Pertronix burnt out?

[Matches]

I was getting on the freeway yesterday and going up the on ramp the car started "misfiring" ( quotations because I am not totally sure what was going on ) the car stopped accelerating and sounded horrible and felt like the engine was struggling to even stay running, I clutched in and the motor died right away. Towed off the freeway for the first time in my life.

I have fuel, carbs are well tuned and happy.

I have a good coil, tests with a multimeter well and the ignition lead throws plenty of spark when laid on the fender and motor cranked.

But if I remove a spark plug and ground it on the fender, no spark. I checked all the wires to the Pertronix unit and they are good.

My car had not been starting before until I put in a new 3.0 ohm coil and removed the ballast resistor. Was running great for two whole days until this. Pertronix manual says no BR could damage the module. But the coil tests at 2.5 ohms, so the Pertronix unit shouldn't be getting fried right?

I though I would ask here before calling Pertronix. Any advice would be great.

[JimmyZ]

Did you try checking for spark at the coil wire? You could have a bad dist cap. Use a new plug for any spark tests.

I'm assuming that the plugs in your engine aren't fouled. Try installing three new ones just to see.

You did try spraying some starting fluid in the carbs to verify that it is not a fuel issue?

Just food for thought

[sblake01]

Just another thought: I had the same thing happen in my truck a couple of years ago and it turned out that the carbon button in the middle of the distributor cap that rides on the rotor had somehow disloged/deteriorated. New cap-problem solved.

[soundmasterg]

If the above don't fix it, then call Pertronix. They were very helpful when I called them.

Greg

[xray]

Pertronix either works or it doesn't, it's just a switching device with a magnetic sensor. They suggest either a 1.5ohm coil with BR, or a 3.0 ohm coil with no BR. I'd call them about using a 2.5ohm one...

I posted in another thread some Pertronix troubleshooting pages...

http://www.vintageperformance.com/retrorockets/troubleshooting.htm

If you have spark at the coil wire and no spark at the plug wire, I'd check the rotor, cap and center carbon button as previously mentioned. If you mash the rotor too far down the airgap might be too large for the spark to jump to the rotor.

Sigh....Well, at least it was an enjoyable couple of days, yes?

[sblake01]

If the above don't fix it, then call Pertronix. They were very helpful when I called them.

That's in his post:

I though I would ask here before calling Pertronix.

[GILDIA]

You could try switching back to points, if she still doesn't starts then the problem is not the pertronix, it could be the distributor cap

[sblake01]

Easier to just try the cap first........

[Matches]

Thanks for all the replies!

The cap is brand new, but that doesn't mean it is no longer functional, just unlikely. Hopefully I still have an old cap laying around someplace I can swap it for.

JimmyZ: I did check for spark at the coil wire. I pulled the single wire that goes from the coil to the distributor and laid it on the fender and cranked the motor. Good looking spark there.

GILDIA: I thought of that and went to find the original bits of my distributor and realized I can't remember at all how it was wired. Oops.

xray: Great troubleshooting link! Thanks. I will test the unit when I get home from work today.

Yes the car was so fun to drive again for two whole days. Sigh indeed.

Thanks guys!

[sblake01]

I did check for spark at the coil wire. I pulled the single wire that goes from the coil to the distributor and laid it on the fender and cranked the motor. Good looking spark there.

That shows that you're getting spark from the coil but it doesn't show that it's getting to the spark plugs. Do you have an inline spark checker? If not, pull a wire off of one of your plugs and put an old but working spark plug in the wire and see is you can see spark jump the gap, or lay that wire on the fender (w/o a plug) and test it like you did the coil wire. I prefer the first test because I deal mainly with electronic ignition and I don't like the thought of possibly sending a spike back into the module.

[Matches]

Yes that was one of the first things I tried. No spark at the plug, so I went to the coil, spark at the coil so I know it is a problem with the distributor someplace. Cap, Pertronix, not sure yet. Narrowing it down! Thank for all the help guys!

[Matches]

I just went through the field test that xray posted and my initial results are that the Pertronix unit has failed. I get constant 12v.

However I don't know that I did it right. Should I have removed the base plate for the test? The instructions do not say to do so.

I will call Pertronix tomorrow and ask their advice on the situation now that I have some real info to offer.

Thanks everyone for the help.