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Unread 04-05-2010, 11:26 AM   #1
jeep1993yj
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1993 YJ Wrangler 
 
Join Date: Jan 2009
Location: Mundelein, IL
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YJ hesitated and now engine doesn't start

my 93 YJ 2.5L with 100K miles is not starting up. The other day, I was leaving to work it started but started hesitating and would stall. During my 5 mile trip to work it stalled 8/9 times and would start right back up after few seconds. But I had to get it towed because in the evening as it wouldn't start.

So when I try to crank, it tries to start the engine but looks like the engine dies right away. Fuel pump is working fine, I can hear the sound everytime I key in. I also checked the knob(for attaching fuel presseure gauage) on injector rail by pressing it with a key, it squirts the fuel so pressure is good.
I noticed little oil in air filter and throttle body. It looks like there is slight leak from valve cover gasket and the oil is getting into intake. I tried cleaning the throttle body by spraying MAF sensor cleaner, sure enough after few cranks, it fired up and died again. It seems like now it tries to start the engine but something kills it. I also noticed the the rubber adapter cracked on (the little pipe that runs from front of jeep on driver side of injector rail to throttle body).

It seems like if I take the intake out and clean it and throttle body it might work, and I have to fix the valve cover gasket as well.

I would appreciate any help on this.

Thanks for your help!

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Unread 04-05-2010, 12:48 PM   #2
cj7guy
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Your fuel pressure check doesn't seem quite adequate.

I'd get a real gauge to test it, that or just swap out the fuel filter for good measure and see if that fixes it.
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Unread 04-05-2010, 01:00 PM   #3
crazyquadder
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I am 90% positive that your SPark plug box is no good. I had this same problem a while back. That and my Cap was cracked somehow. IM guessing water got into my cracked cap and shorted out the spark plug control. At least on my year it mounts on the driver side fire wall a little white square about 5x5
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Unread 04-05-2010, 03:32 PM   #4
jeep1993yj
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Quote:
Originally Posted by crazyquadder View Post
I am 90% positive that your SPark plug box is no good. I had this same problem a while back. That and my Cap was cracked somehow. IM guessing water got into my cracked cap and shorted out the spark plug control. At least on my year it mounts on the driver side fire wall a little white square about 5x5

Thanks! I will check it out. I didn't wash it or it wasn't sitting out in rain. I hardly drive it. It ran fine a day before it started stalling.



How do I check for vaccum leaks?
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Unread 04-05-2010, 03:33 PM   #5
jeep1993yj
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Quote:
Originally Posted by cj7guy View Post
Your fuel pressure check doesn't seem quite adequate.

I'd get a real gauge to test it, that or just swap out the fuel filter for good measure and see if that fixes it.
I have the gauage. I will check and psot back. What should it read normally initially an then at idle?
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Unread 04-05-2010, 03:43 PM   #6
idaholtby
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Quote:
Originally Posted by crazyquadder View Post
I am 90% positive that your SPark plug box is no good. I had this same problem a while back. That and my Cap was cracked somehow. IM guessing water got into my cracked cap and shorted out the spark plug control. At least on my year it mounts on the driver side fire wall a little white square about 5x5
Please realize the differences in model years before lending advice. The OP has a '93 which is MPFI, i.e. no carb or ignition module. Hate to see any confusion injected here. To the OP, are any codes stored? There are numerous sensors that could cause this problem, but they would normally throw a code that can be deciphered from the Check Engine Lamp.
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Unread 04-05-2010, 03:46 PM   #7
idaholtby
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Quote:
Originally Posted by jeep1993yj View Post
I have the gauage. I will check and psot back. What should it read normally initially an then at idle?
31psi is normal at idle. With the vac line removed from the pressure regulator, the pressure should read 38-41psi.
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Unread 04-05-2010, 07:14 PM   #8
HanksRide
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Can you hear the fuel pump engage when you turn your key on?? You should hear it for a couple of seconds. If you can't hear it and your pressure is low don't assume it is the fuel pump until you have atleast checked the fuel pump relay in the PDC. If it is bad, it would be a lot simpler fix then the fuel pump.

Have you pulled a plug wire and checked for spark??
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Unread 04-05-2010, 07:19 PM   #9
wpnschief
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I agree on checking the fuel pressure, I just had to drop my tank because the fuel line from the pump to the sending unit inside the tank dissolved...again! I only had @ 20 lbs pressure during engine operation, after engine shut down it immediately dropped to zero.

The Autozone pump I put in 2 years ago came with a hose that dissolved in gas. I went and got some proper fuel line and now have 31 lbs at idle and 39 lbs when the pressure regulator vacuum is pulled. I chased this for a week before I put a gauge on it and realized it was the pump again. Good Luck!
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Unread 04-05-2010, 08:29 PM   #10
jeep1993yj
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Thanks guys!
no check engine light coming up. I tried checking for code but it didn't seem to through any. I will check again.
I can hear fuel pump engaging.

How to I check for vaccum leaks and where are hthese lines?
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1993 Jeep YJ - All stock
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2009 VW Tiguan
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Unread 04-05-2010, 08:45 PM   #11
idaholtby
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Quote:
Originally Posted by jeep1993yj View Post
Thanks guys!
no check engine light coming up. I tried checking for code but it didn't seem to through any. I will check again.
I can hear fuel pump engaging.

How to I check for vaccum leaks and where are hthese lines?
"hearing" the fuel pump come on is a good thing but has nothing to do with how much pressure it produces. You need to check the pressure at the rail with a gauge attached to the valve. Otherwise you are just guessing that all is good.
Vacuum leaks are easily detected by spraying carb cleaner(or similair) over every fitting. If the idle changes while doing this, then you found a leak.
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