1995 Jeep Wrangler drains fuel back into tank- must wait on

Tiny
EJWEAVER
  • MEMBER
  • 1995 JEEP WRANGLER
Engine Mechanical problem
1995 Jeep Wrangler 4 cyl Four Wheel Drive Manual

Engine Mechanical problem
1995 Jeep Wrangler 4 cyl Four Wheel Drive Manual

I have a 1995 Jeep Wrangler that runs good when it is running, but the problem is when you turn it off. When you turn it off and it sits for 5 minutes or so and attempt to turn it back on, it won't start. I've inspected it and what's happening is when you turn it off, the fuel drains back out of the fuel pump & all injectors and goes back into the tank so essentially it drains all of the fuel. However, if you wait another 2-5 minutes later, the fuel pump kicks back on, circulates the fuel and the Jeep will start right up.
The Jeep has a new fuel pump, filter, pressure regulator & fuse. Does anyone have any ideas as to what it could be? Thanks! Any information would be appreciated!
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Friday, December 18th, 2009 AT 3:22 PM

3 Replies

Tiny
RASMATAZ
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Hi ejweaver, Welcome to 2carpros and TY for the donation and selecting us as your auto repair site Feel free to ask questions at anytime and Merry Christmas and a Happy New Year 2010

Fuel pressure drop:

When the pump is turned off or stops running, the system should hold residual pressure for several minutes (look up the specs to see how much pressure drop is allowed over a given period of time). If pressure drops quickly, the vehicle may have a leaky fuel line, a leaky fuel pump check valve, a leaky fuel pressure regulator or one or more leaky fuel injectors. Low residual fuel pressure can cause hard starting and vapor lock during hot weather.
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Friday, December 18th, 2009 AT 4:32 PM
Tiny
EJWEAVER
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Since the problem started, I've put a new pressure regulator on as well as a new fuel pump. When I turn it off, the fuel goes back into the tank almost immediately, but if I turn the motor off but leave the key on, it keeps working. I wouldn't think that there's a leak in the fuel pump with it going back into the tank that fast though, right? With it happening that fast, I would expect to smell fuel or something.

How would I check the fuel pump check valve? Also, is there a way to tell if the new fuel pump that I put on was just a bad one?

Any ideas of what would make it start back after 5 minutes of being off?
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Saturday, December 19th, 2009 AT 6:06 PM
Tiny
RASMATAZ
  • MEMBER
To find out if the fuel pump is actually doing its job is to hook-up a fuel pressure gauge and monitor the pressure.
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Saturday, December 19th, 2009 AT 6:51 PM

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