Fuel Distributor Question For Techs - PeachParts Mercedes-Benz Forum

87-300E_in_NC · #1 01-02-2004, 04:20 AM

This question goes out to the MB techs (or anyone that knows the fuel distributor like they know their home phone #)........

I have reason to believe that my fuel distributor has been toyed with by someone before I purchased my '87 300E with the 2.6 engine.

The plunger, when depressed by thumb (and under fuel pressure with lines capped) leaks. There is an extreme amount of free-play between the plunger stem and the hole that it travels through, (where the seal is).....so, just replacing the seal will make no change in this situation. My question is: Is this normal, or did someone play put-together the FD and see if it works?

Answers would be appreciated from those that know...instead of those that think they know, because this is an expensive replacement part, new, rebuilt, or used.

Too much fuel in the intake manifold is what my engine is experiencing. It will crank (after I dry the plugs, open the air flow plate and throttle, then spin the engine) and run fairly good for warm-up, then will die.....I took it to 7K without hesitation, so pressure is not the cause, unless the upper/lower chamber pressure is being misguided from a sticking valve in the FD....EHA unplugged makes no change.

Thanks, and Happy New Year!

87-300E_in_NC · #2 01-02-2004, 10:00 PM

Seems like someone would know the answer to this simple question.....

stevebfl · #3 01-02-2004, 10:09 PM

The question may be simple your demand for an exact answer makes it a lot harder. Plus, interpreting your question might be harder than the answer.

The piston should be a very tight fit, but I'm not sure that is what you are asking. A picture would help.

87-300E_in_NC · #4 01-02-2004, 10:17 PM

Quote:

The question may be simple your demand for an exact answer makes it a lot harder. Plus, interpreting your question might be harder than the answer.

Sorry that I don't have a picture, and sorry that you think I have a demand for an exact answer. My question is simple...ok, the plunger fit is tight, but where it travels on the underside, where it is locked by the locking cap is a loose fit. I was wondering if this loose fit with the cap versus the plunger stem is correct, or did someone place the incorrect locking nut on the bottom of the FD?

Thanks for your reply Steve. I appreciate all of your posts on this board, and wish you well my friend.

Happy new year!

pesuazo · #5 01-02-2004, 10:26 PM

I will try to come by tomorrow with my digital camera, so that we can post exactly what you are talking about (the free-play on the stem)
Give me a call when you get ready to work on the car (you are gonna have to pick me up in Bunn again)

87-300E_in_NC · #6 01-02-2004, 10:32 PM

Thanks pesuazo,

I really appreciate your help, and friendship. You are a real team-member! Will call you, and meet you in Bunn...same place. I love my new grill

.....it cleaned up well....surface rust came right off with Naval Jelly.

Weather for tomorrow: sunny & 74 degrees! Ice cream weather again!

87-300E_in_NC · #7 01-04-2004, 07:11 AM

.

Quote:

The piston should be a very tight fit, but I'm not sure that is what you are asking. A picture would help.

Hi Steve - Hope this attached photo helps. If it does not appear, click here to view: http://www.fixmymercedes.com

Thank you

Hope all is well.

stevebfl · #8 01-04-2004, 11:17 AM

Well, I hate to proclaim my ignorance but I have never had a problem such as you speak. I don't think the small diameter shaft clearnace against the fitting is critical. The fine tolerance is needed for the major piston.

Best I can say is that I will look at one when I get back to work. That may be tomorrow but I have had a nasty cold/flu now for near a week.

Hurshi · #9 01-04-2004, 01:55 PM

I think that the plunger seal is only used for keeping the pressure in the fuel system when the car is turned off. When you turn off the car the plunger sits on the seal and keeps the fuel from leaking.
When the engine is running, the rubber seal is useless because it lets fuel through the plunger stem area.

There is a theory that the fuel distibutor leaks because the plunger itself gets thinner by time letting the fuel sneak through its walls. But it is not proved yet.

Hopefully we will have an answer from a professional.

