Ram STILL throws code P0191 WTF

**RBH** · 10-25-2018

This is turning epic.. This is my first Diesel and I bought a Cummins because of its reputation, but now I'm having regrets..
My truck has thrown the P0191 code since I bought it 3 months ago.. only has 82,000 miles.. so far I have done...
*new fuel sending unit
*new fuel pressure regulator
*plug in relief valve
*new Fleece HP fuel pump
*cat fuel filters
Then I take to dealer.. they said it needs reflashed..Ok they reflash it, next I get a lighting bolt and code for throttle, and a communication computer code.. Dealers says I have a faulty PCM.. Geeze, $1800.00 for new PCM and files etc.. Latest updated programming.. I drive off lot and it throws a code for #1 injector.. Took it back, dealer said it needed flashed again a file didn't load.. Ok reflasehed again.. Picked up again drove home again and P0191 code is back.. WTF..

Any ideas before I invest in C-4 ???

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**Dwelsh** · 10-25-2018

Originally Posted by RBH

This is turning epic.. This is my first Diesel and I bought a Cummins because of its reputation, but now I'm having regrets..
My truck has thrown the P0191 code since I bought it 3 months ago.. only has 82,000 miles.. so far I have done...
*new fuel sending unit
*new fuel pressure regulator
*plug in relief valve
*new Fleece HP fuel pump
*cat fuel filters
Then I take to dealer.. they said it needs reflashed..Ok they reflash it, next I get a lighting bolt and code for throttle, and a communication computer code.. Dealers says I have a faulty PCM.. Geeze, $1800.00 for new PCM and files etc.. Latest updated programming.. I drive off lot and it throws a code for #1 injector.. Took it back, dealer said it needed flashed again a file didn't load.. Ok reflasehed again.. Picked up again drove home again and P0191 code is back.. WTF..

Any ideas before I invest in C-4 ???

I say tannerite it will be funner LOL. Honestly it has to be simple. It's all new so ide say its wiring issue. But take it back to the dealer and make em eat whatever it is. You spent 2 grand with them to fix it. So you held up your part by paying them. They didnt hold up their part by fixing it. If it's not a pressure problem. And the sensor is new oem. And the pcm is good. It's either wiring, connection, or something on the same circuit not sure if there is anything else on the circuit. But regardless if you get it back to them and they still cant figure out what the cause is. It definately wouldnt be out of the realm for them to have an engineer come figure it out.

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**Dwelsh** · 10-25-2018

Is your truck tuned and deleted or stock? If its stock is it possible with all the fuel system upgrades the truck has. The fuel pressure is higher than the pcm wants to see? And in turn is throwing the code? Sounds really good in my head. LOL the code isnt saying the pressure is low. Its saying it's different from what the pcm wants

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**Polaraco** · 10-25-2018

Originally Posted by Dwelsh

Is your truck tuned and deleted or stock? If its stock is it possible with all the fuel system upgrades the truck has. The fuel pressure is higher than the pcm wants to see? And in turn is throwing the code? Sounds really good in my head. LOL the code isnt saying the pressure is low. Its saying it's different from what the pcm wants

Yeah What you said. We seem to have duplicate threads. Problems like this are usually easily solved without pilot error

https://www.yourmechanic.com/article...-jamahl-walker

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**RBH** · 10-26-2018

Originally Posted by Dwelsh

Is your truck tuned and deleted or stock? If its stock is it possible with all the fuel system upgrades the truck has. The fuel pressure is higher than the pcm wants to see? And in turn is throwing the code? Sounds really good in my head. LOL the code isnt saying the pressure is low. Its saying it's different from what the pcm wants

Its all stock , Dealer just put a new PCM in it 2 days ago.. it didn't fix the problem

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**Dwelsh** · 10-26-2018

Originally Posted by RBH

Its all stock , Dealer just put a new PCM in it 2 days ago.. it didn't fix the problem

And all your fuel system upgrades are they just like factory replacement upgrades or performance upgrades?

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**RBH** · 10-26-2018

Originally Posted by Dwelsh

And all your fuel system upgrades are they just like factory replacement upgrades or performance upgrades?

I did install the Cat duel fuel filter system, but it was throwing codes before I installed the system.. Was hoping cleaner fuel would help

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**RBH** · 10-26-2018

Dealer installed a new pigtail wiring harness today from fuel pressure sending unit .. I have truck back to test out this weekend.. Hopefully No codes.. Sad to say this is what I suggested them to ck initially , they said it was not a problem. Uggg And to ice the cake dealer said it was also throwing a code for clutch fan speed out of range.. $800.00 to replace.. OMG , has to end soon, Tannerite is sounding better and better..

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**Lone Star** · 11-18-2018

I have the same issue. Spent many hours and much money with same outcome as you. Only thing left is to replace injectors and CP3 and not even sure that would help so I'm holding off. Doesnt really effect mpg just very annoying. Sometimes feel bucking on hwy going 55mph in 5th gear when lugging. Below a list of what I have changed:

FCA
FRP sensor
Low side pump (Now I have Airdog)
Tighten Injector tubes (42 ftlbs)
Reprogram lower setting (Raceme)
Airfilter
Map sensor
Boost sensor

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