1995 E300 runs a second or two after key removal

[thatguy]

Hello,

My 95 E300 with the OM606 kind of likes to run/shut down slowly, even after removing the key from the ignition. AFAIK there are no fuel leaks, nor subsequent air leaks, and the car has an updated wiring harness, as well as new OEM ignition switch.

What do you guys suppose could be causing this? Do you think I'm getting a little excess fuel in, or is something sticking somewhere?

Thanks

[jay_bob]

Check your vacuum shut down system. You are in the beginning stages of the "won't shut off" problem. Many examples of this on this forum. But first confirm that the rubber piece joining the brown hose to the shut off actuator on the back of the IP has not cracked or split. It gets hot down there and it wears out the rubber.

This was the last year they used vacuum shut down, the 96 brought the 210 with electrical fuel shut down.

[sixto]

Can you can see the stub to which the stop lever attaches in 603 IPs or can you fit a vacuum gauge to the line from the key switch to the shutoff actuator? I'm curious how long the shutoff actuator stays in the shutoff position. A good actuator in an airtight system will stay down for days to weeks or until you turn the key to glow. One way to isolate a leak is to hook the actuator directly to the vacuum source with the engine running. If it takes the same amount of time, it's likely a tired actuator. Again, I don't know what access is like to the actuator in a '95 300D.

Here's some related reading - OM606NA manual fuel shutoff (1995 E300D)

Sixto
83 300SD

[jay_bob]

I agree that is the next step. I was trying to get the OP to check the simple stuff first. That was the cause of my no shut down a couple months back and it was a simple fix.

The best advice for the OP is to acquire a Mity-Vac ($40 at HFT) and the vacuum diagram and locate the issue.

I will also caution the OP that if they do have to replace the actuator then be sure to follow the precautions for installation and having an emergency shutdown plan in place on first start. It is easy to insert the new actuator incorrectly and drive the rack to full fuel.

[tyl604]

Jay Bob - agree with the fear of run away engine. The DieselGiant idea of putting a rattlecan top over the air intake (air cleaner) does not work - nor does cutting the air off the air cleaner by hand. Tried both as an experiment.

So how do you make sure you can stop the engine if it is running away? I have a 81 300SD and am awaiting the shut off valve in the mail but am concerned about the runaway prospect.

[jay_bob]

You have to create a nearly air tight seal with the air horn. Depending on the engine you will need to remove intake air components to find a place where you can apply the seal. Be sure the seal method cannot get sucked in and never use your hand!

A CO2 (not abc dry powder!) extinguisher works well.

[vstech]

To shut it off, you have to stop fuel, or stop air. Direct turbo/intake access is required. With runaway fear, just open up the turbo and have a soft piece of wood or flat thick rubber ready to block it off.
A halon or CO2 extinguisher dumped into the air horn will also do it without engine damage.

More often than not, it's the vacuum hoses though.

[mbolton1990]

Yea that's usually a very quick fix,just check the vacuum lines that run to the shut-off mechanism..I bet they're all original vacuum lines and are quite dry-rotted by now. Pretty amazing original vacuum lines have held up as well as they have when you think about it.

[thatguy]

Thanks everyone, I will get a look at it this weekend. Oddly enough today it didn't do it, nor did it last night, so it's somewhat intermittent in nature. I certainly don't want a runaway diesel situation, so if I end up having to replace the valve I will take precautions. I had to replace that little white plastic valve in my 300SD YEARS ago, so it must have slipped my mind, but I admit I'm not quite as familiar with the inner-workings of my OM606 as I was with the rugged 617.

Thanks for the link as well, sixto. Adding a manual lever shutoff like what my 300SD had certainly would make me feel better in the future, I don't really care of that leaky screw on top of the primary fuel filter.

[moon161]

Runaway and won't shut down are not the same.

Won't shut down fueled by diesel only is still limited by the injector pump and the max RPM set by the governor.

Runaway is fueled by a little diesel and lots of blowby oil. A working SOV will not help this condition. Runaway is a positive feedback where it just takes off, see youtube for examples. Stall it or starve it of air.

[tyl604]

Just so I do not kidnap this thread, think I will start a new thread for more specifics about how to stop a runaway engine.