I would recommend you to take a look at this site.

http://www.injectorservis.narod.ru/KE-JetronicClean.html

This russian says that he has fixed some bad fuel distributors by taking them apart and then cleaning them in an ultrasound bath.
No info about leaks but this is usefull information.
Here is a pic from his site.

http://www.injectorservis.narod.ru/KE-JetronicCleanFiles/DozatorUltraSound.jpg

He says he can fix most of the bad fuel distributors. The second picture shows us that he takes a measure of heights of the 4 screws. After the ultrasound bath he re-adjusts them to their original hieghts.

Does anyone want to take their salvaged fuel distributors apart?

87-300E_in_NC · #10 01-04-2004, 07:36 PM

Hi Steve and Hurshi,

Thanks to you both for the replies. That Russian site may take me a while to read, as I will have to convert the text to english via http://www.reverso.net .....this is a really cool translator, free also. It really has opened doors for me around the world, allowing me to communicate with others.

The ultrasound bath sounds very interesting. I am guessing that the high frequencies vibrate the particles out of the places where they are trapped. At this point, maybe I should take my FD with me to the hospital, and see if I can talk someone into helping me in the maternal ward

lol!

At this point, I'm ready to try anything!

I have bathed my FD in 140 degree water for 5 minutes.....rust was in the bottom of the pot, and this is after I cleaned it with carb cleaner and starting fluid, removing rust sediment also.

I would highly recommend everyone that reads this message to remove their fuel tank from the trunk and clean it with Naval Jelly and large rocks like I did, or, get it cleaned (glass beaded) and coated with a special epoxy resin (there are businesses that provide this service). This recommendation applies for anyone that has KE fuel injection especially, and includes diesel operating engines also. If I had only cleaned my fuel tank before I test drove it, I would be driving my beautiful 300E today.

Hope that cold/flu leaves you soon Steve. I went through it also, had the symptoms for a week. My secret is blowing my nose every time I could think about it, which is a proven secret to keeping colds down, just like washing your hands frequently.

Paulwho · #11 01-04-2004, 09:03 PM

87-300,

let us presume you assemble your fd to tha air horn assy, attached the fuel lines and powered the fuel pump relay, when slightly depressing the sensor plate you would see fuel out your injectors but not at the plunger assy. Fuel at the plunger assy would not be metered and would be bad. I have seen fd leak when under snap accelleration fuel spray could be seen under the sensor plate. Only a small amount of fuel leakage is allowed. Good Luck

myarmar · #12 01-04-2004, 10:40 PM

Here is a translation for you. I have no experience with distributors and don't know if the article makes any sence, just a translation.
Regards, Mike

Cleaning Fuel Distributor
For proper cleaning distributor has to be disassembled. In addition ultrasonic cleaner is used.

Disassembly:
- Remove EHA
- Remove screws connecting top and bottom sections of the distributor

Picture

-Using hex socket 19 mm remove the nut and remove plunger
- Carefully separate top and bottom portions, taking care not to damage the membrane
- Using dial indicator measure positions of the set screws in the bottom differential chambers and write it down

Picture

- Put upper portion in the ultrasonic cleaner for 15 minutes, then turn it around and clean additional 10 min. All channels and filters clean by now. Blow with compressed air.
- Repeat same procedure with the bottom portion. Keep in mind that set screws might turn and lose adjustment.
- Using dial indicator, set the screws to the measured positions
- Prior to final assembly distributor has to be completely dry.

Assembly
- Put O-rings on the plunger, oil with clean motor oil all O-rings and mating surfaces and carefully without excessive force put plunger into the upper part of the distributor.
Picture
- Put cups and springs on the set screws, membrane and ceramic plates with the springs
- Connect top and bottom portions
ATTENTION: When connecting top and bottom take care not to pinch o-ring on the plunger

- Put assembled distributor on the air plate, connect all pipes except those to the injectors
- Activate fuel pump and check distributor for leaks. When disk is pushed, gas should leak out of each chamber simultaneously, release disk and gas should fully stop.

