First I tried searching for this specific question, but I couldn't find anything....

I just bought a Auto Meter, ATM-2890, 0-4000 rpm Tachometer, from Summit Racing.

http://store.summitracing.com/partde...0&autoview=sku

My truck is a 1992. it appears to have a harmonic balancer sensor AND some type of pickup on the side of the alternator. It also has the factory 4 prong plug under the steering column for a tach.

Truck 4 pin connector / Tach Sensor End

Black To Black (GRD)
Orange To Green Lamp (Pos)
Black To Red (DC POS)
Grey Lt Blue To White(Signal)

So heres my question - Am I going to have to calibrate my tack after I wire it up to the connector under the steering column?

 

i've never seen that used in our application so i am not sure. i would definately like to hear how it turns out.

 

The factory RPM signal comes off the Crank Position Sensor(?) on 1992- 1993 trucks. If you get your signal from an aftermarket sender/tach you will have to calibrate it.

 

I put on one of these..



I used the factory wiring harness to get power but then ran wires to Alternator to get signal.. factory warness would not give signal off harmonic ballancer..

I had to calibrate mine..

I took off back of tach and let it sit on dash got up to 60mph and then turn adjuster with a very small screw driver..

I used this page to figure out what my tach should be at 60mph
http://www.grimmjeeper.com/gears.html

 

Should work with the switch set to "4 cylinder".

Check out that plug with your meter before you take those wire codes as gospel. I've heard that the wiring diagram is inaccurate.

 

10-4....

 

The Tach showed up and temporarly hooked it up to the factory harness under the dash. Fired it up and it reads about 300 rpm at idle. Doesn't matter if I change the internal dip switch settings in the tach to see 1, 2, 3 or 4 pulses per revolution. It does go up when I rev the engine. Looking through the paper work I got with it, it says the tach is factory calibrated (even had a QC sticker on it) saying it was to spec and there is no mention of it being internally adjustable.

Got any ideas on why its reading so low???

 

Anyone? ........

 

Took the truck out to go beat on it and I could only get the gauge to max out at about 1200 rpm or so with a 300 rpm idle and that was on the 2 pulse setting.

 

Sounds like it only works with certain tachs. Somebody posted not long ago that he was using a cheap Sunpro on 4 cyl that was working fine. I can't understand why the AutoMeter wouldn't work the same.

 

Yeah - I don't understand it either since I'm using the factory harness.....

 

Well I tested it some more last night, idle showed 300 RPM and a max of 1100 rpm. It showed teh same setting on EVERY pulse setting (1,2,3,4). Anyways unless someone has a good idea on how to make this work - I'm sending it back!

 

Nope. Sorry for the bum steer.