2.9 to 4.0 swap

[OrangeMustang93]

ok I've done my research and now I cant find this certain info im lookin for again. I read that you can do the swap using the standard 2.9 wiring harness with the swap. if anyone has any info on this please let me know or know where I can find the info please help.

 

[bobbywalter]

depends on year.

gen 1 has different wiring. gen 2 90 has the same style dash and firewall connector, depending on trans and rpo options it can be plug n play for 91-92 donors though there can be differentials in the fuel pump wiring/routing and lines.

 

[BabyBronco89]

you can use your 2.9 headlight harness, but you will need a 4.0 engine harness and computer, the 2.9 runs a distributor the 4.0l does not, they're two completely different electronic systems.
your year package and options will be helpful in steering you into the easiest swap direction

 

[BabyBronco89]

I've done a few write-ups on this matter search babybronco89 4.0 swap should find my info on there

 

[droland0826]

Using an 89 B-2 the Donor motor is a 97 using an engine harness out of a 93. do I need to get an ECU harness also or can I stick with the existing 2.9 ecu harness

 

[BabyBronco89]

if your going with a 93 your going to have a lot of problems nothing is going to match up at the big white plug you'd be better off with a 90-92 ranger or explorer harness, a lot less pins to swap at the big white plug.
i believe 93 is egr too so thats even more wires to deal with!!

 

[OrangeMustang93]

ok ive got an ecu and engine harness out of a 91 explorer. have engine in and harness's routed. but im not getting any fire to the fuse block inside the cab. has anyone done this swap and can help me with the splicing? such as which system I will be splicing together?

 

[trail B2]

Do you have the plug on the firewall plugged in?What about the fuses in the main fuse box under the hood?Does the wiring diagram show the color that feeds the fuse box does that line up with what comes out the dash side of the plug?The things I'd be looking for anyway.

 

[OrangeMustang93]

Im using the original bronco ii headlight harness with the ECU and Engine harness from the 91 explorer. I have the fuse plug connected at the fire wall. I have no fire to any of my fuses or the power distribution block. Which doesn't make any since to me, unless there is a wire somewhere that needs to be spliced in to the headlight harness somewhere, but like I said I have no fire anywhere except to the alternator.

 

[SenorNoob]

It sounds like you need to run power to the distribution block. It should be connected to the battery side of the fender mounted relay. At least that's the way mine is...

 

[OrangeMustang93]

The only wire coming off the distribution box to the solenoid switch is the the black wire that is grounded on the one of the bolts that holds the switch on

 

[OrangeMustang93]

Yea I'm an idiot. Had that wire grounded instead of going to the switch lol. I have two more problems now. I have fire going to my coil, but no fire out. Changed coil. Same problem. I thinking control module or or crank sensor? Also the only way to get the fuel pump to come on is to hot wire the fuel relay. Any ideas?

 

[SenorNoob]

I'd check for power to the ECU at that point. It should turn the fuel pump on for two seconds when it gets power on an ignition line.

If the ECU isn't getting power that'd cause both problems.