Hi so I'm looking for some help here with these pre emissions C7 w/ HEUI fuel system approx 1500HR.i has a racor water separator then goes to the factory fuel filter set-up. all fuel filter are new and running 15w-40. I got an engine the is hard to turn over and sometimes gets no smoke when turning over. This machine has 3 group 31 batteries I would say plenty of juice to get it running, I have bench tested starter and alternator and both are good. I went out to it because it would not start, found a bad intake heater relay which I replace and tested, it works. I was then getting no fuel now. when I monitor the actuation pressure though cat et is when it gets odd. It will make 300 at the beginning then jumps up to 1400-1700 intermittently, that is the only time I get smoke, once I get the machine running it runs excellent with out any problem and it will start up again with out problem 14-17 hundo actuation pressure right off the bat. Like I said I have gone through this fuel system in and out, inspected pick up tubes in tank then lines from separator to primary to secondary, I ever inspected inside the heui and transfer pump. pretty much the only thing I didn't get into is the valve cover to look at the injectors. I guess my question would be is there anything I'm missing here. I'm starting to lean on something with the electrical side of the chassis. help is much appreciated
Well let me take a shot at it. I'm not super familiar with the Cat setup but I've been into several Powerstrokes. Same basic function. You need a minimum pressure on the high pressure oil side of things to even get the ecm to fire the injectors. Sounds like you have a high pressure oil leak or a weak pump. Even one cut o-ring in the right place will do it. You can rig up some test fittings to pressure up the high pressure system with air to find your leak. Could be a number of places. Time to dig into that side of things. There's a guy who has a video on YouTube of how he tests injectors etc.