Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #46  
Old 08-16-2009, 01:22 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
It was simply a matter of disconnecting and clamping off the thermo/heater to lift pump line, and then switching the feed line (with primary filter attached) from the thermo/heater inlet to the lift pump inlet. Idling does not show much difference. I will test drive to purge any air and see if there are any different results.
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...
Reply With Quote
  #47  
Old 08-16-2009, 02:03 PM
Registered User
 
Join Date: Nov 2004
Location: Nova Scotia, Canada.
Posts: 6,510
I do not personally liike the way this going for you. If the fuel tank does not have an obstructed vacuum relief line. I am going to assume you have been testing with the cap loose or off? Stuffing a rag in the neck stops most fuel slosh out if tank has any amount of fuel in it by the way. Retained and building tank vacuum over a few days would cause major problems. Just removing the cap now when idle is rough. Idle should restore in less than five minutes if the vent is closed.

Other than that you only have one test left. The totally independent fuel supply source to the pump in my opinion. Normally the pump should clear itself of air once running if in good shape. Plus stay clear of air. For a better opinion on this others should comment that have or have owned your engine type. I do not know it all. Or if you do an absolute test and problem remains Talk to an injection pump place.

One last thought as well. As system was using alternative fuel previously try running the injection pump on it. If problem leaves pump may have excess wear internally. I hope that is not the issue. Probably not in fact but no easily turned stone should be ignored.

Last edited by barry123400; 08-16-2009 at 02:15 PM.
Reply With Quote
  #48  
Old 08-16-2009, 03:29 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
Sealed off cracks in aluminum fuel filter housing with RTV.

IMHO the fuel heater thermostat is shot. Inlet (from fuel feed) barb is loose - will have to rebuild - new one is $165 . Closed off thermo/heater loop and took it out of fuel feed circuit. Running direct from fuel feed to primary filter to lift pump now.

5/16 NAPA (Gates, I think) fuel hose is cheap and not very durable - let along the wrong size (5/16 - s/b 7.5mm). Had a small piece of German metric stuff and replaced primary filter to lift pump section. Will get more German metric tubing from injector shop on Monday.

I am still not convinced the return relief valve is sound. Engine has 246K on it and this part has never been replaced. Still need to thoroughly troubleshoot that part.

Will be testing lift pump pressure Monday.

Tank does not seem to retain vacuum and removing the cap does not change idle noticeably.

Thanks a ton for all of your input Barry - all has been illuminating. I am getting closer now.
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...
Reply With Quote
  #49  
Old 08-16-2009, 03:36 PM
Dionysius
 
Join Date: Jan 2006
Location: Seattle WA
Posts: 261
Since this is a tough one I will offer a thought.

What if the thermostat failed and you were over-heating the fuel. This would cause trapped air to come out of solution.

I know it is a long shot but never underestimate the enemy......
__________________
Dionysius
Reply With Quote
  #50  
Old 08-16-2009, 04:48 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
I disconnected the thermostat - it seemed to be worn out anyway - I will test and update as circumstances change. Stay tuned!

Oh - forgot to mention - I have ordered Monark nozzles and will have the local shop install those soon - should be interesting to see what that change will yield...
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...

Last edited by sasquatchgeoff; 08-16-2009 at 04:54 PM.
Reply With Quote
  #51  
Old 08-28-2009, 12:46 AM
Basstrip
 
Join Date: Dec 2008
Location: California
Posts: 111
Question Can the IP losse compression

Diesel, do you think a leaking IP can losse compretion and may cause unbalance fuel delivering and nailing.
Quote:
Originally Posted by Diesel911 View Post
This is what I think:
I have not understood why yet but apparently some nailing can be caused by too advanced or too retarded IP timing. The Nailing/Knocking sound has to do with too much of the Fuel bruning at the wrong time and or place in the Pre-Combustion chamber.
Burning and the wrong time and place includes most of what you said.

You also left out low/bad compression.

Weak Injection Pump- I am not sure what you mean by this. Worn or abused IPs have erattic fuel delivery and deliver less fuel. I am speaking of the high pressure fuel that goes to the Injectors.

This can be caused by worn Elements/Plungers and Barrels (scratches on the parts due to bad fuel or poor filtration or some alternate fuels) or if the Rollers, Tappets, and Camshaft inside of the IP are worn (the makes the internal timing of the IP).

[On other vehicles with Rotary type Fuel Injection Pumps (like VW Rabbits, my Volvo and vehicles with Standyne IPs) the advance mecanism is built into the Fuel Injection Pump and as the pump wears the advance become retarded over time. The advance pistons are also at the bottom of the IP and that is where any water will also settle. If the water sits long enough the advance piston can stick.]

Aparrently on those IPs with O-rings that leak; when they leak it some time causes nailing (from what I have read in the threads).
Quite a few members have reported that after the O-ring changing job they experienced Nailing until they have driven 200 miles or so. The reason for this has yet to be explained.

I am not sure if a weak Fuel Supply pump will cause Nailing or not. I guess with the OP saying it was his filter there could be something but it is not clear to me what it is.

