Mitchh218

Here is a strange problem. When the air temperature is 70'F or more, the car will not start. The car turns over. I checked for fuel at the needle valve and when the car turns over, it squirts out. I tried to check for a spark from the plug, but I am not sure that I was able to get a good ground and a good connection with the plug boot. In the evening time and in the morning, the car starts and runs. I will take it for a 30 min drive, come home, turn the car off, and start it again. It will still start. I have been wrestling with this for more than 2 weeks now. I have tried to get the ignition module tested, but none of the car parts stores have that capability, and spending $100 for it to try is hard to swallow. I hooked up the ODBII computer analyzer and there are no errors or any indication of what the problem is. I had my mechanic friend looking at it tonight, and we saw a TSB from Chevrolet that the connectors in the fuse block could have corrosion, and to take it apart and clean the connectors and pins. We did this and is started, but, the temperature outside dropped below 60 'F, so I am not sure that it solved the problem. I took it again for a test drive and came home, turned the car off, and started the car. I repeated the start and stopping and my mechanic friend and I saw something very strange. When we turn the key on, but not start the car, sometimes the check engine light turns on, and other times it is off. Through many starts, I was able to surmise that if the check engine light is OFF before starting the car, it will turn over but not start. If the check engine light is on before starting, then the car starts. Does anyone have any thoughts on this link with the CEL on or off prior to starting the car or am I out in the woods chasing gremlins?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

Mitchh218

Update. Today, sure as ever the air temp us above 70'F and the car would not start. It turns over, but does not start. Also, the check engine light is not on. Another mechanic friend had a spare ignition module and coil pack that work. I swapped them out and still the car will not start, it again turns over, but does not start. Also, again, the check engine light is not on. (hum). I put the original ignition module and coil packs back. I tried once again to start the car, it turns over, but does not start. I finally spent 30 min tuning the key on, then off until the check engine light turned on and stayed on. I engaged the starter, and presto, the car started. Ahay. So I turned the car off, pulled the key out, inserted the key, turned the key to on, and guess what, the check engine light was not on. So, I tried the process again, key on, check for the check engine light to be on, if not turn the key off, and repeat the process. After 20 min, I gave up, no check engine light on. I will try again tonight. The air temp is around 80’ now. Texas weather.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

Mitchh218

Another update. In trying to figure this thing out, I decided that the heat problem was internal of the car. With the inside temp around 100' with the windows up, outside degrees > 70', I tried to start the car. Again, the same symptoms as in the previous thread, check engine light off when the key is turned to the on position with out cranking the engine. I decided to pull the PCM out of the car, heat related problem, put the PCM in the refrigerator for an hour, and reinstalled the PCM. Well, it would not start. Still the check engine light is off. I waited to later that night and tried to start the car and it started, when the air temp got below 70', just to make sure that it still followed the same symptoms. So, continued to read all I can and study the wiring diagrams and all the information I can get and decided that it might be the BCM. This afternoon, when it was warm, the car would not start, same symptoms. I removed the BCM, put it in the refrigerator for an hour, reinstalled it, and still it will not start. No check Engine Light. There are some very smart people here on this site. Does anyone know what are the parameters that cause the check engine light to turn on and off? There has to be multiple inputs in the the PCM that makes it turn on and off. Also, I purchased the an ODB ii reader form http://www.obdcom.com/. This is a nice software package, but it does not access the PCM and he "HIDDEN" information that GM has in there. I found software that is specific around GM, http://www.scantool.net/software/sca...-enhanced.html. Does anyone have any experience or knowledge with this type of information from these tools?

Mitchh218

Final Update: After working this problem for weeks now, I was able to solve the problem with the check engine light. In my many attempts to find consistency with repeating I was able to find one repeatable symptom. When the check engine light was OFF, I would turn the turn signal on, and the turn signal relay would buzz. Hum, that would suggest either a bad relay or low voltage, bad ground, to the relay. That night I talked with my mechanic friend and he suggested that I read the schematics and try and find where either there was a grounding problem or a voltage drop in a connector. I read the schematics and started at the ignition switch. I removed the switch from the car, following the removal procedure, and at each step trying to start the car. After each step, the car would not start. After I had the switch in my hand, I looked at the contacts, and there was not any obvious corrosion or any burn marks in the wires or contacts. I cleaned the contacts anyway with Radio Shack Contact Cleaner. I tried to take the switch apart to see if internally there was any damage to the switch (I did not want to buy a new switch) and was it successful. So, I reconnected the wire harnesses and the cable that connects to the back of the switch and with the switch dangling, I tried to start the car. It started. The temperature was above 70’ outside and the internal temp was warm, I was sweating. I ended up starting and stopping the car at least twenty times with success each time. For the next 5 days, I did the same thing during all times of the day. Finally yesterday, I reassembled the entire switch and panels, and the car continued to start. I am not 100% sure that the contacts were dirty on the switch, or there was something else that was not making a good connection in the switch assembly, this was the process that I did to fix my problem, at least for now. I am skeptical because I did not find a physical problem. Time will tell. I hope this helps some else with a similar problem.

Mitchh218

Final Update: After working this problem for weeks now, I was able to solve the problem with the check engine light. In my many attempts to find consistency with repeating I was able to find one repeatable symptom. When the check engine light was OFF, I would turn the turn signal on, and the turn signal relay would buzz. Hum, that would suggest either a bad relay or low voltage, bad ground, to the relay. That night I talked with my mechanic friend and he suggested that I read the schematics and try and find where either there was a grounding problem or a voltage drop in a connector. I read the schematics and started at the ignition switch. I removed the switch from the car, following the removal procedure, and at each step trying to start the car. After each step, the car would not start. After I had the switch in my hand, I looked at the contacts, and there was not any obvious corrosion or any burn marks in the wires or contacts. I cleaned the contacts anyway with Radio Shack Contact Cleaner. I tried to take the switch apart to see if internally there was any damage to the switch (I did not want to buy a new switch) and was it successful. So, I reconnected the wire harnesses and the cable that connects to the back of the switch and with the switch dangling, I tried to start the car. It started. The temperature was above 70’ outside and the internal temp was warm, I was sweating. I ended up starting and stopping the car at least twenty times with success each time. For the next 5 days, I did the same thing during all times of the day. Finally yesterday, I reassembled the entire switch and panels, and the car continued to start. I am not 100% sure that the contacts were dirty on the switch, or there was something else that was not making a good connection in the switch assembly, this was the process that I did to fix my problem, at least for now. I am skeptical because I did not find a physical problem. Time will tell. I hope this helps some else with a similar problem.