Oh no, I have air in fuel lines... PICTURES! - Page 2 - PeachParts Mercedes-Benz Forum

vwnate1 · #16 09-13-2018, 12:56 PM

What he's talking about is properly called the 'siphon' ~ in general, if you disconnect the rubber fuel hose under the hood from the metal pipe leading from the tank forward, as long as there's 1/2 tank of fuel or so, fuel should begin to pour of of the open stell pipe in a hood diameter stream, not just dribble straight down .

Dirty in tank fuel screens are much more common than many realize, to the point that I check every one that comes through my hands ~ even those that run O.K. because a marginally cruddy in tank screen will allow good running in town but starve the engine for fuel on the open highway .

It's normally a very simple if greasy anf filthy job to clean the Mercedes in tank screens with a toothbrush and whatever cleaner you choose .

Be certain to let it dry fully before re installing ! .

: Originally Posted by Clemson88 View Post

If the car is parked level and the tank has a significant amount of fuel in it the head pressure of that fuel should push it through the filter. That's one of the reasons the left side engine mounts go before the mounts on the right. Fuel runs through clean lines without assistance other than gravity.

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David"

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spock505 · #17 09-13-2018, 01:03 PM

Cheers nate, it was this bit that confused me -

"That's one of the reasons the left side engine mounts go before the mounts on the right"

Engine rotates to this side giving mount a harder time, that was my understanding.

Doc, you will need a large wrench to undo filter, can't remember size off hand - maybe 22 - 24mm?

Clemson88 · #18 09-13-2018, 03:47 PM

Quote:

Originally Posted by spock505

Cheers nate, it was this bit that confused me -

"That's one of the reasons the left side engine mounts go before the mounts on the right"

Engine rotates to this side giving mount a harder time, that was my understanding.

Doc, you will need a large wrench to undo filter, can't remember size off hand - maybe 22 - 24mm?

That is so. That mount also is often exposed to fuel leaks from changing filters and leaking lines which pass over it. Diesel is responsible for the loss of many young LH engine and engine shock mounts.

Diseasel300 · #19 09-13-2018, 08:47 PM

Quote:

Originally Posted by Clemson88

That is so. That mount also is often exposed to fuel leaks from changing filters and leaking lines which pass over it. Diesel is responsible for the loss of many young LH engine and engine shock mounts.

Don't overlook the IP leaking oil down on it either. Between IP oil leaks and diesel fuel leaks, my 2 year old LH engine mount is toast. RH side under the turbo is still just fine.

Clemson88 · #20 09-13-2018, 09:47 PM

I didn't notice my IP leaking but the cam cover had both sides of the engine covered including both engine shocks, shock mounts and engine mounts.

I haven't started my engine in two years. I probably have an IP leak and didn't know it. Oh boy, I've been looking forward to dealing with the injection pump on his car. It will be my first.

vwnate1 · #21 09-13-2018, 11:26 PM

@ David ;

Oops ~ I wasn't sure .

Oil leaks more on the left side of the engine most of the time and Diesel contaminated oil attacks and destroys rubber (motor mounts) and plastic like you can't believe .

This is why it's so important to keep after the weeps & seeps plus wash the engine every so often ~ failure to do so creates a cascade effect wherein something is always breaking because the oil leaked onto it degraded it .

spock505 · #22 09-14-2018, 06:00 AM

Sorry missed the interpretation, read across - agree, diesel works it way into all sorts especially rubber.

Doc Brown · #23 09-16-2018, 07:03 PM

Update.

New right angle pre-filter with correct clamps

Air bubble in filter is nearly impossible to get rid of

Picture of engine bay right before a cold start. The car had been sitting +12 hours. Zero air bubbles were seen during cold start and idle.

Video of start up...https://youtu.be/TKEK23SUgd4

vwnate1 · #24 09-16-2018, 08:18 PM

It looks fine to me, some of my Diesels have these bubbles, others do not .

As long as there are no bubbles in the fuel coming from the tank when the car is running you're good to go .

Diseasel300 · #25 09-16-2018, 09:25 PM

One thing I noticed in your video is the stop lever bobbing up and down. That means it's not properly attached to the stop mechanism and is resting on the linkage inside. Believe it or not, that could be your problem. When the engine is running, that lever should be fully up and feel like it's spring-loaded.

Back to the fuel issue - lack of bubbles is a good sign, that means your fuel system is tight. The bubble in the prefilter is normal, don't lose sleep trying to get rid of it.

Check glow plug resistances. If you find one high, it needs to be replaced (probably the whole set in that case). That startup is pretty rough.

Doc Brown · #26 09-16-2018, 10:25 PM

Interesting observation on the stop lever. I honestly have no idea what it is connected to inside the IP. I do know the lever will shut off the engine when pushed.

Is the lever somehow connected to the vacuum shut down device ?

Diseasel300 · #27 09-16-2018, 10:33 PM

The lever should be connected to the vacuum pod, the spring inside is what keeps it pulled up. With it resting on the stop linkage internally, the bobbing up and down can cause the engine to pulse or hunt, similar to how it would behave if you were feathering the stop lever by hand.

I had the same thing happen the first time I changed the O-ring on the stop lever shaft. I wasn't careful and it fell off inside. The bobbing definitely caused a lot of loping and weird behavior at idle, I can only imagine it would do the same thing when hitting chugholes and dips in the road.

Doc Brown · #28 09-30-2018, 02:34 PM

It took a while, but I was finely able to investigate the odd behavior of the shut off valve Diseasel300 mentioned. I'm not really sure how the valve was connected, however when I removed the valve and put it back in, it operated normally. I suspect the valve was not engaged correctly. Anyway that issue is solved, so a big thanks to Diseasel300 for the heads up.

This shut off valve was difficult to get to because of all the stuff that had to be removed. Perhaps whomever replaced it before took a few short cuts and installed it improperly.

While in the neighborhood I went ahead and replaced the glow plugs. I also reamed the cavities prior to putting in the new plugs.

Also while in the neighborhood I checked the compression.
cylinder#1 350 psi
cylinder#2 340 psi
cylinder#3 330 psi
cylinder#4 310 psi
cylinder#5 350 psi

Diseasel300 · #29 09-30-2018, 03:59 PM

Is it running any better though? That's the important question!

Doc Brown · #30 09-30-2018, 06:26 PM

The car seems to run the same, I'll have to wait a few hours and see what is does on a cold start.

While looking for fuel leaks after servicing the engine, I discovered the fuel warmer gizmo was starting to drip fuel. I went ahead and removed the warmer and attached the fuel feed line directly to the lift pump.

Looks like this thing was previously mended with spit and chewing gum.

Anyway how important is the fuel warmer? will it effect fuel economy or is a cold weather thing? The car is not fitted with a block heater so it will pretty much not be used in the winter.