1990 4.0L Cherokee No-Start

[thetandycollector]

Hello,

I have a 1990 Jeep Cherokee Laredo, 4.0L, 4X4 Automatic. January of 2007 I started having problems where it would occasionally not start. It was as simple as the engine turned, but didn't appear to be getting any fuel. I would give it a shot of ether, and it would usually start right up.

Then at the end of the summer, It started actually having no spark. I could leave the truck alone for a few hours, come back later and try and it would usually start right up.

As the Fall progressed, the starter seemed to be intermittent, so I replaced it, only to find that something else is wrong, and that the truck would then only start with the key about 20% of the time. Then, the fuel pump stopped working. I had it tested, and they told me that the pump was fine, it needed an ECM, so that was replaced as well. This seemed to solve things for about two days, then back to the same old crap. By December, I had to start using a push button to start the truck because it hardly would start with a key, and was having more and more issues with the ignition.

Now, the truck does not start with they key except maybe one a month, randomly dies and won't start because of no fuel/spark. What could be the issue? I'm a mechanic, but not great with electrical crap.

Thanks guys

[fredjacksonsan]

Crankshaft Position Sensor is my first thought. It's a common issue at over 90K miles or so. Do a search and you'll find lots of interesting (they're irritating when they're yours, interesting when someone else's) issues caused by this sensor.

[thetandycollector]

Originally Posted by fredjacksonsan

Crankshaft Position Sensor is my first thought. It's a common issue at over 90K miles or so. Do a search and you'll find lots of interesting (they're irritating when they're yours, interesting when someone else's) issues caused by this sensor.

Replaced the camshaft position sensor... still gives me issues. This engine was recently rebuilt anyway, so I didn't think that was the issue, but tried it anyway.

The no-start problem with the starter was resolved yesterday though... there was a short in the neutral safety switch, so the starter wasn't getting signal. Wiring harness was repaired, and I got it to work So far it's a hundred percent, but still occasionally cuts out and won't start but will crank.

Thanks all,

The Tandy Collector

[fredjacksonsan]

OK the NSS is also an issue...and I see you replaced the CAMSHAFT Position Sensor, when I'd think it is the CRANKSHAFT Position Sensor.

[thetandycollector]

Originally Posted by fredjacksonsan

OK the NSS is also an issue...and I see you replaced the CAMSHAFT Position Sensor, when I'd think it is the CRANKSHAFT Position Sensor.

Forgive my typo, it was Crank.... I even went back and looked through all my reciepts :P However, I did take apart the sensor and find quite a bit of gunk (oil and etc) in the sensor assembly... I'm thinking maybe it was just dirty? Anyhow, I haven't had the no start issue at all since I cleaned it, so I am assuming this is case-closed.... at least for the moment. Except someone tried to break into it the other night via the tailgate and ripped off the entire right side of the tailgate.... now I have that problem to face. Anywho, thanks for the info

The Tandy Collector