Dave Simkus

Every time I start my 99 Trans Am, the Speedo and Rev dials go up all the way and down as well as my trip computer goes back down to 0. It's like it resets every time I start.

ULTIMATEORANGESS

iTrader: (4)

mine did that when it was new. my gauge cluster was replaced under warranty.

MonmouthCtyLS7

iTrader: (6)

W/ a V8 do you really care lol

Firebrian

My '99 SS was doing this same thing on last weekend's errands. I don't recall it ever doing this before. Certainly don't ever recall the trip monitor automatically resetting every time the car was restarted. Had the car 3 years. The speedo and rpm cycling full range during startup didn't seem like anything I've ever seen before. The car had sat for 2 weeks and I didn't give the battery the usual charge I often do. Didn't give it a whole lot of thought....until I saw this thread today. Nice coincidence!

A quick search here and I come up with the thread below. Seems this is a known problem on the 99's. There is a technical service bulletin on the gauge cluster having an issue with a "volatile memory chip." Others have reported that a weak battery or loose batt connections give the same problem. My battery is 6 years old and needed some TLC 2 years ago to gas off a lot of the deposits between plates after it had run way low on water from the previous owner. My batt connections are tight and free of deposits. But did notice some white deposits tracking down on the side of the battery. It might be time for a new one. Will charge it before the next ride, something I do every 2-3 weeks when the car sits. More than likely it's just the battery. The gauge cluster has a weak link where it can't compensate for a battery in a weakened state or lower voltage. The later models apparently corrected this.

https://ls1tech.com/forums/new-ls1-owners-newbie-tech/268901-very-starange-problem-trip-od-zeros-out-rpm-guage-goes-nuts-startup.html

sawblade99Z

iTrader: (1)

Good info. Mine started doing this a year ago and I assumed it was my battery getting a little weak. But agreed with what Monmouth said! After I swapped from the 2.73 geared 10 bolt to a 4.10 geared 9 inch I REALLY stopped caring about calculating my mpg every fill up

Dave Simkus

Hey, thanks for the reply and info. That is a nice coincidence that you had the same thing happen. My Trans Am is garaged most of the time too except on a nice day I take her out. It probably is something to do with the battery like you said. Mine is a few years old too. Thanks for the reply

Dave Simkus

Hahahah Yeah it doesn't really bother me either but it freaked me out, never seen it do that. It started after I got a 4L60E installed from RPM Transmissions.

Bird Lightning 2.0

I recently bought a '99 30th Anniversary T/A. My trip odometer always resets itself. Not a big deal. But it would be an easy way to keep track of the km's I put on it each summer.
How do I fix this? Also do '99 Trans Ams have an oil life monitor?

sawblade99Z

iTrader: (1)

Can't speak for the trip fix, but my car, also a 99, does illuminate an oil light when it's due for a change. Check oil, change oil, something like that. Typically I change it before that comes on though. Anyway, after you change your oil, turn the key to the on position and pump the gas three times to reset the light.

Firebrian

Oil service resets.

http://resetservicelight.com/reset-o...bird-trans-am/

https://answers.yahoo.com/question/i...8095538AAeLHBh

Bird Lightning 2.0

Thanks. I just changed the oil this past weekend, so I will reset it. Although I'll never put enough miles on it too need to change oil more than once a year anyway....

Firebrian

Saturday, charged my battery for 30 min then drove the car. No issues at all with trip resets or full scale ranging on the tachometer. The battery is taking longer to charge so a new one is warranted.

Battery was changed out and now no problems. That old battery was getting down to 12.1-12.2 volts between runs. But, I would charge it every time as well. New battery hanging around 12.57 volts after sitting for a week. 12.90 volts after a drive though some of that due to temperature rise.

Bird Lightning 2.0

Well my battery is a brand new AC delco that was put in before I purchased the car. But gauges do the sweep thing and trip odometer resets. It doesn't do it every time, but quite often.

So I guess the gauge cluster needs to be replaced?

cnd99hawk

iTrader: (2)

I had the gauge sweep and trip reset.

Put in a new battery and both problems are fixed. I believe the Guage sweep and trip reset are little warning signs battery is weak.

Uziguy18

iTrader: (1)

mine did the same

turned out after doing headers, air and egr delete a bolt found its way between my starter and its positive cable.

check all engine grounds..look for any loose bolts thats wedged between anything that could arch