[pSun]

Hello,

I am currently working out some kinks in our 90 Plymouth Sundance, 2.5 liter TBI, with the A413, 3 speed automatic transmission. The tachometer isn't currently working and my previous attempts to repair have failed (so far).

I have been told that while traveling with my 3 speed automatic transmission in 3rd gear @ 65 mph, the engine is turning "approximately" 2,800 rpm, near or at maximum torque.

What I would like a bit of help with is the following:

1) At what vehicle speed in 1st gear, is the engine making 2,800 rpm? Lets call this vehicle speed A.
2) At vehicle speed "A", if I shift manually into 2nd gear (without increasing the vehicle speed), what rpm is the engine turning (in second gear)?
3) At what vehicle speed in 2nd gear, is the engine speed 2,800 rpm? Lets call this vehicle speed B.
4) At vehicle speed "B", when I shift manually into 3rd gear (without increasing the vehicle speed), what rpm is the engine turning?
5) At what vehicle speed is the engine rotating 2,800 rpm in 3rd gear?

I don't expect anyone to know these numbers off the top of your heads, so I am actually asking you to, perhaps, today or tomorrow, while running a local errand or driving to work, if you (whomever doesn't mind) don't mind doing a stranger a small, seemingly ridiculous favor, to check these vehicle and engine rpm speed for me.

 

[pSun]

FELLAS!!!

Thank you so much for even being interested enough to assist me! I was somewhat uncomfortable throwing out "an" assignment for non-involved members to bite on.

John Wood: thanks for taking the time to real world what you could.
Bob Lincoln: thank you for having thought about my dilemma before it happened. I will pull the board again and check the P/N. I can get a hold of replacement used boards and the actual speed o mechanism. Sounds like it is the board; there was a peculiar "red" marker, mark near one of the capacitors on the board. This made me think that perhaps the previous owner had it looked at and a discrepancy was unearthed.

 

[pSun]

Bob it is completely non-active, "dead", the needle rests on the peg. The illumination lamps are working, that is it.