Speedo acting up?
 

On the way to hockey last night the speedo in the car was intermittingly dropping out, all other gauges were fine. The speedo though would fluctuate wildy and occasionaly drop to zero, stay there, then suddely start working again only to start fluctuating etc..etc...I thought something was just quirky, but on the way to work this morning same thing only now it seems to be accompanied by a slight miss which is also intermitent and when you come to a stop the idle speed is hanging up around 1200 rpms then slowly returns to normal 700rpms +/-......

I did check to see if there was a binding situation at the throttle, but everything seems to be free and working properly, the floor mat is not hanging on the gas pedal in anyway..???

Our speedos are electrionic I am pretty sure so is the send on the tranny acting up? could this also cause the other problems?

Any ideas what would cause this?

Chris

Yes, the speedo is electronic. Is the car throwing any codes at all?

- Justin

No check engine light, yet. I did just take it lunch and the two are definitely related and the miss getting worse. I am thinking that the computer isn't seeing the vehicle speed so it doesn't know how to adjust fuel/spark for engine load??? Tach is and all other gauges are working fine. Odometer isn't working either which makes sense, but something is wrong....oh well another weekend project...

Chris

I don't know LS1s that well, but if all the other gauges are working fine, the sender would be my first thought....

- Justin

a while back i had TQ arm mount issues and while fixing it, i unplugged the speedo connector from my trans. But i forgot to reconnect it, and drove a while, the car was running like crap, it would even backfire. Perhaps one of the wires to the trans got burnt or ripped up, or maybe even the sensor itself went bad. In my case, it was several issues, but once i reconnected the plug it got a lot more driveable. For me though, it did throw a code.

In my case, my main issue had turned out to be a "jet" performance module that piggybacks onto the ECM(installed only a week before) and it had the harness wires rubbing through on the hood hinge, add that and rain and i had all sorts of issues, i threw the module in the trash and fixed the wiring. After that, all was good again.

if the sender starts to go bad, you will see the speedo drop out every now and then. If the car doesnt know how fast its going, its probably not going to run right. price out a speed sensor and see if its cheap enough to replace.

That's what I am leaning towards. I tried stopping at Lucas Chevrolet on Rt 38. (near where I work) and the guy at the parts counter look at me like I was crazy, he said "I'm not showing any kind of speed sensor"??? So I have to try another dealer. I got under the car today and checked for loose/broken/frayed wires and everything looks intact. Truthfully I'm not even sure with of the three connections is for the speedo. One is for the cags?, one for the reverse lights?, one the speedo sensor?

Anyway I put the car up on jack stands and ran the car throught the gears and almost instantly the problems appeared and they seem to be getting worse and finally tripped the ABS INOP light, but no SES light....

I am really thinking the speed sensor took a ****, but we'll see. If its cheap that's my next move.

Chris

speedo connector is the one lowest down and furthest back on the drivers side. the one on the pass is reverse lockout, upper drivers side is cags and one somewhere in the middle is reverse lights.

i wouldnt worry about the abs light coming on. thats not related IMO because if you think about it, with the car on jack stands, only the rear wheels are turning, so the abs computer sees a signal in the rear and then sees no signal from the fronts, so it thinks the cars moving and the fronts just arent registering.

Thanks, now maybe I can pull the sensor out have alook at and try to figure out what's wrong. I did come across a sweet website for error codes, circuits, and trouble shooting guides www.gearchatter.com all broken down my make model year. Looks like good info.

Chris