I have not read of the excessive Carbon explination for Nailing. I would be the result of another problem or problems like Oil burning, bad Injector Nozzle, Ball Ping damaged, damaged Pre-chamber, bad fuel and so on.
Reply With Quote
  #52  
Old 08-28-2009, 09:47 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 24,143
Quote:
Originally Posted by Basstrip View Post
Diesel, do you think a leaking IP can losse compretion and may cause unbalance fuel delivering and nailing.
Sorry I did not see your post yester day.

I believe I have read where other members have reported nailing when their Delvery Valve O-rings were seeping on the IP.

And, as other have said when the O-rings were replaced the IP continued to cause nailing for hudereds of miles afterwards.
In one of the threads I speculated that the Delivery Valves (the small valve in the middle) got shifted around and needed time to reseat themselves. But, I do not know for sure.

In the past when I did Fuel Injection work we would somtimes get IPs in that had worn Delivery Valves that needed replacing or relapping of the valve seating area.
However, our customers Mechanics were the ones who did the trouble shooting and removing of the IP (and almost all were from Direct Injection Engines). So, I have no clue if the worn out Delivery Valve issue was causing Nailing or not.
__________________
84 300D, 82 Volvo 244Gl Diesel

Last edited by Diesel911; 08-28-2009 at 10:07 PM.
Reply With Quote
  #53  
Old 08-31-2009, 10:02 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
Well friends and neighbors I wanted to update this thread and get any input that may be slung my way.

Rebuilt lift pump and fuel thermostat today. Also replaced return relief valve. Lift pump and thermo o-ring seals were flattened and almost to the point of crumbling. Reassembled, cranked up and WOW! Major difference in power, idle, and overall running. In order to not jinx this great circumstance, I will withhold any definitive statement of resolution until a cold start tomorrow and 3 days of smooth performance without even an infinitesimal amount of nailing, but for now, it is literally running like a new car - far better than any of my previous post-air-purge "honeymoons."

stay tuned...
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...
Reply With Quote
  #54  
Old 09-05-2009, 11:38 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
Final Resolution to the Nailing Problem in my Rebuilt 602.91

The lift pump and fuel thermostat rebuild produced improved performance, but after a couple of days the rough starting and rough idle came back. The next day the IP got air-bound again and the nailing came back.

I was stumped. I had replaced the fuel hoses, filters, nylon IP to secondary filter connectors, return relief valve, lift pump and fuel thermostat innards, had the timing checked by the local well-reputed indy, checked the tank strainer, blew out the goop in the hard lines from tank to firewall, checked tank vent lines, had the injectors pop-tested twice, and confirmed good fuel - all to no real change in the pattern of rough starting, rough idling, and eventual nailing due to the IP becoming air-bound over a period of 3-4 days after purging.

It was time to do what Mark at Diesel Fuel Injection Service in Portland (the folks who rebuilt my injectors) had suggested from the beginning. Replacing the seals and crush washers in my delivery valve holders was much easier than I had anticipated. I didn't even pull the intake manifold (unlike 617's, 602's and 603's IP pumps sit under the IM) - Mark had kindly loaned me the special socket and with a 3/8 universal, 8" extension, and a breaker bar I was able to get each one off after meticulously cleaning the top of the IP off w/brake cleaner and compressed air. The rubber o-rings were practically rectangular and literally crumbled while I pulled them off the holders. The original copper crush washers were flattened out pretty good, and I surmised that someone not so thorough had been in there and reefed on those holders once upon a time. The springs were a little tricky to get just right on top of the DV so that the holder could come down on it and allow it to fit up into the recess, but I managed quite well - if I do say so myself. This job was WAY easier than I expected, and I was able to feel confident that I had done a good job while I torqued the holders to the FSM specified 35 Nm.

Cranked it up and there was an immediate difference. Drove it on the freeway, got it up to about 85, and pulled back into my driveway with a big grin on my face. No post-o-ring replacement nailing that some have reported. It was almost as if the car could breathe where it had been choking for the weeks post-rebuild. After nearly two months of banging my head against my garage wall, my engine was running the way it was supposed to - and not reverting back to a sub-standard condition due to air infiltration.

SOOO...,
My original questions:

With no apparent fuel leaks, can worn delivery vales/sealing washers & rings be the cause of nailing? If so, how?

The answer to the first one is YES! Now, I have to understand how it happened. Maybe somehow the worn o-rings allowed microscopic amounts of air in as the element/DV receded, which over time collected in the secondary canister?

Thanks to everyone for their input. This has truly been an intriguing and educational process.

- geoff
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...
Reply With Quote
  #55  
Old 09-06-2009, 03:46 AM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,612
edit: the following information is misleading

May I make a few grand assumptions, as usual?




The rubber o-rings are only a preventative measure against corrosion for the more important seals that it protects. Rubber is not commonly employed to seal such high pressure as is found in the plungers.

Once these o-rings begin to allow moisture in, the copper washers corrode and allow fuel out, or air in.

If you are correct in assuming that this was the cause of the nailing, is it possible to imagine that the retracting of the plunger in the barrel causes enough vacuum to suck air in? If that is the case, then late injection is the result.


