A month ago I replaced the diaphragm in the afc a month ago as well as a couple fuel lines by the fuel filter and electric pump. Previous guy converted to electric lift pump. Prior to doing any work everything ran fine but just had a small leak I wanted fixed. Now my problem is that occasionally when I ask for boost, it sputters and dies and sometimes it restarts and sometimes it doesn’t. If I let it sit for a few minutes or hook it to a battery charger it almost always restarts and runs fine at idle. Had one day I ran it and had no issues at all after charging battery overnight. Battery was replaced a couple months ago but could be bad maybe. Doubt it though. I usually register 13.9 volts at battery while running. Alternator was rebuilt few months ago. Do I have an air leak? weak lift pump? Can a weak battery keep the lift pump from getting enough fuel to the injector pump? Where should I start?
check PM.. How does one "ask for boost"??
Find someone with an amp clamp and an oscilloscope. That's the best way to test the electric pump. Then get yourself a fuel pressure gauge rigged up.
Maybe I missed it but some hint as to what this engine is might be a good place to start. And when you say it won't restart after it quits "sometimes", but putting it on a charger it does are you saying it won't crank over and needs the boost to get it to turn over fast enough to start? I might be a little slow but a bit better description of exactly what is happening would help get better answers, remember we are not there to see and hear what is going on. But if you could post a video of what is happening that could help too!
By mashing the pedal is what I call asking for boost haha
Usually once it kills itself , when restarting it will turn over and “start” for maybe 1-2 seconds then sputters out like there’s no fuel. Engine is a Perkins 104.4T Trying to edit a video to upload. Does it in the first few seconds then ran for about 3 minutes up the hill and killed itself about 1 minute after I stopped recording. The sputtering at the beginning is the usual symptom but usually after a couple sputters it dies.
I like it!
This is the best I could do. Video file was too large so had to reduce resolution and shorten it. Could an inline fuel filter just before the lift pump be clogged and have these symptoms?
AFC pics from my repairs. Please verify I have it back correctly
Yes, any filter clogging would cause those symptoms. Or an air leak in the suction side of the fuel system (before the transfer pump typically, but if the transfer pump won't keep up, then anywhere can be under suction. ) In the video, once it starts stumbling, what are you doing to the throttle? I don't think it's a lack of boost, even with no turbocharger the engine would run just fine with what you're asking of it, it just might slow down when you put full load on it. That sounds like air to me... Can you list what you've tried already, I was getting you confused with another thread.
In the video I’m trying to feather the throttle a bit to keep it running. I haven’t really tried much yet other than pulling the afc back apart to make sure I had the diaphragm and all in the right place and it seemed to be as long as I have it back together the right way if someone can double check me on that. I believe the nipple goes against the rod? I was in a hurry when I took the old one apart and didn’t take any pictures to see how it went together.
I would start with double checking any of the fuel hoses that got messed with, anything that's old rubber is suspect, bend them and check for cracks, you could apply a couple PSI to the fuel tank and see if that cracks get damp with fuel. A suction leak won't always leak under pressure though. If you don't find anything, then tee into the fuel line going to the injection pump and run a line to the cab to see what the fuel pressure does when it stumbles like that, that will narrow down the problem.
How many springs do u have total in the afc?? should be 2.. 1 on top of the diaph, & 1 under it.. Heavyer spring goes under.. lighter spring goes on top. Which rod did u use?? shoulda been the one on the Left. By the looks of the metal portion of the diaph. u got water & rust problems.. not air problems.. Take the pump off & get the leaking front seals replaced along w/ a pump O/H.. THAT'LL prob solve all your problems..
Yup used the one on the left. I didn’t install a small spring. Just had the one so may that’s my issue. So the small spring should fit over the rod and nipple correct ?
You mention an in line fuel filter. The automotive filters are made of paper which swells when water hits it and will shut off the fuel flow. The original in line canisters for diesel engines have a brass strainer inside and will let the water through to get caught in the big fuel filter or in a water separator. Take the in line unit out and let the contents drain into a bowl or something. You will likely see lots of rust and crap. Go to the machine dealer and get the proper "strainer" and your problem will likely go away. The proper unit can be reverse flushed with diesel and air pressure if not plugged up too bad.
It is a small brass canister connected to the pump. I plan on taking it off and running it for a day or two and see if that solves my problem