Anyone familiar with Jeep fuel systems?

[Zoinks!]

I'm wondering if the fuel pump, itself, is interchangable between the MPI and TBI trucks. I know the MPI is returnless and TBI has a return system, but I need to know if the TBI pump will supply enough pressure to support the MPI system. Anyone know?

 

[VIPER]

no it will not. mpi systems i think are pressured constatly at 40 psi plus. The tbi pump wont push that much. double check me but i am sure i am right.

 

[HotFoot]

what year do you have
and what motor

 

[ditchdr]

Typically a returnless system runs a higher PSI then a return type system.

 

[Zoinks!]

what year do you have
and what motor

The donor truck is a 96 with an I6 MPI engine. The one it's going in is a 92, but it didn't have the engine in it when purchased, but it's got the return system.

Typically a returnless system runs a higher PSI then a return type system.

I know they do, but that's because you have fuel flowing back to the tank. I'm wondering if the pump will still supply enough pressure if the return system isn't used. Because in theory, since there's no backflow, I would think it would build enough pressure. I just need to know if the pump itself is the same. I know the specs on the system pressure are different, but are the pumps the same?

 

[Zoinks!]

no it will not. mpi systems i think are pressured constatly at 40 psi plus. The tbi pump wont push that much. double check me but i am sure i am right.

Well, the PSI just depends on the vehicle and the manufacturer, but the reason I'm wondering is because the TBI and MPI pumps physically look exactly the same. The only difference in the assembly is the TBI pump has the return tube on it and has a 3 wire connector, while the MPI assembly has no return port and a 4 wire connector. But the actual pump part of the assembly looks the same. (at least in the pictures I've seen of them. The TBI truck didn't have the pump with it).

The only other option I have is to re-wire the MPI pump to work with the 3 wire connector, if that's even possible, but I don't have a decent schematic to work with, so I can't do that right now.

 

[ajblbv]

If you haven't tried jeepsunlimited.com is the .org of jeeps, or at least used to be

Good luck

 

[Zoinks!]

If you haven't tried jeepsunlimited.com is the .org of jeeps, or at least used to be

Good luck

Thanks, I might have to check em out. I posted on cherokeeforum, but it's gotten 30 views and no replies. I'm kinda surprised no one on there could tell me. Or at least tell me how to wire the MPI pump to work with the TBI connector. If it comes down to it, I'll just buy an alldata subscription for it, but I'd rather not have to make my buddy spend that money if someone else can tell me for free.