Little or NO power after bottoming out suspension- 1981 300SD - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 02-19-2013, 01:02 AM

Quote:

Originally Posted by kerry

I don't think the test I suggested has been performed. A fuel pressure and flow test between the secondary filter and the IP would rule out a problem with the bypass valve (if such a problem is possible.) We know it's not a fuel flow problem upstream from the pump but downstream from the lift pump to the IP has not yet been tested. Maybe even a piece of crud came loose and plugged the line from the secondary filter to the IP.

I have not tested the fuel pressure in any way. However, I do have some interesting info that we all can think about concerning the pressure relief valve. On the original IP on the car (1981 300SD W126), the hose on the side of the IP (toward the engine) on this IP only had a banjo bolt, and not one with the relief valve in it. The replacement IP had the bolt with the relief valve in it. When I replaced the IP, I used the banjo bolt that came with the IP (original-no valve, replacement-valve on bolt). I am not sure that would make any difference, as the engine still runs the same, and the engine ran for years with the banjo bolt without the valve and on the original IP.
I am going to call whunter on Tuesday morning, and have a chat with him. I won't be able to work on this car until Friday anyway, so maybe I can get some good tests to do before then. Thanks for all your suggestions everyone. This is the greatest forum on the www, and I am thankful to be a part of it..Rich