ThaddeusW Posted April 27, 2008 Share Posted April 27, 2008 Sorry Andrew but I couldn't wait to ask this question!Today me and bigrigpardo (Andrew) met up in long island to work on his truck. Well the first task was to get her cranking and after about an hour and a fresh set of batteries we had it spinning by jumping the Series-parallel switch. The dash wiring is all shot as much of the wiring was jerry-rigged so the key switch and start button do nothing. After a few tries to start it our next task was to make sure the lift pump was primed. After I pumped the primer a few times it seemd obvious that it wasnt doing much of anything. Andrew tried pumping it some more but still nothing. Se we got a gallon of diesel and some ether and opened up the fuel filter. We pulled the filter element and cleaned out the housing and filled it to the top with diesel. We then cracked the injection pump feed line to verify fuel was flowing out of the filter housing and then proceeded to try and start it. Still nothing. So we then crack the #6 cylinder injector line to see if fuel was flowing but we got nothing. We also had the fuel return line open and we saw nothing flow out. We also made sure the engine shut off was in the run position. A shot of ether yeilded a short rumble but still no sign of life. So now I am a bit lost as to what the problem might be. My first theory is the fuel rack might be stuck or engine cut off stuck. Second theory is the injection pump is clogged. Another thought is does the injection pump need any soft of positive feed pressure to run? If so that might be our problem and we could rig up a temporary fuel tank to feed the lift pump as the old ones are full of god knows what. I also noticed that when we removed the throttle return springs and manually moved the throttle lever there wasnt any sort of resistance at all just flopped from side to side furthering my suspicion of a stuck rack.Any ideas? Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/ Share on other sites More sharing options...
Rob Posted April 27, 2008 Share Posted April 27, 2008 Sorry Andrew but I couldn't wait to ask this question!Today me and bigrigpardo (Andrew) met up in long island to work on his truck. Well the first task was to get her cranking and after about an hour and a fresh set of batteries we had it spinning by jumping the Series-parallel switch. The dash wiring is all shot as much of the wiring was jerry-rigged so the key switch and start button do nothing. After a few tries to start it our next task was to make sure the lift pump was primed. After I pumped the primer a few times it seemd obvious that it wasnt doing much of anything. Andrew tried pumping it some more but still nothing. Se we got a gallon of diesel and some ether and opened up the fuel filter. We pulled the filter element and cleaned out the housing and filled it to the top with diesel. We then cracked the injection pump feed line to verify fuel was flowing out of the filter housing and then proceeded to try and start it. Still nothing. So we then crack the #6 cylinder injector line to see if fuel was flowing but we got nothing. We also had the fuel return line open and we saw nothing flow out. We also made sure the engine shut off was in the run position. A shot of ether yeilded a short rumble but still no sign of life. So now I am a bit lost as to what the problem might be. My first theory is the fuel rack might be stuck or engine cut off stuck. Second theory is the injection pump is clogged. Another thought is does the injection pump need any soft of positive feed pressure to run? If so that might be our problem and we could rig up a temporary fuel tank to feed the lift pump as the old ones are full of god knows what. I also noticed that when we removed the throttle return springs and manually moved the throttle lever there wasnt any sort of resistance at all just flopped from side to side furthering my suspicion of a stuck rack.Any ideas?Thad, you more than likely have a plunger,(one or more) stuck up in their respective bore(s) from sitting. The pump camshaft is turning but the stuck plunger will not let the rack turn the barrels allowing fuel. When the engine stop cable is pulled, the rack is pulled to the no fuel position where it probably is now.The pump requires positive pressure to the fuel gallery that is supplied by the transfer pump. Since you have checked the filter housing and return line from the pump gallery, the only thing left is the high pressure side which is not getting fuel internally. Take the pump off of the engine, remove the side cover and look for a stuck plunger. the innards look like a cam, and lifter setup for the engine. When the stuck item is located, there will be a space between the cam lobe, and the lifter. You will be able to see the valve spring compressed when it should not be. I usually soak the whole pump in a tub of diesel fuel for a bit and then pry, or force the stuck lifter back down. Once it, or they pop loose, reinstall onto engine and you should have a little better luck.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18610 Share on other sites More sharing options...
