Surging, revving up on its own.
Registered User
Joined: Dec 2002
Posts: 1,810
From: Indiana
Re: Surging, revving up on its own.
I'm not so sure it's a torn elbow. mine is torn badly and had a hole to allow air. i glow it and formed it back together quite nicely and the problem hasn't changed
Thread Starter
Registered User
Joined: May 2006
Posts: 134
From: Marine, Camp Lejeune, NC
Re: Surging, revving up on its own.
well i think we have established that this is something commonly wrong with 94 camaro's, maybe someone from chevy could answer. obvously we are not the only people to have this problem. im gonna ask one of the guys at the speed shop i go to and see if they have heard of this before with camaro's
Registered User
Joined: Jun 2005
Posts: 118
From: Florida
Re: Surging, revving up on its own.
Mine used to do that. (it is a 94 as well) In my case the optical part of the opti was going bad occaisionally fooling the PCM into thinking the rpm was much higher than it really was. The PCM would then open the IAC more based on that false info, causing the surge.
Other causes I've heard from people with surging, but haven't personally had to deal with were vacuum leaks and I believe some have said they've had bad O2s cause it.
Other causes I've heard from people with surging, but haven't personally had to deal with were vacuum leaks and I believe some have said they've had bad O2s cause it.
Thread Starter
Registered User
Joined: May 2006
Posts: 134
From: Marine, Camp Lejeune, NC
Re: Surging, revving up on its own.
Originally Posted by JP94Z
Mine used to do that. (it is a 94 as well) In my case the optical part of the opti was going bad occaisionally fooling the PCM into thinking the rpm was much higher than it really was. The PCM would then open the IAC more based on that false info, causing the surge.
Other causes I've heard from people with surging, but haven't personally had to deal with were vacuum leaks and I believe some have said they've had bad O2s cause it.
Other causes I've heard from people with surging, but haven't personally had to deal with were vacuum leaks and I believe some have said they've had bad O2s cause it.
Registered User
Joined: Dec 2002
Posts: 1,810
From: Indiana
Re: Surging, revving up on its own.
my problem isn't excactly yours, but relative. i will say i never had any problems with the high idling until i went with the new motor, tune and big cam. I'm not soo much worried about my cam surge...i think most of that is because of the crackerjack mail order tune i have for a custom cam. My elbow could still be leaking, but i kinda doubt it.
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Joined: Jul 2005
Posts: 747
From: Baton Rouge, LA
Re: Surging, revving up on its own.
Mine does it whenever i check it i get a TPS low voltage code and if i hook the scanner up right when it throws the code my tps is showing like 10% at .67 volts (normally .67 volts is 0%). If any of you guys are in louisiana and near baton rouge il'l scan you if you have a 93-95 firebird/camaro to see what we get.
Registered User
Joined: Apr 2006
Posts: 14
From: Norcal, CA
Re: Surging, revving up on its own.
mine is also surging at idle, not as bad 500-750 rpm (at temp) after a fresh rebuild. I think the problem was there before the rebuild because I had found the previous owner actually bent the throttle stop in order to increase idle to around 1000 and no surging until I put the idle back. From a thread that was started two years a go there are various solutions from vacuum leaks, torn elbows, dirty MAF sensors, bad MAP sensors, plug wires, plugs, bad injectors when hot, and even program changes to help the problem... there didn't seem to be one common culprit....the problem lives!!!! I'm just starting to go down the same list.
Registered User
Joined: Dec 2002
Posts: 1,810
From: Indiana
Re: Surging, revving up on its own.
on myproblem, here's what i did. I changed the plugs, wires, opti, tps, iac, cleaned the maf, checked the elbow and talkedto the tuner a bunch andtried different tunes. the tune is not the problem. everything else is up in the air. I'm not real sure what to do.
Registered User
Joined: Apr 2006
Posts: 14
From: Norcal, CA
Re: Surging, revving up on its own.
Parts that were replaced during rebuild; opti, egr, temp sensor (wp), temp sensor (head), IAC, O2 sensors, knock sensor, plugs and wires, and some of the vacuum lines.
MAF, MAP, IAC, TPS and O2 sensors seem to functioning according to Freescan (still learning to read data)
Things I still need to verify; tears in intake elbow, clean MAF, check ICM, injectors and check for vacuum leaks.
I found a lot of info on this subject by doing a search for "surging" on this board......if anyone has any new info please share!!...let's put an end to this disease!!
MAF, MAP, IAC, TPS and O2 sensors seem to functioning according to Freescan (still learning to read data)
Things I still need to verify; tears in intake elbow, clean MAF, check ICM, injectors and check for vacuum leaks.
I found a lot of info on this subject by doing a search for "surging" on this board......if anyone has any new info please share!!...let's put an end to this disease!!
Registered User
Joined: Apr 2006
Posts: 80
From: Rochester, N.Y
Re: Surging, revving up on its own.
This fixed my problem with the engine surging. Mine did the exact same thing! I noticed one day that the CCV Air tuve was a little cracked, so I replaced it. Underneath it was the elbow taht came from the evap purge solenoid, and I noticed that it was badly cracked, and allowed vacuum pressure to leak out. After replacing it, the surge was gone.