- Connect hoses and suitable containers for checking each chamber
- Check distributor in three modes: Idle, Partial Load, and Full Load. The volume of fuel should be the same, and after 30 seconds at full load there should be about 70 - 100 ml in each container. Make sure the volume difference is less than +/- 2%.
If necessary, each chamber can be adjusted with the set screws.
Now if necessary, injectors can be checked for the pattern and flow rates.

87-300E_in_NC · #13 01-05-2004, 01:16 AM

Thanks Myarmar, for the translation. I have not had time to translate it, but glad you have....www.reverso.net is the best I know of for translation.

Disassembly of my fuel dist. was the last thing I really wanted to do before replacing it, since I had no technical data on it, but now I do.

My next question is where do I find ultrasonic cleaner? I'll do a search on the net, maybe I'll get lucky

.

Rust sediment is the culprit, and if I can disassemble the FD without damaging the diaphram, everything will turn out well.

I appreciate your time and efforts, and if I can help you out, just say the word. I have a website hosting business (domain names, hosting, custom sites etc.....if you have a need, send me an email at http://www.peachparts.com/shopforum/webmaster@americanwebsiteservices.com.

Thanks again

87-300E_in_NC · #14 01-05-2004, 03:11 AM

Here is an article that I searched for on the web. It is loong, but if you read it, you will have a greater understanding of ultrasonic cleaning processes. It's an eye opener for sure!

============================================

Ultrasonic Cleaning Systems

Agitation systems that utilize ultrasonic waves to remove soils from surfaces are commonly employed in almost all areas of critical and industrial cleaning. This cleaning process works by way of a transducer, which converts electricity to intense, high-frequency ultrasound vibrations within a cleaning bath.

Cleaning Via Cavitation
Cavitation occurs when ultrasonic waves cause pressure gradients within the cleaning fluid, forming bubbles within low-pressure areas. These bubbles expand until they enter a region of pressure high enough to cause their collapse. Small voids (cavitations) open and collapse at the surface of the part being cleaned.

The energy created by these cavitations can effectively loosen and discharge many contaminants from the surface. This action is efficient to clean even complex heterogenous surfaces that contain numerous crevices, holes, and pores.

The cavitations created by ultrasonics have been found in many cases to enhance removal of hydrophobic solvent cleaning films by 30 to 40 percent, compared with spray rinsing methods. Ultrasonic agitation is thus very effective in increasing the degree of cleaning that may otherwise be obtained.

Compatibility Concerns
Ultrasonics is most effective with hard substrates, such as metals, glass, and ceramics, and is not as effective in cleaning soft materials. In most cases, cleaning efficiency decreases with decreasing particle size.

This cleaning process can be used with aqueous, semi-aqueous, and solvent-based systems, and the technique is compatible with numerous solvents, including fluorocarbons, caustics, acids, acetone, alcohols, ether, and other hydrocarbons. Ultrasonics can potentially be used in a vapor degreaser, but only in the liquid boil sump since ultrasonic energy does not transmit through vapor.

Temperature, vapor pressure, surface tension, viscosity, and density of the cleaning fluid all influence the performance of an ultrasonic system. The magnitude of the latter four properties varies with temperature. The viscosity and density will affect the degree of shear imparted by the ultrasonic energy. Vapor pressure will affect the extent of cavitation, and the wettability of the surface will be affected by the surface tension of the cleaning fluid.

The temperature and additive concentrations typically used in ultrasonics are a compromise between the higher temperatures and concentrations needed for optimal cleaning and the lower temperatures and concentrations necessary for optimal energy transfer.

Equipment, Frequency, Chemistry
Due to the vibrational energy, parts cannot rest on the tank bottom. The baskets used to hold the parts should not absorb any ultrasonic energy, which would effectively reduce the shear imparted on a part's surface, thereby reducing the cleaning efficiency. As a rule of thumb, the sum of a part's cross-sectional areas should not be greater than 70 percent of the tank's cross-sectional area.

