1996 Mercedes E300 ifi Electrohydraulic shut-off - PeachParts Mercedes-Benz Forum

veganxxx · #1 08-16-2006, 01:26 PM

Ok, so i've looked high and low, i even have a Mercedes Tech friend at a local delership that hasnt been able to help me... The vehicle is a 1996 E300 im looking for fuel flow diagram for the electrohydraulic shut-off valve... there is 4 ports on the unit one to the ip, one from the screen filter, one to the lift pump and one from the diesel filter... But what is actuated when that is energized? What ports are open when the valve is deenergized? Theres also a fuel temp sensor in there... What point is it measuring the temp? Any help is greatly appreciated...
Thanks

veganxxx · #2 08-17-2006, 11:54 AM

No one knows about the shut off valve?

Matt L · #3 08-17-2006, 12:07 PM

Oh sure, some of us know about this valve. I just don't happen to have the fuel line schematic handy.

But I don't recall if it diverts fuel away from the IP when energized or deenergized (although I strongly suspect the latter). Essentially, it starves the IP when the key is off. I imagine it's to prevent a sticking rack from keeping the engine running, since the rack can fully shut down the fuel delivery as well (and does so on overrun).

The temperature sensor measures the fuel temperature on its way into the IP.

TMAllison · #4 08-17-2006, 01:55 PM

When shut off "solenoid" failed on my 99 E300 it was as if the turned the key were turned off. Engine suddendly not running. Is disconcerting at freeway speeds. If yours does this it ought to create a code.

If yours is leaking it may be the o-ring seal to the IP.

What problem are you having?

veganxxx · #5 08-17-2006, 10:36 PM

thanks for the reply. The concern is that running biodiesel or hot veggie oil would ruin the rubber seals because they are not viton/synthetic. I wanted to see how possible it was to open that piece up and replace the seals in it or for veggie conversions run the veggie through that piece as little as possible (only into the port that directs fuel into the IP) instead of having it run through after the screen filter and before the lift pump. I would have just bought one and cut one open but it's $120+. Any diagrams can be emailed to vegthesystem@gmail.com , much appreciated.

Dave

TMAllison · #6 08-18-2006, 12:30 AM

Know nothing about wvo, but have run lots of Bio B99 through my 99. It likes it, but mpg does suffer ~10% making it a poor economical choice as it costs more than dino currently.

I think your 96 uses viton parts?

review the "sticky" on the diesel page, that should be discussed there.

Biodiesel and WVO - SVO links thread.

TMAllison · #7 08-18-2006, 12:34 AM

Look here under IP/IP.

http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=210020&VIN=

veganxxx · #8 08-20-2006, 11:09 AM

Ok, thanks for the responses thus far. Matt L do you have a schematic? That would be the best. Im trying to locate possible cross contaminiation points for WVO/diesel. TM Allison, i had looked thru the sticky and done a search and havent really found the info i need... Also that last link you posted only goes to a dead picture and the rest of the site is in greek. Thanks

TMAllison · #9 08-20-2006, 01:11 PM

The link works fine when I click on it.

Try this link http://www.detali.ru/ and then click on "Mercedes" on the LEFT HAND side of the page (if you click the center section you will get everything in Russian) then pick your car from the list.

210.020 E300D

veganxxx · #10 08-20-2006, 05:19 PM

Alright, i've figured out why the link wasn't working now on to try and resolve the issue: Fuel contamination?
Ive attached the fuel line schematic so we can all be on the same page. And please correct me if at any point im wrong. My understanding is that in the stock configuration:
fuel comes from the tank to the thermostat/heater 155
032 is the line from the thermostat to prefilter screen
next 056 is from prefilter to shut-off valve
then 074 is from shut-off valve to lift pump
then 083 goes from lift pump to fuel filter
from the fuel filter 095 goes to shut-off valve
the shut-off valve has an open port on rear that fuel heads into the IP from
Excess fuel from IP travels along return line 119 which meets up with the excess fuel from the injectors and the filter this is a 4 way open fitting.
OK, so this outlines the stock configuration.
I feel that there must be some significance in designing the shut-off valve to have fuel pass thru it from the prefilter to the lift pump.If there was not they could have just designed a shutoff between the filter and ip which is also where temp is measured?
So assuming that the shut-off valve allows for two seperate fuel paths 1)from the prefilter thru the shut-off to the lift pump and 2)from the diesel filter thru the shutoff to the IP... for any fuel to cross contaminate it would mean that fuel that hasnt been filtered by the diesel fuel filter would be entering the IP which MB would not allow...

Im replumbing for a VO system I have isolated the return so that it does not reenter the diesel fuel filter. Excess fuel from the injectors and IP meet and are directed to a valve selecting diesel or VO tank return.
Next to isolate the supply systems i have replumbed a few of the supply lines. My current schematic is Diesel fuel from tank to thermostat to prefilter screen thru the shut-off valve to diesel filter out to a selector valve which then goes to the lift pump back thru the shut-off valve and into the IP... The vegetable oil side then comes from vegetable oil fuel tank to vegetable oil filter to the selector valve then follows the same path to the lift pump, thru the shut-off valve and into the IP.

Because i have isolated both the return and supply systems i should have minimal cross contamination. My quest in discovering the inner workings of the shut-off is to make sure that is indeed the best possible fuel plumbing for this vehicle. Also to find out if there will be any negative side effects to only passing the vo thru the shut-off valve once as MB felt the need to plumb diesel thru it 2x.

Sorry if thats alot of info at once. All your help is much appreciated.
Thanks

veganxxx · #11 08-22-2006, 09:00 AM

nothing?

veganxxx · #12 08-23-2006, 11:10 PM

last time.ill let it die after this.

scott19_68 · #13 11-19-2006, 04:36 PM

Quote:

I feel that there must be some significance in designing the shut-off valve to have fuel pass thru it from the prefilter to the lift pump.If there was not they could have just designed a shutoff between the filter and ip which is also where temp is measured?

The shut-off valve actually switches the direction of the suction side of the lift pump from the pre-filter to the inlet port of the IP thereby drawing fuel out of the IP.

Quote:

So assuming that the shut-off valve allows for two seperate fuel paths 1)from the prefilter thru the shut-off to the lift pump and 2)from the diesel filter thru the shutoff to the IP... for any fuel to cross contaminate it would mean that fuel that hasnt been filtered by the diesel fuel filter would be entering the IP which MB would not allow...

Yes, the shut-off valve controls both fuel pathways at the same time (there is a ball valve on both ends of the solenoid). There is a third fuel pathway inside the shut-off value that is opened when the ignition is turned off that pushes the filtered fuel back towards the pre-filter. Its a neat design and I think the dual-nature of the solenoid is primarily for safety. If there were 2 separate solenoids the system would not be as single fault tolerant.

Sorry for the late reply...