94 Mustang No Power High Rpm

[tony M]

Hey all. I have a 94 mustang gt with a 347 stroker in it. It has a Jacobs electronics ignition in it. Last year I took it to the drags. After a few runs it started missing at high Rpms. I replaced the plugs and wires. This year I went again to the drags. And it happened again. So I replaced the pickup coil and bough a new coil and ignition control module to take with me next time. Went again and it happened again. Replaced the coil and ignition control module. Still having issues. Got worse this time. Sputtered and would go any higher then 4600 Rpms.

I know it is a heat related issue. The first run is great. Then after that it gets worse. Doesn't do it on the street. What could I look at next. Thanks for the help

 

[mikestang63]

What is the gap on your plugs
What is your FP set at
what is your timing set at
Have you taken the jacobs off and run the stock ignition

 

[tony M]

Timing is 10 degrees btc. I am going to try taking the Jacobs ignition off next. I will have to check gap and fp

 

[tony M]

Would the gap or fp be an issue though? It only happens when I am doing runs and it is getting hot. Doesn't happen on the street.

 

[jrichker]

The TFI module mounted on the distributor is usually the culprit for a high speed miss on a warm engine. If the problem does not occur when the engine is cold, the TFI module is definitely suspect. You may need a special socket to remove the TFI module, but most auto parts stores will have one for $5-$7.

Be sure to use plenty of the heat sink grease on the new TFI and clean the old grease off the distributor.

See Automotive Tools Specialty | Auto Mechanic & Technician Diagnostic, Testing Equipment | Thexton

diagram courtesy of Tmoss & Stang&2Birds

 

[Dave2000GT]

Not enough fuel pump? That could explain track issue vs street as the fuel pump can keep up banging quickly through 1-2 but on the longer 3-4 pulls it starts to run dry.

 

[tony M]

I had replaced the TFI module yesterday at the track. Didn't fix it.

 

[tony M]

Is there a way to verify a fuel issue myself? Or is that something I need to take to someone with a dyno?

 

[tony M]

So I think I fixed the issue. Today I took the car out for a ride and is misses and breaks up all of the time. Not just when hot. I was tracing the wire from my Jacobs ignition. And I found two connections to the harness coming from it. It was behind the battery. So I pulled the ignition side connectors off and plugged the two harness connectors together. Took it out for a ride and no issues. Thanks for all of you help. Hopefully it stays working