Engine problems 3.4L Camaro - Team Camaro Tech
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post #1 of 8 (permalink) Old May 1st, 11, 11:50 AM Thread Starter
Jan
 
Join Date: May 2011
Location: Germany
Posts: 21
Engine problems 3.4L Camaro

Hi there!

My camaro makes me crazy. For months I and my dealer try to find the problem.
The problem is the following:
When I start the engine it seems to run very rough (hot or cold makes no difference). A light smell of fuel comes from the exhaust. The spark plugs are black! When I try to drive around it feels like the engine has no power at all. It shakes and backfires all the way. Sometimes the car would not start but when you wait for 10 or 15 minutes it starts! Then mostly runs perfect. But now it always runs that "too rich" way.
My mechanic is convinced that it must be an ignition problem but these parts have been replaced:
- Sparkplugs
- Coils
- Cables
- ICM
- ECM
- EGR (was leaking)
- Camshaft sensor
- MAP sensor
- Catalytic converter

Fuel pressure seems ok (40PSI) and there seems not to be a vacuum leak (tested with startpilot).

I read the codes, no ones were stored. The BLM and INT values told me that the engine runs WAY to rich! The values were around 100 / 110 !!!

Does anyone have another idea what could cause this problem??

Last edited by sateng; May 1st, 11 at 12:54 PM.
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post #2 of 8 (permalink) Old May 1st, 11, 01:04 PM
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George
 
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Location: Madison, WI.
Posts: 407
Re: Engine problems 3.4L Camaro

You didn't specify - carburated or injected, but I would assume injected if you're checking fuel pressures. Have you run injector cleaner through it, and did that change anything? You also may have an exhaust restriction (plugged catalytic convertor - if equipped) causing excessive back pressures, if the engine doesn't want to run up too speed.
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post #3 of 8 (permalink) Old May 1st, 11, 01:07 PM Thread Starter
Jan
 
Join Date: May 2011
Location: Germany
Posts: 21
Re: Engine problems 3.4L Camaro

Oh I'm sorry - sure it is an injected engine. I tried to clean the injectors with injector cleaner and my mechanic also did a cleanup with the help of a computer...no change

What I also forgot to mention: The problem exists on ALL cylinders the same time!!! When the engine runs fine, all plugs are lightly brown, when it runs like crap all plugs are black.

Chevrolet Camaro 3.4L SFI 1993
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post #4 of 8 (permalink) Old May 1st, 11, 04:15 PM
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Dan Ensign
 
Join Date: Jan 2007
Location: Claverack,NY
Posts: 366
Re: Engine problems 3.4L Camaro

I think you have a bad injector that is intermittenly shorting and taking the rest down with it. saw this on a 92 IROC-Z with a 5.7l in it. Good luck.
Dan E.
69 SS396 4spd. 4.10 posi. x66 coupe
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post #5 of 8 (permalink) Old May 2nd, 11, 11:16 AM Thread Starter
Jan
 
Join Date: May 2011
Location: Germany
Posts: 21
Re: Engine problems 3.4L Camaro

okay... told my mechanic today to disassemble the intake to measure the injectors resistance etc.
will have a result in the next days, then will post it immediately

Chevrolet Camaro 3.4L SFI 1993
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post #6 of 8 (permalink) Old May 3rd, 11, 10:59 PM
Senior Tech
darrell
 
Join Date: Feb 2011
Location: texas
Posts: 1,202
Re: Engine problems 3.4L Camaro

better check the fuel regulator too--and make sure its not getting fuel on vacuam port of regulator
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post #7 of 8 (permalink) Old May 3rd, 11, 11:05 PM Thread Starter
Jan
 
Join Date: May 2011
Location: Germany
Posts: 21
Re: Engine problems 3.4L Camaro

I think the regulator is fine. Pressure-tested it at the schrader valve before the regulator and there were the 40PSI pressure.
There is no fuel / fuel odor from the vacuum port.

When I ran the engine and disconnected this vaccum port the engine was sawing, reconnected the vacuum line and then it ran but like before....

Chevrolet Camaro 3.4L SFI 1993
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post #8 of 8 (permalink) Old Aug 20th, 11, 01:20 PM Thread Starter
Jan
 
Join Date: May 2011
Location: Germany
Posts: 21
Smile Re: Engine problems 3.4L Camaro

very much time went on but now the engine runs fine again!!!!

PROBLEM SOLVED

It was the injectors causing this trouble!

Thanks to all who helped me

Chevrolet Camaro 3.4L SFI 1993
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