ThaddeusW Posted April 27, 2008 Author Share Posted April 27, 2008 Thad, you more than likely have a plunger,(one or more) stuck up in their respective bore(s) from sitting. The pump camshaft is turning but the stuck plunger will not let the rack turn the barrels allowing fuel. When the engine stop cable is pulled, the rack is pulled to the no fuel position where it probably is now.The pump requires positive pressure to the fuel gallery that is supplied by the transfer pump. Since you have checked the filter housing and return line from the pump gallery, the only thing left is the high pressure side which is not getting fuel internally. Take the pump off of the engine, remove the side cover and look for a stuck plunger. the innards look like a cam, and lifter setup for the engine. When the stuck item is located, there will be a space between the cam lobe, and the lifter. You will be able to see the valve spring compressed when it should not be. I usually soak the whole pump in a tub of diesel fuel for a bit and then pry, or force the stuck lifter back down. Once it, or they pop loose, reinstall onto engine and you should have a little better luck.RobRob, We did take the side cover off the pump but didn't see any compressed springs but we will take a look again. I believe we might need to rig up a tank to supply the transfer pump as we just let gravity feed the fuel galley from the filter housing. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18613 Share on other sites More sharing options...
theakerstwo Posted April 27, 2008 Share Posted April 27, 2008 Rob, We did take the side cover off the pump but didn't see any compressed springs but we will take a look again. I believe we might need to rig up a tank to supply the transfer pump as we just let gravity feed the fuel galley from the filter housing. If you take the top off of the governor you can feel the rack and it should move in and out . If it will not move it has to have the barrels and plungers re worked. If it will not move freely you dont whant to start because if could overspeed and kill you. If it moves the plungers lifers could still be stuck up but with the dry fuel we have now it is a thing that we see more ever day .If you have to buy a pump i have one off of a running engine. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18623 Share on other sites More sharing options...
HK Trucking Posted April 27, 2008 Share Posted April 27, 2008 I've gotten those unstuck before without removing the pump.Take off the side cover and the governor cover and soak everything real good with PB Blaster.Make sure the stop control is in the run position.Carefully tap on the rack linkage at the governor with a small hammer & drift, also you can tap on the bottom of the plungers toward the direction of full throttle.After an hour or 2 of messing around with it, the rack & pungers will usually loosen up.Keep spraying blaster on all the parts & keep working the rack back & forth by hand until it moves freely.Before replacing the covers and attempting to start the engine, pull the engine stop to the stopped position and be sure the rack returns to the no fuel position. This step is important or you could have a runaway if the stop control does not pull the rack closed. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18629 Share on other sites More sharing options...
fields auto Posted April 27, 2008 Share Posted April 27, 2008 When I purchased my mack the engine didn't want to start so I did as the others recomended. I belive the rack is struck on your engine too. I got to forceful when I took the governor top off and stated prying back and forth on the rack fork I broke the little pin in two where it attaches to the rack . so I ended up taking the whole injector pump off removed the governor from the injection pump and loosened up the rack that way that's what I would do in your case it is not a hard job to take the governor off the pump and you won't break any parts you migth have to take the injection pump off the engine however. As for the pin I was lucky and was able to make one on my lathe with no trouble then case harden the piece to make it hard. I wish you the best of luck and have fun these engines are very forgiving! Quote Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18631 Share on other sites More sharing options...
steve s. Posted April 28, 2008 Share Posted April 28, 2008 Thad, I had similar trouble trying to start my B after it sat many years, but my rack was ok. I had many, many air leaks. The fuel filter canister had to be welded 6 different times before I got all the pinholes. The priming pump bore was pitted and allowed air to be sucked in. The emergency fuel shutoff valve leaked. And most of the hoses leaked too. It was only patience and perseverence that let me find all those pesky leaks and fix one just to find another. But I did get a good education and I did not have to pull the pump, So I wish you luck. Steve Quote Link to comment https://www.bigmacktrucks.com/topic/3674-673-wont-start/#findComment-18675 Share on other sites More sharing options...
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