75 911 Stalling

[toms73novass]

Odd issue with a new to me 75 911 Carrara CIS injection

The car will sometimes stall coming to a stop. I have done a smoke test checking for leaks and all is good. I have done the up down test on the fuel control lever and it seems to be adjusted correctly. Also, did warm up regulator fuel pressure tests.

Here is the odd part, I can push in the clutch and coast for a long time and it will not stall and stay idling. However, once the car comes to a stop within a few seconds it stalls.

Thoughts?

Thanks
Tom

[toms73novass]

Bump, Any ideas?

[EC900]

What’s the rpm on warm idle?
950 is the normal range, little more is expected dead cold start, but should settle at 950. Dropping to 600/700 rpm caused my 2.7 to stall at the traffic light. Fixing a few vacuum leaks caused the idle problems in my case.
Another suspicion might be an injector(s) and also, did anyone tamper with the mixture settings?
Any lean/rich or exhaust smoke? Try to inspect the plugs to get a rough idea to the mixture setting.

Here’s some things I experienced:
On the mechanical side, idle can be interfered by worn bushing in the pedal cluster causing the throttle rod and clutch rod hitting one another and binding up when the nylon bush broke apart from the bell crank assembly. Easy fix btw. Inspect by removing floorboard, right of the accelerator. There’s also another bell crank assembly to the throttle that could also have a worn bushing, this could make adjusted idle speeds to be inaccurate.

[Paulporsche]

Also, check your points, including the gap, and electrical connections, including at the fusebox and the round black plugs under the dash.

[sean m]

Points or electronic ignition?

[toms73novass]

Idles at 1000.
Did smoke test and not vac leaks that I could find.
No smoke. I did the up down test to roughly check for rich lean and it seems ok.
Will have to check bushings.

It has points, relatively new, however I will have to check them.

Thanks, will report back.

[fanaudical]

Have you checked and confirmed operation of the decel valve?

Have you verified no air leaks between the throttle body and the air sensor plate?

[boyt911sc]

How did you do the pressure with smoke test? How did you isolate the air box from atmosphere during the test? Thanks.

Tony

[toms73novass]

Originally Posted by boyt911sc

How did you do the pressure with smoke test? How did you isolate the air box from atmosphere during the test? Thanks.

Tony

Took off rubber boot and put plastic glove over throttle body to keep smoke from escaping. Then fed smoke through a vac line. Used a video I found on Youtube.

[toms73novass]

Originally Posted by fanaudical

Have you checked and confirmed operation of the decel valve?

Have you verified no air leaks between the throttle body and the air sensor plate?

I have not checked the decel valve. But will keep in mind if issue returns.

[toms73novass]

I took everything off the regulator bracket and cleaned all electrical contacts and reassembled, reset dwell to 35 and verified timing.

Right now the problem has gone away. Hopefully for good.....

Thanks for all suggestions.