E4OD/Tach Problems

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Mar 12, 2015 | 06:20 PM

#16

1972RedNeck

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From: Townsend, MT

Quote:

Originally Posted by ifrythings

It's not the wires between the tach and TCM, you can short out those wires all day long and the tcm will just go into tach less mode and shift late. Your problem sounds exactly like the tcm is loosing ground and reseting, the tcm controls the ground side of the shift solenoids and the eec relay supplies the power side, the ground is on the rad support but you can also run a wire from battery negative to I believe pin 60 or 59 which should be a thicker black wire with a white stripe or just black, check/try that and let us know what comes of it.

Thank you much for the tip. I will definitely try that.

Oh, and how are the pins numbered?

Mar 12, 2015 | 06:38 PM

#17

1972RedNeck

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From: Townsend, MT

Quote:

Originally Posted by Mark Kovalsky

I know that, you've said that. I think the problem is in the wiring not the sensor. But if you want to chase other things, that's fine with me.

So are you saying that a tach wire could be shorting to another wire? If yes, I understand now. I am a *little* thick headed at times.

Mar 12, 2015 | 08:57 PM

#18

1972RedNeck

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From: Townsend, MT

In the past two hours, I have done the following:

Ran a new ground wire to the TCM = still hunts
Tried to find something wrong with the tach wires. I couldn't find anything wrong and I was getting a little irritated so I took a pair of dykes to the tach wires at the TCM = still hunts
Pulled the EEC relay and powered the TCM with a wire directly to the battery = still hunts

The thing that confuses me is that everything works great (even the tach before I nipped the wires) when at WOT or almost WOT.

Ideas?

Mar 13, 2015 | 06:56 PM

#19

1972RedNeck

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From: Townsend, MT

Does anybody have any other suggestions of what to try next?

Mar 15, 2015 | 04:14 PM

#20

speedwrench72

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From: western washington

your speed sensor is mounted on tranny, on the speedo cable, its $16 replace this. your speed is compared to tach to adjust shift points, after 92 they went to sensor in rearend....

Mar 17, 2015 | 06:53 PM

#21

1972RedNeck

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From: Townsend, MT

Quote:

Originally Posted by speedwrench72

your speed sensor is mounted on tranny, on the speedo cable, its $16 replace this. your speed is compared to tach to adjust shift points, after 92 they went to sensor in rearend....

Thanks, I'll give it a shot.

Mar 21, 2015 | 02:07 PM

#22

1972RedNeck

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From: Townsend, MT

Quote:

Originally Posted by speedwrench72

your speed sensor is mounted on tranny, on the speedo cable, its $16 replace this. your speed is compared to tach to adjust shift points, after 92 they went to sensor in rearend....

So I stopped by Napa on my way through town today and picked one up. I changed it out and guess what?

IT WORKS LIKE A NEW MACHINE!!!!!!

You have no idea how happy I am right now. I soldered my tach wires back together so my lockup works and the tach never jumps.

I owe speedwrench big time.