Fuel pressure regulator

Chris_M

Chris_M

Well-Known Member
Joined
Apr 12, 2005
Location
Durham NC
I'm having a fuel problem with my 93 Jeep ZJ, I6 engine AX15

when the system is cold, the pump doesn't prime, and the truck will crank, but not start, after a min or two or three or eight, it will finnally prime, the check engine light comes on, and it will start. The warmer the system is, the quicker it will prime and start. When it works, you can actually here the pump prime the system. If the truck is up to temp, and you shut it off, it'll work great as if there is no problem. Also, there is no fuel starving, cutting out or stalling while driving. The problem has been getting progressively worse for the last 3 weeks

My first guess was a relay or fuse, but they all seem to be fine.
Next guess is a pressure regulator, but how can i test it?!!!!!!!!!!!!

@ $60 for a new one I might just replace it, but that's a rich man's way of troubleshooting a problem.


AN help or Similar problems solved would be greatly appreciated
 
Not sure about the 93's but in my 00' jeep it has a pressure schraeder valve on the fuel rail...you can test it there to see if it's preasurizing completely. Mine was around 40lbs. A few more questions I have are:

Does it stall while idoling sometimes, if you step on the gas?
Does it stall for no reason while idoling?
What codes does the check engine light put out? (Advance Auto can help there)
Does the ZJ have the fuel pump assembly unit that mounts inside the gas tank or is it an external in-line unit?

I'll be glad to help out, I just went through something like this and it was no fun.

-staton
 
Does it stall while idoling sometimes, if you step on the gas?
Does it stall for no reason while idoling?

No, and No.
Also it is a tank mounted pump :mad:
 
The pressure regulator is pre set at 40lbs. It usually lasts a long time and wont give you any problems. I would check your wiring to the in tank pump first. Then I would drop your tank and check the pump and in tank filter. Take the wires that go to the pump and disconnect the positive and use a test light. see if it comes on and then goes out when you turn the ignition key. If it does then your prime cycle is working, but your pump is not coming on. Then there might be a problem with the pump.
 
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