I did look at the crank ring. It appears OK. I have about .020each sideand there is no scuff marks on the sensor. It has not been breaking the sensors. they have been failing electrically, only this last one failed by breaking off.
Padgett, when you say runout, are you talking about distance between the rings and the sensor? Can it also get excessive runout around the shaft? Like if the harmonic balancer where twisted? Is that possible?
Thanks

Know the ring could be bent (would have to rotate the engine 360 while watching the sensor clearance). Is the failure mode broken/broken off magnets ?

Yes, that last time it broke, it broke off the center peice of the sensor. This was the only time it did this. Not sure why it did this, but the new sensor went right on and I checked the clearances all the way around.

Well it seems to be getting harder to make it happen now, but I do notice that when the car starts running rough it is accompanied by the tach needle jumping around a little bit. Jumps up about 200 RPM'* or so and then returns to normal. This is surely telling me that it is ignition related, but I don't know what else to do to pinpoint what is going wrong. Help.

well, if it has a magnavox ignition [if you haven't upgraded it yet, it does], then you can do it from a performance standpoint, to buy a delco unit, with some delco or other aftermarket [MSD, Accel, Jeg'*, etc..] coils. But some new wires and plugs [didn't pay attention if you've already done that, sorry if you have], could also make a world of difference.


-justin

No I don't think mine is Magnavox. It has 3 individual coils instead of 3 coils built into 1 unit. I think mine is Delco. I have changed the ignition control module.

Well, I am finally getting somewhere. Car has been driving Ok for weeks. When it would die, it would ususally restart on the first or second try. Now it has started not wanting to crank after dying. When I go outside and wiggle the crank sensor wires, it will crank right back up. I pulled the connector last night and looked at it, but they look good. No corrosion and no nicks in the wire. I guess my next step will be to see if I can find a new connector and splice it in. If it still acts up I guess I will replace the new BorgWarner crank sensor with a GM brand.

Just had a brief stalling problem with my 90 SSE.
One day on start up I noticed the climate control fan on max as if I had disconnected the battery.
I then removed and cleaned both Batt. terminals, both engine grounds, all the grounds inside each fender, and the fuse to the ECU. Also tightened one fuse prong.
The problem has not occured since.
It would just stall then start back up. now its OK.
Just a thought that worked for me.

Finally fixed it! Turned out to be a bad new crank sensor. Replaced the new sensor with another one and all is well. No stalling, no missing and drives great! I would not have guessed that a new sensor would have been bad. Oh well, just glad it runs now.

did you do it yourself? and if so how did you line it up??