OM606 replaced SOV still revs before shutdown - PeachParts Mercedes-Benz Forum

muleears · #1 09-18-2008, 10:16 AM

Here's the story: In January I began to have performance problems and a delay and slight rev after turning off the key. This was fixed by a new shutoff valve (after researching here of course). Lately I had the same symptoms, delay and rev. Yesterday I replaced the SOV again. In the process the threads for the front mounting hole began to strip, so the rear bolt is tight the front not so tight. Replaced the O ring with viton. Now, I have better performance but I still have the rev and delay at shutdown. Could the not so tight bolt be allowing in air and that causes my problems? The SOV itself doesn't seal against the IP. There is an output on the back with the o ring that extends into the IP. The O ring should be sealed even if not so tight. Even if it is leaking air, why would that make it rev? Any suggestions?

notfarnow · #2 09-18-2008, 11:44 AM

I had the rev at shut down too.

Over on the frybrid forum, another member with a 2-tank system said that he had the rev & CEL (code 205) on shutdown, and he cured it by rearranging his fuel flow a bit.

So, being pressed for time, I replaced the SOV o-ring and rearranged the fuel plumbing at the same time. Since then, it's worked flawlessly, but I can't for sure say which fixed it.

more about the change in plumbing here:
http://jakesbenzconversion.blogspot.com/2008/04/fuel-plumbing-revisited.html

muleears · #3 09-18-2008, 11:55 AM

Nothing has changed as far as fuel routing, I haven't even changed a filter lately. I'll go back over it to make sure everything is tight, and I'll replace the stripped bolt. Hope it works.

The car ran great this morning but at lunch it was groggy again.

notfarnow · #4 09-18-2008, 11:59 AM

Quote:

Originally Posted by muleears

Nothing has changed as far as fuel routing, I haven't even changed a filter lately. I'll go back over it to make sure everything is tight, and I'll replace the stripped bolt. Hope it works.

The car ran great this morning but at lunch it was groggy again.

You getting a check engine light?

muleears · #5 09-18-2008, 12:28 PM

Yes, I believe its P0215, whatever the number when I looked it up it pointed to the SOV as the item tripping the CEL and throwing the code.

TIA

notfarnow · #6 09-18-2008, 12:43 PM

Quote:

Originally Posted by muleears

Yes, I believe its P0215, whatever the number when I looked it up it pointed to the SOV as the item tripping the CEL and throwing the code.

TIA

Yes, sorry it was the po215 I got too, not 205. The upside is that once you fix what ails it, the code clears itself after a few hot/cold cycles. Downside is it limits the boost in the meantime.

It's worth trying to get that bolt in tight. One thing I've tried with success with smaller stripped bolts in aluminum: run a bit of copper wire in the threaded hole, then screw the bolt in. It's kinda redneck, but it generally makes the fit tight enough to work like a charm, without chewing anything up permanently.

TMAllison · #7 09-18-2008, 01:27 PM

Cal - I would concentrate on the bad screw and try to get it uniformly tightened down. In my mind, the unequal pressure would likely cause the oring to deform resulting in a leak no different than a deterioated oring does. All the fuel line seals are touchy.

notfarnow · #8 09-18-2008, 03:18 PM

Quote:

Originally Posted by TMAllison

Cal - I would concentrate on the bad screw and try to get it uniformly tightened down. In my mind, the unequal pressure would likely cause the oring to deform resulting in a leak no different than a deterioated oring does. All the fuel line seals are touchy.

Good point... I'd throw a new o-ring on it just to be sure

muleears · #9 09-18-2008, 04:04 PM

Quote:

Originally Posted by TMAllison

Cal - I would concentrate on the bad screw and try to get it uniformly tightened down. In my mind, the unequal pressure would likely cause the oring to deform resulting in a leak no different than a deterioated oring does. All the fuel line seals are touchy.

I'll try to get it replaced this afternoon. Just drove it home from work and it acts like it has an air leak. But it did before I changed the SOV, but not as bad as now. Listen to this: Yesterday after replacing the SOV it ran poorly, groggy power and hesitation, idled fine though. Today going to work (40mi) ran great, thought maybe it was just some residual air last night. Both lunch and drive home its running poorly again, bad hesitation.

TMAllison · #10 09-18-2008, 04:09 PM

Frothy fuel doesnt compress uniformly.

muleears · #11 09-18-2008, 04:19 PM

Why would it run fine for 40mi. then bad again? Cooler air? It was only 54 this morning.

notfarnow · #12 09-18-2008, 06:07 PM

If it's idling fine, then I don't think it's because of air.

When your check engine light is on, it limits the boost and it is dog slow... but not all the time. When I was fighting the po215, the CEL caused limited boost and slow response only part of the time, not all the time.

TMAllison · #13 09-18-2008, 06:26 PM

It may leak more when cold and less when hot because of expansion/contraction, or it may leak only under higher fuel demand conditions. Lots of variables at play.

muleears · #14 09-21-2008, 08:22 AM

I replaced the bolt and reset the code (P0215). When I started it "BING" "CHECK ENGINE ELECTRONICS" I wasn't happy. It still shuts off slowly and has intermittent poor performance. I haven't driven it enough to determine but the performance may be worse when cold and normal when warm.

Could this be my K-40? I have no records before my ownership, so I don't know if it has ever been replaced.

When the car is running poorly it acts as if it has no boost, an air leak and doesn't like to downshift. I know the K-40 controls a lot besides the SOV, but does it have anything to do with these other symptoms? Could, what I think is an air leak, actually be the SOV fluttering?

What is the official name of the K-40? I may need to order one.

I know there are many question marks in this post, if anyone can get rid of some I would greatly appreciate it.

I know it's early but...

TMAllison · #15 09-21-2008, 12:24 PM

#98 is the K40 relay. The detail incorrectly includes it in the left side fuse box when in reality it is located in the right side apparatus box. Front most relay.http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=210025&M=606%2E962&GA=722%2E608&CT=F&cat=45P&SID=54&SGR=040&SGN=03

I don't remember hearing of a K40 failing to provide power in a cycling manner before but suppose it is possible. Power is usually interrupted to the SOV causing it to instantly shut, which shuts the engine down "w/o warning, as if key were turned off".

You might check the fuses on top of the K40; pull, examine and clean them.

The K40 relay gets its signals from the ECU/IFI computer.