Main Menu

1987 911 Carrera Dieseling With Modified Engine


Vehicle Information: Model: 911 Carrera; Year: 1987; Body Type: Targa; Engine (type, size, modifications): 3.4 L (3.2L with 9.8:1 Mahle pistons/cylinders), authority chip, SSI headers.; Total Mileage: 225,000 kms;

I have a 1987 911 with a 3.4L engine (3.2L with 3.4L Mahle 9.8:1 CPRpistons). Recently, the car would experience "dieseling" or "run-on" whenI switch off the ignition key. The problem is intermittent and onlyseems to happen if the car is driven slowly. I can drive the car hard atthe track for 25 minutes on a hot summer day and it shuts off properly,but if I drive the car for 20 minutes in the city (not stop and gotraffic) and turn off the key, the engine sometimes stumbles for up to 6or 7 seconds. I have a fuel pump kill switch, and if I flick this switchwhile the car is dieseling, it stops immediately. I installed new sparkplugs and wires (Magnecor) at the start of the summer. I have triedswitching fuel stations (Sunoco 94, Shell, etc), but this does not seemto make a difference. It seems that the fuel pump is not shutting offproperly, can this be the case?

You must log in to view answers associated with technical questions. Join PCA to participate in our community.
No votes yet