Crankcase Full Of Fuel. 1991 350SDL - Page 6 - PeachParts Mercedes-Benz Forum

BatteredBenz · #76 08-18-2015, 11:48 PM

Sent you a PM

funola · #77 08-24-2015, 09:07 AM

Quote:

Originally Posted by Squiggle Dog

What happened is that the injection pump was leaking fuel from the fuel chamber into the oil chamber at a high rate because of worn and scored plungers. The waste vegetable oil was likely coagulated and working as a seal, and once I did the diesel purge, it cleared it away and allowed free passage.

So, it was dumping more fuel into the crankcase than was actually going into the injectors. It put over 2 gallons of fuel into the crankcase in short time. This caused excessive crankcase pressure which blew out the manifolds.

Is this what the Bosch shop told you or is this your interpretation? The plunger elements is a high pressure high tolerance pump. If they were scored so bad as to leak so much fuel into the oil circuit they would not have delivered any fuel to the injectors. The car was driven from MN to AZ on an electric fuel pump (replacing the mechanical lift pump) so the IP was running OK prior to the work you started doing to it. Didn't you find an o-ring missing in the lift pump when you opened it up which is known to dump a lot fuel into the crankcase? Isn't that more likely source of the fuel? Not trying to argue, just like to have correct diagnosis.

What did the shop charge to inspect the IP? Did they put it back together as a working pump? In order to do that they would have to calibrate in on the bench and that's not cheap. Did they take all the plunger/elements out to inspect or just one? If they did not put the pump back together, can you post up some close up shots of the scored plungers?

GregMN · #78 08-24-2015, 10:02 AM

Quote:

Originally Posted by funola

The car was driven from MN to AZ on an electric fuel pump (replacing the mechanical lift pump)

There was no electric fuel pump in the car when it was driven to AZ.

Squiggle Dog · #79 08-24-2015, 10:05 AM

Quote:

Originally Posted by funola

Is this what the Bosch shop told you or is this your interpretation? The plunger elements is a high pressure high tolerance pump. If they were scored so bad as to leak so much fuel into the oil circuit they would not have delivered any fuel to the injectors. The car was driven from MN to AZ on an electric fuel pump (replacing the mechanical lift pump) so the IP was running OK prior to the work you started doing to it. Didn't you find an o-ring missing in the lift pump when you opened it up which is known to dump a lot fuel into the crankcase? Isn't that more likely source of the fuel? Not trying to argue, just like to have correct diagnosis.

What did the shop charge to inspect the IP? Did they put it back together as a working pump? In order to do that they would have to calibrate in on the bench and that's not cheap. Did they take all the plunger/elements out to inspect or just one? If they did not put the pump back together, can you post up some close up shots of the scored plungers?

The Bosch shop told me that the injection pump was "in very sad condition" and that the plungers and bores were very scored.

I have a theory that running on waste vegetable oil for 50,000 miles could have ended up with coagulated deposits around the plungers which would have caused premature wear and also masked the problem.

I noticed the fuel getting into the crankcase in large volume immediately after doing the diesel purge. I theorize that the purge probably cleaned out the vegetable oil deposits which opened up channels for the fuel to leak through.

The lift pump was missing an O-ring, and had a very worn O-ring as well. But, the parts looked great and I put new genuine Mercedes O-rings in. I have pumped the lift pump with my hand several times to build up pressure while it was still hooked up to fuel. I couldn't see any leakage out the back of it.

The car also didn't seem to smoke before the diesel purge and replacing the delivery valve seals. After that it smoked grey smoke like a freight train.

I was under the impression that the shop would test the pump for free (they advertised free testing of pumps and injectors), but they charged me $90 and ended up taking it completely apart. They gave it back to me completely apart. I suppose I can take some pictures.

funola · #80 08-24-2015, 10:07 AM

Quote:

Originally Posted by GregMN

There was no electric fuel pump in the car when it was driven to AZ.

Good you finally joined in. Maybe you can help with explaining what happened? In post #18 this is what he wrote (I may have mis-read it): "The previous owner had apparently bypassed the lift pump (picture below shows how he had it routed). He had an electric pump installed. I wonder if it was bad before, and was the reason it was bypassed. It may be dumping fuel into the crankcase."

Squiggle Dog · #81 08-24-2015, 10:22 AM

Now that I really study previous pictures of the engine, it appears that the mechanical lift pump was attached and working prior to the work I did (it was just routed directly to the injection pump rather than to the main fuel filter and then back to the pump--most likely the fuel was routed through the filter first and then the lift pump).

But, there was also an electric fuel pump installed. I assume it was working, but I am not sure.

funola · #82 08-24-2015, 02:12 PM

How could the mechanical lift pump have been working if you found one missing o-ring and another worn/damaged o-ring in it? What was the electric lift pump doing?

Squiggle Dog · #83 08-24-2015, 02:30 PM

Quote:

Originally Posted by funola

How could the mechanical lift pump have been working if you found one missing o-ring and another worn/damaged o-ring in it? What was the electric lift pump doing?

