PeachParts Mercedes-Benz Forum - View Single Post - 95 e300d w124, questions about injection pump and delivery valves

Diseasel300 · #4 01-31-2018, 09:23 AM

The DV's are free floating in there, if there's a bit of varnish or other crap accumulated under the 4 that stayed centered, they'll tend to "stick" in place. I wouldn't lose sleep over it. In a perfect world, they'd all move, but this world is far from perfect.

The O-ring needs room to "grow" in the slot as it is compressed. If you pay attention to the top surface of the IP, the holes for the DV holders are bevelled. As you tighten the DV holder down, it pulls the O-ring into the groove and flattens out. If you look at your old ones, they'll have a more or less square profile to them. They leak because the rubber hardens and shrinks slightly as it ages. Kind of a stupid design, but it should go for >10 years before you have to do it again. Less if you run biofuels.

Every time I've done DV's on my car, I've had to reprime the IP. There's no positive "check valve" in the return fuel line unlike the old 617's, so as soon as you expose the fuel rack to air, gravity will pull the fuel in the return line back to the tank along with anything it can suck along from the fuel rack.

35nm isn't very tight, more like snug. If you got the DV holders screwed down almost all the way by finger tightening, then 1/4 turn seems about right.