Subtotal loss of power from one drive to the next

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George Krompecher
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Subtotal loss of power from one drive to the next

#1 Post by George Krompecher »

I am stumped here.
'59A with a '62 super engine, Weber carbs:
From one drive to the next (5 days interval), complete loss of power, feels like I have about 20 HP now. Undriveable on hills (I live in the Alps...).
So far I have checked:
-Spark on all 4 cylinders.
-Timing static 5° before TDC.
-Fuel filter replaced, mechanical pump works, checked at pump outlet. In tank mesh clean. Fuel clean.
-Blew air through the engine fuel lines, no obstruction.
-Distibutor clean, contacts cleaned.
-Idles on all 4 cylinders, gets up to 4K rpm easily in the workshop.

What are my next steps?

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C J Murray
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Re: Subtotal loss of power from one drive to the next

#2 Post by C J Murray »

Low volume output from fuel pump?

That is also what happens when you remove the main jets, not likely your problem but you should inspect the jet stacks on top of the Webers.

Check using a timing light that the distributor is going to full advance.
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George Krompecher
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Re: Subtotal loss of power from one drive to the next

#3 Post by George Krompecher »

Pump delivers quite a lot, but are there reference values?

I'll borrow a timing light.

I also checked all 4 plug wires for damage and resistance, all check in at 950 Ohms.

For sh*ts and giggles, double checked firing order and spark wire position as well - all OK.

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C J Murray
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Re: Subtotal loss of power from one drive to the next

#4 Post by C J Murray »

Does it stumble fart and bang or does it die and fall flat on its face? Dying suddenly, falling flat, is usually a fuel supply problem. Farts bangs and stumbles are usually ignition problems such as a bad coil or bad rotor that give up the job once under load.
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George Krompecher
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Re: Subtotal loss of power from one drive to the next

#5 Post by George Krompecher »

I will rev up in neutral and on flat roads (albeit slower than usual) but it won't accelerate uphill at all. No significant stumble or bangs.
Rotor, cap, plugs and wires are under 1K Kms. Coil I don't know.

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Doug McDonnell
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Re: Subtotal loss of power from one drive to the next

#6 Post by Doug McDonnell »

Try driving it with one carb disconnected at a time to see if you can isolate it to one carb.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: Subtotal loss of power from one drive to the next

#7 Post by David Jones »

Fuel starvation on one carb. Dirt in float valve?
If I had known I would live this long I would have pushed the envelope a little harder.
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Doug McDonnell
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Re: Subtotal loss of power from one drive to the next

#8 Post by Doug McDonnell »

Or a bad blockage in the line behind the fan shroud. Gotta peel the onion.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: Subtotal loss of power from one drive to the next

#9 Post by Wes Bender »

George, was anything done to the car during that 5 days between drives? Fuel it up? Change anything? Many times when I experience a problem such as you have, I can trace it back to something that was done in the interim. For instance, did you possibly get a bad batch of gas?
Some days it's just not worth chewing through the restraints.....

George Krompecher
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Re: Subtotal loss of power from one drive to the next

#10 Post by George Krompecher »

Solved.

It was the coil. Although it checked out OK resistance wise, It would not spark every time when the coil wire was grounded and the points opened.

Put in the (sketchy) coil from the beetle, and it drives again like nothing ever happened.

At least it made me change the fuel filter, check the plugs, the plug wires, the points, the main jets and the emulsion tubes in the carbs. And determine that with the Weber carb inlet manifolds, removing the plugs is a b*tch.

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Re: Subtotal loss of power from one drive to the next

#11 Post by Doug McDonnell »

Happy you solved it.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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C J Murray
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Re: Subtotal loss of power from one drive to the next

#12 Post by C J Murray »

Coils do fail very suddenly
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Re: Subtotal loss of power from one drive to the next

#13 Post by George Krompecher »

:) Thanks to all for the suggestions

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Re: Subtotal loss of power from one drive to the next

#14 Post by Rick Cabell »

In 50 years of Porsche ownership and service, I can count on one hand how many coils I’ve changed. Glad it is fixed.

George Krompecher
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Re: Subtotal loss of power from one drive to the next

#15 Post by George Krompecher »

Hi Rick!
It is also a first for me in 10 Porsches and 35 years. I guess you got me beaten on both counts.

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