4.0 head swap parts pull help

[justinfonder]

hey, i'm wanting to do the 4.0 head swap/efi on my 81 CJ5 AMC 258 i6 / 4.2l . I found a guy with a 93 cherokee sport 4.0 that is going to let me take what i want for $AMC 150 . can someone give me a comprehensive list of things i should take. I already have a serpentine setup on my jeep, but i may take his just to have spare parts. i would like EFI as well, is this a good year to use for this? any and all info will help. thanks guys

 

[jasonmark1993]

Going to EFI is going to be a lot of work.

If he will let you do it, I say go for it because youre going to be taking thousands of dollars worth of parts.

Someone may say different, but I'm sure 95 is as good a year as any.

When you are taking the head off, keep everything that you remove to get it off.

Intake, bolts, valvecover, everything.

To go to EFI, you're going to need pretty much the whole harness, ECM, fuel pump, fuel lines,.....

Not sure what the norm is for this upgrade, to run the in tank pump you'll probably need his tank. It may be easier to run an external pump but you'll still need his lines and then have to modify something on to your tank.

 

[Sasquach]

Head, head bolts, injectors, valve cover, exhaust header, intake, fuel rail, throttle body, enjector harnes/engine bay wire harness, computer, charcoal canister, throttle cable, distributor, intank fuel pump?
+ whatever I forgot.

 

[IOPort51]

give him $250 and take the silly thing home with you.

 

[sponge]

It has been 7 years...so I am rusty...

I think it has all been covered except don't forget to get the vss off the bell housing and keep its bracket. I would say pull every single thing you can or think you will need...

I think 92 is the last year of ODBI and why I went w-a 92 harness, ecu, and fuel rail...

I ran an external pump.

The site I use to mod on had a complete write up on this swap...but the owner of the domain went MIA...I bet if you google cjoffroad.com 4.0 write ups your bound to find repost of our old articles and write ups...

 

[jasonmark1993]

Pretty sure OBDII was later than that; but not sure.

It'll say on the sticker under the hood.

I agree with Sponge, I'd prefer an OBDI due to its simplicity.

 

[doublec]

The Cherokee OBDI was from 91 to 96. I pulled a doner head from a 91 Cherokee. Look for a 7120 marking on the middle of the head - drivers side, this is considered a high output head. You can google for other numbers that are consdiered high output also.

If you decide to use the MPI there are a lot of wires in the harness not used. Attached are some drawings I did to help me figure out what is needed and what is not.

The one item most forget to grab is the ballast resistor. You can bypass it, but it's used to help the fuel pump run quieter and cooler.

View attachment ECU PIN CONFIG.pdf

View attachment ECU.pdf

 

[sponge]

Yup I bypassed and it is LOUD and I think I really used less than 10% of the wires....