94 4.0 Fuel pressure issues - JeepForum.com

 
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post #1 of 4 Old 02-26-2017, 02:43 PM Thread Starter
Meboota
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Join Date: Feb 2017
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94 4.0 Fuel pressure issues

Hi Everyone,

I've been undergoing a frame swap on my 94 YJ for some time now, only get to work on it during long weekends, so this has been moving forward very slowly...

(Long story short) I've been able to successfully swap everything over the new frame that has been coated with POR15. While doing this swap, I also swapped a 8.8 rear with factory LSD, gave it a 4" suspension lift +1" body and currently have 38's bolted up as a roller.. I'd say that I was quite successful with the more involved fabrication work.. But I cant manage to get the Jeep to start every time.

I haven't gotten to check spark or if its getting air.. I started with fuel and immediately found that it had no fuel pressure build up at the rail.

During the course of swapping in new parts, I replaced the fuel pump with a brand new unit. The original one was so badly corroded, was pretty amazed that it still managed to work before I began taking everything apart to swap the frame.

Along with the fuel pump, I replaced all rubber lines and fitted a new fuel filter. I also replaced the pressure regulator and swapped the old injectors with the well known "4 hole" mustang units.

A couple of months ago, I did get the jeep to start a few times, but it took a good 30-45 secs of cranking for the pressure to slowly build up to 32psi (as shown on my gauge). But now it wont start at all... I've tried turning the key with the fuel hose to the rail disconnected and pointing down into a gas can. You can see the gas being pumped out very slowly, but when it is all bolted back up, the fuel gauge that is running off the fuel rail shows no fuel pressure build up at all..

I've done some extensive research by reading other threads & watching youtube vids. I've tried many of the things as shown on there, but couldn't get it to work here. I'm having some trouble figuring out what my next move should be.

Was hoping to get some feedback from you more experienced members on here.
Thanks in advance.

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post #2 of 4 Old 02-26-2017, 04:21 PM
TSEJEEPERS
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1993 YJ Wrangler 
 
Join Date: Dec 2003
Location: Morton IL
Posts: 5,656
I know this sounds like a stupid question but is the filter facing the right way?
Do you hear it prime when you turn the key and does your check engine light come on?

93 YJ SOA 2" springs front, XJ springs rear w/main leaf added, High pinon 9 inch rear detroit locker front Dana 44 ARB 4.56 Gears, 36 inch Irok tires too much to list.
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post #3 of 4 Old 02-26-2017, 09:45 PM
Drednot
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1991 YJ Wrangler 
 
Join Date: Aug 2005
Location: Phoenix
Posts: 3,571
go back underneath by the fuel filter. Looking up towards the rear. look for the fuel supply, return, and vapor lines that come from the tank and clamp onto those hard lines. Undo the two fuel lines and rerun the pump. Is there strong flow at the hoses?




91 YJ Sahara, 4.0L, AX-15/NP231, D30/D35@3.07
12 Cherokee 4x4,3.7L,42RLE/MP1522, D30M/8.25@3.73
Emission test=YES
"Non Vi Sed, Arte"
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post #4 of 4 Old Yesterday, 08:46 PM
TSEJEEPERS
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1993 YJ Wrangler 
 
Join Date: Dec 2003
Location: Morton IL
Posts: 5,656
Also check and make sure you have the supply and return hooked up right.
Same with the wires that connect to the fuel pump. It is easy to reverse them.
Pinched line could also be a problem.

93 YJ SOA 2" springs front, XJ springs rear w/main leaf added, High pinon 9 inch rear detroit locker front Dana 44 ARB 4.56 Gears, 36 inch Irok tires too much to list.
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