sprtkr1 Posted September 7, 2017 Share Posted September 7, 2017 I replaced the fuel pump on my CXU613 MP8. Now it has fuel leakage from the weep hole between fuel pump and power steering pump. I took them back off and separated them again. Then I removed the cover plate from the power steering pump where the fuel pump mounts. I found the shaft that drives both pumps to be grooved in 3 places where the seals and small bearing ride. I had no problems with leakage before. My question is do you think extra pressure from the new fuel pump was enough to cause a leak where none existed before? Quote Link to comment https://www.bigmacktrucks.com/topic/50937-fuel-pump-replacement/ Share on other sites More sharing options...
sprtkr1 Posted September 15, 2017 Author Share Posted September 15, 2017 Well, I replaced the power steering pump as well and my fuel leak disappeared. but I am still having the same problem. Every now and then it feels like I'm running over a washboard in the road. only lasts for a second or two and when I let off the throttle it quits. The only other time this happened was I almost ran it out of fuel. Found out how inaccurate my fuel gauge was then. It also seems to have a slight miss and is bogging down when I get to higher rpms. 1600 to 1800. Checked for blockage in fuel tanks but they are clean as a whistle. Not throwing any codes. Seems to be getting worse. I can even feel it when bobtailing. Could the dealer pull codes even though they aren't showing up my dash? It's a 2008 CXU613 with 485HP MP8. Thanks for any thoughts. Quote Link to comment https://www.bigmacktrucks.com/topic/50937-fuel-pump-replacement/#findComment-379698 Share on other sites More sharing options...
bbigrig Posted September 17, 2017 Share Posted September 17, 2017 You may want to get tour fuel system checked for combustion gases getting into fuel system through tour injector cups. If they have never been done it may need them. A sight glass test in the fuel system will help in the diagnosis. Quote Link to comment https://www.bigmacktrucks.com/topic/50937-fuel-pump-replacement/#findComment-379880 Share on other sites More sharing options...
sprtkr1 Posted September 18, 2017 Author Share Posted September 18, 2017 Thanx for the input. I had them done last fall for the third time. Starts and idles fine. Some times feels like a governor kicking in at about 1600 rpms. The bad thing is it doesn't always do it but getting more frequent. Do you think I got some bad fuel? No water in the separator and the fuel in tanks looks good. Thanx again. Quote Link to comment https://www.bigmacktrucks.com/topic/50937-fuel-pump-replacement/#findComment-380029 Share on other sites More sharing options...
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