I don't know if the mechanical pump was working or not. It was just hooked up still and the injection pump was making the push rod move. The O-ring that was missing, seals fuel from leaking down the threads of the back of the lift pump "nut". The one that was damaged was the main one that seals the fuel from leaking out the push rod.

I don't know if the electric pump was just an auxiliary pump, or if it was even working or not.

At this point, I don't really care what explanation there is as long as the replacement injection pump works and the problem is gone. I can theorize it and try to explain it until I'm blue in the face, but I'm ready to move on because I just don't care anymore. If the replacement pump solves the problem, then that's all I care about.

funola · #84 08-24-2015, 03:07 PM

Sorry, I was just going by what you wrote in #81: "it appears that the mechanical lift pump was attached and working prior to the work I did". I guess you mis-wrote that?

Too bad this will remain a mystery as to the cause of the "crankcase full of fuel".

Maybe I wasn't clear in my prior post that I think the hydro-locking fuel came from the over filled valve cover via the valve guides into the cylinders with open valves. The hydro-locking fuel could not have come via the IP and injectors.

GregMN · #85 08-24-2015, 04:05 PM

There were electric valves for fuel selection. They could have been mistaken for pumps. I have never used an electric pump on the VO side on a 60x engine.

That car sat for long periods of time between uses. Polymerization of VO is aggravated by time, air, and heat.

Squiggle Dog · #86 08-24-2015, 06:07 PM

Quote:

Originally Posted by funola

Sorry, I was just going by what you wrote in #81: "it appears that the mechanical lift pump was attached and working prior to the work I did". I guess you mis-wrote that?

Too bad this will remain a mystery as to the cause of the "crankcase full of fuel".

Maybe I wasn't clear in my prior post that I think the hydro-locking fuel came from the over filled valve cover via the valve guides into the cylinders with open valves. The hydro-locking fuel could not have come via the IP and injectors.

The lift pump appeared to be working, but that's just guessing as I couldn't see the internal parts lifting fuel up. Although, if there was no electric pump, as Greg says, then the lift pump must have been working.

I imagine polymerized waste vegetable oil was acting as a seal to some effect. After I put B99 in the tank (so it would easily pass emissions), I immediately started noticing a significant loss in off-the-line power (the engine wouldn't respond until several seconds after pressing on the accelerator), probably because the B99 was starting to clean out the polymerized oil, which would have caused the lift pump to no longer be sealed and start sucking in air/leaking fuel into the crankcase. Then the diesel purge was the icing on the cake (for both the lift and injection pumps).

The hydro-locking could have well been caused by the fuel/oil leaking through the valves into the cylinders. And to cause the fuel level to get that high, the pump was dumping lots of fuel until it ended up with about 2.5 gallons of fuel into the crankcase. Pretty crazy.

Squiggle Dog · #87 09-01-2015, 11:44 AM

I was able to get a bargain on a very nice injection pump from dieseldiehard. I don't think I could have got a nicer used one at any price! I'm ordering some parts and should have it on in about a week.

dieseldiehard · #88 09-04-2015, 12:07 AM

Hey, too nice! Gosh its cleaner now than when it was on my '87 Blue Bomb.

Here's photos of the 603.971 which I replaced it with, after it was rebuilt.
I took this off my 350SD before I scrapped it but honestly it doesn't work any different than the one I sold you.
As built, the fuel delivery curve on the .971 is slightly different, an internal capsule in the IP determines the flow of fuel at initial acceleration, or something like that.
The one in the 3.0l engine has less fuel at start of delivery than one for the 3.5l engine. The delivery curves are different according to Gus who described the differences while I watched him calibrating this pump. I guess I was just eager to throw $$ at a project while I was sinking in debt on the SD

DDH - now driving a gasser! at least its still a Benz tsk tsk.

Squiggle Dog · #89 10-02-2015, 10:02 PM

Good news! I installed the injection pump that I got from dieseldiehard, and it runs great! I replaced the delivery valve O-rings with new Viton ones and also replaced the side and lower plate gaskets, as well as the front shaft lip seal and O-ring where it mounts to the block. I rebuilt the lift pump with new Viton O-rings.

My roommate and I are very pleased with the injection pump. It cleaned up like new and the problem is gone. The old-style vacuum pump was replaced with a used updated version as the bearings were worn and one of the balls had cracked.

I want to thank dieseldiehard for giving my roommate such a great deal on this pump. If he didn't come through, the car could have well been setting at the wrecking yard.

cooljjay · #90 10-03-2015, 01:45 AM

Just an fyi from someone who rescued an vo burner.....You will continue to have problems with the car, the more it is driven and the more it is cleaned....The more issues that will arise...I would never want to rescue any vo burner with a newer engine this complicated. I replaced everything from the injectors back to the tank, all the hard lines where caked with wvo.....wvo builds up more carbon then burning straight diesel....thus the issues that kept popping up......carbon burning off valves, clogging oil filters, fuel filters clogging from residue in hard lines, bad valve steams, rings worn....list goes on.....I am proud you saved this car but even for free I wouldn't have taken it, specially with rust/rot issues....Doesn't this car also have the issues with spring perch? I would really worry about that!