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Speedo issues with trans swap

3K views 16 replies 4 participants last post by  Performa 
#1 ·
I recently put a Verde Trans in my '83 GTV6 assuming that I could find info to get the speedo working. Alas, I have scoured every forum, purchased a Dakota Digital signal thingy and have had no luck getting any signs of life out of my speedometer. The transaxle has a new sender, tried 2 amplifiers to no avail. I'm convinced it is the transaxle side of the Digital decoder as I can get a signal from the decoder to my Speedo. Has anyone had any success with this? Specifically, the older GTV6 Speedo? If you have a definitive answer I would love to hear from you before I go scouring the globe for a late GTV6 Speedo with Hall Sensor (It's my understanding this works) Or, if you have some other clever solution, I'm all ears!.......... I'm losing it men

Grazi,

Greg
 
#2 · (Edited)
I have done two for Milano transaxles in '84 and 85 GTV6's and I wrote up the details. I can also test Milano senders and amplifiers and I have repaired two or three amplifiers. I updated the thread a few weeks ago.

None of the Milano or GTV6 speedometers use a Hall sensor, that is in the distributor.
 
#3 ·
I have confirmed the parts I have are good. Again, looking for anyone that has had success with the early style speedo. Specifically '81-83' my understanding is they are different than the later models. It's also my understanding that there is a hall effect sensor on later speedo's (not associated with the distributor in any way). It is used to detect pulse via the sender.
Correct me if I'm wrong?
 
#4 ·
Correct me if I'm wrong?
You are wrong. It is an inductive sensor in late (85.5 & 86) GTV6's and Milanos. It is a gear driven magnetic pulse generator in the earlier cars. The late GTV6's had the electronics built into the sensor and they were unreliable. Milano's have their electronics in a separate "amplifier box. I have posted the electronic schematic.
I don't see why your 83 would have a different speedometer than my 84 since they both originally had the same pulse generator sender.
 
#7 ·
Update

I never figured this out so I went with Dakota Digitals GPS-50-1 speedo sender. It's easy to install (under rear seat) and all it needs is AC power, constant hot from the battery and signal wire from factory speedo. The antenna is inside the unit (unlike some of the other GPS units) and has no problem staying connected in this location. After powering up, the unit sends a 60mph speed signal so you can calibrate , if necessary, the factory speedo. Mine was off by 10mph so I drilled a hole on top of the speedo to access the potentiometer, There is about 15mph of adjustment so it was easy to dial in the 60mph signal. It now works perfectly and is accurate. Odometer was unaffected and works great also. I highly recommend this to anyone that has made the swap and or has an inaccurate speedometer, The unit costs $199 available directly from Dakota Digital. My only complaint is that there is a little lag at a standstill to about 20 mph but it's only for a brief moment.

Here is a link to the unit:
https://www.amazon.com/Dakota-Digit...sr=8-1-fkmr0&keywords=dakota+digital+gps+50+1

If you need more details, let me know.

Cheers
 
#15 · (Edited)
You also need a late model GTV6 speedo and that was the deal breaker for me.
The GPS unit is accurate and interfaced with my 83 Speedo. On a separate note,
I have 2 perfectly good milano senders and 1 sgi-5 unit if anyone is interested.
I will let them go cheap! (free to someone that can make them work with an early speedo and post the results)
 
#16 · (Edited)
You also need a late model GTV6 speedo and that was the deal breaker for me.
Not so. Mine is an 84 and it has the same speedometer as all GTV6's up to the late 85's and 86's. I have a couple of spare Speedometers from 81-84 and they all work fine.

I re-read your posts and I see no information on how you determined that your amplifier is good. I have repaired a couple with blown transistors, probably caused by shorting the output to ground.
 
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