911 sc engine cuts out at high RPM

[danscomp101]

My '81 sc engine is cutting out/sputtering at high RPM under heavy throttle. If I climb to 5500 RPM slowly, it does not "cut out". However, if I am hard on the throttle, that is when it "cuts out" around 5000-5500 rpm. It has only started doing this in the cold weather, 10 degrees Celsius outside temperature (Canada ). It almost feels like its not getting enough fuel or it's getting too much air.

Anyone have any idea what's going on?

I should also mention this problem is intermitent. Does not do it all the time. Once it did it at around 2500 RPM in first gear!

[Bob Kontak]

Sounds like spark. Fuel starvation from my experience causes a slower death. When my fuel pump relay acted up it would take a bout two seconds to die.

Do you have a Permatune box? Those can die but usually there is a few minute period of waiting before it will fire again.

Look at your coil at night and see if the fat wire is grounding out to one of the two smaller primary terminals when you blip it by hand. That is a common problem across all cars with old fashion coils. If it jumps to ground then no secondary spark gets to the distributor.

Suggest the dark night test of the engine bay as preventative maintenance (wait five minutes in the dark to let your eyes adjust). If you have tired wires coupled with a larger than stock gap on your plugs you may find more electrical cooties than you expect.

Beyond the above the green wire between the distributor and the CD box can be a PITA if it is losing integrity and the signal from the dist is interrupted for any reason.

Welcome to the forum.

[Bob Kontak]

Originally Posted by danscomp101

Once it did it at around 2500 RPM in first gear!

Makes me think the motion of the engine is moving a wire that has a poor connection?

[danscomp101]

Hey Bob,

Thanks for the response. I think you're right. Had time to investigate last night. I pulled the wire off that goes from the coil to the distributer and the inards pretty much fell apart in my hand (A plastic pole and a metal terminal that were quite corroded). Must have been a weak connection. I bet, like you say, the motion of the engine was causing it to move which was causing the connection to hit and miss! Hense the spuddering engine.

Winter's coming, seems like a great time for a full tune up

[Bob Kontak]

You can just buy a cheapie wire at the local parts store to confirm the problem then invest in some decent wires.

Clewitt has some nice ones that are fairly priced - probably available here. Do some research though.