Another note: Have you read the DIY for the 603 on this procedure? It recommends (from an update by MB) that when torquing, you torque 3 times. The third being the final setting.

If anyone was every in a bind, you could put off doing the o-rings but re-torquing as suggested by MB:

30 nm ...release
30 nm ....release
35 nm ... finish
Attached Thumbnails
A Question for the Injection "Masters"-deliveryvalve.jpg  
__________________


Last edited by whunter; 09-13-2009 at 07:29 PM. Reason: attached picture
Reply With Quote
  #56  
Old 09-06-2009, 04:35 AM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
I am basing my theory on the idea that some sealed barriers, especially worn EPDM o-rings, may actually admit gasses but still present a barrier to liquids. Check the Parker O-Ring Manual. Depending on the size of the gland and the material, pressure resistance up to 5000 PSI can be realized with ordinary run-of-the-mill seals. While the o-ring is on the outside of the DV holder, pressurized fuel does not normally come into contact with the EPDM seal, but this seal is the only barrier between the pump element well and the atmosphere, aside from the threads of the DV holder. In order for air to be drawn into the pump, it has to bypass that rubber seal if all other entrances are restricted to fuel-only (as is the case with my fuel system). Honestly, I can't see air getting past the copper seal, regardless of condition. It is buried inside the element well and DV holder with the crushing force of some garage-gorilla's over-torquing bearing down on it. The air is coming from the secondary canister placed there by a frothing, air-bound pump and enters the prechamber via the route that fuel-only should be present.

At least thats what I am imagining at this late hour....

On the triple torquing: The OM602 section of my W201 FSM, including tech bulletins up to '93 made no mention of a three-staged tightening sequence. My experience was different from the DIY. I tried to make it a surgically clean operating room



Attached Thumbnails
A Question for the Injection "Masters"-dvreliefchoke_cropped.jpg  
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...

Last edited by whunter; 09-13-2009 at 07:28 PM. Reason: attached picture
Reply With Quote
  #57  
Old 09-06-2009, 04:51 AM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,612
edit: the following info is misleading

I see where you're going w/ the 'no fuel out, air in' idea... gotcha.


My personal dilemma with the "fuel filter air pocket build-up" theory is, as you mentioned, the fact that the system is self-priming.

The lift pump, under normal operation (and e$pecially now that you have rebuilt your$), is always over-fueling the system. The only way air could build up in the fuel filter would be if the LP was pumping more air than fuel....


Perhaps I am missing a crucial diagram, but I thought that copper washer (7f ?) was the seal for the plunger in the barrel / perimeter of the DV and there is no fuel in the chamber around its outer diameter.
__________________


Last edited by jt20; 09-06-2009 at 12:30 PM. Reason: bad info
Reply With Quote
  #58  
Old 09-06-2009, 05:03 AM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
From what I could see when removing the holder, the copper ring is slightly smaller than the I.D. of the inside of the holder. This allows for fuel (part of the pumps feed, I imagine) to be present (non-high pressure, mind you) in the annular space and in the threads of the holder. I figure this is another of the reasons for engineering the o-rings around the holders. The holders do not bottom out in the element well, they stop at the copper ring on top of part 7G, which just sits in there.
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...
Reply With Quote
  #59  
Old 09-06-2009, 05:15 AM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,612
in your diagram in post #56, item 7g is the DV body while the DV is that little guy being squished by the spring into 7g. That region that contains the spring is filled with fuel and is sealed by the copper washer.

When you loosen the DV holder (7 - the entire unit) you release pressure from the copper washer by unscrewing the DV holder.

This allows the fuel in that chamber with the spring to run down into the surrounding chamber outside of the DV's sealed area. Is there a chance that fuel was only there b/c the DV chamber was opened up?

The delivery valve should see ALL of the fuel that is pushed up by the plunger below it in order to achieve maximum performance. I can't imagine why fuel would be routed around the DV and the copper washer.
__________________

Reply With Quote
  #60  
Old 09-06-2009, 12:10 PM
sasquatchgeoff's Avatar
Cascade Foothill Lurker
 
Join Date: May 2007
Location: Portland, OR
Posts: 561
I guess I am trying to better understand the innards of the pump. 7G is the delivery valve carrier, and I assume that the barrel (and plunger) is below that. If the annular space around the carrier (and copper seal) within the DV holder contained no fuel then the carrier would have to fit tightly within the holder and that was not the case - the holder just drops right on top. The mystery to me is how and where the fuel is routed to the inside of the pump (other than in the barrel). I will assume that the pump cam and roller tappets are lubricated by diesel fuel. In the diagram below, the fuel arrives at a port which is revealed by the down-stroke of the plunger, and fuel enters the barrel to be pressurized by the lift of the plunger. That part is clear. Is there excess fuel swirling around somehow in the pump body?

Attached Thumbnails
A Question for the Injection "Masters"-tech_43_mw-pump-1.jpg  
__________________
327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...

Last edited by whunter; 09-13-2009 at 07:26 PM. Reason: spelling
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 03:50 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page