In short, I am running LS2 Coils in COP in my FC. How do I get the tach signal? I've got the correct jumpers in place per the build manual, and I am 99% sure I have it wired correctly (it was hooked up to the same wire with my haltech e6x and worked).

I swear I read somewhere that a pull up resistor was needed or something, but I can't find it anywhere now. Do u need to do the relay mod it mentions?

Also, possibly related, I can't get the VSS to work either. It's hooked up via the writeup on here (speedo pulsed output into nitrous in). Could it be related, or am I chasing two issues?

Not in a position up upload my setup, but the tach is turned on and set to the correct output. VSS is set up per the writeup.

Edit: it's a MS3X with v3.0 pcb.

 

I just hooked up my tach out wire directly to the test connector off the trailing coil plug and it worked fine. no pull up resistor or relay needed.

(MS3 Gold w/ IGN-1As)

 

That's the problem, though - I don't have the OEM trailing coils so I can't pull it off the coils (unless I'm missing something about the LS2/Truck coils).

 

I don't have trailing coils either. I'm talking about the connector in the harness. it has 1 4?pin plug, a 2 pin plug and then a weird black bullet connector. That bullet connector is a tach input into the gauge cluster unless you've cut it somewhere else.

it's yellow with blue:

 

I ran all new wires with a direct run from the megasquirt to the coils, so I don't have that.

If that works without the stock coils, though, can I tap into one of the signal wires for the tach?

 

Yes, that's what I did. that wire is the signal wire for the tach. you can just plug the MS right into it so it gets it's signal from the MS instead of from the trailing coil like it does stock.

 

Well, that's easy - no wonder I didn't find any threads on it. I don't know why I thought that wouldn't work. Thank you!

Now I just have to figure out the VSS.... Unfortunately there's a decent chance I hooked up the wrong wire and I'm going to have to yank the dash again.

 

VSS can be had at the power steering connector under the left side of the steering column. No need to go directly to the cluster.

 

That's where I pulled it from, but there were some hacked up wires behind the dash. I didn't think that was one of them, but I could be wrong.

 

Well, after all that I just had stuff wired wrong. There's two Y/L wires on the back of the harness for the gauge cluster - when I redid my wiring last year I connected the wrong one. It works now.

As for the VSS, I also connected into the wire right off the harness plug since I suspect something was cut along the way. Can't drive car until end of week when a part comes in, but I'm hopeful.