2004 FX4 power loss
 

I have a 2004 FX4 with a 5.4. I just had the engine replaced for the second time in 2 years and it does not have any power after 2500 RPMs. It will not pull my camper. It does not have any codes, it is not misfiring at all. Just after 2500 RPMs it does not gain speed or power like it should. Does anyone have any ideas were to look. I have removed the CATs, changed the battery, changed the fuel filter, still nothing. the first engine with the cam chain hitting the cover had more top end power than this thing. HELP:help:

"Does not gain speed or power like it should" makes it seem like a tranny issue to me.

Having gone through 2 engines you should have gone through a trans too.

Tranny has been replaced about 10,000 miles ago, before engine problems. Talked to him because someone mentioned the torque converter. It is shifting fine, just around 2500 to 3000 RPMs, the way it gains is not as fast. It feels like it is not getting enough fuel or air, but the intake is clear. Stepping on it right from the start it cherps the tire and then falls off around 2500 like I said. Pulling my camper it won't go over 40 MPH.

Has the FPDM been checked or replaced. The FPDM controls fuel pump output pressure.
Check it to see if it has corrosion or is cracked.

Have you gone back to whoever rebuilt or replaced the engine? They should have some responsibility.

Yes I have called them. Funny you asked about the FPDM. Looked at it today. Was really corroded. I took it off and cleaned it up and noticed a crack on the back. Could that be what is doing this? The truck has sat quite a while for the engine problem. But it has no code at all. Could the FPDM still be the issue? The company I bought the engine from, Powertrain Products say check fuel delivery.

With corrosion and a crack on it, who knows what the electronics are doing?
Need to replace it whether or not it may be part of the issue.
Get one from Amazon for under $60:
https://www.amazon.com/Dorman-590-00...&keywords=fpdm


Before and or after the FPDM, check the fuel pressure at idle and when power drops off.

I will get back to you on it and see if that works.

OK, so I changed the FPDM. Still hits 2500 RPMS and no power. Noticed today driving it, that it will not go over 4000 RPMS. Then it has a slight vibration when it gets to 4000 RPMS. Any more Ideas, cause I am at a loss and this thing is killing me.

***gt Pool,

Sorry your experience with the 5.4 has been less than acceptable. You say it will 'chirp' the tires from a start but struggles above 2500 R's - that's where My 2004 5.4L (with 220k miles on her) really packs you back in the seat and comes on. It will scat wind up and shifting between 5200-5400.


I think you may need some live scanner data to properly diagnose some areas to concentrate. Suggestions you have gotten so far are good. I can suggest a couple of other "Subtle" things I have learned by monitoring live data from sensors on my 2004.


One possibility might be Knock Sensors, located underneath the IM. They are basically little microphones mounted to the block on both banks. VIA them, if the PCM senses labor knock - it reacts by reducing Spark Advance. That can dramatically effect power. The PCM gradually recovers advance (OVER what timeframe IDK). But the PCM constantly monitors (those "microphones") for Knock. Any constant source of noise could confuse them. I had to replace a NOISY A/C Compressor - and was very surprised to note the Knock Sensor on Bank 1 read noticeably lower voltage level afterwards - It could 'HEAR' that noisy A/C Comp. And I noticed a marked improvement in accelerator responsiveness. If you have 'spurious' noise (A/C Compressor or idler pulley or ticking lifters), it could have negative impact on power. Knock(s) do not produce a DTC, although the sensors are monitored for 'electrical integrity', so I do not suspect failure of either sensor.


Another possibility might be the IMRC (swirl control) valve. You practically have to use a borescope or USB camera & laptop to observe / verify it. The 5.4L IMRC valve operates 'butterflies' (similar to throttle body butterfly) in EACH intake port of the intake manifold, right below the injectors. They should close at low MAF volume air flow to improve fuel atomization in slow moving intake air. They must begin to open between 2000 - 3000 RPM depending on air temperature, engine temp and some other UNK factors. BUT - I can Monitor live data from my IMRC valve, and FEEL the torque and power increase when they open. If they are stuck closed or inoperative, that would cause your symptom. However - you should get a trouble code --- if that is it.

