Mechanics

GRAND CHEROKEE WON'T START

1997 Jeep Laredo

Hello,

Vehicle description: 1997 Jeep Grand Cherokee Laredo with 160,000 miles on it. This has been a great vehicle for me with minimal repairs. Engine: straight-line 6-cylinder displacement 4.0 liters, 185 horse.

Problem: Won't start

Symptoms: Engine cranks but does not fire. I do not hear my fuel pump turn on when I turn the key to run (as I usually do) nor do any of my gauges move when I turn key to run. I do not have spark.

What I have Tried: Removed every fuse/relay and cleaned pins on the fuses and re-inserted. I'm hooking it up to a code reader tonight and see if any codes come up. I will re-post, however would like any insight or thoughts. Sounds like it may be the on-board computer? Strange though, no gauges, no fuel pump, & no spark. Three different systems (unless there is one connection that interlinks them to the ignition system). Voltage off the battery is fine, headlights, horn, dome lights, door ajar are all fine. Engine cranks over strong. Battery good. Removed cap and cleaned all connections and checked for cracks. Everything looked good there, although that wouldn't explain the fuel pump and gauge problem. Used the vehicle with no problems in the AM and went to start it a few hours later (engine was still warm) and nothing.

Thanks in advance for any advise you may be able to offer.

Greg.
Avatar
1997JeepGrandCherokee
September 24, 2007.




I hooked up the code reader last night to the OBD-II connector and the unit turned on but said it couldn’t establish a link. “Unable to connect to the on board computer”. Hmmm, something not making connection possibly, I then removed all the grounding bolts (one from the body, three from the engine), cleaned them up and reconnected. Still nothing. Switched a few relays around just in case it was the ASD relay. I switched it with several other relays (relays that I now still work…like the AC and also tried the wiper relay because those still work). Still nothing. I have no antitheft on this jeep, so nothing like that engaged to cut engine. I see no lose wires throughout the engine. Unhooked several connectors and made sure they were secure. I wanted to avoid it but looks like it might have to go into the shop. Thanks again guys for any insight.

Greg.

I didn't get much help here so I hope that my three posts can help other people. It was a bad camshaft sensor. That's all. That was one of my notions after doing research on the internet, but though it might be as easy as a lose wire. Didn't cost me much at all though. Good luck to everybody else!

Greg

I too had the same issues crank but no start, no fuel, no spark, no dash gauges including check engine light, and code reader wouldn't work. After researching and buying the manual I traced it to the crankshaft position sensor. For some unknown reason when this goes bad it shorts out the PCM so you get no lights or no error codes. Wonderful engineering! The quick way to check is to unplug the connector which on the inline six was below and to the left of the distributor. Then the dash lights and gauges worked. Replaced the sensor which was a pain to get to and required a universal joint on the end of two long 1/2 extensions to remove the bolt. The part was reasonable $45 at O'Reilly, and we were back up and running. No doubt an average joe shmoe shop would replace the PCM, and numerous other parts and charge big dollars to solve the problem for an unsuspecting owner.

Hope this helps someone else!
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Tiny
Gflea
Sep 15, 2010.
MY 1997 JEEP Grand Cherokee - my jeep would just shut off occasionally as I was driving or sitting at a stop light. Sometimes it would crank back up and be fine. I took it too a "reputable" mechanic shop and they tested it. "It shows the crankcase sensor". Fixed it for about a day. Took it back and took it back over and over again. After costing me a lot of time and money they were then "fixing it" for free. They tried various relays, 3 computer modules, 3 more crankcase sensors, a distributor, checked wiring and checked and checked. Finally they called and said, "we think we fixed it, it is starting really good for us." When I got there to pick it up, it woulded start. They finally admitted that they were stumped. So that night in my driveway with the Jeep running for 2 hours, I did my own "wiggle" test. I crawled all over that thing pulling and wiggling wires and wiggling relays. All of a sudden when I wiggled the right most plug on the computer located on the passenger side firewall, it started to cut out and sputter. I could even wiggle it enough to shut it down. Finally I figured it out. So I used some heavy zip ties to hold it tight. That worked for a few days and even somtimes I could get a couple of weeks out of it. I carry a hammer with me and when it cuts out and shuts down I have to jump out and lightly tap the plug. Usually gets it going. It is pretty embarrasing in rush hour stuck in 3 lanes of heavy traffic, some people are just not very friendly. After visiting a local 4x4 Jeep shop they gave me a phone number of a gentleman that is supposed to be very good with electrical. We have played phone tag for 4 months and I have finally moved on. He did leave a message saying that there is a plug kit that he can solder each wire onto and that would cure it, but I can't get ahold of him any longer. So I have resorted to making a "clamp bracket" today that hopefully will hold the plug on tightly. A flat piece of 1" steel bar on the back and a 1" angle steel across the front of the computer with a bolt at each end and lock nuts to compress the plugs onto the computer. It went on really easy but I won't know if it works for a few days. At least the water pump went in fairly easy today and the new spark plugs, now it purrs and the noisy crackling bearing in the water pump is gone - but that darn "rear gate ajar" light keeps flashing and beeping at me. So now I have to fix that too. Hope I can figure that one out. Dave

Tiny
Davehughes
Dec 28, 2012.

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