I changed engines in my '85 W-150 a while back, before I took it apart there were 2 wires attached to the negative side of the coil. Both are black with yellow tracers. There is no tach in the truck. I only have one of those negative wires hooked up right now, and the truck runs but I'm wondering what the other wire could be for? I have a miss I'm trying to track down.

Well I have an 83 wireing book and it has a second wire on the coil neg terminal to an emission unit. The emission unit looks to be the EGR timer as it works a solenoid that controls vacum. It counts how long the eng is running before it will allow EGR. If your not using the EGR just leave it unhooked and taped back. Ron

correct,it is for egr delay relay.

I delete egr on mine then used the 12 volt power wire to the delay relay to power my choke on the aftermarket carb I run.

its a good keyed hot wire when deleting the egr/relay.

Thanks guys, that makes sense. The egr timer is still on the fender but isn't hooked up. The intake I'm using doesn't have egr anyways.

On the miss, I took the distributor apart cleaned and lubed the weights and advance plate, and stuck in a new pick up coil. It seems a lot better now, but getting that .006-.008 on the reluctor gap was a royal pain.

I was wondering where a good place to hook the electric choke would be. Right now it's hooked to the 12v side of the ballast resistor, but this causes a slight over-charging condition. I have about 15.2v at fast idle, if I unplug the choke it goes right back to 14.6v.

that's why I used the keyed power wire from the delay relay over on the fender..IIRC it is the middle wire..just sniped it from the plug and splice a wire to the elect chock.

I can get a pic of where I did this if you want.