Idle Problem after Header Install
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Joined: May 2004
Posts: 9
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From: Beaufort SC
Idle Problem after Header Install
Car idles down to 400 rpm after letting off throttle. Then slowly climbs back to 800rpm. Starts and idles fine. Problem only when releasing throttle in neutral or when clutch is pressed. Heard O2 sims on rear o2's will fix. Also heard LS1 edit will fix. Please reply with answers! If tuning shop is needed please recommend one in SC or GA.
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Joined: May 2004
Posts: 9
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From: Beaufort SC
I have new Power cats, with rear o2's behind them. The only thing I can think of, is that when I installed the passenger header, I bent the pollution pipe that connects to the header. It is almost creased shut. I was told it would not hurt. Could this affect the idle. Also when I reinstalled the rear o2's I may have touched the sensor. Could this cause this? Also when installing the rear o2's, do they criss cross from right to left and vice versa or do they install on the same side as the wires lead from? This may also be my problem. Please help.
I am not throwing any trouble codes. I checked my PCM from the onboard dash cluster and I have no codes.
I am not throwing any trouble codes. I checked my PCM from the onboard dash cluster and I have no codes.
Racer
Joined: Mar 2004
Posts: 338
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From: Lancaster Ohio
I'm just a lil ole f-body guy so I'm not familiar with where your O2 wires go. I would definately be finding out if you have those hooked back up correctly. I'm also assuming you're talking about your A.I.R. pipe that goes to the header being bent? The pipe itself being bent shouldn't cause a problem. If there's a problem with the a.i.r. system you'll throw a code eventually but not right away. Did you take that system apart when you did your header install? On newer f-bodies there's a vacuum line that connects to a T fitting, you didn't by chance take that apart and not plug it back in did you? I would just do another once over on all your fittings and connections just to rule those out. Any way you can get some one to log it for you and see what it's doing at idle? That would help you out too.
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Joined: May 2004
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From: Beaufort SC
I have checked and changed all o2's. Replaced the AIR tube I bent. Nothing fixed the problem. I am the other thread with this problem fixed his with the vacuum hose to the throttle body. I have an aftermarket 80mm BBK throttle body. The hoses are all correctly installed. However I am going to check them all again. The problem has to lie in some kind of vacuum hose or throttle body tune. O2's are new and correctly installed. Headers are correct and all hoses connected. Very confused? Please help.
Melting Slicks
Joined: Dec 2002
Posts: 2,061
Likes: 1
From: Valley Village CA
Originally Posted by chadadally
I have checked and changed all o2's. Replaced the AIR tube I bent. Nothing fixed the problem. I am the other thread with this problem fixed his with the vacuum hose to the throttle body. I have an aftermarket 80mm BBK throttle body. The hoses are all correctly installed. However I am going to check them all again. The problem has to lie in some kind of vacuum hose or throttle body tune. O2's are new and correctly installed. Headers are correct and all hoses connected. Very confused? Please help.
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Le Mans Master
Joined: Oct 2003
Posts: 6,126
Likes: 19
From: Streamwood illinois
Originally Posted by Torched
I'm having the exact problem you are experiencing.After installing the LG long tubes with random cats and GHL exhaust my car started having a strange idle when letting off the gas at higher RPM'S putting the car in neutral and gliding to a stop the idle will sometimes(not every time) drop to 500RPM and seems like it wants to stall then it slowly climbs back up. I've been going nuts trying to get some direction to fix this problem but so far no luck. Since the headers and exhaust and Blackwing install(When I noticed the problem first) I've installed heads,cam,ported and polished throttle body and underdrive pulley.After all these mods the car still does it.I'm guessing it might be with the MAF and the blackwing.Some 02 Z06's reported strange idle with the blackwing.I may put on my stock air box to see if it goes away.If I find a fix i'll let you know.Please do the same for me.What a PITA! Greg
dave
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Joined: May 2004
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From: Beaufort SC
I fixed mine, Check your hoses to the throttle body, then you must tune your throttle body. What I did was check my codes by holding option then pressing fuel 4 times. Reset all codes. Then adjust your throttle body open at idle a half turn at a time until you through trouble codes or fix your problem. Usually at startup it will say Reduced engine power. Reset the codes again and restart if they come back then turn back the throttle body a quarter turn and repeat code check. After your throttle is open as far as it can go at idle without codes, you must do an idle reset. Disconnect your battery for 12 hours minimum to completely reset the PCM. After that idle for 30 minutes and do not touch steering wheel, leave A/C off, etc. Engine will tune the idle perfectly. I checked everything including diagnostics to find out problem. This is a time consuming but effective fix. The screw is usually on the bottom of the throttle body underneath the throttle motor. Another fix is to use the ls1 edit or HP Tuner VCM edit to adjust fuel mixture at idle. But if throttle body is closed too much a tune won't fix, throttle has to be adjusted.
Team Owner
Joined: Jun 2000
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From: Just trying to make it through each day.
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St. Jude Donor '03-'04
Originally Posted by Torched
Does resetting the PCM remove any custom tuning that mine has? Greg
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
I`m getting ready to install headers(Lingenfelter),and x-pipe(Corsa),and exhaust(Corsa).I installed a Blackwing about a week ago,no problem at idle.Wonder if I should be concerned? My vette is an 04 with 5000 miles.Gotta say that the blackwing brought my car to life!
Burning Brakes
Joined: Oct 2001
Posts: 1,116
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From: Alhambra Calismognazifornia, in the country everyone comes just to complain but won't go back home!
well now it's my turn to have this idle problem
the ONLY thing i changed was adding the RT x-pipe and cats. Funny thing is, doing this got rid of the pre-cats that my car had even though my car (2002) was not supposed to have them to begin with (GM deleted pre-cats with 2001 model). It's not throwing any codes either.
It never did it with any of my other mods. Should I try this TB tune procedure?
the ONLY thing i changed was adding the RT x-pipe and cats. Funny thing is, doing this got rid of the pre-cats that my car had even though my car (2002) was not supposed to have them to begin with (GM deleted pre-cats with 2001 model). It's not throwing any codes either.
It never did it with any of my other mods. Should I try this TB tune procedure?
