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This is a 2005 E-150 Van 5.4 2v engine 60k miles. I am posting here due to very little action in the van section. 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.
The negative fuel trims on both banks makes sense, given the reported misfires. (The unburned fuel reaches the upstream O2 sensors and they register "rich" condition to the PCM, which in turn shortens the injector pulse widths [-% fuel trims] in its closed loop attempt to correct the rich condition). However, ALL the above could be happening correctly as a result of other things - perhaps indicated by the P0340 code.
The MotorCraft Service Manual on OBDII Theory gives some information on the P0340 Code that provides insight.
-------- Quoting from the Manual at page 66:
Ignition
Distributor Ignition systems (TFI) are no longer in production. Electronic Ignition systems (Electronic Distributor-less Ignition System - EDIS or Coil on Plug - COP) systems are being used on all applications.
The EDIS system uses a chip to process the 36 (or 40) tooth crankshaft position signal, generate a low data rate PIP signal for the PCM microprocessor and control a 4 or 6 terminal coil pack which fires a pair of spark plugs. One of these sparkplugs is on the compression stroke, while the other is on the exhaust stroke. The EDIS chip can be incorporated within the PCM or in a separate ignition control module.
The COP system also uses an EDIS chip in the same way as described above, however, each sparkplug has it’s own coil which is fired only once on the compression stroke.
The ignition system is checked by monitoring three ignition signals during normal vehicle operation:
Profile Ignition Pickup (CKP, commonly known as PIP), the timing reference signal derived from the crankshaft 36-tooth wheel and processed by the EDIS chip. PIP is a 50% duty cycle, square wave signal
that has a rising edge at 10 deg BTDC.
Camshaft IDentification (CMP, commonly known at CID), a signal derived from the camshaft to identify the #1 cylinder
Ignition Diagnostic Monitor (IDM), a signal that indicates that the primary side of the coil has fired. This signal is received as a digital pulse width signal from the EDIS chip. The EDIS chip determines if the current flow to the ignition coil reaches the required current (typically 5.5 Amps for COP, 3.0 to 4.0 Amps for DIS) within a specified time period (typically > 200 microseconds for both COP and DIS). The EDIS chip also outputs status information when the engine is not running.
First, the relationship between successive PIP events is evaluated to determine whether the PIP signal is rational. Too large a change in 3 successive PIP indicates a missing or noisy PIP signal (P0320). Next, the CMP edge count is compared to the PIP edge count. If the proper ratio of CMP events to PIP events is not being maintained (for example, 1 CMP edge for every 8 PIP edges for an 8-cylinder engine), it indicates a missing or noisy CMP signal (P0340). Finally, the relationship between IDM edges and PIP edges is evaluated. If there is not an IDM edge (coil firing) for every PIP edge (commanded spark event), the PCM will look for a pattern of failed IDM events to determine which ignition coil has failed. If the ignition coil cannot be identified or if the engine is running and there are no IDM edges, the IDM circuit is malfunctioning (P1351).
------------------- End Quote
Based on the above, I would carefully check everything associated with the Crank Position Sensor and Cam Position Sensors including ALL connections and wires for chaffing, damage or anything that could be causing those circuits to be susceptible to noise or interference. Or try replacing them. I've also heard OLD / WEAK battery or poor battery connections and bad diodes in the Alternator cause noise problems with CPS signals.
Good luck.
Last edited by F150Torqued; Oct 17, 2015 at 01:43 PM.
Reason: paragraph formatting
Thanks for the input. Today it really ran like crap from the start. I ran a data collection graph and looked at fuel pressure relative to to manifold. I caught it at 0 psi several times. That can't be right or can it. So is it an FPDM issue or a Pump issue.
I did order a new Crank position sensor to try an address the p0340 issue. 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. 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. All the flow chart test for the Cps circuit passed.
...
From reading Ford documentation the CPS is only used once during a drive cycle and that is at start up.
"Bull Butter"!
Not being argumentative, and I see you've replaced CPS & CKP. But for future temperance of what the Manual / Flow chart says .....
The P0340 code is often (or even typically) "set" during startup - because startup conditions (V Bat after soak, start current, lowest RPMs) make the system most vulnerable to it during startup. The CPS sensor is very high impedance and the signal generated by it is not powerful enough to overcome or not be effected by electrical noise. But it is not 'only "used" once during a drive cycle, etc. etc.'
My p0340 is never set at startup. Thats the first thing the Diagnostic pinpoint tests try to make happen. I think it is noise from somewhere just not sure where to look.
I notice (according to the wiring schematic diagrams for my '04 F150) the CKP sensor wire is a shielded cable and the SHIELD is grounded at "G103" at the Right Rear of the engine compartment. [That's right next to the PCM]. !!! That suggests to me engineers thought it might be susceptible to noise. In your case, it could be something as silly as a bad ground connection or a poor connection in some electrical plug. I'd unscrew and clean all ground connections I could find and unplug and spray connections with a good electrical contact cleaner and use dielectric grease when re-plugging everything. Even including the PCM connections. (You probably already know it but its best to disconnect the battery before unplugging the PCM plugs).
Once again thanks for all your help.Here is graph (don't laugh at my Excel skills) of the fuel pressure issue i am seeing. I swapped the FPDM with another one I will swap the fuel pump relay. But unless you pros think of something else I am changing the fuel pump. Also this run was about 13 mins long no p0340 code pending or set. As you can see there are a lot of zero pressures. and that corresponds to the missing episodes
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.
Wow, I didn't see that coming! But we often gloss over the fact that the ECUs on the vehicles are every bit as powerful (and also similar) to our desktop computers. They have to multi-task at staggering speeds to keep up with RPM by counting the 36 spokes on the crank ring / spark timing / valve timing / knock sensing / closed loop O2-Injector pulse width / closed loop VCT solenoid-Phaser advance, fuel pump pressure !!!! and the list goes on and on.
Congratulations and glad for another DIY fix - without the big stealership labor $$$BILL$$$. And by the way, they would have certainly had as many 'false starts' as you experienced, so don't feel at all bad.
Anyone had any luck getting a replacement PCM thru fleabay? I myself am tracking down the CMP codes on bank 2 with no luck solving the issue and am leaning on the possibility of a PCM issue.
noisy Crank or Cam position sensor signal maybe
