04 LQ4 into 92 c1500

[vortecyota]

I am swapping an 04 LQ4 and 80E into a 92 chevy c1500. So far everthing seems to be working well except the tach. I ran a wire from pin 10 (C2- PCM) to the white coil wire behind the glove box. Fired the engine the first time Sunday and the tach didn't work so I added 670 ohms of resistance in the tach circuit and still nothing. I have removed the cluster and checked the two grounds, and the three switched power wires... all good. I also checked continuity from the tach pin in the cluster connector to my pin 10- C2 PCM wire. Exactly 670 ohms. I can't think of anything else to check and this issue is keeping me from moving forward. Iv'e lost two nights already. Anyone have any suggestions?

[vortecyota]

I must be missing something. I have triple checked the pin 10 C2 location and the white coil wire behind the glovebox. I removed the entire TBI harness. I built a firewall pass thru plate for the fusible links that power the cab, AC wires, tach wire, etc...

[classic1]

I sent an email to autometer asking about the tach when i swap my 5.3 into my 92 k1500. They said I would need to use their tach adapter which is p/n 9117. It gives a more accurate reading supposedly. That is for the autometer tach that I have since my stock cluster doesn't have one. Not sure if it works with the stock tach. I haven't fired my engine yet, but when I do I will try without the tach adapter and see if the tach works without it before I buy it.

[vortecyota]

Thanks for the reply. I don't feel like it should need an adaptor so I'm hoping someone else will chime in. On your swap, I don't know what year PCM you have, but I have a Toyota 4x4 with a magnacharged 5.3 and an 02 PCM. I run an Autometer tach in it and didn't have to use an adaptor. Good luck on your swap!

[RedHeartbeat]

The issue is the 2004 pcm not the tach.

[vortecyota]

Care to elaborate? It seems that I misunderstood the circuit modification. Apparently I was supposed to run source voltage through a resistor and tap(tee) into the tach circuit. I just put the resistor inline with the tach circuit and did not tap into source voltage. Gonna give this a try tonoght!

[vortecyota]

That fixed it.

[RedHeartbeat]

The 2004 pcm has a weak tach signal. That is why you had to add the amplifier.

[vortecyota]

10-4. Thanks.