Got everything working, except the tach. From the diagram, it looks as if the whole cluster shares a single power and a single ground...at least for the gauges. My volt meter works, so I figure it's safe to assume that the power and ground are there.

The tach has no function. It doesn't move. The system looks fairly straight forward....the new harness has a wire that goes from the igniter to the tach through IK2. The old setup runs a wire from the ignitor into the driver's side of the firewall going to the tach, then something else, then the A/C amplifier.

I grabbed the black wire from the new harness (verified continuity with terminal 8 on the igniter) and spliced into the existing black wire on the A/C amplifier (verified continuity between this wire and the black going to the tach) ...and still, the tach doesn't work.

What am I missing?

 

https://www.yotatech.com/forums/f160.../#post50797975

 

Right...I saw that, but I was under the impression that without doing the mod, the tach would still work...but it would be inaccurate. Can someone confirm this? Has anyone run there's without doing the tach mod first and did the tach atleast read something? Mine doesn't work at all...needle just sits there like it's not even running. I'm going to scope the tach output from the ignitor tonight to see if I'm chasing a component failure or a wiring issue I guess.

 

I haven't done the mod yet to my 87 or my 91, my tachs just sit there not moving a hair.

 

Cool, that's the info I was looking for. I'm headed to Radio Shack to pick up a potentiometer.

 

i dont know if the 4 cyl tach will work even with the resistor. its made to interpret a 4 cyl signal. but good luck with that!

 

I pulled the tach out again tonight and gave it a little closer look. There are 2 circuit boards...on of them on the back sitting vertical and one on top sitting horizontal. The top one has a little white potentiometer on it....is the one that supposedly, when adjusted, will make everything work?

 

pat, did you get it worked out?

 

no. My tach looks different than all the pictures I can find. I soldered in a resistor where I thought it should go, but of course...it still doesn't work. So I've got to do some diggign and figure out how this thing works and where to solder in the new resistor.

 

http://www.mindspring.com/~jayk3/toyota/tachmod.htm

here we go. Hopefully this will work. This is the what my tach looks like.

 

Crap...still doesn't work. no signs of life outta the tach. I give up.

 

you need to get a cluster out of a v6 truck or 4runner.

 

I recently did the 3.4 swap into my 22RE 4Runner. In order to get the tach to work I soldered the 10K resister to the spot located in this link.
The wiring goes like this: Tap into the the igniter port #8 (black wire on mine) and run a wire across the engine bay to the driver's side in front of the master cylinder. You should have an exististing green cylindrical connector with two ports. One port has a black wire with red stripe, the other is all black. Connect the wire from the igniter to the all black wire. I just used a male blade connector and it worked fine. Next, install your gauge cluster without the speedometer in it and run the engine. I fine-tuned the factory potentiometer to match what my scanner in the OBDII port was reading. It's accurate to +/- 25 to 100 RPM, depending on how high the RPMs are. I hope this helps. I also had a helluva time getting mine to work.