2022 Ram ecodiesel hard start issues after driving 2 hours

[Doctor D]

help ! truck is acting up again after driving hot day I stop and get back in truck after eating and start it up it might do a hard start and turn over 3 or more seconds after push to start function . once it does start it with run rough at idle and then die and electronic throttle service light and check engine light will come on, I will clear codes and drive at highway speeds and it is fine until I kill it and get back in and sometimes it will run ok and but really acting up with hot weather . replaced lift pump and recall on High pressure fuel pump already . also replaced fuel filter after lift pump . going to pull MAP off and clean if I can find it on GEN 3 . might be another sensor somewhere like EGR but need location . hoping I might get some help here ! thx! Doctor D , codes are low fuel rail pressure but I think that is false readings .

 

[Doctor D]

checked codes again and noticed P054E code codes are cleared but this was one .

 

[2021EcoDiesel]

That code makes me think you have a blockage somewhere in your fuel system. I'd wager maybe some dirt or debris in your fuel tank jamming up the fuel pickup. I've seen this on trucks, tractors, and generators. Sometimes when running for a while the suction of the lift pump will pick up some garbage and cause it to plug up. Parking the vehicle for a long time can allow that garbage to fall off the pickup screen and back to the very bottom of the tank. Which will make the truck seem like it starts well when "cold."

Another possibility may be algae/water in your fuel. Do you fill the truck up often? Do you get your fuel from a reputable station? Try some Hot Shot's Diesel Treatment maybe!

Did it ever do this before the High Pressure Fuel Pump recall? maybe there is a fitting on a fuel line that wasn't sealed up/tightened down correctly allowing air in the lines when you shut the truck down, or fuel out when the lift pump is attempting to prime.

Also, how many miles does the truck have on it, how long ago was the recall performed?

 

[2021EcoDiesel]

Another thing to maybe check out is the idle air control valve. Could be stuck up with carbon, or simply malfunctioning. Works similar to a throttle flap on a gas engine, and I do believe these engines have one. But feel free to correct me if I’m wrong.

 

[n8zcc]

Do you have the same hard start on a cold start?

If you have access to an OBD scanner that can show live data, look at the fuel pressures. At first look, it sounds like a fuel starvation issue. Don't fall into the trap of thinking that replaced parts are 100% functional.

 

[Doctor D]

truck has 50K miles and still getting service electronic throttle control and check engine light . will come on until you drive it several miles kill it get back in and start it will start idling rough and sometimes die and when you try and restart it will have a hard start and turn over several times before cranking . once you clear codes get back on highway speeds it is fine . going to clean MAP sensor and see what happens .

 

[Doctor D]

also going to take to local mechanic that I trust to get reading on all pressures and see what comes up .

 

[2021EcoDiesel]

also going to take to local mechanic that I trust to get reading on all pressures and see what comes up .

Keep us posted! Hopefully it is something simple

 

[Doctor D]

Well I cleaned MAP sensor today and truck seems to be running great so far ! got it up to running temp today at lunch and killed it and no hard start and weird rough idle and surging idle anymore and it starts normal . sensor was very dirty 50 thousand miles . also Map sensor was not easy to get to ! one bracket was in the way and made it a difficult job for me !

 

[Doctor D]

pickup is running great ! went out of town and coming home with slight tailwind getting 27 Mpg with .392 gears 4x4 . very happy ! I did have fuel additive in that tank . all the problems were from dirty MAP sensor .