General 90 Manual ECU in 91 Automatic?

[hippy]

I have a 91 Eagle Talon TSi awd turbo auto and the ECU just went but a i got a good one of a friend its a 90. I got the diagram to switch the 2 wires over pin 6 and pin 14 but my question is will the manual ECU work alright in the auto? Thanks!

 

[95burgundyesi]

Yes, there is a TCU that controls the automatic trans.

 

[90laserRSfwd]

Yes, there is a TCU that controls the automatic trans.

and NO, because the auto cars came with 390cc injectors and the M/T cars came with 450cc injectors.

 

[steve]

The manual ECU will make the car run but it will have issues.

The injector issue is a minor one that will cause the car to be leaner than normal when it's open loop.

Corrected for fuel pressure the auto injectors is SQRT(42.7/43.5) * 390 = 386.4 cc/min
Corrected for fuel pressure the manual injectors is SQRT(36.3/43.5) * 450 = 411.08 cc/min

411.08 / 386.4 - 1 = -0.0638 = -6%

So ignoring the differences in timing and fuel maps between the two ECUs, the manual ECU will deliver 6% less fuel when running in a automatic car than expected.

The Manual ECU won't watch the park-neutral switch for idle control. This may cause idle issues when you shift into gear or surging when you shift out.

 

[hippy]

so what if i stuck a set of 450's in it im sure i have a set laying around!! Then would that fix the problem??

 

[steve]

so what if i stuck a set of 450's in it im sure i have a set laying around!! Then would that fix the problem??

No it would make the fueling issue worse in the other direction (Rich) and do nothing for the idle control issue.

Best bet is to fix the auto ECU, followed by swapping both the injectors and FPR from the manual car with the ECU, followed by using the manual ECU and leaving the injectors alone.

 

[hippy]

Well i just liek to get it running decent to sell. So ill see how it works with this. Thanks alot and can any one fix the auto ecu if i sent it to them it wasnt turing the injectors on!!