kampman Posted June 12, 2014 Report Share Posted June 12, 2014 I'm considering buying an '00 VR. The seller states that the fuel pump on the driver's side has failed, so the car runs out of gas when "one tank is empty"-I'm assuming that he means when the passenger side of the fuel tank runs dry. I have a '98 XC and I've replaced the fuel pump seals before, so I'm comfortable replacing the pump if need be, but I'm just curious if anyone else has observed this behavior from their car when the pump in question failed. I was under the impression that the driver's side pump was just a siphon with no electrical function except for the gauge sender and all the pumping was done by the passenger side-is this not the case? Link to comment Share on other sites More sharing options...
burnout8488 Posted June 12, 2014 Report Share Posted June 12, 2014 Correct, there's no motor over there, just a level sensor. I don't think there's really any way to diagnose the problem he described since the system is totally passive over there. It's possible that someone retrofitted an aftermarket fuel pump into the passenger side sending unit. I did this and the car would run out of gas sooner, as you described. As soon as I put the OEM pump back in (correct length) it would suck fuel from lower in the tank. Link to comment Share on other sites More sharing options...
kampman Posted June 12, 2014 Author Report Share Posted June 12, 2014 The seller states that the passenger side fuel pump was replaced in 2013, so I'm wondering if that's what happened. Link to comment Share on other sites More sharing options...
burnout8488 Posted June 17, 2014 Report Share Posted June 17, 2014 Investigate and see if you can find any cut or spliced wires down there. If they didn't drop the subframe, they'd have to splice in the new pump. Link to comment Share on other sites More sharing options...
kampman Posted June 18, 2014 Author Report Share Posted June 18, 2014 After doing a little more reading, it appears that the driver's side pump may do more than I thought and I guess it could get clogged. From a post on MVS; someone mentioned this on the R forum as well. The 98-2000 use one motor pump and an "ejector pump" in volvo's words. The ejector pump is an orifice that pushes a jet of fuel across an opening into a larger diameter hole and then through a hose back to the RH side of tank where electric pump is located. The ejector pump is mounted on the LH sender unit assembly and is pushed against bottom of tank to get all the fuel. The fuel supply for that orifice feed is the excess fuel from fuel pressure regulator. When the vapor emission levels standard was reduced they had to lessen the sloshed around fuel and fuel circulation that contributed to heating fuel. The second electric pump was phased in in 2004 and becomes the feed for the ejector pump. To my knowledge they never came up with a kit to put two electric pumps in the single pump system cars. The ejector pump design doesn't care if there is fuel in the left side of tank or not, fuel goes across opening and either picks up fuel or air and no electric pump risks running air instead of fuel. Link to comment Share on other sites More sharing options...
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