LT1-LT4 Modifications 1993-97 Gen II Small Block V8

annoying problem

Old Feb 12, 2008 | 10:05 PM
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has anyone had the problem where the engine would stall coasting to a light or at a stop? ive been having this problem for a month now and its driving me crazy. itll set off the SES light, but itll fire right back up and not happen again as long as the SES is on.

also, i checked my TPS voltage (.67-.76 idle) and 4.67-4.76 WOT. i checked the MAP voltage and its at 5.07V reference, then the signal back to the PCM is around 1-2V. i checked my MAF/cleaned it and no luck.

also, i checked voltage to the PCM ADL connector and its at 4-5V what sucks too is i cant do the jumper wire/paper clip trick.

fuel pump primes and the filter is new and a new FPR is in for a week.

then i bought a scanner for obd1/2 from innova, and it wont even log into the PCM.

so im going crazy for the past 4 weeks. idk what the hell to look for now. this is a mind fick because itll only do it after driving a few miles and itll only do it once until i shut it off and the SES will reset.
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Old Feb 12, 2008 | 10:10 PM
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i had this happen before and i pulled the IAC motor off and gently cleaned it with gumout and an OLD tooth brush and it solved the problem for me.hope yours is as easy as mine was....
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Old Feb 12, 2008 | 10:11 PM
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Originally Posted by 96lt1m6
i had this happen before and i pulled the IAC motor off and gently cleaned it with gumout and an OLD tooth brush and it solved the problem for me.hope yours is as easy as mine was....
i replaced the IAC, forgot to mention that also there are no vacuum leaks.

Last edited by Revelation Z28; Feb 12, 2008 at 10:27 PM.
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Old Feb 12, 2008 | 11:59 PM
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stop replacing stuff until you find out what the code is lol
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Old Feb 13, 2008 | 12:04 AM
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Mine did the same thing and I replaced the IAC valve..yours sounds like the same thing..but you can get a bad valve that could have been abused in the shipping process..its happened more than once
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Old Feb 13, 2008 | 12:33 AM
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Originally Posted by 3pnt4maro
Mine did the same thing and I replaced the IAC valve..yours sounds like the same thing..but you can get a bad valve that could have been abused in the shipping process..its happened more than once
yea but i cleaned my old valve and it still did it.

the problem only happens once and after it stalls/ses comes on it wont do it again

itll idle great then only after driving for a little bit (mainly after coming off the freeway) itll die once.
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Old Feb 13, 2008 | 12:42 AM
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It might be the egr valve sticking open causing a nasty vac leak or even maybe a map sensor but I guess to know you are really going to have to get that code.
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Old Feb 13, 2008 | 12:47 AM
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Have you ever had your fuel tank out or replaced the pump before?
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Old Feb 13, 2008 | 12:49 AM
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in the 2 years ive owned the car i hacent done the pump. dont know about previous owners.

i tested the map voltage and it checked out ok.
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Old Feb 13, 2008 | 12:54 AM
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Originally Posted by Revelation Z28
in the 2 years ive owned the car i hacent done the pump. dont know about previous owners.

i tested the map voltage and it checked out ok.
I dont think the fuel pump is bad, but sometimes I see people change the pumps and the sock falls off, when this happens the vehicle will want to stall on hard corners and stops.

Maybe the IAC or the EGR as people have stated. Best to check for codes. I think Autozone will check it for free. Its the best way to go.
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Old Feb 13, 2008 | 12:58 AM
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i have a scanner but my DLC port doesnt have power. i dont know why the IAC would do it. both of them do it. the clean one and the new one, so i dont think its that.

also this just randomly started in a parking lot idling one night. so its something simple i know it.
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Old Feb 13, 2008 | 01:12 AM
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Originally Posted by Revelation Z28
i have a scanner but my DLC port doesnt have power. i dont know why the IAC would do it. both of them do it. the clean one and the new one, so i dont think its that.

also this just randomly started in a parking lot idling one night. so its something simple i know it.
Did you check the 5 amp ECM fuse? If you have no power to the OBD port then I am willing to bet it may have something to do with it.
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Old Feb 13, 2008 | 01:16 AM
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i checked the CIG fuse since the LS camaros are powered by it and its good, ill check that one too.

i stuck a volt meter in the port and it showed 5-7 volts in the A/B terminals. but the test light didnt show any power.
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Old Feb 13, 2008 | 01:18 AM
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Originally Posted by Revelation Z28
i have a scanner but my DLC port doesnt have power. i dont know why the IAC would do it. both of them do it. the clean one and the new one, so i dont think its that.

also this just randomly started in a parking lot idling one night. so its something simple i know it.
Can autozone check a IAC , I know they can check a ICM ? Do you even have a egr or did you delete it (just saw the sig).
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Old Feb 13, 2008 | 01:20 AM
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Originally Posted by mtperformance
Can autozone check a IAC , I know they can check a ICM ? Do you even have a egr or did you delete it (just saw the sig).
still have EGR.
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Old Feb 13, 2008 | 01:24 AM
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Originally Posted by Revelation Z28
still have EGR.
Do you have to get emission tested? If not now is a good time to plate it off.
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Old Feb 13, 2008 | 01:27 AM
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Originally Posted by mtperformance
Do you have to get emission tested? If not now is a good time to plate it off.
im gonna leave the EGR until i do a cam so itll be able to bleed off cyl pressure. plus itll be easy to take it off because ive done the FPR so many times haha.
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Old Feb 13, 2008 | 01:31 AM
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Sounds like you need to trace down the OBD problem. Usually when you can not access the computer from the port and the 5 volt fuse is good, the computer is smoked. Them are the worst ones to track down, but if all your sensor voltages are within range what gives?
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Old Feb 13, 2008 | 02:08 AM
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Originally Posted by Revelation Z28
im gonna leave the EGR until i do a cam so itll be able to bleed off cyl pressure. plus itll be easy to take it off because ive done the FPR so many times haha.
You got a point there.
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Old Feb 13, 2008 | 02:23 AM
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ok i checked the PMC fuses and they are all 10 amp and look good. so i dont know.
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