Spout in, no start. Spout out, start

[Skooby]

Ok, history...new pcm a few months back, drove fine. Sat for a couple months building a bumper and stuff then would run for awhile and just shut off randomly till it finally went hard no start.....replaced the TFI and the distributer ( old one had shaft play ) same result. Started running down ohms and voltage on everything when I got to the point of checking the voltage while cranking with the Spout removed it started! Hmmm...I checked timing as long is it was running and locked down the dist, plugged the Spout in and it died immediately, no start, pulled Spout again and fires up and runs great?? Also with spout in the key on/engine off the tfi will buzz randomly and when it does the coil fires, and the tach jumps around (why I changed the TFI first)

 

[RonD]

SPOUT is the "Vacuum advance" done by the computer

So either the computer is sending the wrong spark advance or the TFI module is reading it wrong
Base timing should be 10-12deg BTDC (no SPOUT)

You can test the SPOUT wire, pin 36 on computer to pin 5 on TFI connector to make sure its not shorted to ground

You are using the GREY TFI module correct?

 

[Skooby]

SPOUT is the "Vacuum advance" done by the computer

So either the computer is sending the wrong spark advance or the TFI module is reading it wrong
Base timing should be 10-12deg BTDC (no SPOUT)

You can test the SPOUT wire, pin 36 on computer to pin 5 on TFI connector to make sure its not shorted to ground

You are using the GREY TFI module correct?

Yes, the new distributor had a black one so I swapped it out with the new grey one that I had previously installed on the the old distributer. With truck running I have 5v on one side and batt + on the other side of the Spout connector.

 

[RonD]

Not sure what you are measuring

Do Spark Advance test #8 in this article: https://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

 

[Skooby]

Not sure what you are measuring

Do Spark Advance test #8 in this article: https://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

Step 9 on the worksheet is the measurement I was referring to. But step 8 was confusing to me because I did not have 0 ohms.....but the worksheet does not give info on where to go if you don't have 0 ohms. Tried to find it on the wiring diagram to no avail....

 

[Skooby]

Failed PCM. All better.....