steve i don't want to turn this in to a pissing contest, but i have been exclusively repairing mercedes cars for the past 15 years, i know the functions of the units, if i have offended you i appologize, i would believe that mercedes know what to call there own parts, they do sometimes give them som odd names. most pressure regulators are in the fuel return system, look at the 104 ME engine as an example, is the pressure regulator in the return or supply?

There is no offense, you are just wrong. I love a good technical arguement. You know how it works, tell me what pressure they regulate and the effect on the system. I told you what I think. I hope your excuse for not knowing how it works is that they had already thrown that system away before you started working on MBs. you see I was working for MB when they brought out the first K-jet and I have been in constant touch every day since they did.

But it doesn't matter who did what. They are what they are and I have expalined their function as I understand the system. So it is your turn to explain to me what your concept of their purpose is. Pay close attention to their location in the system its a hint that it is in the fuel return where pressure plays no part of the system. If you have a good arguement you can teach me something, but just reading a poor translation from a parts book don't get it for me. I'm more interested in what the service manual says they do.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

OK, follow this. See what you make of the two parts in this system D-jet. Part 176 and part 206. If you know that system, hopefully you know that one is a pressure regulator and the other is a dampener (diaphram). Now if you know your MB part numbering system you will notice that the diaphram (not the regulator) is a similar number (000 078 xx 92) to the parts you wish to call regulators.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

it controls fuel pressure by controlling the amount that returns to the tank, even the D-jet is in the return side of the fuel rail. the d-jet is adjustable where the cis is not

Fuel pressure regulators are of course attached to the return, but they start in the pressure side. This is basic *****. They control pressure by dumping to the return. Just what purpose can a regulator accomplish with both sides hooked to the fuel return.

If we are to have a technical discussion you will have to state a technical theory of operation that fits your stated concept. I have stated that the fuel from the frequency valve is dumped through the diaphram into the return line. There is no significant pressure there. The frequency valve IS a pressure regulator. It regulates the lower chamber pressure by dumping it. By lowering the pressure the mixture is richened.

There are two other pressure regulators in that K-jet w/Lambda system. The first IS the true system pressure regulator. It is internal to the fuel distributor and regulates by dumping the excess into the return. The system pressure flows through a restricting oriface to the top of the metering piston and is re-regulated to a lower control/warm-up pressure. This pressure opposes the piston and leans out the mixture by resisting movement of the piston. It also regulates pressure by dumping the excess to the return. All of this dumping could buzz the steel lines since it would be pulses of fuel at velocity. Thus they have installed dampeners to keep the vibrations down.

The above is a simple theoretical description of the pieces you wish to call pressure regulators and the real regulators that DO exist in the system. I've worked on this system designed that way and taught that way by MB and Bosch since it came out in Volvos in 1979 and MB in 1980.

I await such a theoretical description as you see it using pressure regulators in the return side of the system. The only way they could regulate any pressure would be to defeat the operation of the real regulators that are before them in the system. Since the frequency valve regulates pressure just what do you suppose takes place between it and what you wish to call a regulator.

What do you say about the obvious part number relationship to the diahram dampener (not the regulator) I stated above in the D-jet system? Or do you claim that both parts 176 and 206 are pressure regulators. Your part book translation don't work there. You have been mislead by a poor translation in a parts book. The answer is in the actual design. Propose to us the system as you see it using two more pressure regulators, besides the system, control, and lower chamber pressures.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Game, Set, and Match to the
esteemed gentleman from Florida.

I've only been using M-B parts diagrams daily for a measly 16 years.
Learned early on that the description is not reliable.
Check how many things are called a valve--

And on the lead-in page of every microfiche
(before the EPC-- that's how old I am),
and also on the opening screen of the EPC:
my favorite M-B Parts quote:

"Pictures do not necessarily conform to reality" -Amen, brother.

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Todd Haven
Parts Manager
MPH Automotive
Houston,TX