85 ranger duraspark conversion

[heisler0]

We did the duraspark conversion over the weekend everything went good got truck running. Started the truck the next day while it was warming up it shut off now no spark. Only thing I didn't change was the tfi coil. is this coil ok to use or does this need to be swapped also?

 

[ford4wd08]

Did you use the duraspark control box? Or GM HEI?

 

[heisler0]

duraspark control box. I was able to grab another control box from a running vehicle and tried that.

 

[franklin2]

If you are using the duraspark II control box, you need to use the duraspark II coil. And don't use any "hot rod" coils with the duraspark II box either. The square type coil and the "hot" coils put more load on the control box. You also need to make sure you are running the resistor going to the + supply of the coil. This is already in the factory wiring, but you have to hook the wiring up correctly to utilize it. Or you can get one for a Chrysler product and wire it in. Running the duraspark II box without the resistor will overheat and usually damage it also.

If you want to double check the resistor, measure the voltage on the coil + with the engine running. It should be around 9v or so. It has to be running to check it.

 

[heisler0]

Thank you for the response we ordered new coil should be in today will put it on in the morning. As far as the resistor are you referring to the duraspark II resistor or is the one currently installed on square coil ok?

 

[ford4wd08]

He is not talking about the radio noise capacitor on the coil.

He is speaking of a resistor that is wired into the wiring going to the coil.

The TFI coil doesn't utilize this, but the duraspark round coil needs it for the duraspark system.

 

[heisler0]

gotcha! Thank you again!