electrical and ignition Symptoms of Pertronix Failure????

[Wahnsinn]

I was driving my basically stock '75 (all smog stuff removed) the other day.  As I was leaving a stop light, I was accelerating in 2nd gear when all of a sudden I temporarily lost power. This happened at about 4,000 rpm.  It was like the engine just shut off; but it was still idling, just would not rev up under load.  I stopped, and checked for any loose connections, etc; but didn't see anything obvious.  

 

I was able to restart the car and carefully drive it back home; but acceleration was slow with a lot of stumbling and weakness as I tried to accelerate.  Once a cruising speed around 55 mph was reached, it would run there; but if I tried to accelerate, it would stumble a bit before gaining a few more mph.

 

As I said, the car is basically stock with a Weber 32/36 carb, and a Pertronix igniter.  

 

My first question is when a pertronix fails, does it go completely bad, so that the car won't run, or could it fail somewhat intermittently causing the type of problem I experienced?

 

Appreciate any thoughts. 

[TobyB]

Usually, but not always, they just die.

 

Yours sounds more like fuel pressure or maybe junk in the carb main jet. 

If you romp on it (open the secondary) does it run?

 

t

 

[Wahnsinn]

Yes, it does. Once I get past the stumbling and hesitation, if I can get the revs up, it will run.  Looks like I need to be checking the fuel side of things.  I hope to get at it in the next couple of days. I'll let you know what I find.

 

Thank You

[percy]

Symptoms of Pertronix Failure????

 

Same as turning ignition key to left and removing it.  Difference being that the failed pertronix [should not] lock/unlock steering.

[Mike Self]

Don't have a Pertronix, but it's like most of the electronic ignition enhancers (MSD, Delta Mk 10 CD unit etc).  Generally they work, or they don't.  In fact in the pre-electronic ignition system days a good rule of thumb was that if the engine just suddenly died and wouldn't run at all, suspect an ignition problem.  If it coughed, stumbled, ran raggedly (but still ran) then check the fuel system.  

 

Agree with Toby--check your idle jets for trash--the jets are tiny and an equally tiny piece of trash will block 'em.  Weber main jets are in the bottom of the float chamber, so if you have any crud in the float chamber, it'll get into the jets with unfortunate consequences.  When was the last time you cleaned out your carb?

 

One more thing to check--loose vacuum line or other source of vacuum leak--including the vacuum advance unit on the distributor.

 

happy troubleshooting

 

mike

[zinz]

I had an igniter in an early Ireland dizzy slowly fail. Loss of power, stumbling, etc... Put in a HotSpark and solved the problem. 

 

Recently had an igniter in a most recent model of Ireland's dizzy... It just quit. No warning. Again, put in a HotSpark igniter and solved it. 

 

I always keep a set of points/condenser in the tool kit to get me out of a jam when running this kind of set up. 

 

My 123 hasn't hiccuped once since I installed it about 10,000 miles ago. 

 

Ed

[TobyB]

Quote

Once I get past the stumbling and hesitation, if I can get the revs up, it will run.

Sure sounds like junk in the carb, then.

 

Not too hard to clean- you can usually just pop the top off the carb, and have at it.

 

t

 

[Russell74Fjord]

I had the magnetic ring let loose, and two of the little magnets escaped, drove home on two cylinders (less than a mile).

 

Also replace fuel filter, check the one at the carb too, and even the screen at the fuel sender pickup, of all else fails. \

Does sound like fuel starvation, not ignition.

[peterschop]

It sounds to me like a dirty fuel filter. That's what happened to me last year on the way to MidAmerica. My car ran fine when I left my neighborhood at 25 mph but when I pulled out in traffic, once I hit 4K rpm's in second gear, it just bogged down with no power at all. I pulled over and it would idle, so I turned around to go back home. Same thing when I hit 4K so I limped home. The car would idle but not run under full power. I pulled the fuel filter off my Triumph, put it on and have been driving it that way ever since, over a year later.

 

Earlier I had a Pertronix type ignition fail when I first bought the car. The car would run fine for about 15 minutes or so. Then it would start stumbling and cutting out while running until it would not run at all. I would have to let the car sit for about 20 minutes to let it cool down. Then it ran fine until it heated up again. First I thought it was the coil because that got really hot. I replaced the coil and still had the problems. I put a new Pertronix in, problem solved. 

 

Check your fuel filter and if you still have problems, check the carb.

 

 

[Wahnsinn]

I want to thank all who replied to my question.  I replaced the fuel filter, and when that made no difference, I removed the top of the carb, and removed and cleaned the two main jets.  I didn't see much come out; but I guess it doesn't take much, because the car runs like a top again.

 

Thanks to Toby, Peter, Mike and Russell for their responses, which were right on.

 

I guess this is why we play with old cars, we can fix them.