Tach

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Jun 14, 2013 | 08:01 PM

danny weimer

Thread Starter

Junior Member

Joined: Oct 2012

Posts: 38

Likes: 0

From: Hartly Delaware

Car: 1989 camaro rs

Engine: 305

Transmission: auto

Tach

my tach as far as i can tell is factory. the engine ildes at 1200 stoped the tach say 2500. at 50 it says 6000 ish its 2500 ish i have it hook to a computer an geting in fo from that. if the ecm is getting the right info how come the tach is off . this is a 89 rs with a 305

Jun 14, 2013 | 10:38 PM

vetteoz

Supreme Member

iTrader: (13)

Joined: Apr 2005

Posts: 7,736

Likes: 14

From: Not in Kansas anymore

Car: 82 Z28

Engine: 383 SP EFI/ 4150 TB

Transmission: T400

Axle/Gears: QP 9" 3.73

Re: Tach

Quote:

Originally Posted by danny weimer

i have it hook to a computer an geting info from that.
if the ecm is getting the right info how come the tach is off .

Because the ECM gets it's tacho signal from the dist and the tacho signal is from the coil on completely separate wiring; nothing to do with the ECM
Observe the white wire off the coil to the IP (tacho )