Engine Dies

[4breezes]

I have an ongoing problem with the '87 Buick Century we bought from my mother-in-law. She seldom drove it, it has only 27,000 miles showing.

The engine dies. It doesn't seem to care when or what I'm doing. Several times I've been driving at 45 mph, and it has died, just as though somebody has flicked a switch. It will generally restart right away. Today I moved the car from the curb to the lawn for washing. The car would not start after being washed. I checked for spark with my timing light, and found none. The timing light indicated no spark when I cranked the engine.

Not long ago I pulled the ignition modual and had it tested. My parts store said that it was good. They said that the test procedure heated the modual, trying to bring out any weakness. I noticed though, that it was not nearly as hot as when under the hood.

Any thoughts or help on this would be greatly appreciated. I'm thinking that either the ignition modual is bad (regardless of the test), or perhaps the crank position sensor.

Thanks, Ken

[GTP Dad]

Welcome to AF!!

This is a classic sign of a bad crank position sensor. The stalling is usually the key with the car restarting right away. If the sensor has totally failed then there would not be any spark at all. Change the CPS and your problem should go away. You didn't say what size engine you have and the locations vary by engine.

[4breezes]

Thanks for the quick and knowledgeable reply. I realized last night, as I was shutting down the system, that I had forgotten that vital bit of information, but it was late and I was tired.

The engine is a 3.8 liter. There are two sensors tucked in behind the pulley wheel low down on the engine. Which one is the crank sensor? My book (Haynes 38005) seems to indicate the one toward the front, but it doesn't indentify the engine pictured.

Must I remove the pulley wheel when replacing the crank sensor? That would be a PITA, but might be necessary.

Thanks,
Ken

[GTP Dad]

Yes, you will need to remove the harmonic balancer and the pulley to get the sensor off. The crank position sensor looks like a flat sensor with two flat sections that the relucator wheel spins through. It is also possible that they are both crank position sensors. Some of the older engines had two. You will need to remove the front wheel to get to it and it will probably take an impact wrench to get it loose. You may want to have a mechanic do this for you if you don't have the tools.

[4breezes]

The job is done. I bought a crank position sensor this morning for $55, a Borg Warner unit. I followed directions which came with it.

I was surprised to find that I did not have to remove anything in order to pull the sensor. It was simply unplug the old one, remove the two bolts holding the bracket, and wiggle it out. It was a bit tight, but it came. The new one went in almost as easily--- mount the sensor on the bracket, wiggle the whole unit into position, bolt it in, being sure it was positioned properly.

The car started right away, and has run close to fifteen miles so far without problem. Tomorrow I'll drive it more, so that perhaps my wife will trust it enough to drive herself around.

I appreciate the help and the expert advise. I hope this has put this problem to rest.

Ken

[GTP Dad]

Thanks for the update. I am really glad you could get the sensor out without having to remove the balancer. They area PIA. I hope this fixes the problem for you. If you have other problems don't hesitate to post.