Hi, guys. Hoping someone can help me give a coworker some advice.

I haven't seen the truck. He says it's a '94 Ranger four cylinder. Don't know much more about it. He said it has 8 plug wires, and I guess 8 plugs. One set of 4 fires OK, one set not fireing at all. Runs very badly, he's not driving it. Discount parts place can't scan a '94 he said.

Coils, wires, and plugs have all been replaced.



Any suggestions on what to look for?

Thanks.

 

Well if he has a CEL lit, he can pull the computer trouble codes himself using the technique listed in the "Tech Info" thread atop this forum.

Advance Auto in my area uses the Actron CP9150 scantool that'll hook up to OBD-1 & OBD-2 Ford, GM & Chrysler vehicles for a scan, so call around & see which store has a scantool with the EEC-IV connector, that'll pull codes on his model vehicle.

That scantool will also display PID's too, so we can see live data feeds from the sensors to the computer, which helps in a trouble shoot.

If he just wants to begin a trouble shoot, maybe check the coilpack that's not firing, for B+ 12 volts at KOEO.

If ok then check the coilpacks primary & secondary coils for continuity (compare it's resistance readings with the good one), if that checks ok, then maybe swap the coilpacks positions & see if it'll fire those plugs & the other coilpack doesn't work.

If swapping coilpack positons doesn't change things, then suspect the ICM, as it provides ground switching to fire the coil packs & is a common problem part, so maybe pull it & have it bench tested.

If he comes to suspect either coilpack, pull the suspect & have it bench tested for output.

Most autoparts stores can & will do these tests & at no cost.

Let us know what you find.

 

THANK YOU for all that info. That should give him a lot to work with.