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Mohave Vice 04-15-2009 11:11 AM

91 Wrangler starting issues 4.0
Greetings! Newbee needs help. I would sincerely appreciate any advise and direction. I have a 91 Wrangler 4.0 5 speed purchased new in September 1990. Current mileage is 200,000. I had a clutch replaced by a dealer (now closed) May 2008. A buddy was the service manager.When I picked the jeep up, I had difficulity starting (never before experienced). Got the jeep started and drove 60 miles from the dealer to home. An hour later got back into the jeep and would not start. Numerous attempts, but nothing. Contacted my buddy and he had no specific answers, except maybe the fuel pump (never changed). A few days later towed the jeep back to buddy's dealer and had the fuel pump changed. Was advised a bunch of crap in the fuel tank and now clean. Started the jeep and still had difficulity. Maybe low on fuel. Filled tank and drove home for 60 miles. This time half way home and going 55 mph the jeep stalled. Finally got started again and got home. Half hour later the jeep would not start. Called my buddy and no answers. I changed the coil, changed the distributor cap and still would not start. I also changed the crank position sensor and the jeep started fine. I believed the problem was fixed. A few days later began to have starting problems again, but was able to start. Now I am at the same position of no starting at all. I have fuel and engine turns over perfectly .... any ideas? Again I appreciate any help!!!

Rainycity 04-15-2009 01:54 PM

sounds like it could be a throttle body sensor. That was just what my cherokee did except for the dying part, (and on occasion, still does). But I`m not sure if that year had them but I know somebody here does.

jpdocdave 04-15-2009 07:52 PM

my first thought is crank sensor wire got pinched, if this never happened till after the clutch work.

but, when it doesn't start you really need to check whats missing. fuel pressure, spark, and injector pulse.

Mohave Vice 04-24-2009 10:12 PM

Thanks!! For all your help. I towed the jeep down to my local dealer (normally good guys). Rolled the jeep down (45 degree angle) from the flatbed. After on the ground ..... it started up .. no problem. We changed the fuel pressure regulator. Today .... no problems. We will see. Thanks Again!!

Mohave Vice 04-25-2009 03:21 PM

Down again! No start ... back to the dealer .... 60 miles from last repair.

jpdocdave 04-25-2009 05:46 PM


Originally Posted by jpdocdave (Post 356022)
my first thought is crank sensor wire got pinched, if this never happened till after the clutch work.

but, when it doesn't start you really need to check whats missing. fuel pressure, spark, and injector pulse.

so did anyone actually test anything, like fuel pressure, spark, and injector pulse? or did they just guess?

Mohave Vice 04-25-2009 05:55 PM

Diagnoised as a fuel pressure regulator. Replaced "O" ring. Same problem. We will see on Moday and advise.

jpdocdave 04-25-2009 06:03 PM

so they guessed.

Mohave Vice 04-27-2009 11:32 AM

Yes they did as always. They are still guesing this a.m. in telling me I have leaks in my fuel line. Now they want to r/r the fuel lines and dropping the fuel tank $$$$$$. Will advise.

Bobby 04-30-2009 05:53 PM

i have a 92 4.0 in my 89 and i have the same identical prob but i got my hands around its neck i have narrowed it down to a sticking relay in the fuse box or a loose conection in the big wire harness going into the fuse box(engine compartment)next time the jeep won't start open the fuse box and tap on the relays hard enough to knock loose a sticking relay.i will laugh if this works because it took me forever to find the prob.i have had my jeep stall out in the same ways you describe i just didn't spend as much as you to find anyways good luck and let me know.

Mohave Vice 05-11-2009 08:50 AM

Approaching the 3 week mark on down time. The dealer thinks they are getting close. Now claim the ground wire on the fuel pump was bad. Maybe something in the harness. Same issues. We will see .......

Mohave Vice 05-16-2009 12:53 PM

Three weeks to the date and back on the road. Dealer claimed after all of the "guessing", that the problem was related to the ground wire on the fuel pump. Speciffically that the ground through the wiring harness was not working. So a decision was made to have a direct ground on the fuel pump. At present a number of parts and hoses replaced. Runs great now. Will see what happens. It does help to get the factory involved .... because my problem started right after the dealer replaced the clutch 4/08. I/we think that the wiring harness was jacked by the technician when the clutch was replaced. Helps to have the factory involved having additional pressure placed on the dealer.

jpdocdave 05-16-2009 07:45 PM

glad to hear you're finally back in biz. thanks for posting the updates.

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