joes mack Posted March 7, 2010 Share Posted March 7, 2010 my friend has a small mining co and he has a old D8k dozer that i run for him sometimes it has a D342 non spacer plate engine the dozer is a 77v series and he had the injection pump rebuilt but now it wont push worth a crap the cat mechanics timed the engine and everything and it made it even slower it dont roll black smoke like it used to it has a new turbo and filters. my question is how do turn up the fuel on the pump do you adj the high idle screw and the low idle screw or what to make it push like it used to..joe Quote Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/ Share on other sites More sharing options...
HK Trucking Posted March 7, 2010 Share Posted March 7, 2010 Sounds like the aneroid control isn't letting the rack go all the way open as boost pressure rises, due to a ruptured diaphragm in the aneroid control, disconnected or loose line from the intake manifold to the aneroid, or stuck parts in the aneroid or pump.Does that machine have an intercooler out in front of the radiator? If so there could be a boost leak in the cooler or connecting pipes causing a loss of boost pressure, which also will not open the aneroid control fully and will not provide sufficient air for full power.We had a similar problem on an old 980B with a 3306 engine.. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50815 Share on other sites More sharing options...
joes mack Posted March 7, 2010 Author Share Posted March 7, 2010 is that thing you said on the bottom of the pump with a oilpres line going to it. joe Quote Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50820 Share on other sites More sharing options...
HK Trucking Posted March 7, 2010 Share Posted March 7, 2010 is that thing you said on the bottom of the pump with a oilpres line going to it. joeIt's a diaphragm looking thing with about a 3/8" dia. line hooked to it. The other end of the line would be connected to the intake manifold. When the turbo increases boost pressure in the intake manifold, the boost pressure comes thru the 3/8 line to the aneroid, causing the diaphragm to move, allowing the inj. pump rack to open all the way up.If this doesn't happen for one reason or another, the rack doesn't open all the way, the engine doesn't get full fuel, and the engine cannot produce full power.. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50827 Share on other sites More sharing options...
fjh Posted March 7, 2010 Share Posted March 7, 2010 is that thing you said on the bottom of the pump with a oilpres line going to it. joeOn a truck these are mounted at the rear upper of the fuel pump governer housing!As stated there will be a braided or steel 1/4 inch line coming from the inlet manifold! Quote Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50828 Share on other sites More sharing options...
HK Trucking Posted March 7, 2010 Share Posted March 7, 2010 Also, if you put the throttle lever wide open with the machine in neutral, does the engine seem to rev all the way up as it used to when it was running right?If yes, then it's probably the previously described problem.If no, then it could be something as simple as the throttle linkage being out of adjustment, or the high idle screw being set at too low of an RPM. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50831 Share on other sites More sharing options...
joes mack Posted March 10, 2010 Author Share Posted March 10, 2010 yes when it is in neutral it sounds like it is at max rpm. i will check for this line when i get a chance thanks for the help.. joe Quote Link to comment https://www.bigmacktrucks.com/topic/12924-fuel-pump-presure/#findComment-50937 Share on other sites More sharing options...
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