Need some technical info...

[lilredtruck]

I got a 1990 fuel injected 4.0L and I need to know what the fuel pressure is at the fuel rail.

 

does anyone know where I can get a wiring description of the firewall (bulkhead) connector for an '86 Comanche?

I need to know where all the wires go in the engine compartment.

 

It's nice to be a member of the club - now I just have to get the little guy running, with your help.

 

Ron

[bigd44889]

not sure what it is soposed to be at the rail but the pump runs at 90 to 110 so i wold guess around 45 at rail my 2.5 pump is 35 to 45 and only 14.5 at fuel injector just a informed guess nobody yell at me lol

[lilredtruck]

You're pretty close I'd guess. I've been given responses on other boards from 25psi to 39 psi and another again at 50psi. I'm going to go with the middle one of 39 psi - I know for a fact that my elec fuel pump that I was using on my LT-1 put out at least 45psi to run it, so it should handle up to fifty if necessary. Thanks for your input...

 

Still could use the breakdown on the Firewall connector if anyone has that.

 

Thanks, Ron

[BLHTAZ]

Go here and download the FSM that I have linked there... viewtopic.php?f=9&t=12517

 

It will have all the info you need about that :cheers:

[lilredtruck]

Hey Taz, You're everywhere... Now you have an MJ!!!? You may know me as BuddyOvrlnd elsewhere... Now I'm working on the lilred(pickup)truck. How've you been?

[BLHTAZ]

:cheers: Hey man...long time no talk. Yeah...I don't go over "elsewhere" much any more as I had a bit if a disagreement with "management" there. Ya, I have had the MJ now for nearly two years...

[Jeepman]

39PSI for all 4.0L with a Fuel pressure regulator on the rail (you will have 2 lines on the rail)...

49PSI for 4.0L with the Regulator at the tank (you will only have 1 line at the rail)...

 

A subscription to alldata may help with the electricall diagrams...