yohon

OK sorry its so late of a reply but we figured it out the pre filters on these trucks has a check valve in it ( for some reason) this particular mopar filter had the check valve too far down in the filter "core" ( when the filter is properly installed a push rod touches the filter body and holds open the check valve) this caused the truck to starve for fuel ( not to mention the air leak at the front filter) i have no clue how this guy made it to work but it explains why we couldn't get a prime afterwards! Thank yall for your help

Hmm it might just be a working pump then but weak and is not able to push fuel all the way to the front fuel filter. Any clue what a healthy pressure or flow rate should be on a stock lift pump?

Agree should have been one of the first upgrades to this guy's truck. I'm just trying to get him out of the parking lot for now. Does anyone have a diagram of a common rail fuel system? I cant figure out why I have fuel at the pre filter but nothing at the filter in the engine bay. Thinking their might be a check valve or a regulator thats stuck.

That was my initial thought. Trucks on side of the road so didn't have a tester but cycled the key with the pre filter lines removed and verified in tank pump was pumping. Do these trucks have 2 lift pumps?

Need help figuring out these new fangled 6.7 a friend of mine at work asked if I could look over his truck he just got an oil change at a jiffy lube and it was running rough after. I drive a older 24v and work on it constantly so I figured they cant be too difficult or different. Check the engine bay fuel filter first thing and sure as **** no o ring on the fuel filter cap and it was insanely tight. Bought a o ring threw it in ( tightened the bolts that hold the housing to the block was missing a bolt and others were loose) crank the key over to prime and nothing. Do a little googling pull the lid of and look at level and nothing no priming. Checked the lines at the pre filter ( one under the bed) and something is pumping unhooked and verified fuel in and fuel out when key is cycled. Got copious amounts of fuel rained over me. Re installed and still no prime. I am completely lost. He drove the truck 30 min to work after the oil /filter change but when we fixed the air leak on the filter cap absolutely no prime but the lift pump is pumping? Is their a check valve suck closed or a regulator that is not letting fuel to the filter housing. Any help is appreciated Sorry forgot to mention truck in question is a 2012 2500 4x4 crew cab that has been deleted

Makes sense thank you tractorman!

Man I love the quadzilla. The fact you can do that is amazing. I sat down and had a long hard think about it and I think I'll stick with a single for now. I dont trust my transmission that much for twins or the factory heads I'd rather save my time and money and mess with water methanol and air to water intercooling.

I guess I'm not that familiar with 12vs but I thought they had basically the same injector set up with a different pop pressure and the P pump do they machine the crossover tubes?

Has anyone messed with different thickness injector washers on 24v? Doing some searching and it's a thing for 12vs but I can't find nothing on 24vs. The theory is the further in or out of the hole the injector determined where the spray pattern hit in the bowl of the piston.

I'm going to say that a 25 year relay was the cause of all of this. Truck has been running great ever since I changed the relay

Well I think it's safe to say that problem is fixed had a relay going out! thank you moparman. That pesky turbo is still haunting my marketplace feed and I just got a set of 7x.011 injectors and some 3 in pipe so I guess this still might be happening! Typically I'm guessing the exhaust manifold is flipped upside down for better clearance? Do I need to move the oil filter? I'd hate to make changing that a pain. Does the hot pipe need to be cast/heavy wall pipe? What i have is schedule 10. Did i go to big on the injectors? Thanks for reading i look forward to your replies!

That sounds electrical to me. What are you seeing for line pressure on the middle test port? When i was working on my transmission this article was gold https://mopar1973man.com/cummins/articles.html/general-cummins/85_transmission-transfer-case_85/fine-tuning-your-dodge-automatic-47rerh-series-46-and-early-48-series-similar-r614/

I always thought that was for the lift pump. Glad you said that. I swapped the vp44 relay for the wiper motor relay and so far the code has stayed cleared only had about 2 longer trips but fingers crossed that was it.

Well I think it was just timing but i put the lift pump relay in this morning. On the drive home I noted the check engine light was out. I'll try and go on some longer drives this weekend and see if it comes back.. feel like it's not gone for long...

Well then the glove box relay is going in lol.