Here is a link to the valve for your engine:
6010700146 Diesel fuel return valve/banjo bolt
6010700146 Diesel fuel return valve/banjo bolt

Plastic fuel lines, injection pump, OM603.961, 603.960
http://www.peachparts.com/shopforum/mercedes-parts-reference-library/204761-om603-960-961-plastic-fuel-lines-injection-pump.html#post1669461


Some other links to help you diagnose the issue.


603.96 IP reseal shopping list
http://www.peachparts.com/shopforum/diesel-discussion/239827-603-96-ip-reseal-shopping-list.html#post2043716

99 e300td injector pump leak
http://www.peachparts.com/shopforum/diesel-discussion/105291-99-e300td-injector-pump-leak.html#post723792

Leaking fuel out of thermostat - 1987 300D turbo
http://www.peachparts.com/shopforum/diesel-discussion/150203-leaking-fuel-out-thermostat-1987-300d-turbo.html#post1138239

Diesel Injection:
Diesel Injection:

Fuel Delivery:
Diesel Fuel Delivery:

Sorry, I believe your Engine does not have a Hand Primer Pump and when I looked at that site I did not see an Auxillary Fuel Pump listed on the part diagram.

There should be at least 1 Valve in the Fuel Supply pump that is between the in comming fuel and the Fuel tank. If something stuck under the Valve or the valve was worn out that could also allow the Fuel to leak back towards the tank.
Since you do not have a Hand Primer fill your Fuel Tank full and park some place or safely raise the rear of your car so that the Fuel Tank is higher; and see if it starts OK like that.

Another test (not a on the road test) would be to get a container of Diesel Fuel to sub for a fuel tank. Run a hose from the primary filter to the container. Get the Car started. Let the Car sit a length of time that would normally cause a starting problem and see if it will start OK. If you can keep the container above the IP.

__________________
84 300D, 82 Volvo 244Gl Diesel

The OM60x series of engines do NOT have a hand primer. They are self priming, although very slowly.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

well the problem is it may work fine for a few days or a week and then all of the sudden, it will do this. Where is this check valve located?

Between engine block and injection pump.
Look at the picture attached to post# 1.

my guess is that there is a setting station when they make the valve, where they set the pressure of the valve and spring combination in assembly. springs, even the best ones have a 10% tolerance on performance. the smaller the spring pressure, the more the variation. this is most likely why you cannot buy the spring seperate, something needs adjusted for the new spring.

__________________

1982 300CD Turbo (Otis, "ups & downs") parts for sale
2003 TJ with Hemi (to go anywhere, quickly) sold
2001 Excursion Powerstroke (to go dependably)
1970 Mustang 428SCJ (to go fast)
1962 Corvette LS1 (to go in style)
2001 Schwinn Grape Krate 10spd (if all else fails)

Gentlemen,
I believe the spring can be seen under section "injection..." om615 of the EPC.
Since both the valve #28,MB 0000747284 and the evasive spring #28F ,MB 0010740893 share the same note *94 and according to the EPC graphic pattern,we can conclude the spring belongs to the valve.
The MB number corresponds to Bosch #1 414 610 008 and has green light on the Bosch online cat.
http://www.bosch-automotive.com/ecat-online/
...it`s available at the dealer too,the price is 44 Russian roubles,acc to the Russian site -1.25 USD...or 0,30 Euro from Bosch dealers.
http://www.teilesuche24.de/ersatzteile/feder,bosch_1414610008

Attached Thumbnails

 

>>my guess is that there is a setting station

I would be really surprised if that were the case.

The fuel pressure in the gallery of the IP doesn't have a strong effect upon how much fuel is injected - the metering is done by the helix on the plunger, and small changes in the fuel pressure can't significantly change the mass of fuel trapped / pumped by the element.

The only real purpose of providing some small positive pressure in the fuel gallery is to avoid cavitation as the plunger descends and fuel suddenly experiences a low pressure as it rushes into the element, and small variations away from the nominal check valve pressure won't noticably affect the operation of the IP. Cavitation would both upset the metering of fuel, and cause mechanical damage to the pump element.

The important thing is to make sure that whatever you do to this check valve an adequate return flow of fuel to the tank is maintained - the fuel flow cools the IP, and an over strong check valve spring may stop this important cooling.

I was just guessing based on the fact you cannot buy the spring. Looking at an assembly you can not always see the adjustment done at the factory. At bendix for example, there was such a huge tolerance stack on the power brake booster to brake master cylinder that they had several bins of rods that looked identical, each one was about .020 different in length. A tool was inserted in the master and the last color band showing determined which bin of rod was assembled. In looking at any of the parts you could see no possible adjustment, but it was there. I was just thinking maybe they had bins of springs ready for the valve after some initial measurement was made, in this way they could tune the tolerance, yet no visible adjustent is there. Maybe they just figure if the spring is shot the valve probably needs replacing too. In looking at MB parts, they seem to allow service where it is feasable, so they must have a reason not to sell the spring seperate.

__________________

1982 300CD Turbo (Otis, "ups & downs") parts for sale
2003 TJ with Hemi (to go anywhere, quickly) sold
2001 Excursion Powerstroke (to go dependably)
1970 Mustang 428SCJ (to go fast)
1962 Corvette LS1 (to go in style)
2001 Schwinn Grape Krate 10spd (if all else fails)

I looked it up under OM615.939
Checking all MB sources comes back no longer available.

I will check directly with BOSH tomorrow, to verify we can get them in North America, and buy one for testing.

I do not see a picture on post #1, just a parts listing.

>>At bendix for example...

Yes, I fully agree that's a critical setting - too tight and the brakes can lock on, and too loose, owing to the pedal lever ratio, the brake pedal will feel awful. On many brake servos (boosters) in Europe, there's a threaded adjustment on that rod to enable the proper assembly of the 2 parts - many don't even know it's there! (until their brakes lock up 3 miles down the road smoking!)

In this case though, I don't see the setting for the IP relief valve being at all critical, and certainly not something to calibrate or to use a selective assembly process for. As long as the opening pressure is above the level required to prevent cavitation in the IP, and comfortably below the maximum lift pump delivery pressure, it will work well.

Is there one of these springs on the M603 engine? Anyone have a picture of it?

The design changed = it is a crimp/press sealed valve = not serviceable.

6010700146 Diesel fuel return valve/banjo bolt
6010700146 Diesel fuel return valve/banjo bolt

I checked with BOSCH.
There where two remaining in North America, I bought them, arriving next week.
They are trying to order more, but warn that it appears to be a discontinued part#...
I will take one of my samples to a spring supplier for matching.