ok so i have a 91 toy 3.blown and i want to swap in the 302 out of my 89 mustang. ive been reading up on everything i could find and found a lot of good info. my question is how to do the wiring. i know that the mustang has basically three harnesses...injectors harness, O2 sensor harness, and the return harness to the ECU. but what i don't get is how it gets tied into my toyota so i can use my guages and warning lights and such ?

im trying to make smog legal in cali.

 

anyone i know a handfull of people on here have done this swap i just want to make sure i have everything straight before i start cramin

 

It's really not difficult to recover the factory wiring harness from a 5.0 EFI. Most of the wiring is to/from the ECM and goes through its own hole in the firewall. That just leaves the loom that goes to the drivers side dash, and there's only 5 or 6 wires that connect to anything. Everything else is for sensors and chassis wiring and can go.

As for the dash, just use the Toyota senders, recalibrate the tach (search), and wire up the check-engine light.

91 Toyota and 89 Mustang? California isn't going to like that. That's federal EPA law, but most states will let you slide unless it's blatantly obvious that the engine is older than the car. I heard that California won't.

 

Not trying to discourage your swap, but I've done some research in this area and CA does not make the swap task any easier.

1) Any engine swap (unless it is the identical engine as was supplied by the factory) will require a referee visit.

2)The engine must be from the same year or newer and have ALL the emissions equipment which was originally supplied with the donor engine from the factory.

3)If the donor engine is computer controlled (OBDI or OBDII), the diagnostic port must be installed and operate properly.

There's a few other small requirements as well, but you get the picture.

Good luck.

 

yea i already figured out the smog issue and i just need to get is checked by a ref and the engine needs to pass smog requirements for the mustang the only reason i am able to use the older engine is because the smog req. for my runner is the same as an 89 runner.

 

dont think it should be too hard actually. there is plenty of room in the engine bay. just make sure that your exhaust manifold is stock too. thats one that most people pass up. im looking to put a 4.3 in my 86. my last car was an Evo 8 with about 320whp so this 90 crank hp isnt doing it for me up hills. i at least need 200. plus it will be a desert toy in a year or two.