One Injector Seems To Be Missing A Part At The Inlet Side--Does It Matter? - PeachParts Mercedes-Benz Forum

Squiggle Dog · #1 07-25-2014, 06:34 PM

I just got back my rebuilt injectors with Monark tips. I noticed that one of them is missing a little metal piece with 3 holes on the inlet side. Does this matter?

scottmcphee · #2 07-25-2014, 10:07 PM

Different brands do it differently.
Both normal.

Squiggle Dog · #3 07-25-2014, 11:03 PM

They are all Bosch housings with Monark nozzles. But, maybe one of the housings is a different year than the rest. It looks like it's missing a piece, but I am not sure. It's odd as I hadn't seen an injector before without the little screen/valve or whatever it is.

Diesel911 · #4 07-26-2014, 12:55 AM

The insert with the 3 holes is actual an edge Filter.
The Older VW Rabbit and Volvo Diesel Nozzles that physically look the same and are otherwise interchangeable don't have the Edge Filter. In fact most other makes of Diesel Injectors don't have the Edge Filter inserted into the Injector.

What is it there for? I don't know if this explanation is true or not. I was told that as the Fuel Injection Lines erode inside over time it is possible for small pieces inside to break off and make their way to the Injector and the Edge Filter is there to keep them from getting any Further.
However, as I said the bulk of the Injectors out there don't have that Filter so it I doubt if the problem happens frequently or all Injectors would have the Edge Filter.

Or the Explanation I was given is entirely wrong.

The first set of Injectors I rebuilt and put into the Mercedes used VW Rabbit Injector Bodies that did not have the Edge Filter and there was no difference caused by them.

I have seen some of the Older Mercedes Injectors that don't have the Filter either. All of them were 4 Cylinders.

Squiggle Dog · #5 07-27-2014, 11:16 AM

Interesting explanation. Well, the injectors are installed and work. I freaked out when I looked inside the top of the last injector and noticed that there was just a hole there and the screen appeared to be missing.

greazzer · #6 07-28-2014, 07:34 AM

How's it running ? I have seen injector sets with and without the 3 hole configuration, and a misch mass of both in sets. The explanation I heard is the same from Diesel 911 plus I also heard it has something to do with how the fuel blasts into the prechamber. I do not think it affects performance, however.

Squiggle Dog · #7 07-28-2014, 10:09 AM

It's running great, I was just worried that the fuel seeping from around the top of the large fuel filter bolt was causing it to suck in air that would become trapped. But, I tightened it up and it stopped leaking.

Diesel911 · #8 07-29-2014, 09:45 PM

Quote:

Originally Posted by greazzer

How's it running ? I have seen injector sets with and without the 3 hole configuration, and a misch mass of both in sets. The explanation I heard is the same from Diesel 911 plus I also heard it has something to do with how the fuel blasts into the prechamber. I do not think it affects performance, however.

The OP is speaking of item #13 in the diagram that is the dark gray line in the Injector.

That passage turns into a single hole further down where the Fuel Exits the upper Injector Body and goes into the circular groove/annulus in that Plate #3 in the diagram. That plate has 2 holes in it and allows the Fuel to go into the top of the Injector Nozzle that also has a groove/annulus.

From there the Fuel goes down through 3 or 4 holes (can't remember how many) in the Nozzle on to the Pintel Needle.

So I cannot see how part number 13 would effect what is happening in the pre-chamber.

Diesel911 · #9 07-29-2014, 09:48 PM

Quote:

Originally Posted by Squiggle Dog

It's running great, I was just worried that the fuel seeping from around the top of the large fuel filter bolt was causing it to suck in air that would become trapped. But, I tightened it up and it stopped leaking.

That part of the system from the Fuel Supply Pump forward is supposed to be under pressure so it is hard to imagine how Air could be pulled into the Filter Housing if the Fuel Supply System is working normally.

Squiggle Dog · #10 07-30-2014, 12:03 AM

It's good to hear that the leaking crush washer at the filter wasn't leaking air into the system.

Wow, there are actually little filters in the injectors... I wonder if those ever get replaced or cleaned when the injectors are rebuilt.

My rebuilt injectors are pouring fuel out between the halves. I am not happy. It looks like they need to come out again.

Diesel911 · #11 07-30-2014, 10:50 PM

Quote:

Originally Posted by Squiggle Dog

It's good to hear that the leaking crush washer at the filter wasn't leaking air into the system.

Wow, there are actually little filters in the injectors... I wonder if those ever get replaced or cleaned when the injectors are rebuilt.

My rebuilt injectors are pouring fuel out between the halves. I am not happy. It looks like they need to come out again.

They are not exactly Filters they are just narrow openings; there is no Screen or somethng like that inside; just 3 narrow passages. The Edge Filters are not supposed to come out.

You can clean them with Chemicals or an Ulatrsonic Cleaning Tank.

Diesel911 · #12 07-30-2014, 11:03 PM

Quote:

Originally Posted by Squiggle Dog

It's good to hear that the leaking crush washer at the filter wasn't leaking air into the system.

Wow, there are actually little filters in the injectors... I wonder if those ever get replaced or cleaned when the injectors are rebuilt.

My rebuilt injectors are pouring fuel out between the halves. I am not happy. It looks like they need to come out again.

It seldom works but it is sometimes possible hold the lower Nut with a Wrench and tighen up the upper Body with a Crows Foot type Wrench.

If you use a Torqe Wrench and you position the Crows Foot 90 degrees from the Head of the Wrench as in the picture the torque is accureate no matter the length.
you just need to be careful not to bend the Fuel Return Nipples on the Injector.

I don't now what method you used to rebuild the Injectors but except for not using a real Lapping Plate the below comes close to what a shop would to when they rebuild Injectors.
Vince Walden how to rebuild IDI Injectors.
http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

I don't like the idea of using Abrasive Paper because I don't believe it is flat enough but People do it with no issues.

I think a Plate of Glass with 600 grit Lapping/Grinding Compound or finer is is better choice.

Squiggle Dog · #13 07-31-2014, 10:51 AM

I mailed the injectors to a shop in California and paid to have them rebuilt. When they came back and I installed them, fuel was leaking out of them. I also think that they were set at 115 bar instead of 135-143. I am having the shop that did the work refund the money and am taking them into the local Bosch shop. I don't have the equipment to rebuild them properly.

funola · #14 07-31-2014, 11:09 AM

Often, injector half leaks are actually return nipple leaks dripping down. Injetor half leaks should have been caught during pop testing. I strongly suggest you rule out return nipple leaks first.

Squiggle Dog · #15 08-01-2014, 03:24 PM

The area under the return hoses was bone dry, but I could see fuel running out from between the halves. The person that rebuilt them said that he took them apart a few times to shim them and said they may have not been totally clean.