TandemB Posted March 26, 2010 Share Posted March 26, 2010 Truck seems to run fine empty.Loaded seems down on power,especially pulling grades. When you downshift you almost have to keep downshifting because it doesn't pick it up. Any thoughts? I'm thinking aneroid valve. Quote Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/ Share on other sites More sharing options...
theakerstwo Posted March 26, 2010 Share Posted March 26, 2010 If you cant check it get some one to help because we here will have to be there but get some one to first if this is a mack engine check make sure it has full thottle on fuel lever and make sure to stop lever is in full fuel position and check fuel pressure under a load.That will tell you something about the fuel lines and filter. Then check the air/air cooler and boots up to the intake manifold for leaks.I would say if it is smoking then it could ba a air leak on the air/air or pull exhaust and check the exhaust wheel for any missing fins. Then you can start to check the air fuel or puff limiter for being bad. If it has apuff limiter then simply disconnect the host to the puff limiter valve cyl on the front of pump. If it runs better then you know the revering relay is bad.If it is not a mack engine then tell us what you have and get back. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-51991 Share on other sites More sharing options...
TandemB Posted March 27, 2010 Author Share Posted March 27, 2010 Sorry i forgot to tell you it is aMack 350.Ichanged fuel filters and air filter. Good idea to check fuel pressure. idid check throtle pedal and linkage. I put a plug in at intake manifold,going to haul a load of fuel tomorrow and see how it works. Quote Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-51992 Share on other sites More sharing options...
theakerstwo Posted March 27, 2010 Share Posted March 27, 2010 Sorry i forgot to tell you it is aMack 350.Ichanged fuel filters and air filter. Good idea to check fuel pressure. idid check throtle pedal and linkage. I put a plug in at intake manifold,going to haul a load of fuel tomorrow and see how it works.Ok but what do you mean you installed a plug at the intake? Is the puff limiter still connected to air?Is the line to the end of the pump still connected to the relay on the intake and is the relay still connected to the air supply? Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-51995 Share on other sites More sharing options...
TandemB Posted March 27, 2010 Author Share Posted March 27, 2010 Ok but what do you mean you installed a plug at the intake? Is the puff limiter still connected to air?Is the line to the end of the pump still connected to the relay on the intake and is the relay still connected to the air supply? Quote Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52005 Share on other sites More sharing options...
TandemB Posted March 27, 2010 Author Share Posted March 27, 2010 disconnected air line from aneroid on injection pump to valve on intake manifold. unsrewed fitting into that valve and put in pipe plug. No air to puff limiter(aneroid) Quote Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52006 Share on other sites More sharing options...
theakerstwo Posted March 27, 2010 Share Posted March 27, 2010 It should be more responcive and have more black smoke on take off and gear chabges now if all is ok other wise.If this cures the problem then replace the reversing relay with proper # valve. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52009 Share on other sites More sharing options...
fjh Posted March 27, 2010 Share Posted March 27, 2010 It should be more responcive and have more black smoke on take off and gear chabges now if all is ok other wise.If this cures the problem then replace the reversing relay with proper # valve.To Make sure were talkin apples to apples!The hose from the puff limit to the fuel pump should be capped off ! as Glenn pointed out. Quote Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52016 Share on other sites More sharing options...
theakerstwo Posted March 28, 2010 Share Posted March 28, 2010 And i forgot to say if the pump has a LDA smoke control on it then you can not disconnect the air line to it or it will be sick.This is the control that takes the place of the puff limiter but is on top of the governor.Test it with a pump up air pump and see if it will hold 25 psi. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52046 Share on other sites More sharing options...
HK Trucking Posted March 28, 2010 Share Posted March 28, 2010 And i forgot to say if the pump has a LDA smoke control on it then you can not disconnect the air line to it or it will be sick.This is the control that takes the place of the puff limiter but is on top of the governor.Test it with a pump up air pump and see if it will hold 25 psi.Funny you should mention that Glenn.The E7 mechanicals that I had, I hooked up an air supply to the LDA with a regulator set @ 25 PSI, and an on/off valve in the line.Under normal conditions the 25 PSI would keep the LDA wide open, insuring excellent response and lots of smoke, and if it was DOT time, you could shut off the air supply valve for a no smoke / no power mode.. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52056 Share on other sites More sharing options...
GreenGiant2 Posted March 28, 2010 Share Posted March 28, 2010 Funny you should mention that Glenn.The E7 mechanicals that I had, I hooked up an air supply to the LDA with a regulator set @ 25 PSI, and an on/off valve in the line.Under normal conditions the 25 PSI would keep the LDA wide open, insuring excellent response and lots of smoke, and if it was DOT time, you could shut off the air supply valve for a no smoke / no power mode..ALWAYS THOUGHT ABOUT DOING THAT ON MY 300L E6, HOW EXACTLY DID YOU DO THAT IF I CAN ASK.THANKS GREEN GIANT2 Quote We the unwilling, Lead by the unqualified, are doing the impossible, for the ungrateful. Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52084 Share on other sites More sharing options...
theakerstwo Posted March 28, 2010 Share Posted March 28, 2010 ALWAYS THOUGHT ABOUT DOING THAT ON MY 300L E6, HOW EXACTLY DID YOU DO THAT IF I CAN ASK.THANKS GREEN GIANT2That control is very easy to adjust also. The screw on the back outside is the so call no air smoke. It will set the rack stop with out no air. Screw it in for more fuel with out air.The star nut inside of the cap on top controls the tension on the spring against the diaphram and less tension the quicker the responce if the rack is not being stopped by the rear screw.I like to set them were there is a little smoke on take off. More smoke the more often you change your oil and filter. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/13193-superliner/#findComment-52092 Share on other sites More sharing options...
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