04 Volvo GXi-E problems at idle and getting on plane

bogeyfree31

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Aug 24, 2015
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I have a new to me 2004 Volvo GXi-E 5.0. Last few times out I experienced some surging of RPMs when in the 3000-3500 range. It will drop from 3500 to 3000 for a few seconds then pick back up to 3500.

Well I thought it might be fuel related so I took off the Fuel Cell and took the pumps off. Screens had some particles but not bad. Put everything back together and now I'm having a constant surging idle. And when I give it throttle it wants to stumble. I hooked up a fuel pressure gauge and the low side pump is a constant 18'ish. The high side is around 40.

I took it to the lake to see how bad it would run in the water. It tried to stumble between 1500-2000 rpms so I hammered the throttle and after a couple backfires it jumped up on plane and ran normal. I eased the throttle back down and brought it to idle fine. But when I went to throttle up, it again stumbled and tried to quit before getting up on plane.
I figure it must have been something I did with the Fuel Cell. I purged the fuel from the schrader valve on the rail and it had some air in it so I'm wondering if I have an air leak somewhere. I've taken the fuel cell off twice and reassembled thinking I would fix the problem without knowing it, but both times it went back together and had the same issue.

The reservoir has a metal plate that I think is installed correctly as it fell out when pump came apart but I' sure there are no diagrams of a "non-servicable" pump.

The electrical connection to the low speed pump was corroded and I was thinking this may be the issue so I cut the harness and wired directly into the 2 prongs and it still didnt run right.

What else should I be checking.
 
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