Hey guys!

New to the Forum and looking for some help.

I have a 95 F250 w/ the 460, EFI. It has no spark at any of the spark plugs. I bought one on those in line testers and tried chasing the problem.

Chased it back to the ignition coil and found that it wouldn't light up the tester when I hooked it between the ignition coil and ground.

I do however have a blinking light when I hook a test light between the positive and negative on the plug going to the ignition coil.

I figured if I had good signal going into the coil, and no voltage coming out, it would just need a new coil for sure! Right?! Easy!

Wrong! I changed it out and I'm still having the same problem.

I work on chu-chu trains for a living, so I can turn a wrench, but I'm not the greatest with cars. Am I chasing this problem correctly?

Thanks guys!

 

Check the pip in the distrubutor.

 

I have ran into this and it always turns out to be the Ignition Coil Plug not making contact with the coil.

 

Thanks for the input guys.

got to mess with it a little today. I have a buddy who swears if I unplug the PCM and I get my spark back, that my PCM is toast and I need to replace it.

I tried it, and I'll be damned, she sparks all 8 with the PCM disconnected. Without the schematic, I can't really decide if I am willing to buy his theory for the $150 or so that it looks like it will cost me.

i guess its worth a shot right? what do you guys think, should I go for the PCM?

any other theories?

thanks again guys!

 

Did it fire up and run?

Plug it back in and check again if no spark then new pcm it is.

 

Try this, unplug the SPOUT connector(small plug near the TFI modual used to set base timing) with the ECU plugged back in.

It may start up and run, if not then check for wires shorted, I had that happen on my 89 F250 and found shorted SPOUT line to ECU caused my no spark condition. With the SPOUT removed the engine ran at base timing.

 

Just to add more fuel to the what-could-this-be fire, when I was chasing a no start condition I also tried the PCM unplugged test. Sure enough, with the PCM unplugged I got spark, plugged it back in and no spark. Turned out to be a blown fusible link. So that's one more thing to check for.

 

Good tip Eddie!

Spark comes back & engine sputters and tries to start with the SPOUT connector disconnected. That's super exciting, but what does it mean!

 

It means the SPOUT wire is being held high or low all the time by the PCM Computer.
You need to make sure that PCM Computer has power on all of its power pins with the key on (pins 1, 37 & 57) and all of it grounds are good (pins 40 & 60).
If the grounds and the power to the PCM Computer are OK the you need to replace the PCM Computer. It may be just the caps but you need to open it up and have a look see.

 

I borrowed a PCM from O'reilly's this morning and I had no change in symptoms. I am getting good positive to 1, 37, & 57 as well as good negative to 40 & 60..

Any other theories? Anyone got a schematic for the ignition system?

Thanks guys!

 

Sure:



/

 

Ok, I'm not sure why I didn't try this sooner, but I tried starting the truck with the spout jumper disconnected, then re-applying the jumper with the engine running.

It works. Sounds just right with the jumper plugged in. Once I shut it down, it's a crapshoot weather it will start with the jumper in; However, it will start without the jumper every time..

Again, I've tried ignition coil, ICM, and PCM..

What would be the harm in running a switch to the dash to open the jumper when it doesn't start. Any clues as to why I am seeing this result?

 

Deleted deleted.

 

Check for a short to ground or power on the SPOUT line, pin 36 of the ECU to the TFI module. As you replaced the coil,TFI and ECU, wiring is the next and last thing could go bad unless you have a defective new part due to the wiring issue.