W115 220D - Running rough, low power, stalling - Page 3 - PeachParts Mercedes-Benz Forum

piccolovic · #31 06-03-2012, 11:22 PM

Quote:

Originally Posted by cj.surr

I would think that if a cylinder has low compression, it won't be enough to ignite the fuel and therefore would cause low power. Which could explain the stalling and rough idle.

I'll look into cleaning the injectors. As far as the gauge, the needle is not pinned, it goes right to 30 when the ignition is turned on, so I would assume it's an electrical problem. Thanks for the help.

Unfortunately, the Marvel's Mystery Oil doesn't seem to have worked. I let it sit for a few more days, but the compression remains at 150ish. Is it pretty much a loss at this point? I guess I will try and do a warm compression test.

I wouldn't worry about one cylinder with low compression at all. It's the beauty of diesel engines. the loss of power is negligible. It can however, cause rough idle. It could also be from a burned valve. Concentrate on the other problems, try to keep the fuel flowing and when warm, do another test. Also, get rid of the exhaust leak. When you get it running, you won't want that going into your passenger section, poisoning the driver with CO.

Govert · #32 06-04-2012, 04:00 AM

Quote:

Originally Posted by cj.surr

I would think that if a cylinder has low compression, it won't be enough to ignite the fuel and therefore would cause low power. Which could explain the stalling and rough idle.

One cylinder with low compression does not cause stalling. Rough idling and smoke very likely, but not stalling.

Quote:

Originally Posted by cj.surr

I'll look into cleaning the injectors. As far as the gauge, the needle is not pinned, it goes right to 30 when the ignition is turned on, so I would assume it's an electrical problem. Thanks for the help.

The oil gauge is not electrical, but mechanical. It should not respond when you put the ignition on, only when the engine is running and the oil pump produces pressure. Maybe some previous owners messed with the oil gauge, perhaps he put it a electrical oil pressure system.

Quote:

Originally Posted by cj.surr

Unfortunately, the Marvel's Mystery Oil doesn't seem to have worked. I let it sit for a few more days, but the compression remains at 150ish. Is it pretty much a loss at this point? I guess I will try and do a warm compression test.

The engine really needs to be warm to do a proper compression test and the valves need to be adjusted.

cj.surr · #33 06-04-2012, 09:03 PM

I took a look at the valve clearances, and they were all pretty close. I got started on getting them all to spec, but I find it pretty difficult. Trying to juggle the two wrenches and the feeler gauge is kinda hard with only two hands.

I realized that the gauge is actually always reading 30psi, even with the ignition off, so it must be a bad gauge.

Also, I plan on cleaning the injectors using this procedure:

Diesel Injector Cleaning DIY

cj.surr · #34 06-05-2012, 08:32 PM

I finished adjusting the valves today. They weren't very far off, but they are definitely closer now.

Anybody have tips specific to the W115 as far as injector cleaning?

bipolardave · #35 06-05-2012, 08:43 PM

Quote:

Originally Posted by cj.surr

I finished adjusting the valves today. They weren't very far off, but they are definitely closer now.

Anybody have tips specific to the W115 as far as injector cleaning?

Here ya go.

Diesel Purge Mercedes diesel maintenance tips

Pretty straight forward.

cj.surr · #36 06-05-2012, 08:50 PM

Great, thanks. That will definitely be useful once I get everything back together.

I was wondering if there were any tips as far as bench cleaning the injectors since I have them off the engine already.

rs899 · #37 06-06-2012, 07:15 AM

I never thought Diesel Purge did much good. Kind of like trying to keep your teeth clean with mouthwash instead of going to the hygienist for a brutal scrape.

To clean them on the bench, invert them, clamp the upper body in a vise tightly. Unscrew the bottom half with a deep 27mm. Remove all parts and dip in carb cleaner bucket ( those gallon paint can deals) Brush all parts with a brass brush- pay attention to the nozzles- rinse in diesel. Assemble- tighten to 60 ft pounds. You may need to lap the sealing surface if it leaks at the middle.

cj.surr · #38 06-06-2012, 04:10 PM

I don't have a brass brush... Is there something I can use instead?

Thanks for the help!

rs899 · #39 06-06-2012, 07:49 PM

If you use that caustic carb cleaner , a tootbrush should work. You might want to scrape the nozzle tips with your fingernail. I wouldn't use anything more abrasive.

cj.surr · #40 06-06-2012, 08:05 PM

I was just using plain old carb cleaner. The internal parts don't seem that dirty, though. The only part where I see anything is the nozzle tip.

rs899 · #41 06-06-2012, 08:11 PM

The stuff in the spray cans is like using piss. It's for wimps....

cj.surr · #42 06-06-2012, 08:25 PM

Hah, I don't have any of the killer carb cleaner sitting around, I'll have to pick some up.

cj.surr · #43 06-07-2012, 03:41 PM

I realized that one of the injectors has different internals than the others. The spring is about 25% longer, and the nozzle has a different part number on it. Is this a problem?

rs899 · #44 06-07-2012, 06:24 PM

they should all be the same and should pop within a few bars of each other.

cj.surr · #45 06-07-2012, 06:37 PM

So no problem?

Probably won't get them pop tested right now because I don't even know if this engine is in running condition. I don't want to spend too much money on an engine that might be gone anyway.