fordsareslow Posted March 13, 2007 Report Share Posted March 13, 2007 I hope this is the right section. A couple of months ago I started to loose a few PSI of fuel pressue. I'm currently running a Walbro GSS340 fuel pump (255lph). The pump is about 7 months old and when I first installed it, the truck would idle at 62 PSI and would be around 57 PSI at WOT. Now it's down to 56 PSI at idle and drops to 52 PSI at around 45% throttle (to affraid to take it to WOT to see what it drops to). Also lately my gas guage has been acting up. For example, it will show 1/4 tank and then after a 10-15 minutes of driving it drops to 1/8 or lower and the low fuel light will come on. I can shut the truck off and start it up again and it goes back to 1/4 tank. Anyone have any ideas? I'm thinking that it's either the fpr (fuel pressure regulator) of the sending unit. Quote Link to comment Share on other sites More sharing options...
Krambo Posted March 13, 2007 Report Share Posted March 13, 2007 Could be but I would measure voltage to the pump first. Measure it at acceleration as well as at rest. it is an easy troubleshoot to start off with. Quote Link to comment Share on other sites More sharing options...
fordsareslow Posted March 13, 2007 Author Report Share Posted March 13, 2007 I haven't tested it yet. Do I use just a regular volt meter and do I have to test the wires directly at the pump or can I test them right as they go into the tank? Also, how do I measure the voltage at acceleration? Do I just put the truck on jack stands and do it that way or is there a volt meter that has a really long cable or ??? I did put another fuel pressure guage on it last week to make sure the guage wasn't bad, but it showed the same results. Quote Link to comment Share on other sites More sharing options...
04CHASE Posted March 13, 2007 Report Share Posted March 13, 2007 sucks man , welcome to the wonderful world of 2004 bull shit fuel systems. if it end up being somethign major my as well modify your system so you wont have to worry about it again. Quote Link to comment Share on other sites More sharing options...
Krambo Posted March 14, 2007 Report Share Posted March 14, 2007 I just said check voltage because it took me a while to find a FP drop on mine. My FP would have a dip everytime I got into boost and then recover. A long bit of troubleshooting showed that my 150psi meth pump actually had an impact on voltage to my fuel pumps when it kicked on at 3psi. Sometimes the most remote things will get ya. Two thumbs up for the 03 return fuel system though over the 04's. Quote Link to comment Share on other sites More sharing options...
SSThunder Posted March 14, 2007 Report Share Posted March 14, 2007 Mine idles at 48 and is 60 at WOT. There really is a big difference in the 2003's compared to every other year. Hope you get it fixed Quote Link to comment Share on other sites More sharing options...
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