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Followup To
Question -
Car starts normal when cold and runs fine til the motor warms up, then starts surging. Fuel pump was replaced as it died and this started about a week after replacing the fuel pump. When the temp gauge is at the middle mark the car will not start at all. Disconnected the Oxygen sensor and it did not seem to affect it other than changing the mixture and timing. I am not sure how to check the codes and do not want to buy a code reader. Help please.
Answer -
Malcolm,
In reading your description of the condition, I can only suggest one of two possiblities.
1. Check the ECT (engine coolant temp) sensor. This sensor helps to control the air/fuel ratio. The ECT is located on the driver's side of the cylinder head, just under and behind the radiator hose. I've seen engines that wouldn't start when warmer, due to an incredibly rich air/fuel ratio, caused by a bad ECT. (There should be two identical sensors right next to eachother, you want to inspect the one closest to the firewall)
2. Other than going to your local big-name parts store to have them retrieve the codes, I would look at the fuel pump again. Fuel pumps from those big name parts stores (the kind that you just get the actual motor and not the whole assembly) are notorious about being bad, especially if they came in a blue box with something like "Master" as the brand. Anyway, I would check your fuel pressure and volume. A pressure test kit is pretty cheap.
Other than that, I can't really think of what could be causing your problem. I have my suspicions that your fuel pump is probably bad though. I've seen it before, too many times. Let me know how it turns out,
Chris
The Fuel pump was the whole assembly from Saturn. I did some messing around with unplugging the Throttle position sensor on the throttle body and it seemed better although when we went for a drive it died again. I agree with you that it could be a coolant temp sensor as the engine was way too hot to touch even at 1/2 normal operating temp, according to the gauge. This car belongs to a fellow employee and I hard wired the fan to get him to work last night. He sent me a message to let me know he made it ok but it lacked power is some ranges. We are going to change out the thermostat and the coolent temp sensor. In all the time I have spent working on this car I did not see or hear the fan kick on as it should, although he says that he had seen it running yesterday morning. We have a 84 Cavalier wagon that use to over heat all the time and I found that it was the electric fan that was not kicking in at all, so I wired it so that it turned on with the key in the run position and there have been no more problems with it. I will let you know what happens with the replacement of the thermostat and coolent temp sensor.
Malcolm
AnswerMalcolm,
To check fan operation, just idle the engine and hit the a/c button, that will tell you if the cooling fan works or not. If the fan will come on when you hit the a/c button, but not when the engine gets warm, you more than likely have and ECT sensor problem.
