1988 MJ 2.5 questions.

[Manimal]

Hey guys, I just started working on my '88 Comanche. The guy I got it from said it has bent valves. So yesterday I took the head off and found 1 stuck intake valve. It had some really gummy residue on the face of the valve and stem. I smelled it and it turned out to be bad gas. I took it to a local machine shop for a valve job($200). BTW this engine is a MOPAR replacement,pistons are .005 over and the cross hatch pattern is still VERY vissible...and SUPER clean in side.
Any how,my question is are the TBI and MPI heads the same,or are they different like the 4.0? I am considering replacing the TBI with MPI and before I start buying parts,I need to do some research. I looked into Alabama cylinder heads and they list them for all years of 2.5 for the same head.
Thank You for any help you can give me.
-Lance

 

[wolfpackjeeper]

I looked into the swap. It is dooable. You need the intake and all the wiring harness stuff. You will need the computer from a MPI truck naturally, and I think you will be doing a lot of splicing. I decided that it was not worth the effort or cost at the time, but there is at least one converted truck on here. In your position I would probably just put it back together as a TBI engine and sweeten that system up with a new set of sensors and a new injector. There is not that much HP gain from the multi IIRC.

I decided that I would rather wait till I have a bit more time and just do an LS1 swap.

 

[Manimal]

So I take it that the heads are the same?

 

[kastein]

Dunno, but I honestly wouldn't put that kind of work into a 4cyl engine, if I was going to be screwing around with the head, wiring, and computer I'd just drop a 6cyl in it and call it a day. On an 88 it should be a bolt in swap.

 

[Johnnie Walker]

Dunno, but I honestly wouldn't put that kind of work into a 4cyl engine, if I was going to be screwing around with the head, wiring, and computer I'd just drop a 6cyl in it and call it a day. On an 88 it should be a bolt in swap.

LSx swap FTW!

 

[cruiser54]

I would just put the head back on, get rid of the old gas and drive it. Go to RackAuto and look up an intake/exhaust gasket and see if they're the same between MPI and TBI.

 

[Manimal]

Well, I pick up the head from the machine shop today. I have to work on a friends 58 Chevy today,so I wont be able to get to the MJ until the weekend. I think I may also replace the injector. Do ya think that running some Seafoam or Berrymans through it will help clean all the old gas out? Thanks

 

[87manche]

disconnect the fuel line at the pump, it's easy to get to. Might want to drop the driveshaft to avoid smacking your head on it every 2 minutes.

Jumper the fuel pump relay and run the tank dry.
Dump some fresh fuel and some "heet" into the tank and fire it up.
My 4.0 sat for 18 months, I did this, it fired up on the 3rd turn of the key. Actually, I didn't even empty the tank, but if your tank is nasty I would.