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Posted by: srreality May 8 2017, 10:55 PM

On Saturday, during a splendid drive through the Colorado foothills, my newly finished '73 914 1.7 liter quit without any warning. No coughing, no sputtering, no lurching.....just quit at about 60mph. Not a hot day, no warnings. On the roadside I found no loose wires, no melted wires, no outward signs of distress. My fuel pump is located up front, so doubt it was vapor lock. After dragging it home, the next morning I tried to start it........and voila, it started up perfectly and ran like a charm. My local pro looked at it this morning (Monday) and after testing things thoroughly, found nothing amiss. He did say that once in great while, the electronic ignition inside the distributor cap goes bonkers, perhaps from heat and the car would die like that, then start later. Those parts are new (Pertronix),. Anyone else had this experience? Thoughts? Suggestions?

Thanks!

Posted by: Spoke May 9 2017, 04:55 AM

About Pertronix, I've heard about folks having issues with it. I've had 3 different engines with 3 different Pertronix modules for years and not a single hiccup.

An issue like yours is difficult to debug especially the next day if nothing looks amiss. With such a stoppage, first determine if it's electrical or fuel related. Spraying starting fluid in the intake can help point to electrical or fuel. If it fires then it's fuel or intake system.

Is this FI or carbs?

Posted by: srreality May 9 2017, 06:59 AM

It's thoroughly rebuilt FI. The mechanic said he had this same thing happen to him once in the 30 years he's been working on these cars and he's heard of it so rarely as to be negligible.....but hard to debug now, as it starts up and runs fine. I've only put a few miles on it since the rebuild, so I'll just have to drive it some more and see if it happens again. I'll carry some starting fluid with me and a few more tools in the future.

Posted by: eyesright May 9 2017, 07:29 AM

Same thing here. Mine happened 2 weeks ago and I haven't been able to work on a solution and won't be able to for another 2 weeks. 40K miles on a rebuild with Pertronix.

That's two of us so there is another out there. I hope this isn't the Kim-Jung-whatzizname testing out his EMP interfering with our 50 year old Bosche computers.

Posted by: The Cabinetmaker May 9 2017, 08:20 AM

Have you tried reinstalling the points?

Posted by: Amphicar770 May 9 2017, 09:00 AM

My 2.0 dies on my a week ago. Died on the road, trailered her home, she started right up the next morning. Turned out the wire to the CHT had come disconnected (not sure if that part is on the 1.7). Did not notice the loose wire along the road but found it when I got home.

I have run pertronix in a half dozen cars over the years and never had a problem. When they do go bad they are usually fried, not the intermittent issue you describe.

I would start with things like disconnected / loose wire at coil, etc. Try replacing distributor cap and rotor if you still have old one. If you used crimp connectors anywhere, give a pull on the wire.

You can always try putting the points back in but I would thoroughly check over wiring, fuses, etc. first. On my Amphicar I once had a cracked battery cable connector and would have intermittent sudden loss of power, took a while to figure that one out.

Posted by: boxsterfan May 9 2017, 10:14 AM

My fuel pump went intermittent when this happened to me. Eventually the fuel pump died.

Posted by: AZBanks May 9 2017, 11:12 AM

marbles in your gas tank?






(A really mean prank from my high school days)

Posted by: Vacca Rabite May 9 2017, 11:33 AM

If it just dies without warning, I'd certainly be looking at electrical / ignition issues.
Fuel starvation would cause bogging, bucking, slower death, etc. Mechanical issues would make very bad noises. If you have fuel injection, there aren't many things that could fail that would cause the engine to just stop.

There are wires that if they ground out will kill ignition. Tach wire is one of them (purple IIRC).

Over heating the electronics in the Pertronics could cause what you are describing.

Improper (low) voltage going into the coil/dizzy might cause it - do you have a volt meter in the car?

But I bet you have a wire with an intermittent ground, or a bad connection from the coil to the dizzy, or something like that.

Zach

Posted by: srreality May 10 2017, 08:25 AM

Thanks for all the tips and suggestions. No loose wires, can't find any loose grounds, no shorts, etc. New distributor, coil, plugs, wires, etc. It was a cool day, sunny and 70, all the engine tin is in place and in good order, so can't imagine heat caused it, but I'm new to 914s, so have no baseline. I'll just have to take it out on another sunny day and drive around close to home for about a hour and see what happens.

Posted by: bowzer May 10 2017, 08:36 AM

i assume you have checked the connections on the relay board.flip it over and see if it is melted.been there done that.

Posted by: rhodyguy May 10 2017, 10:31 AM

Does your car still start? When it died on the drive did the starter still function? When was the last fuel filter change and outlet strainer/screen in the bottom of the fuel tank inspected?

Posted by: cuddyk May 10 2017, 11:44 AM

Could be an overheated coil. Or one that's about to die.

Posted by: porschetub May 10 2017, 02:05 PM

,the amount of time they take to break down can be hit and miss,have heard issues with the latest Bosch blue coils appears they don't last long but never bought one.
I do remember the Pertronix is coil specific but I think that only applies to the Igniter II system,something like 0.6 ohm resistance from memory and the instructions state no solid core leads to be used.
Never had a failure with Pertronix myself or heard they fail due to heat issues,pretty simple system really.

Posted by: toadman May 10 2017, 07:23 PM

This happened to me too.

I have also had my fuel injection brain fail intermittently. Replacement with a known good unit fixed this problem.

Posted by: cuddyk May 11 2017, 06:03 AM

Run the car for about a half hour and feel the coil. If it's too hot to touch for more than a few seconds, there's a good chance that's at least contributing to the problem. You might try getting the 3 ohm flame thrower coil to match your pertronix. Inexpensive and at least you'll eliminate that issue from the equation.

In my experience, sudden shut off is usually electrical-related.

Good luck!

Posted by: brant May 11 2017, 08:54 AM

After the weekend is passed, I'm definitely around to help
I'm kinda far away, but have lots of spare parts if its any help
brant

Posted by: worn May 11 2017, 10:20 AM

Would only keep the tank shiny on our cars. I had an intermittent problem with my 911Sc and it was a connection to the fuel pump relay. Just suddenly died outright. I suppose the fuel pressure accumulator, which we don't have on the teener was able to keep things going until sudden fuel starvation. Intermittent problems are by far the very worst kind.

Posted by: worn May 11 2017, 10:23 AM

I should add that I killed a pertronix unit by reverse polarity hookup. But it was solid dead.

Posted by: The Cabinetmaker May 11 2017, 10:47 AM

Just drive it and the next time it happens, check for spark. If it sparks, it's fuel related. If not, its electrical. Btw, a fuel delivery problem could still be electrical related.

Posted by: cuddyk May 11 2017, 11:36 AM

Posted by: jim_hoyland May 11 2017, 11:53 AM

I've experienced this three times over the years; the last was a faulty fuel pump ground, prior to that, the ignition module in the distributer was the cause - it acted just like your situation; first time was a loose dual relay connection ( L-Jet )
I found a permanent fuel pressure gauge in the engine compartment helps with some of the diagnosis.