I have been trying to fix my 1886 F150 302 TFI with no spark problem

Initially I did some parts changing...replaced the coil (techie friends insisted that even though it passed resistive checks they have checked coils and found them to be bad,,,,I also changed the TFI module)

Time went on and now since I am off work as a teacher I am revisiting the problem....

I attempted to read the PIP signal and was measuring 14-15volts AC or more (while cranking) on an analogue VOM
Interesting that when I turned the start switch off...on RUN It still read 15 v steady while I was cranking the needle jumped around

The manual says 3-8.5v AC is spec

I wasnt sure if an ac signal , even high was not in spec, so I proceded to measure the SPOUT voltage....I also read the same high reading.....

I disconnected the SPOUT connector and read the same 14v on the PCM side of the connector

I went on to measure 2500 ohms to ground from the same point on the SPOUT connector, when the manual indicates it should read 10K ohms or above

So far, this seems to indicate a bad PCM, no?

This is where I dead ended!!! For the life of me, I cant locate where the PCM is on this Lariat.....I looked under the dash, by the oval kickplate(on pass side)..panel to the right of kickplate and only found empty space and compartments..any ideas?

I wanted to follow trouble shooting procedures and disconnect the PCM connector and see if my voltages changed or my resistance reading changed

I cant believe that I have a Chilton, Haynes manuals, have surfed the internet, asked people at NAPA, and AZONE and still no-one seems to have the answer on where that module is located!!!

Any further help would be greatly appreciated

Sincerely

James Goslin
San Antonio, TX

 

the ecm on the 86 f-150 is in the centre of dash above
accelerator pedal
leave spout connector unplugged and check for spark
i would blame the hall effects switch in dist before i condemed
the ecm. unplugging the spout disconnects ign system from ecm
mitch

 

I'm with mitch,....... hall sensor or the TFI module.