Hobert62 Posted July 11, 2017 Share Posted July 11, 2017 (edited) is this the valve that is screwed into the side of my pump, and has return lines that controls my fuel pressure? I have almost no smoke until around 1600rpm's and up. Then it's n nice dark grey/black smoke haze coming out the tops of stacks. I don't think I have enough pressure at lower rpm like a valve is stuck. I talked to a local pump guy and he said I want about 28psi, but I ran out of time to go into details with him. If this is it how does it come apart, and how do I clean it? Edited July 12, 2017 by Hobert62 Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/ Share on other sites More sharing options...
terry Posted July 12, 2017 Share Posted July 12, 2017 (edited) I think the main thing that check valve does is hold prime in the fuel system, if it leaks you will have to crank and crank to start, don't think it will effect running fuel pressure. terry Edited July 12, 2017 by terry Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-374708 Share on other sites More sharing options...
Hobert62 Posted July 12, 2017 Author Share Posted July 12, 2017 Ok thanks. It always starts right up. Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-374724 Share on other sites More sharing options...
Freightrain Posted July 12, 2017 Share Posted July 12, 2017 (edited) I was concerned about my 237 originally when it was having issues last summer. I never did get the check valve apart as I wondered if it was leaking back too much. Though mine always starts quick. I did put a pressure gauge on the pump and mine idles maybe 15-20# and about 10# under load at WOT. Nothing spectacular. I did replace my lift pump as the original pump was only about 5# at idle and near nothing under load.......thus my lack of power. I've heard it should have more pressure, but I know I have new lines from tank to pump so there is no restrictions and new tanks so no issues there. I just tapped into pump line ran a 1/16" line out the passenger fender and zip tied the gauge to my air filter pipe. Still there, though I would like to get some kind of electrical sending unit and install the gauge in the dash. Not that I really need it, but it would tell you if a filter is getting clogged. The electrical units are pricey and just haven't wanted to buy it, yet. If the pressure is fine, have you ever adjusted the rack? I gave my 673 a few flats on the nut and it helped big time. Have to watch how many flats you give as fuel mileage will suffer severely(ask me how I know--though it ran like a scalded dog). I put a couple flats of the nut on the 237 and the pyro went from 900 to 1100 on a hard pull. Edited July 12, 2017 by Freightrain Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-374732 Share on other sites More sharing options...
Hobert62 Posted July 12, 2017 Author Share Posted July 12, 2017 I gave my rack 1 flat past 1/2 a turn. It has no smoke starting out until 1600 rpm and up. Then it gives a nice dark grey haze out each stack. There was a bunch of stuff on my trk done lets just say not right when I got it. The seal on the back of the pump was broke and twisted back together when i went in to adjust. Makes me wonder if maybe someone went the wrong way before me? Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-374738 Share on other sites More sharing options...
Freightrain Posted July 12, 2017 Share Posted July 12, 2017 When I played with my 673, the more fuel the snappier the throttle response. When I went to turn it back, I forgot how far I moved it and went too far. It was lazzzyyyy as heck. I then just kept moving it a flat at a time til it got back to normal sounding when you snap the throttle. I left it that way. It was getting 4 mpg when turned up, with it back down it got 8 mpg. 2 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-374745 Share on other sites More sharing options...
Lukasswaziek Posted December 15, 2022 Share Posted December 15, 2022 Anyone know the part number for that check valve? E6 leaks down after a couple days. Can't find it online Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-518333 Share on other sites More sharing options...
JoeH Posted December 27, 2022 Share Posted December 27, 2022 On 12/14/2022 at 8:58 PM, Lukasswaziek said: Anyone know the part number for that check valve? E6 leaks down after a couple days. Can't find it online You probably have a fuel return line leak. The plastic lines on top of the head that go from injector to injector are prone to leaking. Any dampness up at the injectors is likely caused by the plastic lines failing. Also if any of the hard metal fuel injector lines have dampness at the ends then you can lose prime and have hard starting. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-519142 Share on other sites More sharing options...
mrsmackpaul Posted December 27, 2022 Share Posted December 27, 2022 39 minutes ago, JoeH said: You probably have a fuel return line leak. The plastic lines on top of the head that go from injector to injector are prone to leaking. Any dampness up at the injectors is likely caused by the plastic lines failing. Also if any of the hard metal fuel injector lines have dampness at the ends then you can lose prime and have hard starting. Yep, what he said Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/50448-fuel-pump-check-valve/#findComment-519144 Share on other sites More sharing options...
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