Bullstang360

Ok, I have a 91 Cherokee 4.0 HO (185,000miles) with an automatic transmission. I got in it the other morning and started it up and it ran for about a minute then died. Seemed to run strong didn't stutter just died.
I immediately checked the codes and got codes 17 (running cold), 62 (Emissions reminder), 54 (distributor sync), 55 (End). Tested the spark with an inline tester and had no spark. I had a spare CPS so I put that in. Still no spark and code 11 (Bad CPS) was added to the list . I put the original back in and code 11 went away. So I swapped the distributor ( I marked the position on the old one before I pulled it out and the position after. Used a micrometer to transfer the position marks over to the new on so the timing would stay). Since I had been trying to start it I pulled the spark plugs and used a long match to fire off the gas in the cylinders. I started up and ran strong for a minute then died again..... The only codes I got were 12 ( Batt recently disconnected ) and 55 (End). I tested for spark again between the coil and from the dizzy cap to plugs. Had good spark. Pressure tested the fuel rail and it tested good in the run position (just below 40 PSI) and when cranking (around 45 PSI). I'm stumped ....

Mattloz

Have the same problem but I have a 90 I have spark fuel and air but it dosent even turn on at all I did a engine swap on it k think my timing is off by a few degrees lol going to try again Tomorrow

xjallseasons

So it just stopped right in the middle of the road and couldnt get it started. I got it home with some help and went directly to the shrader valve and nothing happened. I ordered a new fuel pump and put it in. I then went to the valve again and got pressure with lots of fuel. So I went to start it up and nothing. Some people have said its your fuel pressure regulator and others said check for spark and also might be crank position sensor.
Now if its the FPR and its bad then would I still have pressure at the shrader valve. Since my FPR is on the fuel rail and before the valve, I can then rule it out that its not on the fuel pump.
I haven't checked for spark and will tomorrow. But if I have spark then what? Which leads to my next question...
The crank position sensor was changed out recently. A buddy says he had to change his out a couple of times just to get it right.
Any other ideas would be helpful.

Bullstang360

I would think timing too. However, it started and ran for about a minute and sounded like it was good. I have been doing tons of digging and have a short list of other possible reasons.

Battery load test. ( My current battery is only 6 months old but easy to rule out)
Fuel Ballast Resistor ( Not sure because I do have fuel pressure but cheap part)
Carbon build up (again not sure just ran across a thread about this)
Electrical short (I will start checking harnesses....)

Bullstang360

xjallseasons I think you posted to the wrong thread.

Bullstang360

Wold my Cherokee start and run for a minute and not sound rough and then die if my timing is off by a tooth?

Bullstang360

Ok so I'm still having issues. I have been able to start it a few times and it will run for a minute then just die. Then I won't be able to start it again for a few hours, it will just crank and crank. I was able to get my fuel pressure tester on and verify fuel pressure doesn't drop befor it dies. It's around 42 I believe. Anyone have any ideas?

Mattloz

distributor pick up or could be the ecu i had to replcace mine in the 1990 because i accidentally fried it and it gave me nothing but anyways the ecu could be a problem i actually have a 1991 ecu from the jeep i owned untill i pulled the heart and put it in the 1990 so if you need a 91 ecu i have it lol

i also have a cold staring issue my jeep would crank and crank i actually need to spray break clean for it to turn on, after a few cranks with the break clean it stays on and running i could turn it off then 5 min later would crank right up for some reason it dosent like cold starts im thinking it could be my pick up on the distributor

Mattloz

ohhh and change your fuel filter its 12 dollors and easy to do dosent hurt the simplest things can aid alot i learn the hard way im a mechanic so its a daily thing

Bullstang360

I already replaced the dizzy. The fuel filter is less than a year old and the ECM is only 2 years old. How reliable is the battery load tests that the auto parts stores use? I still feel like this might be an issue because it ran fine till we had a cold snap.

TealTornadoXJ

So just get this straight did you replace the crankshaft sensor or camshaft sensor

Bullstang360

Both

TealTornadoXJ

Hmm that was my problem when it did it to me what brand sensors did you put in

Bullstang360

Mopar for the Crankshaft sensor (from the dealer) and the distributor (you have to change the distributor the camshaft sensor is built into it) was from Oriley Auto.

xjallseasons

Mine was doing all the same things as yours as I posted. My crank position sensor, fuel pump, fuel filter are all new and I wasnt having any luck. I had it towed to my shop and found I had a short in the 30amp wiring. They stumbled on it and were lucky they found it within two hours otherwise my bill could have been bigger.