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Unread 04-20-2013, 03:26 PM   #1
jbeebe
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1991 YJ Wrangler 
 
Join Date: Jul 2008
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MYSTERY of the tired old jeep

(lazy people skip to "summary" at the end) About 6 months ago the jeep would just not restart after shutting off. It ran perfectly, but just wouldn't restart for a few minutes. Sometimes it did it when it was hot, sometimes when cold. Then it solved itself a few months ago.

Yesterday, driving to the gym the engine hesitated a bit almost like someone pinched the fuel line for a couple seconds, then it kicked back in and was fine. But on the way home from the gym she just died while driving. Just a slow lack of power until it finally just cut out. All the electrics are fine.

I tested the fuel pressure today for the first time and primed, its at ~35, but when started it was hovering around 70. Now granted, that could have been due to the 20 dollar HF tester.

The only thing besides fuel pump that I can think of would be the cps. What do you guys think?


Summary:

Jeep would intermittently not start a few months ago, then all good.

died while driving yesterday and wouldn't start for a few minutes.

fuel pressure is 35 primed up. at idle my cheapo tester read 70, not sure if that's even possible.



I'll include a little picture just to get some people to respond to another stupid "jeep just dies!?!?!" thread.

How about this little treasure from Wal-Mart:



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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-20-2013, 03:57 PM   #2
Que89YJ
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1989 YJ Wrangler 
 
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You either have a pinched return fuel line or a bad regulator. Disconnect the return line up at the fuel rail and run it to a gas can. If it is still high bad regulator. If it is normal bad fuel return line.
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Unread 04-20-2013, 04:03 PM   #3
jbeebe
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Quote:
Originally Posted by Que89YJ View Post
You either have a pinched return fuel line or a bad regulator. Disconnect the return line up at the fuel rail and run it to a gas can. If it is still high bad regulator. If it is normal bad fuel return line.
If it's the regulator, do I have to replace the entire fuel pump too? All i know about the regulator is that it's in the tank with the pump. I never pulled the pump from the tank (though i have dropped it before) so i'm a little unfamiliar with it

thanks
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-20-2013, 04:04 PM   #4
Que89YJ
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the regulator is on the fuel injector rail.
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Unread 04-20-2013, 04:06 PM   #5
jbeebe
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Quote:
Originally Posted by Que89YJ View Post
the regulator is on the fuel injector rail.
well then let me rephrase my original statement...

" i know absolutely nothing about the regulator!"

haha
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-20-2013, 04:27 PM   #6
jbeebe
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Quote:
Originally Posted by Que89YJ View Post
the regulator is on the fuel injector rail.
where the two lines attach to the rail, is the return line the one towards the front or rear of the engine bay?
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-20-2013, 05:25 PM   #7
Que89YJ
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The return line comes off the regulator at the front.
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Unread 04-20-2013, 05:39 PM   #8
jbeebe
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got it, i'll check it out and update this thread tomorrow with my findings.
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-20-2013, 06:29 PM   #9
Mark05059
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Quote:
Originally Posted by jbeebe;15323316

How about this little treasure from Wal-Mart:

[URL=http://s669.photobucket.com/user/casanova91787/media/walmart_zps60a2bf87.jpg.html
[/URL]
Hey where did you get the picture of my cousin?
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1998 ZJ 5.2 Auto

1989 Wrangler Black Bone Stock 2.5l 5spd
/l , [____],
|---L--[]lllllll[]-
()_) ()_)==O=)_)
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Unread 04-21-2013, 12:10 PM   #10
jbeebe
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Quote:
Originally Posted by Que89YJ View Post
The return line comes off the regulator at the front.
i followed the line coming out of the regulator (it's the line towards the front of the engine bay) and it looks like it runs into the filter, so that has to be the sending line right? Does the regulator regulate the fuel coming into the rail?
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-21-2013, 12:25 PM   #11
Que89YJ
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pull the line. turn the key. see if fuel comes out of the fuel line or the rail.
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Unread 04-21-2013, 12:46 PM   #12
jbeebe
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Well its the return line, I pulled it and drained it into a container. The pressure hovered right above 30.

I don't see how it could be pinched though, I have a 1 inch body lift and can wiggle the line on top of the tank freely
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-21-2013, 01:27 PM   #13
Que89YJ
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It can be in the tank itself. There have been several people here lately that have had the return line in the bottom of the tank touching the bottom and restricting flow.
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Unread 04-21-2013, 01:33 PM   #14
jbeebe
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That would be a whammy, I may have to drop the tank after all. I'm going to do drain from the line in the back right where the metal line meets the rubber, that way I'll find out if the blockage is in the tank or at least in the rubber line on the tank
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91 YJ. 4.0, 4.10's, 33's, 4" springs, 3/4" booms, 1" BL, 1" MML, d30 aussie locker, hand throttle, posi-lock, full cage, bumpers/rocker guards/engine skid, winch.
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Unread 04-21-2013, 01:39 PM   #15
Que89YJ
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You can jumper the fuel pump relay socket from 30 to 87 with a wire and use the pump to drain the tank.
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