Bad module? - Third Generation F-Body Message Boards

eric17422001 · 12-16-2002, 10:15 PM

I tried this on the electronics board and didn't get a bit so I'll try it here.

About two months ago, my auto gage (low end Auto meter) tach would periodicly bounce from the cruise RPM to redline and back. It cot worse and worse, and finally died after a night of several drag strip passes.

I replaced it with a new Auto gauge with shift light in the dial.

All was well until the first road trip. After an hour on the interstate at 3000 RPM it started. A couple of bounces, then back to normal for a few minutes. Then all over again.

I have been given two scenarios, one, the cap is arcing inside, and two, the module is going bad.

I have looked at the cap (stock HEI, coil in cap) and seen no evidence of this, I have no appearent shorting plug wires. The enine has no misfire and runs great. I can find no bare insulation on the tach signal wire. The tach shares a ground wire with two other gauges that have not exhibited any problems.

I have disconnected the unit to save it from damage.

Any ideas?

Eric

88305tpiT/A · 12-16-2002, 10:21 PM

you said you had stock HEI coil in cap dissy right?

if this is true then you should be taking the tach signal right off the cap and the coil.

I would do the standard OHM checks on the coil to see if it is good.

then check all your grounds and connections associated with the ignition.

I know that sound like alot but I had ignition problems related to what you are describing and connections and grounds were a big part of the problem.

Denis.V · 12-17-2002, 01:47 PM

Bad module? = probable code 42 at the scanner.

Check for error codes.

(I'm running with a bad module + code 42 today. Replace?: I need more $$$).

Regards,

Denis V.