Not mustang, but TFI-IV question..

Hey guys,

Trying to help my uncle get his ranger going. The thing ran fine for a long time, the other day in my driveway it stalled, would not fire. No spark. He changed the TFI and it fired for about 15 seconds then died and would not restart.

I checked the harness for visible damage/ shorts, couldn't find any.

We replaced the TFI again, again started and ran for about 15 seconds then died, no restart.

My question is, what would casue this thing to eat up TFIs? I tested them with an ohmmeter, and the values check out fairly close, not exact, but fairly close. TFI doesn't look burned inside. No smell either.


THe only thing suspicious i have found so far is that the coil didn't show any resistance from one of the small terminals to the coil wire post (should be 8-11k).

Getting another coil to try as we speak.

Any help would be greatly appreciated.

New coil fired it right up.

I knew something was up when there was no resistance between the coil wire tower and either of the small terminals.

THanks for the help.

Oh and BTW. when we changed the TFIs it would run for 15 seconds, then not again. After we changed the coil, it worked with the TFI that didn't work before.

Interesting fact how a different TFI can mask the coil problem.