Dan91Z

Ok.. I haven't realy messed around much in this area so I'm not sure what's going on. Basicaly, my tach reads somewhere around 4000 rpm's or so in 5th gear at 70 or so mph.

checked it with a actron volt meter that also does rpm, dwell, duty cycle, etc. The results were 2260 rpm when my tach in the car was reading right below 4000, like 3950 or so.

I did replace the ecm about a year ago, and i'm not sure if that's when this problem started. I normaly don't pay much attention to the tach, but my speedo light burnt out so at night I use the tach instead. My car is a 91 z28 convertible with the lb9 & 5spd.

So, any ideas on how to fix this? I'm prety sure i would have bought the correct ecm, so what could be affecting this besides the ecm?

I also noticed that the wire to the tach had a small hole in it, not cutting the actual wire inside, but just through the insulation. Looks like someone that had it before me had someone check it or something, so it might have been going on ever since i bought it.. who knows.

to give an idea of how far it's off (since i was so vauge at the top of this post...), when i was looking into it a couple months ago it calculated out to equalling a 4.11 rear end with the 245/50/16 tires. The rear actually in the car is a 3.08 though. unless it was changed or something.. don't feel like 4.11's back there. The car also pulls above 6k, so I know the tach's way off..

any help would be appriciated. sorry for all the bad spelling/grammer.. long day