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Unread 07-27-2010, 05:20 PM   #1
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Join Date: Jul 2010
Location: raleigh
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Jeep won't start

1990 2.5 wrangler. Just stopped running in my driveway. Replaced fuel regulater, injector, pump. Timing chain, tensioner. Crank, O2 sensor. Tested throttle postion and temp sensors. MAP has acceptable OHM reading. New plugs, cap, rotor, wires, coil and ignition module. New computer. Seems to have a weak spark. Good fuel spray pattern. Low compression. 65 lbs in all except back, 75psi. Distributer seems to be in correct. WHAT should I replace next?? Thanks for any and all answers!

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Unread 07-27-2010, 06:05 PM   #2
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1991 YJ Wrangler 
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Location: Elizabethtown, Ky.
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What do you mean by a weak spark? What color is the spark?

MJM Powder Coating
Elizabethtown Ky.
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Unread 07-27-2010, 06:37 PM   #3
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1995 YJ Wrangler 
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Location: Los Angeles. California. United States.
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Wow, you did a lot there. I would look into timing issues possibly, that compression seems abnormally low. A crank sensor many times is the culprit, or cam sensor possibly, not sure about this though. I think it is important to take more time to diagnose this first, unless you like to spend money. So the primary things are fuel, spark, and timing for me. I am guessing you are getting fuel now, and it seems you are getting a weak spark, check your timing by taking off the distributor cap, and check the rotor position, and look for play by reversing rotation slowly on the crank shaft pulley/slowly. You can put a socket on the center bolt for the harmonic balancer/crankshaft pulley.

Last edited by moonshinefuel; 07-27-2010 at 06:49 PM..
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Unread 07-27-2010, 08:30 PM   #4
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The spark is more yellow than blue. It just doesn't snap like I think it should. The Chiltons manual says the rotor should be at the six oclock position relative to the block when number one is at TDC. I can get it to either five thirty or six thirty but not exacly six oclock. I can move the rotor back and forth about a quater inch in each direction. Don't know how much is normal. I don't think it has a cam sensor. Funny about the compression though. Why would it just quit because of that. I would think it would start burning oil or running poor before it quit. It has been sitting for almost two years before I took this compression test. It's a new compression tester. Any other thoughts would be much appreciated. Thanks
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Unread 07-28-2010, 10:04 AM   #5
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1989 YJ Wrangler 
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Location: Detroit, Michigan
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Yes you have a cam sensor(Pickup sensor) in the distributor. If your seeing spark at the plug then my bet is its not a spark issue; its a fuel issue. Spray starter fluid into your throttle body and see if it cranks over.
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Unread 07-28-2010, 08:16 PM   #6
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I will try the starter fluid. I don't know why I didn't think of this. I use a lot of it to get my lawn equipment going. This distributer does not any wires that go to it besides the plug/coil wires. I have taken the plate off that resides under the rotor and there is nothing there. I don't know where the pickup is. If I search for a replacement for this '90 model I can't find one listed. I'm wondering if anyone knows if the MAP sensor is bad, would that keep it from starting. I though most cars with this type sensor went to a failsafe running mode if it was bad. Again, thank you for any help.
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Unread 07-28-2010, 09:16 PM   #7
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1994 YJ Wrangler 
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Location: rhode island, rhode island
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im having the same issue right now. my friend bought an 89 2.5 but it only runs for two minutes and shuts off. we cant figure it out.
1994 yj 4.0 5speed, soa 2inch springs,front aussie with tj shafts and 4.10s,8.8 with disc with lsd, on board air,35inch km2s, wj intake,63mm throttle body,costum 2.5 exhuast
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Unread 07-29-2010, 01:05 AM   #8
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1991 YJ Wrangler 
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I had this same problem in my 91 2.5L would run for few minutes and die, I had 2 problems my wires going to my coil had corrroded almost all the wire inside plastic insulation were broke, also I changed the fuel pump inside the tank. I put a fuel pressure gauge on and let it run in driveway it would run fine then i would take it down the road it would die 5 minutes from home. So I left the fuel gauge on while driving and it would lose pressure five minutes down road thats how I figured it was fuel pump hope this helps.
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Unread 07-29-2010, 01:58 AM   #9
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1987 YJ Wrangler 
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Location: Monroeville, Ohio
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when my 87 wont start, I do an assortment of things and it always fixes the problem eventually.
1. swear at your jeep
2. crank the starter way longer than you should
3. pump the gas pedal until you ALMOST flood the engine
4. punch the steering wheel
5. crank the starter again. for way too long.
6. swear at it a little more

(it usually starts here, runs for a few seconds and dies again)

7. beg and plead for it to start because the neighbors are now watching
8. caress the steering wheel and tell your jeep you love it
9. crank the starter again
10. crank the starter again
11. punch the dash and threaten to take your car instead
12. crank the starter while holding the gas to the floor and praying to any and every god there is

Jeep starts! problem solved!
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