1993 GC 4.0 I6 starting problem - JeepForum.com
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Unread 01-09-2011, 12:00 PM   #1
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Join Date: Jan 2011
Location: Eagan, MN
Posts: 1
1993 GC 4.0 I6 starting problem

Ok guys, I new to the forums and need some help. I have a 1993 GC with a 4.0 I6 that is very difficult starting. It needs to be cranked several times before starting. When it does start it does not act as if it is flooded, rather starved for fuel. Starting usually occurs after one or two cycles of the key switch.

What I've done:

- New fuel pressure regulator, and test correctly on the pressure test
- New Fuel filter
- Fuel pressure tested, running psi 31, idle psi 30 psi, max psi 39
(vacuum hose disconnected)
- All fuses and relays test correctly
- The Fuel pump seems to operate normally during starts, idle and normal
operation, meaning it turns on and seems to pump fuel normally
- Oh and no noticeable leaks

My questions:

The fuel pressure will fall to 0 in the fuel injection rail after 35 min, any
ideas on the causes??? I'm assuming this is causing a fuel starvation issue on start up an would explain the rough start issue.

- Possibly a failed schrader valve (valve-stem looking valve on the
fuel rails) causing a bleed down?

- A bad fuel pump?

- Is there a check valve I'm not seeing?

- A leaky injector?

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fuel pressure , fuel pressure regulator , fuel pump , starting issue , starting problem
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