Intermittent Starting (2002)

[dnelms]

My daughters 2002 Alero has started doing something really wierd. It will crank fine in the morning, she drives 2 miles to school and then after school it does not want to crank. I had it towed and had the plugs and fuel filter replaced, because when they started to work on it the next day, it cranked right up. Motor turns over fine, battery was replaced 2 months ago, it just will not crank in the afternoon. Happened again yesterday and left the car at the school. I just went there and it cranked right up.

I'm thinking the fuel pump is the answer, but it is just wierd that it will always crank in the mornings after it has sat a long time. But then again it sits in that parking lot at school from 7:30 am to 2:45pm and will not crank. Only thing different is the temperature.

Anyone have any ideas or suggestions of thing s to check before I take it back in to see if they can diagnose the problem? Could the oxygen sensor be causing this problem?

[BNaylor]

Which engine do you have?

For fuel could be the fuel pump or fuel pressure regulator. Fuel pressure can be tested on the fuel injector rail. If its an ignition or spark related problem it could the crank position sensor. Electrical components are temperature sensitive.

The 02 sensor is inhibited while the car is in open loop PCM mode until it has fully warmed up. The 02 sensor really has nothing to do with the car not turning over.

[dnelms]

The 02 sensor really has nothing to do with the car not turning over.

It turns over fine, just will not crank up and run. Thanks for pointing out somethings to look at,

[boarder_punk]

Originally Posted by bnaylor3400

Which engine do you have?

For fuel could be the fuel pump or fuel pressure regulator. Fuel pressure can be tested on the fuel injector rail. If its an ignition or spark related problem it could the crank position sensor. Electrical components are temperature sensitive.

The 02 sensor is inhibited while the car is in open loop PCM mode until it has fully warmed up. The 02 sensor really has nothing to do with the car not turning over.

I totally agree with that, but it may not actually be the component but maybe a short somewhere in the wiring.

[BNaylor]

Anythings possible. However, you can unplug the Position1 02 sensor and the engine will fire up and run. The 02 sensor is only used in PCM closed loop mode to help control fuel injection after engine has reached proper operating temperature and other parameters.

[dnelms]

OK, let the car set until 4:30 pm. Put the key in a turned, no go. Since I did some more looking on here during the day I noticed the Passlock system seems to be a common cause of some of these problems. I turned the key to on, all the dash lights come on then go out except for the red security light and Service engine soon. Security light was not flashing. Anyway after waiting for the other lights to go out, I turned the key and presto it starts. Since that time I've tried it three times, doing the same thing, waiting for the lights to go out, then turning it over. Has cranked each time.

[BNaylor]

Originally Posted by dnelms

OK, let the car set until 4:30 pm. Put the key in a turned, no go. Since I did some more looking on here during the day I noticed the Passlock system seems to be a common cause of some of these problems. I turned the key to on, all the dash lights come on then go out except for the red security light and Service engine soon. Security light was not flashing. Anyway after waiting for the other lights to go out, I turned the key and presto it starts. Since that time I've tried it three times, doing the same thing, waiting for the lights to go out, then turning it over. Has cranked each time.

The SECURITY light AND SES light staying on in Ignition ON is correct. However, the SECURITY light should be extinguished once engine has started.

You can try a relearn where you leave the key in for at least 10 minutes.

Passlock is a common problem on Aleros. Normally it is a flaky key lock cylinder, wiring or a problem with the body control module (BCM) if it is a bonifide theft deterrent system problem.