Howdy,

New to the forum and im hoping someone will be able to help me with an issue im having with my 1981 D150 3.7L L6. I purchased the truck in fair condition after it was stored in a garage for years and checked the typical issues for it having not been run for soo long. Thankfully it wasnt too mad about sitting around for so long and it seemed to be running great.

I recently replaced the rotor cap, coil, sparkplug wires and spark plugs. The truck ran fine until it clunked out on the freeway after I had to suddenly hit the brakes because of an old granny that was scared of oncoming traffic into the freeway.. The truck turns over but doesnt start now.

The problem is that there isnt any spark in the new rotor after the stall out, oddly though when i put the old rotor on it sparks despite the serious corrosion. I should also mention that I dropped the new coil on the ground when i took it out of the box :-/. It wasnt a long drop and didnt seem damaged but i dont know how durable they are.

Im no mechanic but I have managed to fix up a few cars, however anything as old as this truck is a bit of a mystery to me. Any advice would be much appreciated.

Thanks

 

i would guess if you are getting spark with the old rotor but not the new one then there may be a problem with the new rotor. i doubt dropping a coil would damage it. i have dented a coil before and it would still run my truck.

 

Agreed. I would cross coil off of the list knowing that it will make spark with the old rotor installed. Any wear marks on the new rotor? Signs of it rubbing on the cap? Excessive fouling?

 

Is the new rotor an exact match with the old one? Check the new rotor for cracks. A cracked rotor can send the spark straight to ground. Same with a cracked cap.

 

The rotor seems fine and the truck ran well after it was all installed until the stall.

Something else I have noticed now (I havent had much time to diagnose) is that when im checking for spark by letting it shock me while its being cranked, it will only shock me when you stop turning the ignition, not while its turning.

Thanks for the replies. Y'all rock

 

sounds like you may have a problem with the start circuit on it. could also be a bad ignition switch but could just be bad corroded connections. have you checked what voltage you are getting at the coil when you are trying to crank it?

 

I was going to check the voltage but my friend wrecked my voltmeter somehow and I have to get a replacement. Very busy lately but I will try to get another one today or tomorrow morning and post the voltage I get. A local mechanic that goes to my grocery store told me that I should check my ballast resistor. What do you thinK?

 

the ballast resister being bad should not cause it to give you no spark while trying to starting. there is suppose to be a wire that bypasses the ballast resister when starting.