1fstGM

iTrader: (13)

Just finishishing installing my tachometer, but when I start the car the RPM's don't match. I cut both the wires on the back of the tach. I connected the green wire to the white wire with the letter G. The tach is off about 1000rpm when idleing and seems do double the real rpm as I accelerate. Anyone know what could be going on, and how I can match the RPM's.

PS: I accidently ripped the white wire from the wireing harness, but I added some white wire to connect it back up.

greatwhite99

you need to send the tach back to autometer to be recalibrated. Off the shelve it uses a 12V reference (analog) for the spark or something like that and it needs a 4.5V square wave (digital) for the LS1. Give them a call and they will know exactly what the deal is when you talk to them.

Mike

Supraman

iTrader: (3)

Look into the autometer website www.autometer.com In the tech tips for LS1 engines. Make sure that your connection is in the right place. I have an autometer Tach and was able to get to work right. I believe that it has to be set in the 4Cyl mode.

ZR2877

MIne has been messed up for a long time I just gave up on it. Maybe I'll try this and get it working. Thanks for the info.

1fstGM

iTrader: (13)

Well I got back to working on getting the tach to work today again. I was messing with the wires on the back of the tach, and finally got the RPM's almost dead on. The funny thing is that we are suppose to set them in 4 cyl. mode, but when I did so it was way off. I think it was the blue wires that are in the back of the tach that I connected back up. At Idle it is about 200 RPM off, but when I give it gas it is pretty much dead on. Thanks guys.

GT Griller

iTrader: (8)

Yea some people got lucky and didn't have to have them recalibrated (me). And others arent, those u have to send back and have them redone by autometer.