SYS Troubleshooting

[Whitecorvettes]

Greetings one and all!

With the help of Ted, I swapped out my stock shifter for a new Hurst short throw. The throw works perfectly, all my connections are double checked. After putting it in and driving my SYS flashed. I finally had the brand new AC Delco battery checked and sure enough, it was bad. Swapped it out and away went the SYS error.....for about an hour.

I tried to put on an AUTOXRAY to see if I could read the code but it will not connect to my 95' (#278).

The only symptoms I've have in terms of performance is the SYS flashing, and the night time back light for the speedometer dims and then brightens up. It acts like a short but for the life of me cannot figure out what would have happened.

I am of the opinion that nothing I did with the shifter swap caused the problem and it just happened. Especially since the battery is now brand new instead of two months old. (I did have this new battery checked the very next day to make sure it isn't also bad).

Any trouble shooting thoughts or ideas? Again, thankfully nothing has changed in the driving or performance of the car including all 32 valves open on full power.

HELP!

:-)

[Paul Workman]

Your "SYS" light seems to be voltage related; a new battery "cured" the SYS light for a time, and dash backlighting brightens and dims...intermittently, yes?

I'd want to see what the voltage across the battery was with the engine running (charging), and to see what it was when the dash backlight dimmed (and SYS light came on); i.e., is the alternator intermittently dropping the load?

If the battery voltage is between ≈13.8 to 14.7 (give or take a few tenths), and remains steady whether the dash backlighting and/or the SYS is lit or not, coupled with NO drop in rpm or other indication of increased engine loading, a connector or ground connection would come into focus. Refer to your FSM (of course we ALL have FSMs, right???).

However, if battery voltage drops (to 12.8 or less) in coincidence with the dimming/SYS problem, then the alternator or connection to it (e.g., field connection, etc) becomes suspect.

Anyway...A leeeeetle bit more info/results from some measurements before and after the symptoms occur would help narrow the field of possibilities...

P.

[SteelBlueZR1]

Is it possible that you somehow loosened the ground on the top of the transmission when installing the shifter? The dimming may indicate a grounding problem. We recently resolved electrical gremlins on a member car by tightening and cleaning the transmission ground.

[scottfab]

I think you're dealing with separate issues.
Try turning the dash dimmer switch on all the way till it clicks.
This will set the dash to full on.
Doing this should allow you to see the dash stop fluctuating
so you can focus on the SYS light flashing.
Get the codes out and let us know what they are.

[batchman]

FWIW my panel brightness "flickers" as well and it seems to be the "fader" for the level being dirty - zipping it through the range a couple times helps.

I got a periodic SYS also and have been fighting a bad battery. New battery is in place but have only had one event since (and no SYS yet).

Good luck,
- Jeff