tachometer
01-22-2005, 03:45 AM
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tachometer
hey all, I just got an 84 944 that I brought back from the dead but I think it still needs to be revived a little. The tachometer currently doesn't function. Does anyone have a clue what it might be? All the other gauges seem to work well. Thanks all any help will be appreciated.
01-23-2005, 06:48 PM
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Bump for a better explanation of the signals the tach recieves and how to check?
Buddy of mine is having the same problem, and has done some searching, but not come up with much, other than the signal comes from the DME, and it might come from 3 different sources. (might be getting this part wrong) Anybody done any tach troubleshooting? Other than the "throw parts at it" troubleshooting type?
Buddy of mine is having the same problem, and has done some searching, but not come up with much, other than the signal comes from the DME, and it might come from 3 different sources. (might be getting this part wrong) Anybody done any tach troubleshooting? Other than the "throw parts at it" troubleshooting type?
01-26-2005, 11:27 AM
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I am the other guy having the same problem. I have looked at the wiring diagrams for the car tying to figure out what is the input that drives the tachometer. From the diagrams:
one wire (green & black) goes to the DME Plug
one wire with connections goes to the central warning light
one wire with connections goes to ground (i think)
At the DME there are three connections that could be the signal
1. A green wire from the ignition coil
2. the speed mark sensor
3. the reference mark sensor
I do not know if I am headed in the right direction. I would like to know more or have a troubleshooting guide to fix the problem.
thank you
one wire (green & black) goes to the DME Plug
one wire with connections goes to the central warning light
one wire with connections goes to ground (i think)
At the DME there are three connections that could be the signal
1. A green wire from the ignition coil
2. the speed mark sensor
3. the reference mark sensor
I do not know if I am headed in the right direction. I would like to know more or have a troubleshooting guide to fix the problem.
thank you
01-26-2005, 01:20 PM
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Sort of the same problem. I have an early. When I started up the car after it sat for four years, tach didn't work. Tested the tach and it was bad. Replaced it with a tach from an 87 924S. Now when the tach is connected the needle "floats" and the 2nd rad fan runs all the time....I've been running without it since I have other projects to work on and I don't even know where to start diagnosing this mystery.
02-02-2005, 11:03 AM
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I went to the only junk yard in the area with a 944 and paid $20 for the gage cluster. I cleaned the old tach up and installed it. To my surprise it actually works.
The original tach did not have the MPG gage and the junk yard tach did, I was concerned that the MPG gage would not work on my car, but it also works.
The original tach did not have the MPG gage and the junk yard tach did, I was concerned that the MPG gage would not work on my car, but it also works.
