Slow Shutdown cures Itself! - PeachParts Mercedes-Benz Forum

Fattyman · #1 08-23-2010, 08:10 PM

My 240 has always taken about 3 to 5 seconds to shutdown. There are no vacuum leaks in the circuit and the servo checked out as well. Just one of those nagging things. Actually it really bugged me since I couldn't remedy it

. On Saturday it was well over 100 here in LA. I got to my destination and turned the key expecting to fiddle around with something while waiting for it to shutdown. It shut right off! Just like our other cars. Instantly. I thought it must be a fluke of some sort but ever since then the car shuts right off on command. It must have been the heat. What else could it have been?
I'm afraid of what's going to happen when it gets cold around here.

toddyvol · #2 08-23-2010, 09:00 PM

I had a clogged port on the main vacuum line that was causing a slow shut down. It started out 3 seconds..then 5 seconds..then one day 10 seconds. I cleaned the main line out with a little compressed air and drilled out both ports with a 1/32" drill bit. Now it shuts down instantly.

pawoSD · #3 08-23-2010, 10:08 PM

I just replaced the second shut-down valve on our fleet, I'd be checking those for failure out there! They'll leak oil into the vacuum lines. Neither of ours did, because they are all equipped with a filter in-line from the valve, so you can see and stop the leakage.

Biodiesel300TD · #4 08-23-2010, 10:19 PM

I find that vac leaks seem to lessen or disappear in the heat, and get more severe in the cold. So I'm guessing you have several small leaks that have sealed up with the heat, and will return with the colder weather. When the car was shutting down slowly, did you try blocking all the vac systems other than the shut down system to see if the shuts off immediately?

Fattyman · #5 08-23-2010, 10:59 PM

There were no leaks in the system. Both the locking circuit and the shut off circuit were checked and ran independently of each other to no avail. No leaks were detected with a gauge or vacuum pump (snap on). That's what was so frustrating. Everything checked out and it was still slow to shut down. One thing's for sure now. I'm not touching anything!

Oh, cold for us is 50 F so it will never get THAT cold I guess.

Biodiesel300TD · #6 08-23-2010, 11:01 PM

How many pumps of the hand vac pump does it take to shut down the car? Maybe you have a week shut-off valve.

Fattyman · #7 08-23-2010, 11:08 PM

I can't remember and I dare not touch it anymore. No more than 5 if I recall. If it works, don't fix it!
I had replaced all the components in the shut off circuit and there were no changes until it got over 100F.
I guess I'll give myself till next summer to install AC. It only gets used maybe 3 months out of the year (AC that is) so there is no hurry.