TWS

iTrader: (63)

This is the closest forum to electrical issues, so I'm posting here(and in fact this may be a PCM issue).

Recently my '99 Z28 started doing the following:

Every time I start up the car, the tripometer resets to zero, (without touching the reset button).

Second weird thing: sometimes when I start the motor, the the tach and speedo needles do a "sweep" across the range of the gauges. This happens on start up of the motor, not when I merely have the key forward. I know that the Granatelli gauge cluster does this intentionally, but I'm talking about a bone stock instrument panel. (It should not be doing this).

I am not getting a SES light or any other indicators. This began occuring after I had the battery out of the car a couple times within a couple days' time span. I currently have the Odessey dry cell in there, but it shows excellent voltage and amps. Car starts and behaves otherwise as if a full-size battery was still there.

Any clues on what to do? I took a quick glance through the fuse panel, but otherwise have not tried to diagnose it. I guess I could throw the full-size battery back in and see what happens, but I don't think that's the issue. I have NO starting or charging problems with the Odessey. Like I said, it's like it's not even there.

Welcome any suggestions. Thanks!

Team ZR-1

I would check for a bad ground wire at the back of the engine or elsewhere. This would cause under voltage to the PCM and PCM to protect the engine running will shut down other devices such as dash gauges.

Also a bad cell in battery would also cause lower voltage and the PCM is designed to monitor voltage levels and if its too low then it does what it can to keep engine running.

Also under drive pulley, causes too low of output to Alt and these cars today need lots of D/C voltage and current.

NoGo

iTrader: (2)

A long long time ago there was a TSB out for something like this (gauge cluster sweeping, odometer reseting). I don't remember exactly though.

There are 3 grounds on the back of the driver side head that you could check. They are a pain in the butt to get to, but they can cause alot of odd gauge cluster stuff to occur if not connected properly.

Good Luck

felton316

When mine did this, it was the bad cell in the factory battery. Replaced it, and its been fine ever since.

Smitty

Mine was doing the same thing,and had to have the cluster replaced while the car was still under warranty.There is a technical bulliten on this for '99 cars only...says to replace cluster assem..Hope this helps.
Tony

TWS

iTrader: (63)

Guys, thanks a lot!

Anyone have the TSB or know where I can access it?

Thanks again!

Smitty

Here is the TSB#,may have to stop by the local dealer.They should let you look at it.
Technical Service Bulliten # 99-08-49-009,trip odometer-automaticaly resets to zero
Tony

TWS

iTrader: (63)

Tony,

thanks a lot, man!

I'll do a little trouble shooting myself, as soon as I get time. If I can't find anything, I'll take it in and quote that TSB.