cold start problems

[89camaroperson]

Im having issues when I first start my car in the morning or after its sat for a while. It seems like a nasty vacuum leak but i cant detect any. Could be a partially blown head gasket but i dont know. Im just wondering if there is some sensor or vacuum controlled valve that could be screwing things up for me. Its an auto and it could have something to do with the converter but i again...im not sure. when accelorating from a stop the engine just bogs down and there is a power loss unless i drop the pedal when really cold and is fine once it gets to around 2000 rpms and starts gaining power again. When the engine is warmed up it doesnt bog down every time and no where near as bad but still does and doesnt seem to have full power until in gets to 2000 rpms. I just dont know what to think of it. I thought maybe the torque converter is just screwing up as it has 140000 miles and the original tranny that has never been rebuilt. Its just really weird. My engine as idles at around 1300 rpm when cold first thing in the morning but that could be a separate issue as it doesnt have the original air cleaner on it and i dont know a fix for that. Some help or advice would be greatly appreciated.

[Rally Sport]

Sounds like your ignition control module, i'd try that, run the car for codes too btw before you try trouble shooting.

[89IROC&RS]

well, as posted above, i suggest running your car for error codes before doing anything else. you can do it with a paperclip and your DLC. If you dont know how tell me and ill post up some directions later, or search the forum and see if you can find it, its in several threads on the board.

Also i agree that it very well may be the ICM, its located under your distributor rotor, its very easy to change and not very expensive, i think 50 bucks.

your tranny may have some miles, but a worn out auto tranny wouldnt be causing your problems in all likelyhood. an auto thats giving up the ghost tends to alow higher rpm operation, not bogged down low speed operation.

regarding your non factory air cleaner assembly, if you want to fix it, a cheap and effective method is to hit up the junk yard and score the nessesary parts from a doner car. other than that you can get the parts from the GM dealership and probly www.fbodymotorsports.com

[89camaroperson]

While i havent checked by shorting the two terminals....the SES light is off so wouldnt that mean there arent any codes?

That would be wonderfull if it was the ICM(I like easy fixes) and ill go ahead and do the full tune-up as well and see if it help which im sure it will. Thanks for your help.

[89IROC&RS]

the computer stores error codes that may not be current, but will still point you in the right direction, also many error codes dont activate the SES light untill they have been triggered three times. so you may have error codes without an SES light.

[89camaroperson]

What makes you guys think that it is the ICM? Im just curious what usually goes wrong with these things. Ive talked to a guy at advance and a guy at pepboys. One says its probably a ground issue and/or my fuel pump is going out and the other suggested a throttle positioning sensor. Both say they dont think its the icm. Im just curious about what the icm does and what it would do if it fails because i understand you guys cant ever give a definetive answer on whats wrong with any car. Most of the time anyways. Thanks for the help

[Rally Sport]

Okay it doesnt sound like your fuel pump, but im sure it sounds like your ICM, hell you can take it off and take it over to autozone and get it tested, FOR FREE, so DO THAT. it isnt the Throttle Position Sensor, because if you hit the gas instead going as fast as it should regularly, it would only accelerate slowly, not like it regularly would. If im not clear about this, 89 will probably pick up. About the fuel pump, it'd only be if you havent changed your fuel filter in a while, letting crap get in and mess up the pump, another way to mess it up is running the car dry of gas. It might be time to get a new one because alot are starting to go out after 10 years or so.

[89camaroperson]

autozone can test an icm? do i take it out of the car? and how often should a fuel filter be changed? that sounds like a very possible cause. Altough that would be something that gets worse over time i would think. But maybe a huge chunk of crap flew into the filter...dunnno. Does the icm just manage spark in the distributor? Like a msd box would do...the 6al thing or whatever(very technical terms i know).

[89IROC&RS]

your distributor is computer controlled. instead of using the old vacuum or weight system for an advance timing curve, it is controled by your Ignition Control Module. This module handles your timeing, spark curve and retard. So when it goes wrong, you get a bad running engine.

When my ICM went bad it behaved almost exactly as yours is. it would run rough at idle, and stall when i put it in gear, but upper rpms were fine. and it never set an error code. I tried a shit load of things to fix it and finaly swapped the ICM from my RS and the car ran great, so i put a new one in and havent had a problem since. well, it still runs a bit rough, but i think thats because the timing chain is stretched and needs to be replaced.

however a fuel filter could also be the cause, they are supposed to be replaced every 20k miles i think, (pulled out of my ass, but seems right) but that would cause a delay in fuel flow resulting in slow throttle responce and acceleration. Fuel pumps tend to either work or not, so i really dont think thats what it is.

the throttle position sensor is a distant possibility, but normally they cause driveability problems, not idle problems. so i would replace the fuel filter first, if the problem is still there, replace the ICM, and then go from there.

[89camaroperson]

Thank you all very much, ill see what i come up with.

[89IROC&RS]

hope its cheap and easy whatever it is

[89camaroperson]

ok this module has a flat plate that supposed to transfer heat to the bottom plate of the distributor. If the module isnt making full contact with that bottom plate and over heating(supposing that it would) would that cause it to act abnormally? Because when i tore it all apart i noticed that one screw hole had been stripped out and really wasnt doing anything to hold that side down. Just wondering if it is a possibility. That and i think i found another freakin vacuum leak. grrr..... Could a partially blown head gasket cause all of this? The motor is old....and heat causes a HUGE power loss when it gets up to 200 degrees on the temp gauge. I hope not but i got an itch thats telling me that that could have something to do with something else....hmmmm....

btw i checked for codes again and its all clear everytime.

[89camaroperson]

very little effect with the new ICM. Seems to have a little difference in the running of the car but that could also be the tune up i just did. What is something that could be prone to be affected by moisture? It seems to be very bad in the mornings and here in florida theres tons of humidity. If i start it for the first time later in the day around noon its not as bad as around 7 am. This is gonna drive me nuts. Should an o2 sensor be changed very often? Or with each tune up?

I think im gonna go buy some ground straps and see if that helps me any. I guess it would be best if i grounded the throttle body first. With all of this old wiring and old sensors i dont know what to do.

[wrightz28]

off the wall, did ya double check that all the plug wire boot clips are seated, no cracked wires?

[89camaroperson]

brand new wires but i did check them and went around and checked everything. Ive had this problem for a while now so it dosent have anything to do with the spark plugs, wire, cap or rotor...(i dont think because its all new)