1991 aw4 trans question

badgator · Jul 11, 2008

From what I found out searching here the 1991 4.0 aw4 uses the Power / Comfort switch like the 88/90.

Does the 1991 use the same wiring and transmission control unit - tcu as 88 and 90?

poorboy_616 · Jul 11, 2008

I think it does, but don't quote me on that....

cal · Jul 11, 2008

The power/comfort switch is a feature of the TCU and not the transmission.

And yes, you can swap the 91 and 90 transmissions to get 23 spline on your renix rig.

lawsoncl · Jul 12, 2008

I believe all of the Renix era TCUs are interchangeable. As I recall, they can be identified by having the grey connector. The OBDI units have a green connector.

cal · Jul 12, 2008

lawsoncl said:
I believe all of the Renix era TCUs are interchangeable. As I recall, they can be identified by having the grey connector. The OBDI units have a green connector.

Right, but 1991 being OBDI, he was asking if it was compatible with a renix transmission.

Ecomike · Jul 12, 2008

badgator said:
From what I found out searching here the 1991 4.0 aw4 uses the Power / Comfort switch like the 88/90.

Does the 1991 use the same wiring and transmission control unit - tcu as 88 and 90?

The TPS and ECU changed in 91, thus the TPS input to the TCU changed in 91. In 91 the TPS input to the TCU comes from the ECU, in 87-90 the TPS input was direct into the TCU, so the TCU pin out and wiring input went through some sort of change between 90-91.

lawsoncl could could give you more exact details I think.

Also the TPS voltage signal input to the tps in 87-90 was the reverse 0f 91 and up TPS output.

lawsoncl · Jul 13, 2008

cal said:
Right, but 1991 being OBDI, he was asking if it was compatible with a renix transmission.

Doh. That was a brain fart, thinking 91 was Renix for some reason. Ecomike is correct that the TPS voltage signal input to the tps in 87-90 was the reverse of 91 and up TPS output. The connector was almost identical except the color and the "keying" which could be shaved off with a exacto knife. THe only wiring change was that the diagnostic lines changed to obdI instead of a serial output to yellow diagnostic block for the renix.

So the tranny is identical between the years, and the few differences in the TCUs.

lawsoncl · Jul 13, 2008

Actually, if you're swapping an HO head onto a Renix you could probably swap to the HO version of the TCU and splice the two TPS signals together at the sensor (just the signal line, not the power). That would let you use the HO throttle body TPS sensor. I've seen some interesting jerry-rigged contraptions to put the dual output sensor on the HO throttle body!

cal · Jul 13, 2008

lawsoncl said:
Actually, if you're swapping an HO head onto a Renix you could probably swap to the HO version of the TCU and splice the two TPS signals together at the sensor (just the signal line, not the power). That would let you use the HO throttle body TPS sensor. I've seen some interesting jerry-rigged contraptions to put the dual output sensor on the HO throttle body!

One of our locals runs an HO TCU on his renix rig with a renix TPS, spliced in.

1991 aw4 trans question

badgator

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cal

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cal

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Ecomike

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cal

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