thing on 2000 GC fuel rail

sneaky7980 · #1 04-07-2006, 06:12 PM

What is is the round thing on my 4.0 fuel rail, half way back, that has a blue sliding tab? i know the fuel pressure regulator is combined with filter back by the tank. so what is this and what does it adjust?

sneaky7980 · #2 04-08-2006, 12:32 PM

bump

Bob D. · #3 04-08-2006, 11:22 PM

If you bought it used, the original owner may have added an after market fuel filter.

sneaky7980 · #4 04-09-2006, 07:30 PM

Im pretty sure it's not a filter. looks alomost like some kind of valve or something. I tried moving the blue slide on it and it doesn't seem to affect anything. Just thought i should figure out what it does since iv'e been having fuel pressure problems.

sneakybert · #5 04-10-2006, 09:06 AM

I believe that you are referring to the fuel damper . It is used to control fuel pressure pulsations that are the result of the firing of the injectors . The fuel regulator is part of the fuel filter .

sneaky7980 · #6 04-13-2006, 07:43 PM

Well i discovered that my pressure goes up to approx 10 psi for the few seconds the pump primes then immediatly drops off to 0. I went back and hooked my guage to the engine side off the filter/press regulator and got the same results. I just changed the pump assy and the press regulator/filter assy this month with no change. I've heard that some vehicles have a "pressure relief/ roll-over valve" located on top of the pump assy and wonder if mine does too. If it were slightly open that could be my problem. NOTE: I've had hard starting problems for the last year that have gradually gotten worse over time. I really don't want to pull the tank out again, (half full)!

btw what does the slide adjustment on the fuel damper do?

Bob D. · #7 04-14-2006, 05:15 AM

Quote:

Originally Posted by sneakybert

I believe that you are referring to the fuel damper . It is used to control fuel pressure pulsations that are the result of the firing of the injectors . The fuel regulator is on the fuel pump in the tank.

Actually, sneaky7980 is correct, the fuel regulator is located near the fuel tank and is a stand alone part.

Quote:

Well i discovered that my pressure goes up to approx 10 psi for the few seconds the pump primes then immediatly drops off to 0. I went back and hooked my guage to the engine side off the filter/press regulator and got the same results. I just changed the pump assy and the press regulator/filter assy this month with no change. I've heard that some vehicles have a "pressure relief/ roll-over valve" located on top of the pump assy and wonder if mine does too. If it were slightly open that could be my problem. NOTE: I've had hard starting problems for the last year that have gradually gotten worse over time. I really don't want to pull the tank out again, (half full)!

Fuel pressure issues are a common cause of hard starting/long crank times.
Follow the info below and you will find out if that is the cause of your starting problems.

Fuel pressure should be measured at the fuel rail, next to the engine. Measuring pressure by disconnecting the regulator takes the system out of the loop and may give false results.

Attach your gauge at the port in the injector rail, then here is what to look for:

Fuel pressure at idle - 50 psi.

Fuel pressure at high rpm: not to exceed 60 psi or drop below 50 psi.

Then turn the engine off, keeping the gauge connected.
Fuel pressure should not drop below 25 psi in 5 minutes.
If it does anything different, you may have a bad fuel pump, leaking fuel injector/s, a leak in the fuel line, or if the pressure is high, a faulty fuel regulator.
If the fuel pressure becomes excessive, the fuel regulator feeds fuel back to the tank...that's all it does.
This is the "pressure relief/ roll-over valve" as you call it.

sneakybert · #8 04-16-2006, 06:12 PM

Did you replace the complete fuel module or just the fuel pump ?

sneaky7980 · #9 04-18-2006, 07:02 PM

I just changed the electric pump. Re-used the sending unit/ housing assy.

sneakybert · #10 04-18-2006, 09:41 PM

There is a "o-ring style" seal between the upper and lower fuel pump housing that has possibly failed . You can purchase a repair kit ( Chrysler part number 5019308AB ) .

sneaky7980 · #11 04-20-2006, 05:41 PM

If what your talking about is approx 7-8 inches in diameter, then that was replaced also. I did have a hard time getting the screw-on ring that goes over the seal secured. But i thought that seal just kept dirt out of the tank, not for pressurization purposes. Maybe i'm thinking of the wrong seal.

sneakybert · #12 04-21-2006, 09:44 PM

No this "O - ring " is about the size of a dime . You will have to disassemble the fuel pump module to replace it .

sneaky7980 · #13 04-23-2006, 04:36 PM

Yeah i did replace that, it came with the rebuild kit. BTW i found my problem. The new press regulator/fuel filter assy was bad. Swaped it out with a new one problem solved.
The crappy thing is all the time and money wasted assuming the new parts you have bought will function properly, only to find out they don't after your knuckles are scarred and your wallet is empty that they don't!

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