Did my pertronix fail?

[cldonley]

351W, 1996 roller. Pertronix dizzy purchased from a member on here, Accel coil. 2100 series carb, 3040 pump with explorer serpentine. Went to bed last week with it running great, next start it's missing, no power, barely idles. Checked for vacuum leaks, all good; manual choke opens and closes fine. Checked the timing and find that the No.1 plug is firing intermittently. Checked other plugs and found intermittent or no fire using the induction timing light on the plug wire. Inside of the cap looks good, wires are all firmly plugged in on the cap and the plugs. Did my pertronix unit fail?

 

[nvrstuk]

Petronix are great BUT you need to make sure of a couple things... We put these in so many boats and old rigs...

What is the voltage on the coil? They must have 12v, NO ballast resistor. Bypass it.

Did you leave the key on for an extended period? Used to be an issue and since this is a "used" unit it could be a 1st Gen that was more susceptable to burn out with the key on.

It needs to have a 1.5 ohm coil. 4 & 6 cyl coils running at 3.0 ohm's won't work properly.

I'd swap in a buddy's coil then... 12V

I'd borrow another timing light if you still have an issue to determine if you really are getting some wires w/o spark.

 

[cldonley]

No ballast, Painless harness. 1.4 ohm coil. Didn’t leave the key on.
12.01 volts at the coil with key on, not running.
I’ll try a spare coil and see what happens.
Thanks!
And-it’s an Ignitor II module.

 

[nvrstuk]

You are on the right track.

Keep us posted. Petronix are tough & last "purt-near" forever!

 

[cldonley]

Subbed in another coil, no joy. Read up on troubleshooting the module so I’ll try that tomorrow. Thanks for the help!

 

[guilty1]

No ballast, Painless harness. 1.4 ohm coil. Didn’t leave the key on.
12.01 volts at the coil with key on, not running.
I’ll try a spare coil and see what happens.
Thanks!
And-it’s an Ignitor II module.

Having similar issues with same tests and module as above. Trying a new coil and while exchanging it, my coil wire to distributor fell apart. wire end that plugs into coil looked like got hot and the connection crumbled when I took it off. I had a spare set so replaced all plug wires. Will test drive tomorrow. Mine would idle/run fine when cold, as it heated up would start missing intermittingly, finally wouldn't hold speed.

 

[cldonley]

You are on the right track.

Keep us posted. Petronix are tough & last "purt-near" forever!

I tested the module and coil using the guide from summit, everything is like it should be. Pulled off the module and looked for evidence of overheating, all looks good. Tested the timing light on my 88 Bronco, works like it should. Checked fuel flow, looks fine. Used a circuit tester between the negative side of the coil and ground and the light flashes like you'd expect while cranking. Still have intermittent spark or no spark on at least three cylinders. I have an HEI style distributor on the shelf I could stab in there and see if it fixes the problem. Anyone have any ideas what I can try next? If I had any hair, I'd pull it out.

 

[cldonley]

Having similar issues with same tests and module as above. Trying a new coil and while exchanging it, my coil wire to distributor fell apart. wire end that plugs into coil looked like got hot and the connection crumbled when I took it off. I had a spare set so replaced all plug wires. Will test drive tomorrow. Mine would idle/run fine when cold, as it heated up would start missing intermittingly, finally wouldn't hold speed.

I just made a new coil wire not long ago. It seems to be fine. Hope it corrects your problem!

 

[nvrstuk]

So..... we've been assuming it's ignition because of what you witnessed with the spark on the plug wires correct?

Is it still doing these spark symptoms? Erratic spark on ALL plug wires not just #1?

For clarification, ran great when parked (like all the want ad "for sale" posts say right ) ?

We're assuming ignition because of the timing light flashing erratically. Lot's of other dead ends to chase but we need to be 100% that the spark is doing weird things and it's not the timing light or connections.

 

[m_m70]

Sheared off distributor gear pin?? Heard some pretty bizarre stories that ended up with this being the issue.

 

[cldonley]

So..... we've been assuming it's ignition because of what you witnessed with the spark on the plug wires correct?

Is it still doing these spark symptoms? Erratic spark on ALL plug wires not just #1?

For clarification, ran great when parked (like all the want ad "for sale" posts say right ) ?

We're assuming ignition because of the timing light flashing erratically. Lot's of other dead ends to chase but we need to be 100% that the spark is doing weird things and it's not the timing light or connections.

Yes, it was running great when I parked it. Had been test driving on a dirt road by my house. (No tags yet).
My first thought was to check timing, that’s when I discovered the intermittent spark. Timing appeared to be where I left it after the last adjustment.
Fuel flow to the carb is normal.
I checked to make sure the timing light was working correctly on my 88 Bronco and it is working normally, like it should.

