Author Topic: MPFI Gas Tank with TBI Engine  (Read 365 times)

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Backroads

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MPFI Gas Tank with TBI Engine
« on: November 30, 2010, 09:59:40 PM »
Maybe someone would want to split this thread up since its kind of taking a new direction....

I finally got to do a little tinkering tonight. I was pleasantly surprised at the similarities the pumps share and compatability.

What I have:
stock steel gas tank and pump from TBI equipped 90yj
stock 15/20 gal plastic tank and pump from MPI equipped 94YJ

Both pumps side by side


TBI pump wiring


MPI wiring


Both have 3 wires inside, 1 for the sender, 1 for the pump, 1 ground. Each had the same in similar enough positions that wiring was a no brainer. I had to mix and match wires because of length only.

There are 2 brackets for holding the pumps in place. The bottom one is fixed and determines depth in tank. The top bracket bolts into a slotted hole along the assembly itself.

Removed the rubber grommet from the TBI housing and installed in onto the MPI housing. Fit perfectly



after test fitting it TBI pump into the MPI housing it seemed to bend the top bracket and while it would have held fine I wanted it to fit better. So I entended the slotted hole about 1/4"

just drilled and filed, nothing fancy



mounted up the pump, fit like it was meant to be there


then wired it up and plumbed it. I actually reused the hose that was originally attatched to the TBI pump. It was slightly longer than the MPI hose, and the holes had a slight offset to them so it helped make up that distance just about perfectly.



The strainer from the TBI pump will have to be re-used as they were a little different

I checked the wires coming from the top exterior of the housing, 3 wires. 1 for the level sender, 1 for the pump and a case ground.

It will probably be a few days before I put the tank completely back together and see if it actually works!

Other things I am gonna need (and already have) are new fill/vent hoses as they are shorter and wider than the originals. New gasket for the rectangular pump cover.

Backroads

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Re: MPFI Gas Tank with TBI Engine
« Reply #1 on: December 01, 2010, 09:34:33 PM »
Couple more things I worked on tonight.

Little brass tab on the bottom of the pump bracket was interfering with the sock, so I snapped it off!

the tab


afterwards (i didnt leave the sock in this position its just to show)



finally! Tanks ready to be bolted back in with some nice new stainless hardware!



on a side note I had 2 of the larger tanks, one had sort of a 'cradle' in the middle of it that the pump sat into somehow (i didnt pay enough attention to it when I took it out) and while it wasnt any longer or different than when I took it out I couldnt figure out how to get it to seat in there. Then I remembered reading about warped tanks and in particular, that cradle warping and the pump not sitting right.

Regardless of whether that was fact or not my other 20gal tank (true 20gal  :dance: without having to modify further) did not have this cradle, it was simple all open inside. The pump dropped right in without having to fiddle with anything. So I used that one with a new gasket.

Probably wont be for a couple days until I get back to it but I need to extend the soft lines as they arent long enough to reach the center of the tank now. They only need maybe 6" each, but I'm going to do the whole soft line and new filter while I'm in there.

I'm so sick of smelling gas  :brick: