99E300 turbo bizarre symptoms - PeachParts Mercedes-Benz Forum

#1 09-01-2006, 04:04 PM

Three days ago, after a cold start, my car stumbled for a few seconds as if one or more of the glow plugs wasn't working, then ran fine. I ran the car by the shop and my tech discovered some leaks around the fuel lines and on the lines coming out of the IP. No problem, replaced all the o rings, new serpentine belt, oil change. Picked up the car, drove home ok, ran fine all day.
Next morning, same problem, stumble at first start then everything ok. Took it back to the shop and while we were looking at it it started to run rough at times as if missing, revved ok but ran really bad at 1500 rpm. Then it became increasingly hard to start as if starving for fuel. Bubbles seen in both plastic fuel lines. Checked for leaks. No leaks, no codes, full tank, new filters, lines now clear. Car barely runs now, and once it starts after long cranking, it idles rough, and wer'e stumped.
Suggestions please.

Thanks,

Steve

TMAllison · #2 09-01-2006, 04:55 PM

I'll bet you've still got a leak somewhere.

Was the pre-filter o ring changed? It is oftentimes forgotten.

Check under the shut off solenoind on the side of the IP to rule out a leaky o ring there.

Finally, re-check the connections of all the plastic lines and make certain they made a good click when seated. The horseshoe clips should be loose and floppy after being installed. They are pushed tightly closed to spread the shoulders of the line for removal.

raMBow · #3 09-01-2006, 05:07 PM

First Honorable mention as it looks like that is post #210 about a W210.

When you say replaced all o-rings, what do you mean? There are more to replace, as noted in some of these threads.

If you are seeing air in the lines, then maybe not all are replaced or one improperly.

Also seems like a recent thread on this, let me look it up.... oops, gotta go to dinner, sorry, I'll just slam you with a handful I have in that folder.

http://www.peachparts.com/shopforum/showthread.php?t=162305
http://www.peachparts.com/shopforum/showthread.php?t=119963

http://www.peachparts.com/shopforum/showthread.php?t=156867

http://www.peachparts.com/shopforum/showthread.php?t=159808

#4 09-01-2006, 06:35 PM

Thanks for the replies. We've replaced, as far as I know, all the O-rings in the general area of the main fuel filter except the pre-filter O-ring. Will tackle that next to see if that clears it up.
Should there ever be any air bubbles visible in the line going into the main filter at any time for normal operation? If not, then a seal is bad and the system is sucking air. Secondly, can the prefilter O-ring be sucking air yet not leaking fuel?
Sorry if I've asked any redundant questions answered in other posts, but my car is unconscious and not responding.

Steve

scott19_68 · #5 09-02-2006, 11:59 AM

I had the same issue earlier this year and just changing the O-rings was not enough for me. The major source of air leaking in for me was the short fuel line from the fuel heater to the pre-filter. I'm not sure how air was getting past the new O-rings on the old one, but replacing entire thing worked like a charm.

Carleton Hughes · #6 09-02-2006, 12:06 PM

ALL the O rings,ALL the snap-on plastic lines,including the one which fits atop the pre-filter.

Read my post about the shut-off valve O ring that fits in the engine block,some nice guy late for dinner posted it{thanks!}

crmont · #7 09-02-2006, 02:36 PM

Where exactly is the pre filter anyway? Anyone?

#8 09-02-2006, 02:47 PM

Now waiting for parts, will replace all clear lines and all o-rings as suggested.

Steve

#9 09-02-2006, 07:04 PM

IF it is leaking a top of the IP it is probably the copper washers....been there done that and o-rings......

Carleton Hughes · #10 09-02-2006, 07:12 PM

Quote:

Originally Posted by steve hutson

Now waiting for parts, will replace all clear lines and all o-rings as suggested.

Steve

You a handy sport with a digital cam? I'm telling you the intake manifold is a cakewalk to remove with the right star bit and a 10mm socket,really facilitates it,but not necessary,just unbolt the windshield washer tank,remove the top wire and the 2 coolant lines and put it atop the wheel well,all the room you'll need.

Although I took a number of pics I do truly regret not shooting every step from manifold removal to the actual leak,when I do the glow plugs and one engine mount this winter I will shoot everything in sequence.

TMAllison · #11 09-02-2006, 11:51 PM

O-rings CAN allow air to enter with no fuel leak being present.

The o-ring at the pre-filter is a separate part number from the pre-filter and is missed very often. The pre-filter itself with its clip type extension washer/holdown can be difficult to make seal sometimes.

The only line that should drain at shut down is the line from the pre-filter back to the fuel theromstat mounted in the cyl head. It will drain back ~3/4's the length of the line. It is a short (3" or 4" line) mounted on the top left of the fuel filter housing.

You should not see bubbles in any of the lines connecting to the shutoff valve when running. If yu do there remains a samll leak somewhere.

crmont · #12 09-03-2006, 01:09 AM

Check my thread. I just changed the o-rings only without removing the manifold
http://www.peachparts.com/shopforum/showthread.php?t=162751

#13 09-03-2006, 07:08 PM

Carleton,

I could remove the intake manifold but sadly the car is in Forth Worth and decided to crap out the day before I was supposed to move. Here I sit 600
miles away while the troubleshooting goes on. I've passed along all of your suggestions to the shop, many of which have been implemented. Pe-filter o-ring is the one that hasn't definatevly been ruled out.

Steve