Cant solve rough idle
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Sounds like the pump is weak. What is the voltage to the pump when you hit WOT? What is the pressure then? Does it drop severely?
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
I will have to go back over my data logs but I beleive voltage held steady at around 13 volts WOT, when I did the fuel pressure check the fuel pressure increased to low 40's I had a hard time reading the gage with all the sun glear. I now have a new problem as soon as I start it the ses light comes on and its throwing a code 32 for the EGR so I will dig into that this weak.
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
Do you have a temperature switch in the EGR tube? If so, error code 32 at startup means that the switch is closed. It should only close when hot exhaust gasses are flowing through the tube, so that's an error. This can happen if the EGR temperature switch is bad or the wire is shorted to ground.
Racer
Joined: Dec 2010
Posts: 427
Likes: 124
Ignition problems follow through all RPM. I know you said vacuum is steady, but you might have a vacuum leak. Have you tried propane enrichment or similar diag? Also ,While its running, pull off one wire at a time 'till you find the one that has no effect. Check compression on that cyl.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Ignition problems follow through all RPM. I know you said vacuum is steady, but you might have a vacuum leak. Have you tried propane enrichment or similar diag? Also ,While its running, pull off one wire at a time 'till you find the one that has no effect. Check compression on that cyl.
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Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
Do you have a temperature switch in the EGR tube? If so, error code 32 at startup means that the switch is closed. It should only close when hot exhaust gasses are flowing through the tube, so that's an error. This can happen if the EGR temperature switch is bad or the wire is shorted to ground.
Race Director
Joined: Oct 2011
Posts: 16,086
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From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Ignition problems follow through all RPM. I know you said vacuum is steady, but you might have a vacuum leak. Have you tried propane enrichment or similar diag? Also ,While its running, pull off one wire at a time 'till you find the one that has no effect. Check compression on that cyl.
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
Did That no change, I am betting on the EGR being the problem even though I checked it earlier in this thread I may have missed something and now that I have a code 32 showing I will check it one more time.
Thread Starter
Drifting
Joined: Jul 2009
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From: Ashland PA
2021 C4 of the Year - Modified Finalist
Ok I did the check's on the EGR as described in the FSM, everything checks out good. I went and removed the EGR anyway and it everything looked good, wasn't even that dirty, It holds vacuum and seals up like it should, the test on the solenoid all were good. I decided to do more tests on the fuel pump and according to the FSM I should supply 12 volts to the fuel pump test connector I did this and got sparks and it did not activate the fuel pump. any suggestions, the fuel pump does come on for 2 seconds when I turn the key on and I do get pressure.
Race Director
Joined: Apr 2002
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From: Anaheim CA
Burning Brakes
Joined: Apr 2012
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From: Ridgecrest Ca
Just thinking. The code 32 is a strange distractor. No way should an EGR fault code be set at idle. The EGR should not even crack open until above 15-1800 rpm. A rough idle and worst with a load (in drive) is almost always a vacuum leak. Isolate the brake booster and check idle. Something is leaking somewhere I'll bet.
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
Just thinking. The code 32 is a strange distractor. No way should an EGR fault code be set at idle. The EGR should not even crack open until above 15-1800 rpm. A rough idle and worst with a load (in drive) is almost always a vacuum leak. Isolate the brake booster and check idle. Something is leaking somewhere I'll bet.
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
I just discovered this thread. Not that I'm any kind of authority, but when you state the problem seems to have started after the plug wire was off, I've seen this scenario cause damage to the ign coil. The theory behind it is that the spark has nowhere to go and causes breakdown issues with the coil. It's not a 100 % cause all the time, but is can cause issues. Just an idea to check. If you have access to a spare coil, maybe try it and see what happens.
Another possibility is that there two or more overlapping issues resulting in the problems.
I hope you get your car fixed soon.
Another possibility is that there two or more overlapping issues resulting in the problems.
I hope you get your car fixed soon.
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
I just discovered this thread. Not that I'm any kind of authority, but when you state the problem seems to have started after the plug wire was off, I've seen this scenario cause damage to the ign coil. The theory behind it is that the spark has nowhere to go and causes breakdown issues with the coil. It's not a 100 % cause all the time, but is can cause issues. Just an idea to check. If you have access to a spare coil, maybe try it and see what happens.
Another possibility is that there two or more overlapping issues resulting in the problems.
I hope you get your car fixed soon.
Another possibility is that there two or more overlapping issues resulting in the problems.
I hope you get your car fixed soon.
Thread Starter
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
I just ran 12 volts directly to the fuel pump and barely was able to get 40psi, FSM states should slowly go to 47.5 so I ordered a new pump.