I am swapping a 3.4 from a 1996 4runner into my 1994 4runner 4x4 5speed. We have everything runner except the tach wont work. We hooked up the black wire from the ignitor to the black wire in the cluster. Also have a signal from the ac amp to the ignitor. We can get a AC current with our meter. Put still nothing. Also We are having trouble understanding how to get the ac to work properly. Any help would be appreciated.

 

Did you do the resistor mod for your tach? If so did you possibly short something else out to cause the tach to not work at all now? The tach is pretty straight forward, black ignitor wire from harness to black tach wire of body harness.

There is a pretty current thread for the AC to work, that UKrunner and myself are working out. But basically you take the A/C wire from the amp that goes to the clutch and ecu, and hook that to the new clutch wire, and AC1 of the ecu. You leave the ACT wire unhooked. Its working for us. Are you sure the the black wire is properly connected to the plug of the ignitor?

 

What resistor mod?

 

search in this forum man. And that answers my question then. So I am unsure as to why your tach wouldn't be working. Because the tach I believe should work without the mod. Just the RPM's will be off. i.e., at 1000 rpm on your tach, the motor may actually be a little lower or higher. Not sure which way it is.

Next I would test the wiring from the IH2 plug to the plug on the back of the combo meter itself, and then from the other side of the IH2 plug all the way to your ignitor.

 

Mine either didnt work or went to around 1100rpm and just stayed there regardless of revs.

IH2 pin 20 black wire is tach.

 

https://www.yotatech.com/forums/f160...23/index8.html

Everything is right there about the mod. Scroll about halfway down.

 

UKRunner... you ever figure out your tach issue? I may have used the wrong wire... I pulled pin 8 from the igniter. I checked the volts from that pin and the voltage went from 1v upwards as I revved the motor.

My tach will read until about 1000 rpm, but won't go past that. Any info on this?

Here is the reason I pulled from pin 8 off the igniter:

 

I never had a tach problem. I ran it without adding the 10K resistor which gave me the 1100 rpm constant reading. Added the resistor a couple of days later when I had time and never looked back. Works perfectly and has done so for over 11,000 miles now.

 

I misunderstood your post. Anyone else had that problem?! In the snapshot of the factory manual above, is that the wire everyone used?

It's so strange... the tach will attempt to function, but never gets about 1000 rpm. To test the tach, can I just put 12V on the positive lead, ground the negative, and vary the voltage on the third contact?

PS... I have added the 10k resistor

 

Varying the voltage wont do anything because its a pulse on that pin.

And yes, that pin in the diagram carries the tach pulse to the tachometer. If you try disconnecting it from the pulse input pin on your tach, what readings do you get on your tach with the engine running? Have you checked continuity between the igniter and the end of the wire?

 

iIRC when i disconnect it the tach goes to 0 and stays there. Ill double check in the morning. Seems to me that is what it should do without receiving the pulse signal, no? And I have tested continuity, but it doesn't hurt to check again!

 

Yes it should go to zero. Are you sure you did the resistor mod correctly?