'83 300D- No Spring/Brng in Relief Valve Bolt - PeachParts Mercedes-Benz Forum

caracine · #1 09-12-2009, 02:38 PM

Hello!
My '83 300D Turbo does not have a few components in the fuel pump and the IP that you all seem to have on your cars. I'm missing the light spring and bearing inside the Relief Valve bolt that attaches to the engine-side of the IP that meters the fuel exit from the IP and I don't see a plastic metering piece w/ washer beneath and inside the intake line connection on my fuel pump that meters the fuel flow just before the 'lift' inside the fuel pump. I know that there is a valve on the bottom of my fuel pump facing up that may have the 'T' shaped piece behind it I'm speaking of. I'm the 2nd owner of this fine vehicle and it was quite 'virgin' when I bought it and I've been very respectful of the OEM aspect.
Thanks for sharing the wealth of information you all have on this great site!
-chris

toomany MBZ · #2 09-12-2009, 03:06 PM

Not sure what you mean, could you "point" it out in one of the pics?

caracine · #3 09-12-2009, 04:04 PM

Hi-
Thanks for your insight on this matter. Attached is the photo with bolt I'm speaking of.
-c

caracine · #4 09-12-2009, 04:07 PM

This is bolt with arrow (oops!)
-c

the heap · #5 09-12-2009, 10:05 PM

I have the same situation in the engine on my '79 300D. No spring. When I installed one from another pump, the engine wouldn't run. Removed it, engine started and ran like before. WTF?

barry123400 · #6 09-13-2009, 10:11 AM

Quote:

Originally Posted by the heap

I have the same situation in the engine on my '79 300D. No spring. When I installed one from another pump, the engine wouldn't run. Removed it, engine started and ran like before. WTF?

Both of you gentleman with no return valve springs should check your operational fuel pressure between the second filter and the injection pump. It has been proven they will run without a relief spring but not as well.

You do want some fuel pressure in the injection pump. What the two of you describe might be a method of covering up very weak lift pumps was my first thought.

toomany MBZ · #7 09-13-2009, 11:03 AM

Quote:

Originally Posted by caracine

This is bolt with arrow (oops!)
-c

Okay, I've never had that off any of mine. Thanks for letting me know something is in there.

caracine · #8 09-14-2009, 03:01 AM

Hi-
I found another bolt with spring inside at Pic-n-Pull and installed it after making sure the spring length was correct. Drives rather poorly with the new 'spring/bearing-loaded bolt' mainly due to the fact that the IP is now leaking (drawing air) at the input fuel connection- it did not leak before this. Good idea to check fuel pressure (will do) but I'm assuming my Fuel Pump seems to be motivating the fuel with plenty of pressure as it gets 'tickled' by the IP.
Thanks for the insight!
-chris