4.2 Fuel Injection Conversion

Gary747

Member
Supporting Member
Joined
Nov 7, 2020
Messages
53
Location
Lancaster, CA
I had my 1990 4.2 with a two-barrel carburetor converted, and it went extremely well. At the time, Mopar sold a kit to make this change but it is no longer available. It was worth it regardless of cost as the 1990 4.2 vacuum and emissions systems were extremely complicated and unreliable with many aging parts that were no longer available. In California, it was getting very costly to pass the Smog testing.

All has been good since the conversion, including one engine change not related to Fuel Injection. The entire system moved right onto the new 4.2L long block.

The conversion included a computer control that turns the fuel delivery system essentially into a 1994 4.0, except, the engine is still a 4.2.

If I had it to do over, I'd do it in a flash. I only regret not doing it sooner.
 
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clint551

New Member
Joined
Mar 17, 2023
Messages
2
Location
Arizona
Has anyone done a EFI conversion on a 4.2L? Worth it? Issues?
Did you end up switching to EFI? What system did you purchase? I am failing emissions on 89 wrangler I just bought , seems like best way to guarantee it will pass and continue to pass in the future
 

Gilaguy23

YJ Enthusiast
Joined
Apr 12, 2021
Messages
835
Location
Q town New Mexico
Yes, at that time I lived in Commiefornia. The leader of all that is screwed if it runs on fossil fuels. IIRC and likely still there was 2 kits. One was CARB approved and came with the sitcker with the CARB reference number so the goons at the smogs shop would know its Ca approved. It also cost more.