So I looked over my wiring, looks like the SAFC AND AVCR both splice into the blue/yellow wire at the ecu. I checked the voltage there and it was about the same almost 5V.

So I unplugged my SAFC and AVCR and rechecked the voltage at that wire, and VIOLA, voltage disappeared.

In the morning I'm gonna start my car without the SAFC and AVCR plugged in and see if I have a tach.

Although I'm pretty sure this would help my tach work, does anyone know if this would or would not have an affect on how the coil fires? I still have the problem that the brown/yellow wire and blue/green wire are showing the same voltage and one of them is supposed to be much less than it is.

 

Seems like you are getting Vref voltage on those two wires for some reason. If the coil is unplugged I believe two of the wires would have 5 volts w/key to on at the ECU (and the third wire would have 12 volts). This is what you are getting thus the connection to the coil is poor or perhaps the coil is bad.

 

I don't quite follow you. The one that is supposed to have zero volts that used to have 5 volts (blue/yellow) now has zero volts when the safc and avcr are unplugged, not 12 volts, regardless of if the coil is plugged in.

*EDIT* You're totally right. Except about the 12 volts, but I just rechecked the wires after actually plugging in the coil (I had been testing those two wires only at the connector with the coil not plugged in) right at the ecu, and the one wire had just under 1V (under 2) and the other one had like 4.35 (about 4.4) volts, so I believe everything there is fine, I was just not checking it right.

I'm gonna plug my cluster in (took my dash out) and try to start it without the avcr or safc plugged in, to see if I have a tach.

 

So I had also not checked the voltage of the Blue/Yellow wire with the coil pack plugged in. Now I get what you meant about the 12V (although in my case it was 5V?). I just checked that, WITH the AVCR and SAFC plugged in and trailing coil plugged in, and it was basically zero volts. So I was just not checking it correctly. Without the trailing coil plugged in, all 3 wires were reading around 5V, but with the coil pack plugged in, all 3 wires are reading correctly.

So I think that puts me back at square one...

 

Did you check these wires while idling. Have you ohmed out the plug wires as they should read under 10k ohms. Have you got around to replacing the spark plugs yet.

 

I have ohmed out the plug wires and they are good. On Sunday I'm gonna pick up new plugs.

I was going to check the voltages while idling the next chance I get, I'll let you know how that goes.

 

Ok, so I figured it out. After all this, is was just a rich tune, probably combined with the plugs being pretty fouled. I got new plugs and leaned it out and was able to rev it up to redline in neutral last night. Just got back from taking it out and putting a base tune on it and it pulled really well. It was SO damn rich. Wish I had listened to you guys when you first said that lol.

Thanks everyone for the help, especially satch.

 

Oh and the tach, I'm pretty sure it just went out at the gauge. I measured the voltage of the wire going into the back of the cluster and I was getting voltage that increased as I revved higher. I'm gonna plug another cluster in and see if it'll work.

 

Glad you stuck with it to figure it out, despite having to take the 'long' way round. At least you're wiser than when you started. Now go burn some rubber in celebration.