I just had a tune up, and yesterday my tach started going higher then the actual rpm's, but it will usually settle back to normal.

I am guessing its a loose ground or something.

Where do I need to look?

 

My car does the same thing and I've never been able to figure it out. Maybe someone has found the culprit.

-Tom

 

Mine just started to jump too. M2 said that it was a fairly common problem and that if It did not bother me too much to just leave it, because it can get expensive trying to locate what exactly is wrong .I have hear that it can be a number of things such as a weak solder link at the back of the tach, or one of two sensors that the signal passes through is going bad, to the tach itself going bad.

I did notice that somtimes when I turn right I can induce the tach to jump, which might be a hint that the soldering is loose. The only thing that does not make sense to me is that if there was a short, I would expect the tach to drop towards zero, not jump up. Have you guys been able to make the tach jump at will, or does it jump randomly?

 

I had this problem

solved it by resoldering the joints

 

maybe youre reving the engine but you dont know it...

 

Hey pump which joints did you resolder???are they easy to get to??

 

My tach does it randomly. But even then, it will only do it like once or twice in a month so it's not a major issue with me, but to a potential buyer (sooner or later we know we will decide to sell it) it would probably freak them out and they would think the car has electrical problems.

Anyway, soldering the connections sounds like a good place to start. Thanks Pumped and overkill. And thanks to VeeTec for starting this thread. For some dumb reason I never thought about posting the problem here.

-Tom

ps, COsborne, I hope you were being sarcastic in saying maybe we are revving the engine without knowing it. Don't you think we would hear it?

 

I am going to check the wiring to the coil first, since it started right after the tune up. I'll let you guys know if it helps. Right now its only sporatic.

I did a search after starting this thread, and apparently this is more common than I thought.

 

I have the same problem too, it shoot right for the red line everytime and I have no luck finding out why... I actually have the Profec E-01 and it can show the highest rpm that your car has reached, and it said 34450 rpm.... I thought that was kinda funny... What that hell am I driving? a missile???

 

I have the same problem nothing like racing someone with your tach jumping to 9k and you are like um... yea i dont wanna hit the rev limiter.

i have the e-01 too and it doesnt go up it stays the same when the tach goes up.

my friend said stand alones can screw it up. dont know if it was his stand alone or all stand alones.