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My Jeep's Been Running Great and It Bothers Me...

tempest411

NAXJA Forum User
Have you ever gone digging to try and find a problem and somewhere along the way the problem 'goes away', and you have no clue what the problem was? My '88 had an intermittent stalling problem, which eventually got to the point of being a no-start condition. I fiddled with it for several weeks. I tried all the usual checks, and everything appeared to be fine. All I can say is that I took off all the fusible links ganged up on the starter relay next to the battery, replaced the starter relay, cleaned the link terminal ends, and put them back, and it tried starting it for 100th time and it fired right up! Yet in my checks I had determined I was getting a solid 12.5V or so everywhere I was supposed to, so how could that have been a problem? This spurred me to examine the fusible links more closely. A few looked as though they'd gotten pretty hot at some point in the past. I ended up ordering some lengths of fusible link wire in different gauges and replacing them all to be on the safe side.



The only other thing I discovered, by accident, was that I had a poor connection on the crankshaft position sensor. As it idled in my driveway I was moving it around a bit to decide how to best secure the wires when it died. I could start it right back up, but moving the CPS connector ever so slightly would cause the engine to sputter or die. I don't think this could've been the cause of my no-start though...I had checked for a CPS signal at the ECU connector and I definitely had one.



It's very strange...Perhaps I never found the problem at all. Perhaps it just 'went away' for a while and will come back and surprise me one day when I have to be somewhere, like work.



Can you tell work is slow tonight???
 
There is nothing like knowing that your Jeep is plotting against you.

Carry plenty of spare pieces and a good multimeter.
 
For me, there is nothing worse than having a problem go away without understanding what changed. When repairing a car, a stereo or anything else, I try to fix one thing at a time and confirm that it is working properly before I start the next project. Invariably, if I don't do this, the problem comes back when I can least afford it.... Hope you accidentally fixed the issue!
 
Well, you wouldn't be the first person to unplug and replug the crank sensor and have it magically work again. A poor connection there seems to be common on the Renix jeeps, and often a sign that the sensor is marginal.
 
Having similar issues on my 88, I ended up cutting open the main harness from the front of the engine all the way back to the C101 connector. I found multiple splices that looked pretty sketchy (sketchiest was fuel injector grounds) and numerous breaks in the insulation on various wires. My worst offender was the #3 fuel injector. I ended up replacing all of the FI connectors, ran new 12v feed to them. Used a lot of electrical cleaner to spray out the connectors for all sensors. Found and fixed a few small vacuum leaks with a homemade smoke tester using some small tubing and a good cigar.
 
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