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1990 Cherokee Stalls, but ALWAYS restarts

My 1990 Jeep Cherokee (automatic trans) will occasionally stall. The engine stops turning, the tachy goes to 0, no power steering, no power brakes. After I come to a stop I can always start it right back up. The previous owner suspected it was the ignition switch because the vehicle was stolen multiple times, column broken, etc. but I took the switch out and everything seems good and tight there. I tested the switch, not connected to the lock and I couldn’t get it to duplicate the problem. It locks cleanly into each position. Start position has strong spring. I tested all the positions with the ohmeter. I drove around with the switch disconnected from the lock and wiggled it as I drove and I couldn’t get it to stall. Sometimes I can go days without a problem and other times it will do it three times in a mile long drive.

I’ve searched the Internet for an answer but all the other posts about stalling the owners have trouble restarting their vehicle. Mine has never failed to restart after stalling.

When it stalls it is a sudden loss of engine, no coughing or sputtering. The tachy drops to zero along with oil pressure, etc but the radio, lights, etc stays on. If I wiggle the key in the ignition I can’t get it to start back up even if I’m coasting along at 40 mph. I have to turn the key back to the start position.

Any ideas?

You just might want to look at the Crankshaft Position Sensor. It’s at the top of the bell housing for the transmission on the drivers side.

The wife had a 90 Cherokee that did this and it was the crank sensor. Thank God that vehicle is gone!

Tester

The ignition switches on that model were somewhat notorious for intermittent problems as were crank position sensors. But then, several relays are prone to dropping out intermittently, also.

When you say “after I come to a stop I can start it back up”, do you mean that you can start it by moving it into neutral or park?
An automatic can’t be started in ‘drive’. What happens when, while you’re rolling with that stalled engine, you shift from ‘D’ to neutral (NOT PARK - clearly!) and try to start it?

Or do you really have to be standing still for it to restart? Does the key really need to be out for it to restart, is that what you mean? If so, don’t try that while rolling because that would lock the steering wheel.
If it doesn’t start unless you’re standing still it would surprise me but maybe that’s a clue.

If I shift it to neutral I can start it by turning the key. I usually wait until the vehicle comes to a stop, but I’m not sure if that is necessary or not? I have started it while it was moving simply by shifting into neutral and turning the key to start.

Gotcha. I missed that.

I truly hate suggesting this, since you don’t know for sure whether the part is bad, but perhaps change the crank sensor, as tester and Rod mentioned that this part often goes bad. You have a decent shot at fixing it and, if it doesn’t, it will buy you a clue. The part apparently likes to go bad anyway.

i say that because this is difficult to troubleshoot. Besides it being intermittent while driving, usually you look for fire or fue and narrow things down from there but the fuel pump will stop running if the crank signal doesn’t come. It is the classic chicken and egg problem.
The crank sensor is often not crazy expensive (maybe $40) and usually not too difficult to replace.

Do you have a lot of keys on your key ring? If so try taking off the ignition key And use that alone. If the problem stops either replace the ignition lock, not switch, or remove all extra weight from your key ring. Sounds stupid but i have see it happen before, the excessive weight of a lot of keys or junk on the keyring will actually turn the ignition lock just enough to shut the car down.