Sheared off distributor gear pin?? Heard some pretty bizarre stories that ended up with this being the issue.

I considered this too. I’m at the point where I want to pull the dizzy and see.

I bought this engine running out of a van. I had the heads done and replaced all seals and gaskets, installed new timing chain and gears. It’s a 96 351W. Cylinder walls looked great with no ridges and clear cross hatch. Up til this point it seemed to run great, plenty of power, started easily. I was tinkering with the timing.

So yeah, assuming the ignition is the problem because of erratic spark and the turn the key off with everything fine and next start it will barely run situation.

Found at least one plug not firing at all, with the others erratic.Distributor cap and rotor look fine, don’t see any cracks.

I’m looking for any other tests I can do before starting emergency surgery.

Gotta go do some work on an airplane today, hoping to get back on it this afternoon.

 

[acropilot]

If you have a multimeter you can ohm check your plug wires.I just went through this and showed no continuity on my coil to distributor wire.It was enough to make it run but would start to stumble under load.I made up a new wire and checked it with my multimeter making sure it was all good and it solved my issues.

 

[Brush Hog]

Check battery cables and battery ground wire. I had battery ground wire that got all frayed and caused some misfire issues. Have had loose battery cables that have caused similar problems too.

 

[Jdgephar]

1996 351W should be a roller cam, if I've googled correctly. Make sure the gear on the distributor is the correct material type for that.

 

[cldonley]

I haven't been able to determine for sure what's wrong with this thing yet, so I'm in the process of dropping in an GM style distributor that I had on the shelf. We'll see if it works.

 

[nvrstuk]

Anybody around that you can drop your Petronix in and check it on their rig? Any 302/289 will do. Hot wire 12v to it. Beats buying a new Petronix.

Can you call Petronix and have them check it? Wouldn't be great if you needed your rig every day but...

 

[cldonley]

Anybody around that you can drop your Petronix in and check it on their rig? Any 302/289 will do. Hot wire 12v to it. Beats buying a new Petronix.

Can you call Petronix and have them check it? Wouldn't be great if you needed your rig every day but...

Nobody around with a 351 I can think of. I am gonna contact Pertronix and see if they can take a look at it. I've followed all the test procedures I can find and it just doesn't seem to be right, even though it doesn't exactly seem to be bad either. I went to it because I don't like the size and look of the GM style distributor.
The frustrating thing about this is I'm at the point of my build where I should be installing new seals in the top and putting in the new seatbelts so I can get it tagged and start driving it, not going back to the drawing board.

 

[nvrstuk]

Yeah, I understand how you feel. But maybe that can be shipped out and back and checked out by them before your first cruise day!

It sure sounds like you went through all the proper testing and everything have them check it out. Save yourself some time and effort.

Did we ever get to see a picture of your rig that you're building?

 

[ntsqd]

I've never personally been burned by a failed Pertronix, but I got to help with enough field failures in their early years that very early in the game I decided to go with converted OEM electronic ignitions instead. Like with a Mallory Unilight, I'm just not impressed and rate them equally unreliable.

Was it me, I'd go with a D-S II distributor (large or small cap is your decision) driving specifically a Dyna-Mod GM HEI module with a Ford or GM E-type coil. I've used both and prefer the GM coil for it's sealed connector, but either works well. Build the wiring harness to use original connectors so that any one of the main components can easily be replaced with a part from your local auto parts store.

 

[nvrstuk]

Long...

It's amazing how different stuff can work for different folk without any flaws.

I know when Petronics first came out, they had a couple of small issues, but since then, they've been flawless, except for maybe this one...

I tried a Mallory HEI distributor ( before holly bought them out) bought brand name pickup modules and they would die after maybe a month, I would never go back. Just my experience.I'm sure there's great ones out there.

I used to have two blue Duraspark OE modules bolted to my fender for a quick easy wire plug in replacement for when they failed.
These were all Motorcraft, and when you got a good one, they would last five to ten years, and then you might go through two or three in one year...

Find something that's works for you and run with it.

I went back to OE with Ford's wasted spark ignition w/o a dizzy for yrs & loved it. Course it needed a Moates Qtrhorse chip, that would piggyback on a mustang computer... during covid, when those got super rare and I built a different engine, I went to the Holley Terminator X.

I put that decision off for about 9 years because I ran a Holley Projection when they first came out, and they were not supported, very long.

That's the other concern for those that keep their Broncos any length of time. Can I get parts to replace what I put in 10 or 20 yrs ago?

Hope you figure this out and when you do let us know.