I have a small problem with my 96 cavalier LS 2.4 automatic. Say I'm doing 75 mph, with my cruise control on, The speedo varies a few miles above and below that speed (doesn't show a constant 75) The cruise control also seems to react to this. I can constantly feel the car accelerating or deceleratin a little. Not really a problem, but really annoying and I would also see this affecting my fuel consumption. It seems to me like it's an electrical problem (loose connection or broken wire not necessarily a bad sensor ). Can anyone tell me where the cruise control gets it's signal from? I'm assuming it is just connected to the speedo singal wire at some point? this would possibly narrow down my search for a loose contact or partially broken wire.
and this doesn't happen when you're out of cruise? i.e. having to move the pedal a lot to stay at the same speed.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
The speedometer acts just the same with cruise on or off, (varies a few miles above and below the driven speed) The speed of the car itself of course stays constant when out of cruise (steady throttle). just seems to me that the cruise contorl gets a variying speed input and hence won't keep a constant speed.
I just hate to guess... but I'm going to imagine that the cruise module gets an input from the PCM based on the VSS signal. from the way I "think" it should work, when you turn your cruise on, the PCM enables the output that sends the VSS signal over to the cruise module so it can sense your speed.
again, I'm purely speculating man, but I don't see how else it would work. I would think the PCM would have to be in the "loop" between the cruise switches on the stalk and the cruise module.
I'd try a different cruise module to see how it behaved.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
That's ture, It would make sense that the VSS signal would be distributed from the PCM to the cruise module and to the speedo. I don't think the problem is with the cruise module, because the speedometer also acts a bit erratic. I guess the first thing would be to check the wiring from the VSS to the PCM. No idea though if half of that wiring is even accessible. It's prettycult for me to get my hands on cavy parts. Only seen one other 3rd gen cavy in Fnland besides mine. Pretty much have to order everything from the states. I wonder if any other cars have the same cruise module?
http://www.gmpartsdirect.com
that website has helped me find out if some j-body parts were used on other cars. I bet the N-body cars used the same module.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
The VSS is connected to the module. And when the signal is interrupted it will be felt and the speedo will vary. I had to cut and splice my VSS for the tranny swap and the patch held for a couple of years. Started doing just what you said and I knew the connection was the problem. I would guess the wiring first, the VSS second and the cruise module third.
Labrat
If your speedometer is not behaving erratically, why would you suspect the VSS?
That behavior is normal. It takes a lot more power to cruise at 75 than at 55 and the ECU is probably overcompensating which causes your speed to bounce around. If you're concerned about your fuel economy, slow down.
2002 Cavalier 2200 5spd
Because the speedo is behaving erratically.
I've always noticed the speedo to be a little "delayed" on my car as to its actual speed. Kind of like the PCM is "averaging" the speed over a couple seconds and sending "that" to the gauge.
The Civic had more absoluteness in its gauge cluster.
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We all drive in a yellow Cavalier...
Thanks for the tips, I'll be changing to winter tires this week and I'll try to get a look at the wiring and the VSS at the same time, Where on the transmission is the VSS located at? will removing it drain my transmission?
