Guys,
Thanks for the advice. I just talked to mechanic and I will try to reproduce the problem for him. I really want to replace my PermaTune unit just to see if that's the culprit. My Pertronix unit has been trouble-free since I installed it. I have already replaced the WUR, my car doesn't have an Aux Air Valve. The problem (stall and fail to restart) occurs after the car has reached operating temps and is very sudden and without any stumbling or roughness. Weird...

Check for a cracked air box, poorly seated flapper valve or the air boot came off.

In order to solve the problem, you have to know what the problem is.

Engine dying and not restarting right away is the sympton. The problem could be fuel delivery, (Bad fuel pump) or no spark (bad CDI box, bad points if you still have points, bad coil, etc).

If you can determine what is causing the problem you halfway to determining how to fix the problem.

I tried to reproduce the problem this afternoon when I got home from work and I started the car and let it run until it stopped (35 minutes), then tried to restart it and no go! So, now I can reproduce the problem. I'm going to test the PermaTune CD unit later this week and then take it to a local Porsche mechanic if I can't figure out what's going on. I don't think it's a fuel problem becaue the car stops abruptly, no stuttering, sputtering, etc... dies immediately. Cranks and cranks, then finally starts and runs great and smooth until it dies again...

Checked the pop-off valve, airbox, all hoses, and wires, everything is nice and tight and is as it's supposed to be...

Have you inspected the distributor cap and rotor? Had the same problem and it was due to a bad rotor.

Mike,
I'll check that later this week, thanks for the tip!

If you can get a can that is similar to freon so that when you spray it on the component you can cool it down, try spraying it on the perma junk and see if the engine will start right away. Could be a heat related compnent failure in the perma junk. Try Rat Shack for the spray cooler.

ruf,
Thanks, that's what I'm going to do as it seems the stalling occurs at a certain temp. Maybe a can of compressed air will coll the PermaTune down? I've got a replacement Bosch unit that I just bought from a fellow Pelican here on the board to replace the CD unit. I've only had the PermaTune and coil for a little under three years...

What the heck?
 

I just purchased a Bosch CD from another Pelican and took out my old Permatune unit and compared the two. They are obviously different. Did I get the wrong Bosch unit for my '74? If this is the correct Bosch CD unit, why is my plug different? My PermaTune has three connectors and a spade connector above the three-prong plug and the Bosch unit has a 6 connector plug. What should I do?

http://forums.pelicanparts.com/uploa...1113429263.jpg

http://forums.pelicanparts.com/uploa...1113429313.jpg

You got the later Bosch unit. You need the early 3-pin unit.

Yep, John Walker is going to trade me the unit I have for the one I need. The '74 that the new one came off was a twin-plug engine, but I didn't know that. I hope the Bosch unit works and stops the stalling problem! Thanks!

I had the same thing happen with my problem
tune junk ignition box , it also did something to my distributer inside replaced it with msd ignition box and a red coil car runs better then it has ever run since i've owned it . Good Luck !!

This is just a guess Art, but a fuel pump will work until it heats up, then just quit, then cool down and work again.

While waiting for my Bosch 3 pin CD unit to arrive from John Walker, I put the PermaTune back in and replaced the dictributor cap and rotor. The car has not stalled since, but the weather is not too warm and I haven't had the car abve 160 degrees yet. My theory is thst the PermaTune Cd unit stops at 190 200 degrees. I'm going to replace it and see if the same stalling problems occur with the Bosch unit.

Art,
Let's drop back a little before you start replacing too many parts - maybe unecessarily. Have you checked for spark? for fuel?

I'll assume you have the 3rd item for combustion - air. It should be easy enough to verify it's the spark box. Position a plug wire end close to ground. Crank engine. Spark should jump with a snap. Do that before you spend too much money.

Sherwood

Sherwood,
Thanks! I agree that "basic troubleshooting" is necessary... but when the car dies, there isn't any spark and the CD unit is very hot! This only happens when the car gets above 190 degrees and I have a Bosch replacement CD unit to swap in and then I'll do more troubleshooting. I've driven the car on brief runs this weekend and no stalls!!

I just replaced my PermaTune (PermaDoom) unit with a used Bosch unit that John Walker kindly sent to me and I drove the car for an hour with no stalling! Looks like the 2 1/2 year old PermaDoom unit was faulty!

Great news, Art. Just in time for the snow this weekend, too!! Looks like you have the same kind of timing as me.:)

Wayne,

Yeah, what a bummer! I'm just glad the stalling problem has been fixed. I'll never buy a PermaDoom unit again, I'm going to stick with Bosch! We're working on the house this weekend, so the weather doesn't bother me too much, April in MI is always a gamble... Thanks for the support!