Multi Port Injection on older 258?

[Dolamite]

Hi Guys,
I've determined that I want to ditch my carb and go to fuel injection. My preference is the Mopar MPI conversion, but I see the kit is for 1981-1990 Jeep AMC 258 i6 / 4.2l automatic. My jeep is a 1980 with a rebuilt 1978 258 and has a T-176 manual tranny. What changed on the 258 in 1981 that prevents the MPI kit from working on older engines? Is TBI my only option?

Thanks for the help!

 

[tinman]

I found this quote on the Morris 4x4 website-

"Jeep changed the AMC 258 i6 / 4.2l in 1980 and again in 1987 and the various year builds have specific breaks that do not cross (exhaust headers, for example). Depending on your location, I can get you either a California CARB legal kit or a standard offroad injection kit that will work for your specific vehicle. Give me a call and we can get you taken care of; my name is George and you can reach me directly at 877-553-5337 then press * then 484."

I'm not sure it's that big of a deal to make it work, maybe just some minor tweaks. I did the junkyard Cherokee MPI on mine, but it was an 84 and I also did the 4.0 head, which I would HIGHLY recommend doing along with the FI. I did a write up on here about the whole thing, so if you go that way I'll be happy to answer any questions.

Good luck!

 

[ttuseth2]

Not sure about the change between those years, I'm sure someone on here does and will chime in.
I recently did the tbi conversion with a kit from performance fuel injection and I'd do it again in a heartbeat. Same kit and parts as the others out there (affordable and Hamilton) but a little less costly.


Sent from my SCH-I605 using Tapatalk

 

[Dolamite]

I found this quote on the Morris 4x4 website-

"Jeep changed the 4.2L in 1980 and again in 1987 and the various year builds have specific breaks that do not cross (exhaust headers, for example). Depending on your location, I can get you either a California CARB legal kit or a standard offroad injection kit that will work for your specific vehicle. Give me a call and we can get you taken care of; my name is George and you can reach me directly at 877-553-5337 then press * then 484."

I'm not sure it's that big of a deal to make it work, maybe just some minor tweaks. I did the junkyard Cherokee MPI on mine, but it was an 84 and I also did the 4.0 head, which I would HIGHLY recommend doing along with the FI. I did a write up on here about the whole thing, so if you go that way I'll be happy to answer any questions.

Good luck!

Ha! That was the reply from Morris to my question yesterday! He didn't offer any specifics though, so I thought I'd check here. So you are happy with the 4.0 head swap, eh? I'll will read the write up. Thanks!

 

[tinman]

I wondered if that was you before I quoted it...

I love it, and I think any problems involved with that MPFI conversion(year differences), would be solved by doing the head swap.

 

[Lumpy Grits]

IIRC-Part of the changes were some of the head bolt dia.
Not sure about the rest.........
LG

 

[tinman]

IIRC-Part of the changes were some of the head bolt dia.
Not sure about the rest.........
LG

I agree, and that's a fairly simple fix.

 

[Lumpy Grits]

There was something about the coolant passages not lining up on some head swaps also.
LG