1993 jeep cherokee, cranks but won't start

distortedworlds

New member
Hey all.

I've got a 1993 Jeep Cherokee Country 4.0 L 2WD. Recently my ladyfriend was driving it home from work and it died on the freeway. Towed it to my place, and tried to start it up. It cranks, but won't start.

I've ruled out the fuel pump, as I can hear it engage when I turn the key to the accessory position. Also, fuel squirts out when I push the schrader valve near the engine.

Any ideas?

Thanks in advance.
 

With any no start , you'll want to verify fuel and spark. You've already found pressure at the rail but we need to know if the injectors are firing. That's when you'll need a computer safe test light to probe the injector harness . Be sure your getting voltage and ground. The voltage is constant when the key is on as voltage is supplied from a relay. The ground however , is supplied from the pcm . The PCM grounds what injector it intends for it to fire in a sequential firing order much like the firing order of the distributor. Speaking of firing order and distributor , you'll want to check for spark while cranking. Everyone has their favorite way to test for spark. You can pull out a spark plug and ground it or just hold the wire terminal close,to,ground with a screwdriver or something metallic touching the plug wire terminal to a ground ( never the battery) but I like the in line spark tester. Never a guess , always a reading. Autozone or a good parts store should have these items . Sometimes they bundle them together and call it a no start kit. Very handy to own in such cases as this. Well , an in line spark tester , fuel pressure tester is nice , and a computer safe test light to check the injector harness. Never put a 12 volt test light on a computer circuit . PCM's are sensitive to over draw and will burn up internals. Forgot to mention the NOID light . They plug into the injector harness and make checking injector harness simple . You'll see the light bulb blink when cranking engine.
Incidentally , have you checked the fuses ( maxi and mini ) in the PDC ? You want to look for anything pertaining to ignition and pcm .
 
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In this situation , I have found that the usual suspect is the flywheel (crankshaft) sensor . It sits on the top of the bell housing toward the drivers side right up against the block . Try wiggling the wires around on that unit while someone cranks the starter from the drivers seat . If there's a break in those wires or that sensor has gone bad it will not signal a spark .
There is a lot of heat back there as the exhaust manifold is so close to that unit . That would be the first thing I'd check if there's fuel but no spark .
 
Since its a 93 it isn't OBDII. Google up the key shuffle to get the OBD code through the Check Engine Light. BUT the reality is since it died while in motion, it isn't likely it is any sensor, and is most likely a broken or slipped timing chain
 

When I had that problem on my Comanche , I died while in motion . It just so happened that the connection into the crankshaft positioning sensor went unconnected while the vehicle was being driven . But with an extra person available , the ability to turn the key and wiggle the wires to the sensor simultaneously revealed the problem when she fired right up as soon as the faulty connection again made contact . Of course it died again right away , but with a new unit in place , it's run like a top ever since .
This seems to be a typical situation .
I would think that if it were a timing chain being the culprit , that there would have been excessive noise involved prior to the die out .
Of course I could be wrong . It has happened once before . ;-)
 
Timing chains most often go bad when the vehicle is shut down or at stall. The jeep design has a tensioner in the cover that quiets it down and prevents excessive noise. Another point of information to correct a false idea that is floating around about Jeep timing sets, is the factory and MOST aftermarket gears are IRON NOT Hardened steel as many think, so if you ever have to replace the chain, go for the whole set, as the wear on all three pieces will add up and between them will show a significant amount of slop.
 
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