fuel pump change same problem

[rkeith]

1988 grand wagoneer 4.0L changed fuel pump and filter because I had no fuel pressure the new pump worked intermittently as the old pump did. Sometimes it will run for a bit then die you can hear the fuel pump turn off right before it dies. Sometimes when it does start it will run at a higher RPM. I have checked the four relays on the passengers side by the wheel well and the were ok. I have checked the pressure regulator and it was ok. Is there a sensor that could be causing this problem my Haynes book does not have the info that I need.
Help needed (I hit the ECM and the fuel pump came to life its either a bad connection or a bad ECM)

Thanks:

 

[Bounty__Hunter]

Have you changed the fuel filter?

 

[90Xjay]

its got to be relay or related to electrical

 

[rkeith]

Have you changed the fuel filter?

Yes I did change the fuel filter I spaced that off on my posting.

 

[Bounty__Hunter]

Sounds like you need a FSM to track down all the related circuits involved. I guess it could be in the ignition switch as well, strange it's an intermittent problem.

Was the 4.0L ever offered in an '86 model? Or do you have the 4.2L?

This is the FSJ right? Not an XJ?

 

[rkeith]

Sounds like you need a FSM to track down all the related circuits involved. I guess it could be in the ignition switch as well, strange it's an intermittent problem.

Was the 4.0L ever offered in an '86 model? Or do you have the 4.2L?

This is the FSJ right? Not an XJ?

I had a type error its an 88........

 

[90Xjay]

Thats first year for EFI I think.

 

[rkeith]

It ran fine in the drive way today for about 1/2 hour then died. I checked the resistance of the crank shaft position sensor and it ran between 190ohms and 210ohms when the motor was cranked over. The haynes manual said it should read open circuit during a static check I don't buy that do you know?

 

[Bounty__Hunter]

A good shop can hook a diagnostic computer up to it through the ports on the pass. side inner fender and see exactly what is going on.

 

[90Xjay]

BH,
Woud that system be OBD1?

 

[Bounty__Hunter]

Unsure, but it uses a Chrysler adapter to plug a diagnostic computer into the Renix system. I had my '88 4.0L MJ plugged in before, told exactly what sensors were acting up.

 

[rkeith]

BH,
Woud that system be OBD1?

It has OBD but it did not flash any codes when the terminal was jumpered and iginition switch to ACC.

 

[Ragtopman]

Did you check the ground to the pump? My friend had an intermitant problem like this and we did everything till we found the ground was all corroded

 

[rkeith]

where is the computer located

 

[rkeith]

I hit the ECM and the fuel pump energized maybe a bad connection or ECM.
I will get a new ECM soon there only $100.

 

[rkeith]

1988 grand wagoneer 4.0L changed fuel pump and filter because I had no fuel pressure the new pump worked intermittently as the old pump did. Sometimes it will run for a bit then die you can hear the fuel pump turn off right before it dies. Sometimes when it does start it will run at a higher RPM. I have checked the four relays on the passengers side by the wheel well and the were ok. I have checked the pressure regulator and it was ok. Is there a sensor that could be causing this problem my Haynes book does not have the info that I need.
Help needed

Thanks:

I found the problem I hit the ECM and the fuel pump powered up.
Maybe a bad connection or ECM.

 

[drwood]

sorry wrong section
.