I just put a new gauage cluster in my 1998 Neon. I didn't have a tach before so I found one with a tach a swapped them. Now my speedometer is out of whack. It says im going faster that what I am. (I had a friend tail me in a new Neon to check) I'm resetting the PCM today, and hopefully that works, if any of you know whats wrong it would be greatly appreciated. TIA

 

I reset the PCM the other day and it did nothing. It still says that I'm going faster than what I really am. Is there any way to reset the Gauges? I don't understand what's going on, please help me out. Thanks

 

Ya, the PCM itself isn't going to cause that. There is a limited number of items that would cause. 1) Possibly (though not too likely) the speed sensor itself. 2) Putting smaller diameter tires on--lots of people do that and don't have a clue the effect so I'm just pointing it out just in case. 3) a wire/connector bad. 4) gauge/circuit board bad.

Since you indicated only real change was swap gauge clusters, and it's relatively difficult to damage wires you may have a bad cluster. Hopefully you didn't spend too much. There is a procedure on Neons.org where you can get access to the circuit board and use a sodering iron to re-soder your connections. It's not actually all that difficult to tell you the truth. In fact, recently I disassembled a television remote my kids were throwing around and did the same thing on it--works beautiful now.

Since you didn't say the speedometer was jumpy that would be my guess is just a bad gauge or bad signal from the PCM. You should have disconnected the battery just to play it safe will unhooking and plugging back in. But it could possibly be right at those two connectors in the dash. Take the thing back out, clean very carefully, make sure not damage, re-insert and see what happens.

Good luck.

 

Did the donor car have the same transmission as yours? If not, there are probably some mods needed to account for the different gear ratios between the 3 speed AT and the 5 speed manual.

 

Oops ... not with VSS (I'm dating myself). I can confirm that the bad solder joints on the cluster PCB mentioned earlier can cause the speedo to read low, but don't know that they can make it read high.

 

as an FYI my guage cluster came from an auto 3 speed and went into my stick. mph is actually fairly acurate. Essentially the voltage the PCM sends to the gauges is the same scale. (Cheaper to make it that way than to have two different scales.)

EDIT: Ooops--I did the same thing as you--i was so busy thinking about how to make a simple explanation about electronic speedometers as opposed to mechanical that I didn't realize you'd already corrected yourself in the next post. Sorry. I'm stuck in mechanical mode right now I guess.

 

Thanks for the confirmation. I couldn't recall if the speedo got it's signal directly from the VSS or through the PCM. Thought the AT PCM might be different from the Manual one to support TC lock, so incorrectly suspected it might be related to the PCM. Had to look at the schematics again to see the VSS signal goes directly to the speedo regardless of xmission type.

 

Would removing the needles mess everything up? I thought I put them back in the right places. Is there any way to put the needles back in their original positions? Any help would be greatly appreciated.

 

ooops--hadn't checked back on this topic for a while. ya. . .you MIGHT have hit the nail on the head. You know that when the gauge cluster is disconnected that the needles are not zeroed right? They actually hang about 1/3 to 1/2 way. . . . that just might be your problem.

 

when i changed my gauges.. we guess what i was really going.. and while i was driving the car in a straight line.. i put the needle where i thought it should be... and then went past one of those stupid "this is how fast ur going" things and voila.. i was going the right speed that was shown on my speedometer.. took forever to get it right before i tried that though.. it was off by 10 miles