition Coil at the same time.

I'll know more once I get Cat done and back, and Ill clear it and drive it for a bit, and get back to this.

Thanks everyone. Hopefully I'll have something else to say soon. Hopefully positive.
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