91 Wrangler stalls and won't restart

I would start by cleaning the connection on the CPS. They get corroded around that age. The best cleaner is a spray contact cleaner but WD40 will do in a pinch. The plug and socket are located at the rear of the intake manifold with the CPS on the bell housing back there.

Second I would verify the ground strap from the rear of the head to the firewall is ok. If ratty, it will cause stalls as the vehicle steals grounds from other locations.

Mike

Assuming you perform regularly scheduled maintenance, the most common cause for your description is the Crankshaft Position Sensor (CPS). Have you checked your codes? What are they? If you don't know how to check the codes -- set emergency brake, start the vehicle in neutral, and run the RPM up to 2500 rpm. Let up on the accelerator and let the RPM fall to idle, then turn the key off, on, off, on -- leaving it in the on position, your check engine light will begin to blink out a paired number sequence. Common codes usually always present are 12 and 55 and of no concern. Remaining codes are listed below.

11 Ignition

13 MAP Vacuum

15 Distance Sensor or Circuit

21 Oxygen Sensor or Circuit

23 MAT Sensor or Circuit

25 Automatic Idle Speed (AIS) Circuit

33 Air Conditioning Clutch Relay

42 Automatic Shutdown Relay

46 Battery Over Voltage

51 Oxygen Sensor - Lean Condition

53 Internal Engine Controller Fault

55 End of Code Display

63 Controller Failure EEPROM Write Denied

In case it makes a difference, I just went out after letting it sit for 45 min, and again, it started right up. Both stalls occurred within 2 minutes of startup and each time, the engine died because of shifting issues not mysteriously.

Thank you

CTM

It flooded then....

You can hold the throttle to the floor which is supposed to send a 'clear flood' signal to the computer I believe and shut down the gas flow.

This can help it start right back up.

Or pull the plugs and dry them out....

A distributor cap and rotor getting too old can contribute to this by sending a weak spark, especially when cold.

Mike

A bad choke pull-off will act like that, flooding so bad it won't restart. A carburetor kit and new number forty, will fix it:

The 1991 4.0 is fuel-injected. All of them are.

Earle

I remember my '91 4cyl doing this... seems like the best solution I found was pulling one of the circuit breakers from the fuse block under the hood... can't remember which one now... been too long. But I had this problem well away from civilization a couple of times, would start it in a difficult situation and then stall it doing the clutch/brake thing with all three feet. I did start it the first couple of times by holding the pedal on the floor, but found it was quicker to pull that relay. sorry can't remember which one.

Matt

I have a '93, 4 cyl and have had the same sort of problem related to two different things. The first was the computer fritzing out. Some numskull put a screw through the firewall that eventually worked it's way through the case around the computer. The board began to short once in a while and wouldn't start back up immediately. After a few tries it would though. The local dealership were the one;s to finally diagnose and fix the problem about a $1000 bucks later.

The other one was a relay in the relay box in front of the battery. It was corroding and not making good contact. i fixed that one with a can of electrical cleaner fluid and running fine emory boards in the contact hole. If you look in the cover I think it will tell you which one is related to the ignition. An interesting way to see if it is the contact is the next time it won' t start try jumping the contact using a wire in the holes. Someone showed that to me and that was how we narrowed it down to the contact.

Jim '93 4 cyl - a>

The problems is solved. My wife will no longer be able to drive my Jeep. ;-)

I tried that and lost..............

Although she compla>The problems is solved. My wife will no longer be able to drive my >Jeep. ;-)

You need to figure out, what made this guy's Jeep stall and not start for a half hour, whenever his wife drove it. Then duplicate that. ;^)

Earle

Geese guys, 'my' wife 'bought' the CJ7 in the first place!!

I had to go out and get a Cherokee so I could get to drive the CJ7... :-)

Mike

Mike, When is the last time Mel drove the Cherokee?

Actually she has it today. It is more comfortable than the CJ7 and has automatic hubs so she doesn't mind driving it.

Mike

billy ray wrote:

Hell, my wife sold her Cherokee and bought a Wrangler of her own. She also bitched about no a/c, until she figured out how to get the top down.

-- Old Crow '95 Wrangler YJ '94 Wrangler YJ

It's winter, it's cold out, it's snowing. She is driving 'my' Cherokee and I am driving her CJ7...

Mike