No fiire from coil

[stang22]

Here is something to add that seems a little strange to me. If I turn the key on, loosen the distributor hold-down and turn it, it's like the fuel pump primes or comes on. I hear it pressurize and watch the FPR gauge and it goes up and down. I can turn it back and forth and I hear it prime and then shutdown. Is this normal?

Tim

 

[HISSIN50]

if you turn the dizzy like that, it should energize the injectors, IIRC. not sure about priming the pump.

how is the fusible link to the ignition? on mine it is a 16 gauge (IIRC) feed. it comes off the starter solenoid.

good luck bud.

 

[stang22]

The only thing left to replace is the PIP. I bought one from AutoZone and will get it installed next week. I will let you know if that was the problem. Thanks for everyones help!

Tim

 

[jrichker]

Tim, I think that the neg side of the coil connector gets ground from the TFI (the ground pulse lights off the coil). I would check with JR first (to be sure).

good luck.

You are right. All the power circuits that use computer or solid state control operate as current sinks. They switch from open circuit to ground. This prevents damage to them if a short to ground occurs, since they supply no power, only ground.

The resistor in the tan/yellow wire is a 22,000 ohm resistor used to isolate the TFI power from the computer. It also keeps the coil from being constantly energized should a short to ground occur in the wiring between the computer & coil. Pin 4 on the computer probably is used to get some timing information for the computer's use. Pin 4 would not have 12 volts on it, but a lower voltage because of the 22k ohm resistor.

Pin 4 tag is IDM (?), pin 56 is PIP, pin 10 is ACC (?) & all 3 are inputs. Pin 36 is the SPOUT & is an output.

 

[stang22]

Just an update on my problem. I was on vacation last week and didn't get a chance to work on this. Although I have not fixed my problem yet, I have become very familar with the computer system... in particular, the ignition system from everyone's help as well as searching the internet. I have found a couple of good write-ups that someone could add to thier libraries if they wanted to. I found a Wells article that was very informative that might help others understand the power of true troubleshooting as they have explained.

I bought a PIP sensor last week and plan on changing it this week, so hopefully this is the problem. I had the TFI module tested this morning at Autozone and it checked out ok. Anyhow, there are 2 articles from Wells. They troubleshoot some ignition problems on a 1994 Mustang and tease you at the end of the 1st article, but the 2nd article has the diagnosis with the corrective action. I recommend anyone who has or has had ignition problems to read them. Good stuff!

Wells Article 1
http://www.wellsmfgcorp.com/counterpoints/counterp_v8_i2_2004.pdf

Wells Article 2
http://www.wellsmfgcorp.com/counterpoints/counterp_v8_i3_2004.pdf

Other TFI/PIP Articles
http://www.onr.com/user/pbooth/mustang/tfi.html

http://fordfuelinjection.com/?p=6

I will let everyone know the results after I change the PIP.

Tim

 

[ALMOST STOCK]

Tim,
The articles seem a little lengthy, but definitely well worth the reading!

 

[stang22]

I changed the PIP in it today... No fire yet. I am off to do more research and hook a computer up to it.

Tim