Vertical tanks, with a large height:width ratio, that have transducers on the tank bottom provide a more cost-effective method of parts cleaning. The workload mass-to-volume ratio (25 to 30 percent for general parts cleaning) should be no greater than 10 to15 percent for precision applications.

The frequency of the ultrasonic energy is the most crucial element within an ultrasonic system. More noise is created at lower frequencies. At less than 20 kHz, the ambient noise might be at a level not in conformance with OSHA safety standards. On-site monitoring should therefore be performed.

Lower frequency ultrasonics, which provide more aggressive cleaning action, produce larger cavitation bubbles, and this type of process is not generally used for precision cleaning. Cleaning applications typically fall in the frequency range of 40-400 kHz. Frequencies between 72 and 104 kHz are most often employed, in conjunction with a subsequent distilled water rinse, to minimize cavitation erosion that would occur at other frequencies.

Surfactants, wetting agents, and other additives are often difficult to remove from the substrate. This may entail additional quantities of water, higher temperatures, and longer rinse times, as feasible. For many precision applications (eg, microcircuitry and precision optics), longer cycle times may introduce contaminants to the substrate, especially those with complex geometries. Leaching of construction materials may be a problem.

When using flammable solvents within an ultrasonics environment, "intrinsically safe" tanks and equipment must be employed. Standing wave damage is also a possibility within the cleaning bath, incurring frequency resonance damage to the parts being cleaned. This can be corrected by the use of a sweeping frequency generator.

Regulatory compliance with pertinent OSHA, EPA, FCC, and other federal, state, and local requirements is a necessary consideration when using ultrasonics. Also, interference with computers, microprocessors, etc. must be controlled. Line-conducted interference is controlled by use of a suitable radio frequency (RF) filtering device at the AC power supply. Radiated RF interference can be avoided by grounding and scaling the metalwork, which houses the generator and transducers, and the braided metal sleeve, which acts as one of the conductors of the interconnecting coaxial wiring.

References
Fuchs FJ. Ultrasonic Cleaning: Fundamental Theory and Application. Presented at the 1997 Precision Cleaning Conference, Rosemont, Ill.
Manchester RC. The precision cleaning of delicate structures using aggressive ultrasonics without damage. Precision Cleaning. April 1997;5.
Awad SB. Ultrasonic cavitations and precision cleaning. Precision Cleaning. November 1996;4.
Bardina J. Methods for surface particle removal: a comparative study. In: Mittal KL, ed. Particles on Surfaces. New York: Plenum Press; 1988;1.

This article was found at
http://www.cleantechcentral.com/KnowledgeBase/TechnologySpotlight/ultrasonic.asp .
==============================================

Now when I can locate the fluid, I'll be in business. Maybe my local photo shop, or radiator shop could help me. If anyone has any suggestions on locating UltraSonic cleaning fluid, please email me at webmaster@americanwebsiteservices.com

Thanks!

Looks like team work will pay off, but if you have any old 6 cylinder fuel distributors hangin around that are bad, let me know. Hope this helps someone in the future!

87-300E_in_NC · #15 01-05-2004, 03:29 AM

I appreciate your info., and I do have minimum leakage while under a pressure test, with injector lines capped. But, my fuel builds up in the intake, pudling up (I can see it after the flooding occurs). It floods so bad that I have to remove the spark plugs, clean and dry them, spin the engine over to dry the cylinders of raw fuel, then it will crank again to repeat the same process.

Rust sediment is the culprit, as the engine was running exceptionally well after the head rebuild, but the fuel sending unit had stuck at half a tank reading, so when I ran out of fuel, rust sediment clogged the injectors and FD, and EHA. As a matter of fact, one hole in the EHA is clogged, the other air blows freely. So cleaning is due, with the ultrasonic cleaning fluid. Just one more mountain to climb until I believe the problem will be resolved.

After cleaning, I will have to adjust the FD......(after assembly) so if anyone has any hands on with that, it would be appreciated.

Thanks again Paulwho, and to everyone that has been willing to help me! I'll be sure to take photos of my disassembly and cleaning process....and I'll try not to pull too much hair out in the process! LOL!

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