Another possibility might be one of the various temperature sensors producing FALSE readings. The PCM Logic will reduce POWER in response to elevated ECT, CHT, or OIL Temperature (and perhaps others) in an valiant effort to protect the engine - well before a DTC is set. Recently, I read about PCM logic reducing power if it senses elevated Oil Temperature to keep from breaking down the oil, thus possibly damaging the engine. IDK, but almost certainly - that logic might adjust valve timing TOO in order to reduce power - intentionally. Verifying outputs from those sensors would require a live data scanner, but are ideas that might help you out.


Just some thoughts that might help.
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P.S. Thank you for your 20 yrs service in the Marines for us.

Thank you for the info. I am beginning to think that the shop who put it in forgot to hook some sensor up, which there are so many. Where can I find one of these live scanners? I get the feeling it is the IMCR but, without checking it I don't want to pull the manifold to find out. Your very welcome on the 20 years. It was a fun time for me.

Torque Pro is a good / inexpensive live data scanner - code reader
 

You're right, there are a bunch of sensors and its easy to miss one. However, there are practically none that I can think of that could sugnificantly effect power that are not monitored for circuit integrety - opens or shorts. That just highlites the need for a scanner, and the preferability of one that reads live data so you can 'monitor' certain sensors.


Live scanners? There are lots of code readers available, some that can read live data. I use Torque Pro app on my Android phone and a bluetooth OBDII dongle. I can hardly talk about Torque Pro without sounding like a salesman for them, but I'm not. But based on a rather extensive programming background I have a healthy respect for the developer's intuitative design and ability to customize the App.


Customizeability is an absolute MUST for an OBD tool. When you consider the vast 'range' of differences in vehicle manufactures and models ---- you realize how difficult it would be to produce or sell an all inclusive OBD Tool. Just consider a Powerstroke w/ glow plugs, direct injection, and a turbo versus a 5.4L 3v w/ spark ignition, EFI, and variable valve timing. Then there is the Honda Prias hybrid electric. It would cost a million dollars to get a ONE FITS ALL.


The simplest ones will read/clear DTC codes. Some will display the basic (approx. 20-30 or so) sensors and perameters mandated by federal law dealing with emissions. But some (including Torque Pro) will send OBDII commands, read live data and allow you to create new dashboard screens and customize them with new gauges displaying any standard or extended sensor, or adding additional sensors that your specific vehicle is equipped with. (I have found 220 on my 2004 5.4L Lariat). It will log any sensors to a file, send files / screenshots via email, facebook, or twitter and lots more. And it only costs $4.95 on Google Play (do not use knock offs that are shipped with some dongles!).


A good online review of Torque Pro is here:
http://www.androidauthority.com/torq...th-obd2-95772/


There are lots of bluetooth OBDII interfaces - prices range wide - IDK much about the differences. I just bought this one for 10 bucks:
https://www.amazon.com/Bluetooth-Elm...H+OBDII+dongle


So for $15.00 - you can start getting you mind 'blown' as to how much smarts are programmed into our vehicles! Have fun. :thumbsup:

OK. So I just got my live scanner and went for a drive. I would like to have everyone take a look and see what they see.
https://cimg3.ibsrv.net/gimg/www.f15...545832a381.png

https://cimg5.ibsrv.net/gimg/www.f15...e537d9ae46.png

https://cimg7.ibsrv.net/gimg/www.f15...5b3140562d.png

It looks to me like bank 2s fuel trim is not right, but I don't know why. Any ideas?

I do not see a thing funny or flaky about your readings. Fuel trims are WELL within normal variations under operation (ie: 1750 rpm / 62 mph). The PCM maintains a multi-dimensional table for fuel trims at different engine RPM's, engine Load conditions, etc. Then it constantly updates STFT with live '+''-' adjustments from 1 and migrates those into LTFT over time. That allows compensation for aging or deteriorating components while maintaining optimum fuel/air mixture. It is not uncommon for them to vary up and downwards as much as maybe 10%. (DTC is set when LTFT exceeds 25% -while STFT is > 10%). And, there are NO trim sensor 2's for fuel trim on either bank, so the 99.22% is the maximum produced by the fuel trim formulas.


