B&WIROC

ok so my tachometer is reading way to high there is no way i'm doing 4500 rpms. was wondering how to just disconnect the tach all together reason is that my computer shuts the fuel system off when it reaches 4500 rpms and i figured if it didn't read the tach anymore then it wouldn't be a problem... needing help

coolram62

iTrader: (2)

What year is your Camaro and is the ignition still stock?3rd Gen Camaro's,and Firebirds to a lesser extent,are notorious for tach problems.The problem usually is in one of the resistors on the driver board bolted to the tach.You can disconnect the tach,it's labeled tach the other is battery,at the distributor is you have the large cap HEI.There are several post on the problem and repair for the '82 - '90 and the '91 - '92 which have a similar problem but a different remedy I believe.the tach in my '83 had the same problem that I solved with a different board.I hope this info gives you some direction.

B&WIROC

my camaro is a 1986 iroc z and the tach is still stock. i'm gonna try to disconnect it first and see if that does anything to the computer if it doesn't then it has to be somethign else thanks for the help though.

Siggy

Correct me if I'm wrong but disconnecting the tacho (white EST wire) would not affect the ECM set rpm limit. The ECM must read the magnetic pole pulse from the EST, the tacho reads the coil discharge pulse, sounds like the tacho has a read fault?

BigBadLou

iTrader: (3)

I second that. The tachometer is independent from the ECM, they don't influence each other. They just read frequency, that's all.

Lou

Toyota h8r

Maybe someone put a 6 cylinder tach/gauge in a 8 cylinder car??

D BERRY

iTrader: (2)

Yes, today is the first time I really drove my car, 89 RS, and the tach read 7000 RPMs before it would shift, I know that SBCs can do that but this one wasn't.

Dave Berry

BigBadLou

iTrader: (3)

Yes, our tachometers are notorious for reading incorrectly (mostly high). There is a simple fix for it (works for most) for pre-90 tachometers. Do a search and you'll find it. It involves just one capacitor.

The 90-92 tachometers, however, have a more involved solution. A search will again reveal it. (sorry, don't have the links)

Lou

ville04

hey lou, where u talking about to search (and what to search for) about fixin the tach... got and 86 iroc-z tach is all messed up

TIA

Brian

bilms01

I think this is the one he is talking about.

https://www.thirdgen.org/forums/elec...=tach+resistor