Laggy Tach

Elaborate on the "laggy tachometer" theory, please . . . I read about it in Sport Compact Car's review, but I tested the car 3 or 4 times (you know, to really get a feel for it ) and I never experienced a lagging tach; it seemed to be keeping up to me.

urbanmonkeygod04 said:

Elaborate on the "laggy tachometer" theory, please . . . I read about it in Sport Compact Car's review, but I tested the car 3 or 4 times (you know, to really get a feel for it ) and I never experienced a lagging tach; it seemed to be keeping up to me.

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Well say your rolling in first gear a little... then you NAIL it... you will hit the rev limiter and the tach will still only be at ~5,000rpm.

Comparing the stock tach to my Autometer tach, the stock tach is sluggish to say the least.

kenwood599 said:

Comparing the stock tach to my Autometer tach, the stock tach is sluggish to say the least.

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Where did you mount your tach and I also see that you have a boost guage, where is that located at in your car?

The boost gauge is mounted on the top plastic cover of the steering column in a gauge pod and the tach is mounted to the left of the steering wheel on the plastic dash just above the moulded pocket.

I didn't get mine completely fixed yet, but before I bought the car I told them to take care of the tach problem. They said they "did nothing" but they had just gotten it back from a service shop 10 miles up the road and the service tech I spoke with said he went to get it fixed. Kind of sneaky - sneaky. Anyways they have to hook up an obd2 scanner and measure what it says vs what the scanner shows. Then they recalibrate it.

It's alot of work but it should be covered under warranty.
Now mine is only 2-3 hundred rpm behind instead of 1000+ rpm behind - I Just shift at 6000 RPM so that's good enough for me for now. (It's the woman's car anyways).

The problem is they will not be able to get it exactly correct. I guess that is what aftermarket parts are for. Damn software driven tachs.

that makes absolutely no sense that the car would not have the correct reading on the tachometer; I don't know exactly how a tachometer is hooked up but it probably should be fairly accurate. Why won't GM do anything to fix this?

You know, before I got my ECU flash, I used to ping off the limiter under 6k. Ever since then, I'd been running it pretty easy, shifting at no more than 6k, and generally taking it easy. In fact, I'd guess I only ran the car hard about 6-7 times in the last 3 weeks. I mean REAL hard. 1-2-3 redline each time, etc. It dosen't hit the limiter in mine until, well, redline. I tried 3 runs yesterday, and all 3 made it to the redline before I felt the bog and shifted. It was still a little short, maybe a needle width before the actual redline, but not even close to where it was before.

Could this slow tach have something to do with either the ECU reflash or the Cam Sensor? I ran the car all the way to redline this morning in second gear without ever hitting the redline either. Who here has had the ECU done, who as had the Cam done, and is EVERYONE still getting a slow tach? The difference in mine is enough that getting a shift light fell right off the bottom of the list.