Resist the tendency to look for one that says "HEY look here - I'm the problem". They all have to be weighed against each other and actual operating conditions/circumstances. (Ie: the variation in the three throttle positions, 21.57% - 9.41% & 14.51%, are not necessarily unusual in a 'snapshot' for our 'fly by wire' systems.) But a subtle problem in accel position sensor or throttle position sensor and the PCM's reluctance to command the throttle actuator open further could certainly cause a problem. Watch those under varying conditions, although there is a VERY extensive rationality check against the electronic throttle being ran in the PCM constantly.


I'm more familiar with gm/sec mass air flow than Lbs per minute, but (lbs/min*7.55987 = gm/sec), which = 32.58 gm/sec and that is around where mine would run (at 62 mph, 1700 rpms, 80% load, 21% throttle, 30.5º spark advance - all pretty normal - unless I floored it). Fuel Rail pressure is right where it should be (39-40psi) and I suppose for where you live - 34º intake air temp (slightly warmed by engine compartment) might be pretty close. If it is that cold outside, while not "WORKING" the engine very hard, coolant temperature might run (181.4º), slightly below the thermostat temperature some of the time.
I do not see anything out of order here.


If you get a DTC, be sure to read and save the Freeze Frame data

So if you think that nothing is out of order, where do I go next, because it still does not seem to have the power it should. Is it possible to have a manifold gasket leak, and no DTC code? It has not given me a code since the motor was installed.

Hummmmm? "... where do I go next"? Having thought about it a good bit - the only thing that I can think of - WITH NO DTC - might be the engine is in a condition known as "FMEM" (Failure Mode Effects Management). Our trucks make a valiant effort to protect themselves from self destruction or further damage based on a S*@!&!%t load of logic running in the ECU. Under some conditions - the OBDII readings are STUFFED with a value that will keep things going - preceding a DTC, and perhaps (IDK) for longer by limiting power or stresses that might damage another part.


According to my research and 'hacking' on my truck, I have found that there are TWO OBDII ports that contain eight 'flags' (bits) each that are set to tell technicians when corresponding OBDII readings are NOT ACTUAL READINGS, but rather substituted values for MFEM mode. They are located at PID # 1106 and 1107. I do not know each of the "bit" locations (from 0 to 7 right to left), but know that both bytes should be ZERO if nothing is in failure mode and no OBD values are "substituted".


I would try to verify these two readings are both ZERO (if not try to figure out which system is represented by the flag).


1106 b? PCFM - In Electronic pressure control failure mode
1106 b? MAFFM - Mas Air Flow in FMEM mode (mfmflg)
1106 b? ECTF - Engine Coolant Temperature Failure FMEM mode
1106 b? EGRFM - EGR system in failure FMEM mode
1106 b? IATFM - Intake Air Temperature Failure FMEM mode
1106 b? VSSFM - Vehicle Speed Sensor Failure FMEM mode
1106 b?
1106 b?

1107 b0 CMPFM - Camshaft Position Sensor Fault MFEM Mode
1107 b2 TFTFM - Transmission oil temperature sensor failure MFEM mode
1107 b3 TCCFM - Torque Converter Clutch unlocked due to excessive slip MFEM
1107 b? O2S11_FL - HO2S21 Lack of switching failure
1107 b? O2S11FM - EGO1 sensor failure
1107 b? O2S21_FL - HO2S11 Lack of switching failure
1107 b? O2S21FM - EGO2 sensor failure
1107 b? OSSFM - In Output shaft speed failure FMEM mode

As for a manifold gasket leak ---- I do not think so. Any slightest vacuum leak will quickly result in whacked out of shape Fuel Trims and a lean DTC.