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Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

2014 ram 3500 6.4L run lean condition at idle

  • watchcat2011
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5 years 1 month ago #41923 by watchcat2011
2014 ram 3500 6.4L run lean condition at idle was created by watchcat2011
-GOT THIS TRUCK ON MONDAY ,DTCs P0171 AND P0174 AND P0300 .
VEHICLE STARTED AND RAN NORMALLY WHEN FIRST TIME START IN MORNING .BUT AFTER COOLANT TEMP OVER 70 C ,BOTH BANKS WILL RUN
LEAN CONDITION .STFT AND LTFT WILL INCREASE AND REACH 32% AT IDLE .HOLD RPM AT 1500 ,STFT STILL STAY AT 32% ,BUT LTFT WILL DECREASE TO 0% ,HOLD RPM AT 2500 ,STFT WILL STAY IN + - 10% ,AND LTFT STAY AT 0% .
-ROAD TEST VEHICLE ,IDLE ROUGH AND LACK POWER ,ENGINE RAMDON MISFIRE IN ALL CYLINDERS .VEHICLE SILL STALL WHEN STOPPED AT STOP SIGN OR TURNING .
-HIGH WAY SPEED ,NO MISFIRE, DTCs P0171 AND P0174 NEVER SET BACK .STFT AND LTFT ARE IN THE SPEC ,TOTAL FUEL TRIM ADAP NEVER
OVER 10 % .
-PERFORMED VACUUM LEAKS TEST ,USING WATER SPARY ,PROPANE AND SMOKING MACHINE ,NO LEAKS FOUND .SWAPPED PCV AND BLOCKED EGR VALVE ,NO CHANGE .
-CUSTOMER SAID THIS TRUCK WAS REPLACED FUEL PUMP BY BACKYARD TECH .SO CHECKED FUEL PRESSURE AND VOLUMN ,57-59 PSI ,PASSED .1.2 L GAS VOLUMN IN 20 SECONDS ,PASSED TEST TOO .
-DRAINED FUEL TANK AND FILLED WITH NEW GAS ,NO CHANGE .
-ALL SPARK PLUGS WAS REPLACED WITH OEM ONES BY OTHER TECH .
-EXHAUST LEAK TEST ,NO LEAKS FOUND .
-SWAPPED MAP SENSOR AND BOTH UPPER STREAM O2 SENSORS ,NO CHANGE .
-THE NEXT STEP ,I AM GOING TO CHECK ENGINE COMPRESSION AND PUSH RODS .DOES CAMSHAFT

DID I MISS ANYTHING ?

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5 years 1 month ago #41924 by Hardtopdr2
Replied by Hardtopdr2 on topic 2014 ram 3500 6.4L run lean condition at idle
Looks like you covered most of the bases....

I would look at secondary and primary waveforms of coil

Ohm plug wires

(I would focus on injectors first given the info provided)
Injector waveforms
injector pressure drop test
Ohm injectors

Tps or iac condition possible

carbon buildup sticking valves?? Kinda doubt this one

Crankcase vac leak or brake booster

With your symptoms happening once it warms up has me thinking restricted injectors or shorting injectors when warmed up or a coil problem but positive fuel trims at idle typically are vac leaks you might have to smoke intake when hot and when cold same with exhaust and crankcase. Try pinching off brake booster when its doing it to see if fuel trims are different.

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