3000GT TCU in a Talon??

[josue91FWD]

Just bought a 1 owner, 46kmi 1991 TSi FWD auto, stuck in 3rd gear/limp mode. The guy was selling it for his mom, who just didn't want/need it after her husband fell ill and passed away. The timeline is hazy, but it obviously did a TON of sitting around...and at some point, went into limp mode.

The son/seller did some research, and of course the first thing you see with this issue is, a bad TCU. He sent it out to Crites Core Company in Spencer, IN for repair, but said they kept his stock one, and sent him a refurbished replacement instead. It did not fix the issue. He gave me the tip that the company suggested....that the ECU's can go bad when cars sit for prolonged periods of time with no juice to them. (I don't believe they kept a tender on this thing...just let it die all the time) Sounds plausible enough, so I was all set to send this ECU off to the same company for inspection/repair.

Doing my own research here though, I took notice of the part number on this TCU....after having seen the info posted on here that a 91-92 Turbo FWD should have a MD750093 TCU. This one has a MD740087 TCU....which Google says is from a Stealth/3000GT?!

Should my diagnostic plans stop right here until I get the proper part numbered TCU? Doesn't seem to me that the 2 would be interchangeable.....but I have no knowledge of the matter to back up that theory.

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[josue91FWD]

Welp, got a solution I figured I'd throw out here, in case someone runs into this down the road....

Found a MD750092, 90-92 AWD TCU at the Shootout for $50, so I figured it was worth a shot to try. Wouldn't you know....I guess a 3000GT TCU will NOT work in a Talon, cause it drove fine with the 0092! I read that the shift points are different between the 2 drivetrains, but since I got the car this way, I have no base line knowledge of where it should be shifting. So, for all I know, it's normal to me.

I'd still sleep better at night knowing the correct 0093 TCU was in the car, so I'll continue to look. But, at least I can enjoy the car in the meantime!

 

[steve]

If you look at some of the other TCU threads you will find that there is a 47uf capacitor in the TCU power supply that leaks and kills them. If you have a good TCU you want to make sure that cap is replaced before it can kill yours.

 

[josue91FWD]

Absolutely. It would be nice to know for 100% sure that, this won't happen again (for a long time at least). This will mostly be a mild street build similar to how we did it 20 yrs ago when I had my last Talon, so I'm not too interested in a shiftbox or anything like that to get rid of the TCU all together.

Do you know of any services that can do this? I'm coming up empty in my searches. I have a line on a couple 0093's, but I'd definitely get them inspected and rebuilt before installing one.

 

[steve]

Do you know of any services that can do this?

Not anymore. The capacitor replacement is not difficult but two factors stopped me back when I was doing ECU work. The first was testing and the second was that most of the TCU's that came in were already dead from this capacitor leaking. If you have a working TCU the hardest part of changing the capacitor is releasing the power resistor(s) from the case so you can get at the bottom to unsolder the cap.

 

[josue91FWD]

Gotcha. At least I can take this information to someone who might be of service locally, and see if it's something they can tackle.

Thanks!