I are a mechanic -maybe... My 86 dodge d150 ram w/318, will only fire the instant you let up on the start spring. One out of 6 trys will usually get a start. I've replaced:
electronic spark control (advance)
coil (autozone)
dist. module (advance)
starter switch (wreckers)
but still the same thing.. I am pulling my hair out. Coil has 13+v both posts, and drops to 11+ when starter activated. suggestions please?

 

I's been awhile since I've worked on older truck but.... Does it have the white ceramic resistor on the firewall????
Those used to fail just like your describing!!!
Just a guess!!!

 

Thanks!
There is no ballast resister on the firewall, underdash or anyplace. I understand it's handled by the spark control unit. Funny, If I join the battery wire to switch with acc. wire (which is cut out at start position) the coil will fire.

 

I would find the wire that's hot in start only that comes out of the ignition switch and make sure it's not an open circut or grounded, Sorry I can't be more help..... Chrysler Info only goes back to around '92-'94

 

Hey!
thanks, J.C.!
If you've ever read "beetle Bailey", you know that sarge is happy to see any rope when he's hanging on the edge of the cliff.

I will start unwrapping loom to follow color.. I can only find locally a "Haynes" (1974-1993" w/ a no account wire diagram w/ no color code.

We lived in Florida a bunch on old 44 ft sailboat (17 yrs) Need info on guitars, mercedes, pool tables, farming or boats - you've earned it. Thanks!