tach help (wiring)

[pontiackid15]

I put a sunpro tach in my 94 grand am se, and i have a reoccuring problem. It seems like the thing reads really low ( says the car idles at 500 rpm, bounces off the rev limiter at 2500, etc. I know the car is revving much higher.........its annoying me. I was told to run the signal wire to the white one on the wire harness, and that is what i did. If anybody can help me with this I would appreciate it. The tach is set for 4cylinder, and it should be working right. This is the second one, i took the first one back bc it did the same thing.

[RomeoGAOC]

well before i give any advice, i just wanna ask which directions you used to install the thing. the tach didnt come with any directions so i bought the haynes manual for my car and it showed me where the wires should go. with that being said, i suggest checking the power and the signal connections. sounds like it might be comng loose.

[WhiteSpeed36]

Well this is how it is for the 2.4 engines. So I don't know if it is the same for the 2.3's but i had a similar problem. You see some of the GM engines send the rpm's only twice for some stupid reason. If you set your tach to the 2 cylinder position it will work correctly. Stupid GM... makes the computer even more inaccurate. I had to do this with my Faze Tach. I think it has something to do with the two coils in the direct ignition system.

[RomeoGAOC]

wow thats quite odd. i didnt even know the tachs came with a 2 cyl position. but try that first before you get your hands dirty, its quick and easy to do.