Can't find the wiring right now but I did notice the red-line's are at different rpm's. I don't know jack about Sunbird engines but the two red lines make me think there are 2 versions of the turbo engine. Do you have the proper Turbo Tach? Your tach is different then the ones I posted below.



Respectfully borrowed pic.
Spoon


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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

[This message has been edited by Spoon (edited 06-05-2023).]

Fresh pics below show 2 Turbo tachs with less increments. Both red-lines are at different rpms. Yours at 6500. The other at 5500. That's the difference I was trying to show. The The Turbo tach with more increments also red lines at 6500 rpm. So that makes (3) versions of turbo tachs so far.
Emphasis is where the red line rpm area begins.
If I'm leading you down the wrong path please make me understand. I welcome and respect criticism.

ps: I also recall Chevy having a small pickup truck with a Turbo Tach.


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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

[This message has been edited by Spoon (edited 06-06-2023).]

quote Originally posted by Spoon: Fresh pics below show 2 Turbo tachs with less increments. Both red-lines are at different rpms. Yours at 6500. The other at 5500. That's the difference I was trying to show. The The Turbo tach with more increments also red lines at 6500 rpm. So that makes (3) versions of turbo tachs so far. Emphasis is where the red line rpm area begins. If I'm leading you down the wrong path please make me understand. I welcome and respect criticism. ps: I also recall Chevy having a small pickup truck with a Turbo Tach.

That's alright it looks like we're making headway here. So there's 3 turbo tachs that have this overall look. Does anyone know why there seem to be 2 of these with the 6500 redline? Your next idea is there's a truck that had this, I don't remember a GM 4-cylinder turbo truck or something. Only other turbo GM vehicle I can remember from that era is the Grand Prix GTP from 1989-1990?

Next thing I'm doing, I just looked at this thread on my 43" 4k computer monitor and I can read the traces on the other tach pretty well (up until now I was using my phone). I'm going to try to compare that with the 1 I have and see if I can make sense of the differences.

[This message has been edited by sdgdf (edited 06-06-2023).]