99 e300d td om606 injector wells filling with diesel (not return lines) - PeachParts Mercedes-Benz Forum

crmont · #1 04-20-2011, 12:03 AM

My 99 e300d turbo is leaking diesel in the injector wells from the bottom up. I replaced the return lines but the wells continue to fill up with raw diesel (no oil just diesel) It seems like they are all filling up at the same rate with #6 being the fullest because of the angle of the motor.

I didn't realize fuel could get between the wells without going over the top.

Cracked head?

compress ignite · #2 04-20-2011, 03:32 AM

to the Injectors.
1.Maybe the Little Nipples for the Fuel Return Hoses are Buggered?
2.Maybe there's some other reason the FRH aren't sealing?
3.Does your Mercedes Diesel have All Those Plastic/Composite Fuel Lines and
Clips?

KarTek · #3 04-20-2011, 06:27 AM

I chased this for quite a while on my car. I even replaced a couple injection lines at $50 a pop.

It turned out to be the injectors themselves leaking at the division line. I had to remove them, clamp them in the vise and re-torque them.

Fishnchip · #4 04-20-2011, 07:41 AM

I also suffered through this with my 97 E300. I had used a utility knife to slice the original hoses for removal, causing a small nick on the nipple of one or two injectors. At that time I replaced all return hoses using viton hose. Unfortunately, the viton hose does not seal around any imperfections as well as the OEM braided style. Although leak was only in one or two wells, fuel would migrate to almost all. After going round and round with this looking for leaks, retorqueing injector lines, checking injectors, ect., I replaced all return lines with the braided style. Leak gone.

Diesel911 · #5 04-20-2011, 11:35 AM

Swap the suspected leaking Injector with another Injector on the Engine. If the leaking follows the suspect Injector to the new position there is something wrong with the Injector.
If the problem stays on the same Cylinder you have an issue with your Fuel Injection Hard Lines.

If this has happend after the Injectors were worked on it could be the lapped surfaces inside of the Injector are leaking.

The Injector Nut chould have a hairline crack in it or may be loose.

This is on the top but the little Return Line Nipples are pressed into the Upper Injector Body and a circular crimp is applied around the hole the go into. Sometimes they become loose and leak return Fuel.
There is no fix for the above with the exception that one of the Member cut a leaking Nipple off and Welded over the spot. He used that Injector on the very end where one if the Fuel Return Nipples would have a Rubber Cap to plug it off.

crmont · #6 04-20-2011, 11:56 AM

Quote:

Originally Posted by Diesel911

Swap the suspected leaking Injector with another Injector on the Engine. If the leaking follows the suspect Injector to the new position there is something wrong with the Injector.
If the problem stays on the same Cylinder you have an issue with your Fuel Injection Hard Lines.

If this has happend after the Injectors were worked on it could be the lapped surfaces inside of the Injector are leaking.

The Injector Nut chould have a hairline crack in it or may be loose.

This is on the top but the little Return Line Nipples are pressed into the Upper Injector Body and a circular crimp is applied around the hole the go into. Sometimes they become loose and leak return Fuel.
There is no fix for the above with the exception that one of the Member cut a leaking Nipple off and Welded over the spot. He used that Injector on the very end where one if the Fuel Return Nipples would have a Rubber Cap to plug it off.

When #5 fills with diesel there are air bubbles coming up from that injector well but not from around the threads of the injector. They seem to be coming from the outside perimeter of the well nearest the exhaust manifold. Revving the engine doesn't seem to impact the rate of the bubbles.

A pain in the ass working on the injectors with a cup of fuel in each well every time I run the engine.

I don't see fuel coming anywhere from the top end of the injectors or the lines. It seems to be filling from the bottom up. I think I'll get the engine level and try to determine which well fills first. Then I'll swap injectors. BTW what is the torque setting?

How much of a passage way is there between wells anyway?

Diesel911 · #7 04-20-2011, 02:02 PM

Quote:

Originally Posted by crmont

When #5 fills with diesel there are air bubbles coming up from that injector well but not from around the threads of the injector. They seem to be coming from the outside perimeter of the well nearest the exhaust manifold. Revving the engine doesn't seem to impact the rate of the bubbles.

A pain in the ass working on the injectors with a cup of fuel in each well every time I run the engine.

I don't see fuel coming anywhere from the top end of the injectors or the lines. It seems to be filling from the bottom up. I think I'll get the engine level and try to determine which well fills first. Then I'll swap injectors. BTW what is the torque setting?

How much of a passage way is there between wells anyway?

I have no info on the Torques.
However, besides the Injector to Prechamber Torque you may need the Injector Nut to upper Injector body torque (incase the Injector Nut is loose or cracked).

lupin..the..3rd · #8 04-20-2011, 03:03 PM

I had a leaky one a few years ago. My injectors had 125k miles on them, so I figured it was time for a rebuild anyhow. I bought some new Bosio nozzles and took them to the local diesel shop. They rebuilt the injectors with the new nozzles for me, ultrasonic cleaned everything, pop tested them, etc. Upon reinstalling them, I have no more leaks.

TMAllison · #9 04-20-2011, 09:29 PM

Guessing this is related to you having replaced the return lines. Either the barbs are dirty/damaged/scored, the line is the wrong size or type (viton needs clamps oftentimes), the plug in #6 has disappeared or all of the above.

MB return line is gray braided fabric with a rubber core. Old stuff is black.

There is no reason the two injector halves should leak unless they have been taken apart sometime in the past and not put abck together correctly.

Atomized fuel that is sprayed at 2100psi into a hot combustion chamber shouldn't be able to come back up as a solid. Look for other solutions.

You asked about the inj socket.....it is "very" thin walled, maybe 3mm, with two vertical cutouts to clear the return line barbs. Its also around 4.25" long. If someone ahs removed them using something other than the factory tool the barbs may have been damaged which could be the cause of your fuel leak.

I'd concentrate on return lines and what I'd done to get them on and off it if it was mine.

crmont · #10 04-21-2011, 01:50 AM

Quote:

Originally Posted by TMAllison

Guessing this is related to you having replaced the return lines. Either the barbs are dirty/damaged/scored, the line is the wrong size or type (viton needs clamps oftentimes), the plug in #6 has disappeared or all of the above.

MB return line is gray braided fabric with a rubber core. Old stuff is black.

There is no reason the two injector halves should leak unless they have been taken apart sometime in the past and not put abck together correctly.

Atomized fuel that is sprayed at 2100psi into a hot combustion chamber shouldn't be able to come back up as a solid. Look for other solutions.

You asked about the inj socket.....it is "very" thin walled, maybe 3mm, with two vertical cutouts to clear the return line barbs. Its also around 4.25" long. If someone ahs removed them using something other than the factory tool the barbs may have been damaged which could be the cause of your fuel leak.

I'd concentrate on return lines and what I'd done to get them on and off it if it was mine.

Any thoughts on the air bubbles coming up through #5?

I replaced the fuel lines and #6 plug with MB grey fuel line from peach parts. I also purchased a socket through peach parts.

compu_85 · #11 04-21-2011, 02:21 AM

Quote:

Originally Posted by KarTek

It turned out to be the injectors themselves leaking at the division line. I had to remove them, clamp them in the vise and re-torque them.

I've had this on my old VWs as well, you just don't notice it because the fuel runs down the front of the motor instead of pooling. Same fix though.

-J