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post #1 of 6 Old 08-24-2011, 07:07 AM Thread Starter
grandboost98
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1989 YJ Wrangler 
 
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Location: Durham/East Haven
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electrical or fuel?

so ive been doing some research trying to figure out whats up with my heep and im not positive on what it might be. sorry for the lengthy read but i want to describe the problem best i could.

http://www.jeepforum.com/forum/f12/e...bucks-1010402/
http://www.jeepforum.com/forum/f12/r...d-help-933803/
http://www.jeepforum.com/forum/f12/c...g-pics-380858/

while searching i couldnt really find anything to specific to my problems, but these threads gave me the most info, i think.

the problem : while driving, the engine will stop dead. the rpms drop to 0 and then shoot back up to where it was before it dropped with a little backfire and a buck and i continue on driving but my lights and radio stay on. in all the other threads ive read through, theirs will actually shut off and will have to key on the ignition to get going again and they say they have no electrical inside either.

this has happened to me maybe 2 or 3 times since ive owned it (december 2010) never was a big deal, never gave me problems off-road. but this morning on the way to work it was really bad to the point i had to pull over and let people by because it kept coming on and off by itself. once everyone went by i continued on my way with no problems to work(another 20 miles)

my theory : 1) there was a good amount of condensation this morning and i could possibly have a crack in the cap but i had no problems sunday going through various mud holes and creeks.

2) the coil or TPS could be on its way out giving intermittent problems?

3) there could be a loose wire somewhere?

ill be spending my lunch break trying to figure this one out, ill start by letting it run while i shake individual wires in the engine bay. i have a meter here at work aswell if anyone could give me pointers on what to check and what i should be checking for before i get out of work and start throwing parts at it that it may or may not need.

wheww, thanks for reading and for any help


89 Wrangler-3.5" HD BDS lift,M.O.R.E HD 5/8" booms on 35" KM2s
99 Cherokee-2 door,5" lift on 35" KM2s
04 Grand Cherokee Overland
72 Chevy Nova-in progress
http://tiny.cc/BRASSBALLSOFFROAD
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post #2 of 6 Old 08-24-2011, 07:36 AM
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit
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If the rpm's are dropping to 0 the crank sensor, wiring to the crank sensor. It's on the top of the bell housong and responsible for rpm and stalls the Jeep when it starts failing.
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post #3 of 6 Old 08-24-2011, 07:44 AM Thread Starter
grandboost98
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thanks for the quick response! ill be sure to check that out on lunch as well. is there a way to test it before replacing it? also, you say its responsible for the jeep stalling but mine isnt actually stalling, the rpms will drop and then come back quick enough that i dont have a chance to even look at the other gauges to see how they react

89 Wrangler-3.5" HD BDS lift,M.O.R.E HD 5/8" booms on 35" KM2s
99 Cherokee-2 door,5" lift on 35" KM2s
04 Grand Cherokee Overland
72 Chevy Nova-in progress
http://tiny.cc/BRASSBALLSOFFROAD
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post #4 of 6 Old 08-24-2011, 08:08 AM
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit
Posts: 21,698
Yep, thats the crank sensor. It's difficult to troubleshoot an intermittant. If it's the sensor begining to fail then there is no easy way to test it if its intermittant. The CPS is probably the #1 failure issue on the YJ's.
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post #5 of 6 Old 08-24-2011, 08:59 AM Thread Starter
grandboost98
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Join Date: Aug 2010
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well thanks alot for your help! now you made me feel like i made a bigger deal out of a little problem lol ill post back and let everyone know if this worked or not because i HATE reading through threads trying to figure out a problem to find out the OP never posted back their solution

89 Wrangler-3.5" HD BDS lift,M.O.R.E HD 5/8" booms on 35" KM2s
99 Cherokee-2 door,5" lift on 35" KM2s
04 Grand Cherokee Overland
72 Chevy Nova-in progress
http://tiny.cc/BRASSBALLSOFFROAD
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post #6 of 6 Old 08-24-2011, 10:08 AM Thread Starter
grandboost98
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Join Date: Aug 2010
Location: Durham/East Haven
Posts: 4,040
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UPDATE!!

so im pretty sure you were right, although i dont have a way to be sure, when i went to look at the crank position sensor it was nearly falling off! i dont know how it hasnt been giving me constant problems but the 2 bolts holding it on were only a couple thread away from falling out. so i tightened the bolts up, started it, jiggled the CPS wire and a few other wires and nothing happened. let it run for about 10 minutes and everything seemed fine.


So again, thanks alot for your help!

89 Wrangler-3.5" HD BDS lift,M.O.R.E HD 5/8" booms on 35" KM2s
99 Cherokee-2 door,5" lift on 35" KM2s
04 Grand Cherokee Overland
72 Chevy Nova-in progress
http://tiny.cc/BRASSBALLSOFFROAD
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