Electrical Problem???

[jmartindba]

I have a 1999 Grand Am SE with the 2.4L 4 cyl engine. Lately when it is cold in the morning and I take off for work, the car acts really strange. The speedometer starts jumping all over the place and the trans actually shifts to compensate for the speedometer jumping. Of course, I cannot use the cruise while this is happening. The car is VERY jittery during this time. It usually takes about 30 - 45 minutes for this to stop. I even drove it 10 minutes this morning and then pulled off and turned the car off and started it back up and it was still doing it. It was doing it really bad this morning for at least 45 minutes before it finally quit.

A little background on this car, it has 218,000 miles. I had a computer problem about a year ago and they replaced the computer and flashed it. It ran fine after I got it back but ever since then when I sit idling anywhere for any time at all the car fills up with fumes really bad. It did not do that before the computer change.

Anybody ever see this before?????

HELP!!!

Jeff

[ctwright]

Sounds like you may need a new speed sensor. Other problem sounds like an exhaust leak.

[xeroinfinity]

yeah could be a speed sensor on causing the speedometer to jump.
Are all the other guages working properly ?

How about any Service lights on the cluster(s) ??

On the fumes, do they smell like exhaust or raw gasoline ?

[jmartindba]

Only the speedometer jumps all over the place and it only does it on cold mornings for the first 30 minutes or so.

The exhaust smells like half burnt fumes, not raw gas. The car has a slight miss in it when I sit idling too which may have something to do with it. I am pretty sure there are no leaks or holes in the exhaust pipes.

Thanks!

Jeff

[xeroinfinity]

Your speedometer probly is just from the cold, high moisture areas can make it worse.

If your 99 has an EGR look around that area for any exhaust leaking.
Could also be running rich on the fuel, have you had it scanned lately for trouble codes ??
You can also pull the vacum line off your fuel pressure regulator just to see if any fuels in there. This would cause fumes to come from your vents.

[ctwright]

Originally Posted by jmartindba

The speedometer starts jumping all over the place and the trans actually shifts to compensate for the speedometer jumping.

I said speed sensor because the transmission is also affected by this. May also instead be a loose connection at the sensor. Makes too much sense, if the vehicle gets its shift control from the speed sensor and the sensor also controls the speedometer.

[xeroinfinity]

A scan at a trany shop would tell you if that was the VSS making the speedo jump around. These usualy outlast the other components in the transmission. But with over 200k miles its possible.

Id also check/test the IAT and IAC sensors.

[ctwright]

Originally Posted by xeroinfinity

A scan at a trany shop would tell you if that was the VSS making the speedo jump around. These usualy outlast the other components in the transmission. But with over 200k miles its possible.

Id also check/test the IAT and IAC sensors.

I agree he should take it to a trany shop. Like I said though the fact that his transmission is also shifting to compensate when the speedometer is acting up is why I would start with the speed sensor, because it controls both speedometer and shift control. I am more leaning to a loose connection at the sensor as apposed to the sensor being bad but I still like you think that it is possible.

[xeroinfinity]

Originally Posted by ctwright

I agree he should take it to a trany shop. Like I said though the fact that his transmission is also shifting to compensate when the speedometer is acting up is why I would start with the speed sensor, because it controls both speedometer and shift control. I am more leaning to a loose connection at the sensor as apposed to the sensor being bad but I still like you think that it is possible.

Though if it was the Vss or its wiring, I would think it would do it whether it's cold or hot. No fun replacing this either!

I mentioned the air intake temp sensor because if it is faulty or has a short, it'll make it shift funky and not run quiet right.

Hopefully it's something inexpensive.

[ctwright]

You are probably right about that either way I hope he gets it fixed soon.

[jmartindba]

Speed Sensors... can anyone tell me where on the tranny these are located? A picture would be great!

Thanks!

Jeff

[ctwright]

Originally Posted by jmartindba

Speed Sensors... can anyone tell me where on the tranny these are located? A picture would be great!

Thanks!

Jeff

You can probably look up at autozone.com and see a pic of the sensor and see what the plug looks like and you should be able to then look around your transmission for the same thing, sometimes to in the parts stores some of their Haynes manuals already have the plastic off you might be able to sneak a peak and look it up in the book.

[xeroinfinity]

The sensor is inside the transmission, drivers side where the shift solenoids are. Good Luck!

[xeroinfinity]

~bump~
Ok thier is a Vehicle Speed Sensor - VSS on the side of the trans wasnt sure of your year GA, but here's a crapy pic of the 99-05 VSS.



Hope the helps and sorry for the confusion!

[jmartindba]

Well, I had the same problem again this morning. It is getting more frequent. The one thing I did forget to mention, when it is doing this, it only messes up when I am going over 45mph. When I slow down to go thru towns it works fine.

I am going to try to locate the wires to the sensors tonight to check the connections.

xeroinfinity, Are the speed sensors replaceable without removing the transmission?

Thanks!

Jeff