I have no trailing spark. I have the ignition wired up according to the schematic and leading works, but trailing doesn't. I replaced the trailing coilpacks and ignitor and this didn't fix it. I will do a continuity check on the trigger wires to rule that out. Is there a way to test the ignitor? Is it the ECU? My friend has another coil pack assy if I want to try it. Maybe thrid time will be the charm.

 

Are you testing during cranking or with the engine running? Because the Microtechs don't fire trailing during cranking.

 

That explains the spark test failing durring cranking. But, I also can't time trailing and have no tach signal.

 

Is it possible that I have done something that configured the ECU not to turn the trailing on after startup? Wrong mode?

 

What ECU is it?

If you don't have trailing after the car starts then there's an issue.

 

LT8 factory configured for tII style ignition.

 

try pulling the spark plug wire off after the engine is running just to confirm there is no spark. obviously use something insulated to keep from shocking the hell out of yourself.

 

I have spare plugs. I can disconnect the trailing wire and connect to a couple external plugs. Checking timing should tell me the same thing, but I suppose seeing is believing.

 

OK. How do you have the wires connected to the trailing coil? If I'm not mistaken, the Microtech manual references the connections to the wiring colours on the IGNITOR and not the HARNESS.

If you have a scope available, you can scope the ignition signal the Microtech is sending to the trailing and verify that it exists.

 

Ran the car with the tailing ignition wires firing plugs externally. Both fired. Trailing ignition does work once started. Thanks for the help. I am running Taylor ignition wires. They are so thick that I couldn't get a timing signal through them reliably.

Tach still doesn't work though. Tach is 11K VDO. Thought I wired it up right. Yellow wire from trailing coil pack right?. Any other wiring options?

 

Yellow wire with blue stripe as I recall. There are several of these wires inside the cabin which are not the same wire so I always end up taking it directly from the coil or from the stock tach. You can also wire the tach to the leading if you want.

 

take it from the coil, its your best bet..

 

Yellow with BLUE STRIPE.
And you cant take it from coil pack it self.
Must come from ignitor.
Its on the 4 pin plug.

 

What would happen if you took Tach signal from the coil pack?

 

If you took it from the negative of the coil pack it self it will show have the amount of rpms you really have.

Dont you have a yellow/blue wire on your ignitor?

 

That makes sense. Would it be OK to take signal from the leading coil pack then?

I do have the yellow with faint blue wire and that was how it got wired up orignially. It could be a power or ground issue with the tach wiring. I will track down all wires going to the tach and make sure they are connected OK.

I was going to install one of my MSD 6As on the leading this weekend. I was thinking about just getting a signal from the box.

 

Well.
that i havnt tried.
I think it will still show half the rpms. But try it. See how you go.

Can you take a pic of your trailing coil pack wiring.
?
May show me what your problem is?
Normally when your tacho stops working it usually means your ignitor is on its way out?

 

This is the second coilpack Ihave tried so far. I really hope this one isn't bad too. At least it fires the trailing plugs.

I wired the tach up to this yellow wire show in the pic.

http://i123.photobucket.com/albums/o...RX3_121806.jpg

 

From what i can see that wire isnt yellow/blue.
Ill go to my garage.
Check one and come back.

 

Just went out and checked..
That yellow wire should give you a tacho signal.
either your ignitor or your tacho is a dud.