TPS and ESC codes - Third Generation F-Body Message Boards

chekbaka · 10-11-2004, 12:44 AM

Hello, everybody, I need some help to figure out what is wrong with my 91 TPI 305 automatic Camaro. About a month ago I started getting the obnoxious SES light every once in a while. It mostly light up when the car was very hot specially during hot summer days. By hot I mean, it had been running for at least an hour under heavy traffic with outside temperatures over 100 F. The car was not overheating though. When that happened, the car started to run like crap, almost as if it wanted to shut down, sputtering a littloe bit, not responding immediately to the gas pedal etc. It just gave me time to pull into a parking lot and wait for the car to cool down. When cool, everything would work just fine. I decided to install a 160 degree thermostat because during those days the car would get really hot. The symptoms dissapeared. Oh I forgot to say that I was getting a whole bucn of codes when the SES light came up. I received the codes for the TPS, VSS (this sensor hasn't been working for about a year so I know this wasn't an issue) MAP and ESC. Everything worked fine for about two months. During that time I replaced the fuel pump which was failing for a new one. After that and after running the car under very cold weather, the symptoms appeared. When I say cold weather I mean very cold nights in the mountain and since I had a 160 thermostat that motor was running for prolongued periods of time under very cold temperatures. Around 100 etc. I don't know exactly how the ECM operates in these conditions but I think it tries to enrichen the mixture to warm up the car faster. Well my gas mileage was really bad and I could see the rpms usually high and at some points I think the ECM got a little crazy sometimes by increasing the idle rpms to over 15000 rpms in an effort to warm up the engine. Is this what it was really happening?. Well anyway, after several nights doing this the SES light came up again but every once in a while. Now its on most of the time, since the car is started. Still it sometimes goes away for a few seconds or minutes and then comes back again. When its out the car goes back to normal driving conditions but when its not, the car runs rreally crappy. When stepping on the gas the car does not respond immediately and when it does it does it very hesitantly. Still it is an intermittent problem. Initially I was getting the same codes as described above. The other day I unhooked the battery for a few minutes and hooked back again the car ran a little better but this time with less codes. Now I am getting mostly the TPS and ESC. the symptoms I get are almost as if I am not getting enough of a spark to ignite the mixture which would be the ESC retarding the timing , right. Also when stepping on the gas, the car does not respond as it should, which would indicate a TPS problem. But the TPS is three months old. Now according to what I understand, the ESC would be set off if there is detonation sensed by the knock sensor. When this happens, I don't hear no detonation. Anyway, what is detonation supposed to be like. I assume is like an uncontrolled explosion of the mixture with vibration of the motor etc. Well, this does not happen running my car with the SES light. The only wierd thing that happens is at startup. When starting the car in the morning, it won't start up at the first try, but on the second and stepping on the gas initially, the car kind of wants do die on me, but immediately afterwards the rpms go up and revs normally. Why does it do that at startup? This problem started after replacing my fuel pump. OK I have written enough. Can somebody help me with any suggestions?. Could the ESC be the problem or the TPS or could there be another explanation. What are the symptoms when these two sensors go out? Please let me know...

CaptPicardsZ28 · 10-11-2004, 01:34 PM

Quote:

Originally posted by chekbaka
Hello, everybody, I need some help to figure out what is wrong with my 91 TPI 305 automatic Camaro. About a month ago I started getting the obnoxious SES light every once in a while. It mostly light up when the car was very hot specially during hot summer days. By hot I mean, it had been running for at least an hour under heavy traffic with outside temperatures over 100 F. The car was not overheating though. When that happened, the car started to run like crap, almost as if it wanted to shut down, sputtering a littloe bit, not responding immediately to the gas pedal etc. It just gave me time to pull into a parking lot and wait for the car to cool down. When cool, everything would work just fine. I decided to install a 160 degree thermostat because during those days the car would get really hot. The symptoms dissapeared. Oh I forgot to say that I was getting a whole bucn of codes when the SES light came up. I received the codes for the TPS, VSS (this sensor hasn't been working for about a year so I know this wasn't an issue) MAP and ESC. Everything worked fine for about two months. During that time I replaced the fuel pump which was failing for a new one. After that and after running the car under very cold weather, the symptoms appeared. When I say cold weather I mean very cold nights in the mountain and since I had a 160 thermostat that motor was running for prolongued periods of time under very cold temperatures. Around 100 etc. I don't know exactly how the ECM operates in these conditions but I think it tries to enrichen the mixture to warm up the car faster. Well my gas mileage was really bad and I could see the rpms usually high and at some points I think the ECM got a little crazy sometimes by increasing the idle rpms to over 15000 rpms in an effort to warm up the engine. Is this what it was really happening?. Well anyway, after several nights doing this the SES light came up again but every once in a while. Now its on most of the time, since the car is started. Still it sometimes goes away for a few seconds or minutes and then comes back again. When its out the car goes back to normal driving conditions but when its not, the car runs rreally crappy. When stepping on the gas the car does not respond immediately and when it does it does it very hesitantly. Still it is an intermittent problem. Initially I was getting the same codes as described above. The other day I unhooked the battery for a few minutes and hooked back again the car ran a little better but this time with less codes. Now I am getting mostly the TPS and ESC. the symptoms I get are almost as if I am not getting enough of a spark to ignite the mixture which would be the ESC retarding the timing , right. Also when stepping on the gas, the car does not respond as it should, which would indicate a TPS problem. But the TPS is three months old. Now according to what I understand, the ESC would be set off if there is detonation sensed by the knock sensor. When this happens, I don't hear no detonation. Anyway, what is detonation supposed to be like. I assume is like an uncontrolled explosion of the mixture with vibration of the motor etc. Well, this does not happen running my car with the SES light. The only wierd thing that happens is at startup. When starting the car in the morning, it won't start up at the first try, but on the second and stepping on the gas initially, the car kind of wants do die on me, but immediately afterwards the rpms go up and revs normally. Why does it do that at startup? This problem started after replacing my fuel pump. OK I have written enough. Can somebody help me with any suggestions?. Could the ESC be the problem or the TPS or could there be another explanation. What are the symptoms when these two sensors go out? Please let me know...

Try a 180 stat. That should cure the problem. Reset the ecm.