Archived Tach problem in my 93

[paccool]

Posted this in the first gen section but thought I'd try here as well in case some former first gen owners see it and can help.





I had a set of gauges installed about 1 1/2 years ago at Camping World. The boost and Pyro work good, they could never get the tach to work. I tried a different tach, I replaced the crank position sensor. I talked with Piers a few weeks ago at the Norcal get together and he said there had to be a special harness installed or it wouldn' t work. ordered a new harness, found out there was one installed already, replaced it in case the filter was blown.



Tomorrow night I'll check for 12 volts to the tack, the ground is ok as the light works.



My question is - does anyone know what the signal is on the gray/ blue wire at the plug for the tach? I want to be sure there is a signal coming from the ECM. If there is, the problem almost has to be a bad tach. Also want to be sure the installer didn't short something out under the dash.



Anyone out there know anything about this problem? HELP!!

 

[RamAZ]

I went through the same thing that you are with the ISSPRO tachometer.



I checked everything that there was to check and finally bought a new Isspro tack and installed it myself. I took the original tack back to camping world and they bought it back.



I bought the new tack from a speedometer shop and they said that it was not unusual for ISSPRO tacks to go bad or be bad right out of the box. When this one goes bad and it will, I will purchase another brand for sure.



The morons at Camping world said that there was no signal and it had to be something wrong with the controller. I will never have anything I own worked on again by the so called technicians at camping world.



Jim

 

[paccool]

Jim,



I checked the 12volt hot lead, had 13. 5 volts with the engine running. Checked the tach signal lead with a digital voltmeter, haad about 5 volts on DC scale and 11 on AC scale. Since this is a pulsing signal I didn't know which scale to use so I did both.

Tried bypassing the filter as Steve recommended, didn't make any difference.



Guess this means the tach is bad. I have another ISSPRO tach, goes to 6000 RPM, will try hooking it up tomorrow night to see if it will work.



Thanks for the help.