Why does my 911 engine quit?

[laneranch]

When i sold my 356 cab last Aug. i joined the early 911S Registry and started looking for a vintage 911. After owning 4 porsches i was ready for my first 911 and a good friend in Seattle who was on his 7th pre 1974 911 was providing detail advice on cars as they came to my attention. A 1971 T Targa that looked to be in excellent shape and was in stock unmolested condition came up in June. I called the seller and arranged to have the car delivered to a shop for a PPI. The intital reports were favorable with excellent compression and leakdown results. There were some electrical issues like intermittent operation of the wipers and turn signals but a new optima battery and replacing all the fuses seemed to solve that. I flew to Portland, OR to pick up the car and drive it 600 miles to my ID home. I got away mid morning after finalizing payment and 9 hours and 500 miles later I got a hotel. The car ran excellentand I had no mechanical issues while driving 60 -70 miles per hour with 4 brief stops for gas and restrooms.

The next morning i headed out for the last 115 miles to home. Drove 100 miles at 65 average and then while going slow for 2 miles (25 mph zone) thru a town a few miles from home the engine just quit. I coasted to side of the road and called my insurance and then a flatbed tow. I tried immediately to restart the car and it cranked strong but would not start. After a 20 minute wait i tried again and it started immediately. I was dubious about driving the remaining miles so i had the car delivered to a shop near my home that does a lot of aircooled work and services some 911's. After the car came off the flatbed I got in to move it and the electrical system was dead - not any sound like the fuel pump and not even cranking. When I called the shop several days later the owner said he could find nothing wrong with the car and when he went to move it the first day it started right up just several hours after I got nothing from a start attempt.

Lastly, several days after driving the car home from the shop I drove it about 12 miles to the local DMV to register it and get ID plates. 11 miles at speed- 65- and then while driving the last mile at 25 mph the engine quit again in front of the DMV where I again pushed to to the side of the road. 40 minutes later, after getting it registered and my plates, i got in started it up and drove it home with no problems.

Any ideas or recommendations? After talkng to several knowledgeable peoplei have just purchased a new ignition swithch from Stoddard - part 91161301701.
Any tips on installing it - looks like the 10 pin element plugs into the ignition switch from the back with access thru the open hood to the back of the instrument cluster.

al

[beh911]

What is the condition of the inside of your fuel tank?

[lemonlib]

Sounds like it heating up and shutting down...not the motor....but more like ..cdi, or coil...

Best of luck
Lemon

[lemonlib]

you think it may be fuel clogging in the lines?

[prez!]

It definitely sounds like an ignition issue cdi box, coil or points. I had a very similar issue recently in the North GA mountains and its was the points.

[M_deJong]

I had a similar problem and it was the CD box getting hot and quitting. See if you can here the CD whining next time it quits. If it does then its something else...

[RSTarga]

If it was the points or cd it would at least crank. I think he can start by changing out the ignition switch. I'd still check fuel filter at bottom of tank and put new points in at the same time. If there is a whine from the cd box when switch is on i'd suspect the coil.
Be a good idea to check all the ground wires and cables to starter and ignition. Shorts anywhere?

[69Sman]

I had all the same exact problems with my 356. Installed a hot start relay kit and all was well. Never had this problem with a 911 tho. With a 911, I would say: If absolutely nothing happens when you turn the key (intermittently), then it is NOT the coil, COULD be the CD box (probably not tho), probably is not ignition switch, could be the wire that connects to the starter motor from the ignition (loose, corroded etc). I know all this from bad personal experiences...CHECK that wire to your starter motor...carefully.

[laneranch]

Thanks for all the replies so far. Here is some car background. Car was off the road 11 years, last licensed 3/2001, and kept in enclosed storage. the new dealer/owner purchased the car and trucked it from CA to Portland for servicing and reburbishment. Reciepts for about $5k in parts and labor only 30 days before my purchase. engine removed and all seals, gaskets etc replaced along with numerous other parts; oil lines, oil return tubes, axel assembly, cv joints etc. etc. Also tune up, new plugs, oil, valve adjustment etc.

I just got C of A yesterday and it is # matching. I also have the owner's manual and servicing stamps in the origonal owners Maintenance Record book for first 33,800 miles of driving from 1971 to 1975. Possible the 59,000 miles on odo are actual but I will probably never know. the mechanic who did the servicing said the engine may have never been out of the car before??

I have attemped to attach a photo of the Permatune Electronics (Wylie, TX) CDI system showing the current system.




As a 911 newby I am inclined to first try the ignition element first. I am dubious about gas as an issue due to the crank/ non crank/ start/ non srtart different responses to starting. Also why would it run 500 perfect miles one day and then only 12 miles on another before stopping?

Anybody have a tip on installing the ignition switch?

al

[Flieger]

Ahhh. Permatune. That could be the problem.