TFI no start issue

[66HertzClone]

While driving my Mustang a few weeks ago I noticed a miss under part throttle acceleration, I would be some light back-firing and then it would run normally. I started heading for home but didn't make it without help from a flat bed tow truck. As I pulled away from a stop light the back-firing and miss went for a few seconds and then the engine stalled and shut down.

I have a MassFlo fuel injection system on the 331 stroker, it uses the TFI style distributor, the supplied unit in the kit is made by Mallory, same style module as the Ford unit. Once I got it home I checked for loose wires and found none. I purchased a TFI module on the chance it had failed but that changed nothing.

I did some searches and found some diagnostic assistance at this web site,

http://easyautodiagnostics.com/ford_ign ... le_3.php#2


I do not get a spark, so I then went to Test 3, made the LED test light to check coil switching. When I tested this I found the LED lights up as soon as it is connected, at this point the key is off. When I turn the key to the RUN position the light goes out and does not flash when the engine is cranked.

I went on to test 4 and tested the PIP sensor, same results as with the test above. So, it appears the PIP sensor has failed as its signal does the coil switching. Does this sound correct? Could I have missed something? Any other tests I can make? The PIP sensor in this distributor is available only from Mallory, so if it is bad I'll have to pull the distributor and send it to Mallory for r & r.

 

[66HertzClone]

Resolved

I pulled the cap off to get a look at the PIP sensor, found I could rotate the dizzy shaft by hand. Hmm, connected the remote starter switch and the dizzy shaft sits still, pulled a plug and the compression popped my finger off the hole. Pulled the distributor out and found the roll pin had sheared, taped a socket on a long extension and thankfully the oil pump turns freely. Going out to find a new roll pin.

 

[BobV]

Thanks for the link though - that's an AWESOME diagnostic article. i've bookmarked for future reference.

We just went thru ignition issues with my son-in-law's 87 GT. With an upcoming trip, we took the easy way out and replaced the entire distributor and coil. Richporter makes a new dizzy including the module and new PIP. Together with their new coil, he spent <$75 on Amazon. Well worth it just to have the spare parts.