72 911E Engine Cutting Out

[bahman]

My 1972 911E, mostly in original condition, has developed an engine problem which exhibits itself by cutting out, stumbling, coughing, spitting, and almost dying when throttle is depressed rapidly. I have done the following, but none has helped:

- Replaced fuel filters (2) and drained fuel tank
- Replaced fuel pump and lines
- Replaced all electrical parts (coil, dist cap, rotor, points, plug wires, connectors and plugs)
- The fuel return check valve at fuel filter console works fine
- The MFI pump was rebuilt and calibrated a few years ago; have not had any issues until recently.
- The ignition timing is spot on

I would appreciate any information which can solve this problem.

[Jonny042]

If you feed the throttle in slowly it's OK?

Does the problem improve as it warms up?

Did you make any changes to the engine (exhaust, muffler, intake) prior to the problem?

And, last but not least did the car sit for some time before the problem started?

[991gts6s]

Its usually The warm up thingy on the pump.. How is the tube to the SSI?

That is why MFI got switched to carbs or sat in a garage back in day .... if you getting back fires its the ignition system then plug wire short etc...

[bahman]

Jonny042,
991gts6s

Thank you both for your inputs and suggestions. I was able to narrow-down the problem to a faulty combination of points and CDI box. Replaced them both, and the car now purrs as it used to.

[cmcfaul]

Best upgrade you will ever make is to replace the points with a breaker-less alternative. I used Petronics and never looked back. Completely invisible to the eye (inside the distributor) and the car just runs perfect all the time.

Chris
73 911 E