Reader Question: Hi,
I read your site and other people had my problem but they never followed up to say what fixed their problem, which I hate. My car 1992 Oldsmobile 88 Royale starts runs for about 5 minutes (use to be longer, it is getting worse) then dies and will not start for 15 min to 2 hours.
We determined that there is fuel air and compression but no spark. We have changed a few parts including the ignition module. My car has three coils so we did not suspect the coils because none of the plugs are getting spark and the likeliness of all three going intermittently bad at the same is excessively high.
In addition, we replaced the computer and we are running out of things to check. So in you expertise what components should we troubleshoot?
If you were in my shop, I would test for fuel injector pulse with a voltmeter to see if the injectors were getting a signal. If you do not have injector pulse, I would suspect a bad crankshaft position sensor.
This sensor is located behind the harmonic balancer pulley. You have to remove the pulley and slide out the old sensor. Make sure you mark the old sensor position as the new sensor must go back in the same exact place or it will rub on the balancer pulley.
You can also get someone to bang on the bottom of the fuel tank with their fist or a rubber hammer as you crank the engine over. This can help jump start a weak fuel pump. You might want to rule out a weak fuel pump first before you replace any sensors.