1988 300SE Enginge Just Cuts Out
 

My 1988 300SE has been running and starting fine. Last week while driving my son to the bus stop in the morning, the engine just cut off like I turned the ignition off. The tach went right down to zero. I pulled to the side of the road and it started right up. No further incidents until yesterday. Once agin in the morning, it started fine. dropped my son off and drove about 1 mile when it just cut off. This time it took 3-4 attempts to start. the first few times it just turned over, giving no indication it was going to start. Then the next turn over, it started right up. I drove maybe 3 miles and it happened again. Once again 3-4 attempts and it started and ran fine. No further problems.

I had a tune-up less than 12,000 miles ago including cap, rotor and wires. teh engine never studderd, it just cut out completely and instantly. Any suggestions are welcomed. I was thinking the fuel filter or fuel pump or fuel pump relay as I don't know when they were last changed. But wouldn't that make it more of a stumble as it ran out of gas. If there is a relay for the fuel filter, can some one let me know which one it is? It might just be a fuse instead. If it happens again, I'll hop out and listen to see if the fuel pump is running or not.

Thanks,

Ron Brooks

Ron, I had the same issue. My plugs, but not rotor, cap, or wires, were replaced prior to the cutting out.

Here's what I did: http://www.peachparts.com/shopforum/showthread.php?t=133543

I only have about an hour on the new parts, but knock on wood...so far so good.

Thanks for the reply. It looks like the "powerlead" to your cap broke. I'll take a look at mine. I see you have a 911. I had an '83 944 for 7 years. It was without a doubt, the BEST vehicle I ever owned. I still miss her. My neighbor the "Porsche Certified" mechanic installed and adjusted the infamous timing belt for me and it blew in less than 48 hours taking all eight valves and my love with it. I'll never forget that car or forgive my now former neighbor.

Thanks again,

Ron Brooks

Suspect fuel pump relay.

If it loses power/dies gently (within 1-2 seconds), fuel-related problems are possible (you still have residual pressure in the system). But if it cuts out instantly, especially during the hottest parts of the year, ignition-related faults are almost certain. Common causes are Ignition control units, crank sensors, intermittant power loss to ignition circuit (faulty wiring or ignition switch), and occasionally coils (my experience with coils is you also tend to experience loss of power and stumbling with the cutout). The obvious items to check are going to be your cap/rotor/wires/plugs, but there is usually miss/stumbling/loss of power with those as well; that doesn't mean that you shouldn't check them out to eliminate the problem, as you have seen above that it can cause the same problems given the right circumstances (a broken spring-loaded carbon center lead on a distributor rarely fails naturally before the cap does; however, because the cap is difficult to remove and install without breaking the center lead tip off, it is always good to check for this).

The 911 is my fourth...I would take working on it over the CE any day of the week! I had a 951 (the turbo variant of the 944) as well, but it finally gave up the ghost...tough break on the timing belt issue with the 944.

Good luck with the stalling issue...so far mine has been ok, however, I have only put around 45 miles on it...I'd put more on it, but with the recent heat wave and a non-working A/C (another issue in itself) I prefer to take the 10mpg Land Cruiser with ice cold A/C.