Running Great then It died, wont start. Help!
 

Yesterday I started my 74 targa 911. (It started up great and I drive it about once a week). I backed it out of my garage. (no problems doing great). Put it in gear (sportomatic) and took off. (Still running great!) When about 150 feet then it died! Like someone just turned the key off. I can still hear the fuel pump running. Maybe the perma-tune or points? It has a full tank of gas! It still cranks fine. Put never fires up or even tries to fire up. Anyone got any ideas!?

Thanks
Dan

Sure sounds electrical. I would start at the distributor, points, rotor etc.

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Robert Stoll
83 SC
83 944

Fuel filter, or strainer screen in bottom of fuel tank?

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Warren Hall
1973 911S Targa

Just had a new fuel pump installed last month with a new filter.

I did some tests with a multimeter while the ignition was on. The perma-tune is recieving 12 volts from the middle terminal. One of the side terminals appears to be a ground. The other side terminal runs to the coil. Testing the two small wires that go into the coil: nothing. So if the perma-tune is receiving power but the coil is not then I believe it is a defective perma-tune.

I took the perma-tune off and tested it as explained at:
www.permatune.com/Tech_Support/Porsche/911.htm

The "pin a to d test" is normal.
The "pin b to c test" is normal.
The "pin d to flange test" is normal.
My multimeter does not have the ability to do the "pin d to b test". This "pin d to b test" tests the spike suppression circuit inside the perma-tune.

Does anyone have any experience with this before or think I missed anything?

Thanks
Dan

visually check your spark. saves a lot of time. pull the hi tension coil wire out of the cap, and see if a spark will jump 1/4" to something metal, while someone cranks the starter. if no spark, clean the points and check again. check push on wire on the side of distributor too. if still nothing, and you have power to the CD unit, that must be it. 90% chance.

Dan,

You have not said whether the Perma-Tune unit whines with power applied, or what your system Voltage is with the ignition switch on. Pin C is not supposed to be a continuous ground ... have you looked under your distributor cap to see if anything is amiss with the points?

Connect the Perma-Tune unit back to the engine. If you have a spare sparkplug, remove the #1 sparkplug lead, and connect to spare plug and directly to the coil output terminal. Ground the body of the sparkplug with wire, test leads, etc. Remove the quick disconnect terminal on the side of the distributor, and momentarily touch to ground, then break the connection. You should have a spark at the test sparkplug if Perma-Tune and coil are OK.

If you don't get a spark as tested above, check the coil windings' resistance with your multimeter. The primary should measure between 0.4 and 0.6 Ohms, or slightly higher due to test lead resistance or calibration of the meter ... most meters are not very accurate below 1 Ohm. The secondary should measure between 650 and 790 Ohms. If coil is OK check all connections for corrosion. If test generates a spark, then look at distributor for problems!

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Warren Hall
1973 911S Targa

Dan:
Had a similar thing happen to my '72 several years ago. Drove me crazy, because I & a mechanic couldn't find any reason for it. Finally had it hauled to a good independent Porsche outfit & they fixed it really fast. IT WAS THE GROUND WIRE FOR THE COIL! The old one had lost enough gounding capacity over time that the ignition couldn't fire. They installed a new, heavier duty ground, cleaned contacts, & it worked fine after that.

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Marv Evans
'72 911E

Yes, by all means, the grounding continuity between distributor, coil, and CDI/Perma-Tune unit are very important ... clean each connection and lead if there is any question!

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Warren Hall
1973 911S Targa

Warren, I don't think the PermaTune box puts out the whine like the stock Bosch box does. At least mine doesn't.

Kurt V
72 911E

You are correct the Permatune boxes do Not
Whine like the stock boxes... This can also
be verified at the Permatune Website

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• Joe A.
• 84 911 Targa
• 75 914/6 3.0

Guys,

I have a working spare Perma-Tune unit, and have tested it ... and, in spite of their claim at the website, it does whine/whistle audibly with the ignition switch on! Granted it may not be as loud, and is probably higher in pitch, but ... ALL DC-TO-DC INVERTER CIRCUITS WHINE ... to some degree! Ever listen to a camera flash unit charging up? Same sound!

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Warren Hall
1973 911S Targa