Brian Bagnall

Has anybody out there replaced an 86 ECU with an 89-91 ECU? Later wiring harnesses needed? How to fool the ECU on the lack of elec.oil pump?

Has anyone replaced the 86 AFM with an 89+ retaining the 86 ECU? AFM connectors? Fuel pump switch?

B

13BAce

I put all of the electronics from my 91 turbo convertibleinto my 88 turbo convertible, but I used ALL of the 91 wiring harnesses. I did this to transfer my turbo conversion from one car to another. You MAY be able to do it without changing all of the harnesses, but I doubt it would be worth the effort. Nobody has ever really figured out a good way of tricking the ECU into thinking the oil metering pump is working. Why are you trying to do this?

I know people who have used an 87-88 TII AFM in an 89-91 TII, but I forget how they did it. You have to splice some of the wires together.

HWO

unless you are going from a n/a to a turbo i cant see the point, in fact you would gain NOTHING what so ever, you would spend hours and hours with no gain. why on earth would you even consider doing such a thing? both OEM computers SUCK, they are right royal crapola, they cant control my ****, let alone my engine.

13BAce

I agree. The main difference in power between 86-88 and 89-91 cars comes fromt the higher compression rotors and the better intake manifold, not the ECU. The air flow meter on both cars is actually a huge restriction to air flow.

Brian Bagnall

I agree these AFM's and ECU's arn't like aftermarkets,but under SCCA CSP and ITS competition rules they're all I can use on my 86 NA. The later AFM (cone)does flow better than the earlier(flapper),and the later ECU has better mapping and twice the processing speed. Is it worth all the effort? Yes!Every bit helps!
The motor is stripped off all the crap. I'm only concerned with the AFM,water temp sensor, Air temp, TPS ,O2,crank angle sensor etc. and the absent elec. oil pump.I'd like to here from anyone with practical experience with this, and anyone with a good suggestions.
AS for anyone having trouble controlling their ****, I'd suggest maybe a down pipe,or catalytic converter.
B

HWO

do you have to use the original chip?

13BAce

That's what I was going to ask. If they don't check then just get an ECU upgrade.

Brian Bagnall

There may be a rule change concerning the ECU and upgrades,which would be great. I'd still be limited on the AFM. The 89+ has a different connector, The resistance values on the meter I think are the same,but the fuel pump switching is different.
If anyone has a 89+ workshop manual, I could use a copy(attachments) of the emissions electrical Schematic showing the AFM wiring and also the AFM check resistance values.
I appreciate everyones help. Trying to keep all those BMWs,Acura's and Nissans in my mirrors!
B

HWO

i still say rempaed replacement chip

turborotor

iTrader: (1)

You got to remember the variable intake runners in the 89+ n/a. That makes up part of the hp and help it rev up to a higher redline. The ecu controls the actuator to the runners via a vacuum and solenoid.

I think is a lot of work to make it worth it. you got to change at least the passenger side harness and all the sensors. The fuel injectors clips are different I think, they are the round plugs not the square plugs. So you'll probably have to use the 89+ injectors or splice in the old square injector clips. YOu'll also have to use the electrical omp.
Probably the other side of the harnness will not plug in to the 89 ecu because it could have a different type of plug. This side of the harness is where it receives the signal from the crank angle sensor and outputs to the coils. You'll have to do a lot of splicing I believe. You might end up

I know a guy at the club that just changed his 87 intake to 89+ style and gain more top end. His name is jeff wosniak (don't know if I spelled it right) he might be on this forum.

C

Brian Bagnall

Thanks,C
I Think you're right about the amount of work involved. I have already changed the intake to 89 + with the rotary valve locked in the short runner position. I know a way to make this operable. I 'd like to figure out a way to make the 89+ AFM adapt to my early setup.
Thanks,B