It is a 2005 E-150 Van 5.4 2v engine 60k miles. After warmed up and under partial load this thing misses, Scanner shows very negative short term fuel trim when the missing occurs -29% both banks. There are no misfire codes. There is a p0340 but it has been happening for awhile and hadn't been affecting performance. help me fix this so wifey doesn't decide it's time for a new ride.

 

DTC P0340 as you probably already know is circuit malfunction of the CPS so how that isn't affecting performance eludes me. Something there has to be amiss otherwise OBD-II wouldn't typically throw that code.

Something to check would be fuel pressure----something in that system could also be an issue.

If definitive help doesn't arrive here soon post these same issues in the Modular Motor V8 forums too.

Hope the Wifey lets you keep your ride----this is but one reason I no longer have one of those-----------wife I mean!

 

Thanks for the input. From reading Ford documentation the CPS is only used once during a drive cycle and that is at start up. I have ran the through the diagnostic flow chart and it ends abruptly that this is an intermittent problem. Ie it can't be replicated by three rpm run ups above 1500 rpms. My plan today is to follow through the flow chart as if the failure is being detected during the initial testing phase. Will probably also replace the connector to the CPS. The CPS is a new motorcraft. One thing that can cause issues is noise in the circuits with the alternator being the usual suspect. I did have .125 milli-volts of ac on the charging system. I now have that down .015 milli-volts with the replacement of the alternator. The new alternator did bring the voltage up to 14.2 - 14.5 range. It had been down as low as 12.8 with air on and the old alternator.

 

Here is freeze frame data at the time of the p0340. Anybody anything wrong
P0340
Camshaft Position Sensor A (Bank 1) - Circuit Malfunction

Status of this DTC
Confirmed DTC

Engine state when the fault appeared
Freeze frame trouble code: P0340
Fuel system status 1: Closed loop
Fuel system status 2: Unused
Calculated load value: 80.0 %
Coolant temperature: 195 °F
Short term fuel % trim Bank 1: -5.5 %
Long term fuel % trim Bank 1: +3.1 %
Short term fuel % trim Bank 2: -6.2 %
Long term fuel % trim Bank 2: +4.7 %
Engine RPM: 2161 rpm
Vehicle speed: 42 mph
Timing advance: 12.0 °
Intake air temperature: 82 °F
Maf air flow: 10.34 lb/min
Absolute Throttle sensor position: 33.3 %
Oxygen sensor voltage bank1 sensor1: 0.805 Volt
Short term fuel associated to bank1 sensor1: -3.1 %
Oxygen sensor voltage bank1 sensor2: 0.595 Volt
Short term fuel associated to bank1 sensor2: +99.2 %
Oxygen sensor voltage bank2 sensor1: 0.800 Volt
Short term fuel associated to bank2 sensor1: -6.2 %
Oxygen sensor voltage bank2 sensor2: 0.660 Volt
Short term fuel associated to bank2 sensor2: +99.2 %
Time since engine start: 394 seconds
Fuel rail pressure relative manifold: 39.9 psi
Commanded EGR: 56.1 %
EGR error: +4.7 %
Commanded evaporative purge: 50.2 %
Fuel level input: 99.6 %
Number of warn-ups since DTCs cleared: 3
Distance traveled since DTCs cleared: 11 miles
Evap system vapor pressure: 32.268 inH2O
Barometric pressure: 30.1 inHg
Catalyst Temperature bank 1, sensor 1: 1488 °F
Catalyst Temperature bank 2, sensor 1: 1488 °F
Control module voltage: 14.655 Volt
Absolute load value: 66.7 %
Fuel/air commanded equivalence ratio: 0.999
Relative throttle position: 20.8 %
Ambient air temperature: 77 °F
Absolute throttle position B: 54.9 %
Accelerator pedal position D: 40.8 %
Accelerator pedal position E: 46.7 %
Accelerator pedal position F: 35.3 %
Commanded throttle actuator control: 32.9 %


Report generated with EOBD-Facile App compatible with iPhone/iPad

 

I replaced the fuel pump an the Fuel pressure sensor. No fix *@$%. It was the F*****G computer replaced it with one of the exact same part number and short code VPN1. Runs Like A champ. I know the vin doesn't doesn't match but so far no codes of any sort. time will tell.

 

Glad you got this fixed---we so often overlook the PCM as the source for problems like you've encountered.

Question though about your direct replacement----does it require a reflash to bring it up to the newest strategies for your year, model and engine?

 

Though I would update this. The PCM didn't fix the problem. I fought this off and on for almost the whole year. Finally got with a very good tech with the nesscary scopes and scanners. It turned out it was a loss of 5 volt reference voltage to a whole host of sensors causing the system to go dead rich. This can be caused by a shorted sensor a bad connection or wire. Mine was a loose connection at the PCM. Tighten the pin connector and problem went away. And hasn't been back in almost 1500 miles.

 

How did you find that?

 

The tech was able to hook up real time scanners and saw it go away.