I am in the process of putting an engine out of an 89 4runner in to an 86 x cab I thought I could just swap the wiring harnesses but I was wrong has anybody else ran into this? or does anybody have an easy cure? everything plugs in ok except one plug, it is one of the two that are not plugged into the computer here is a pic of the two different plugs, the yellow one is the one that matches the truck but the grey plug is the one that is wired to the engine. and it does not look like I could just swap the harnesses because it does not look like all of the plugs match. ANY help would be much appreciated.

Jim

 

You've bitten off a much more major project than you think.
The 86 is going to have a resistor pack in line with the injectors. I don't think the 89 has that, as it *should* have high impedance injectors to begin with.

Translation: The harness, ECUs, and EFI shouldn't be mixed and matched. Bad things may happen.


My suggestion would be to use the harness from the 86, the ECU from the 86, and the injectors/sensors/engine accessories from the 86. Using the longblock is fine.

 

So much for a simple engine swap/ do you think I could just swap the harness and computer?

thanks for the help

 

I'm not an expert on the harness, but I believe the engine harness looks fairly self contained to me - it does include some wiring for gauges and sensors - so I can't tell you the easiest way to to it.. Might check for "22re efi swap" on pirate - I bunch of people have done it.

Worst case, you can buy a stripped down OEM harness "painless wiring" style for around $400.

 

Just use the engine from the 89, and all the electrical and intake from the 86. You cant use the 89 harness with the 86 computer. There are a number of different sensors, and things like the throttle body may even be different.

 

Ya like everyone said i don't know why you would have changed the harness?? You are bridging a generation gap. Mechanicaly they are the same and most electrics are the same but the wiring is different. The only thing you need to change on the 86 is the injectors from it. So take your 89 and put the 86 injectors in it and you are good to go.

 

OK got the intake and harness swapped out and done it is running but it will not idle. and adjusting the idle screw makes no difference. the problem prob has to do with nost of all the vac lines have been plugged on the intake being used. any ideas on what might not be hooked up that needs to be?

 

Which wiring harness are you using?
Which ECU are you using?
Which injector set are you using?

Will it run and just not idle?

 

all off of the 86 it will run above 2000rpm but below that it runs real rough and will not idle . the bad part is most of the emmision stuff has been removed and vacuum lines plugged so i don't know if something is not hooked up that needs to be or that something is not getting vacuum that is supposed to or vise versa

 

Swap the narness and change the injectors. The 86 uses lo resistance injectors, 89 uses high. Low will work in place of a high for about 23 days and burn ou tthe driver in the ECU, other way around, it wonr run. Lo resistance measures about 2-3 ohms, high is about 13-15 ohms. I susgest using the original harness. I suspect the injector connector will be different forcing you to swap injectors.

 

Found a vacuume leak and that cured the idle problem but now I need to figure out why it is running like a carb motor with the choke stuck