inimicaljords

I bought a 2004 Ford F150 5.4L at an auction so I only know the history of what I have done to it. I am not a mechanic by trade (I am an IT guy) so diagnosing mechanical problems has been my downfall... I have probably done more to the truck then was needed, but I have enjoyed the learning experience. I am just frustrated that I can't figure out this problem. I am hoping someone on here can help lead me to the next step. Here goes...

The truck starts and runs well when driving (no knocks or any weird noises). However, at idle it tends to choke out and stall. It sounds like it is running out of gas and sputters. I have tried numerous things to fix this, but haven't found the culprit.

Here is what I know/have replaced on this truck:
-Error codes that I get on the truck:
P0171 - System too lean (bank 1)
P0174 - System too lean (bank 2)
P1450 - Unable to Bleed Up Fuel Tank Vacuum (I got this error one time, but after replacing parts, this error quit coming up.
P2195 - O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 1)
P2197 - O2 Sensor Signal Biased/Stuck Lean (Bank 2 Sensor 1)
I use dash command and a wireless OBD sensor to read codes. I noticed that the truck starts to stall when the short term fuel trim gets to high. It can get up to over 50. Also, the O2 sensors seems to stay in the 0.02 range a lot.

Based on these error codes and symptoms, I suspected an air/fuel problem.

The Truck appeared to have had little maintenance work done to it. It was a Repo. One of the coil packs died on the first drive so I went ahead and did some tune up work to it.

-I have replaced all spark plugs and coil packs with motorcraft parts
-I replaced the fuel filter with a motorcraft FG-986b
-I have used Lucas Fuel injector cleaner
-I have cleaned the mass airflow sensor. I have put in a used sensor just to verified that my sensor wasn't bad which it wasn't.
-I did an oil change and used Motrocraft 5W-20 with a motorcraft FL-820S filter
-I put in a new motorcraft cx2082 Vapor Canister Valve
-I replaced the PCV hose
-I replaced all 4 oxygen sensors with motorcraft (DY835 and DY-992)
-I cleaned the throttle body using throttle body cleaner as well as trimmed the gasket that was in there. It was over hanging inside the throttle body by a lot.
-The truck has a K&N 57-2556 cold air intake on it. It was already on it when I bought it. It seems like it was just recently put in. Everything looked new and cleaned. I called K&N and they verified that the CAI fits the truck without any factory tuning. I saw others have lean codes with CAI and I suspected that this might be the culprit of my problem, but K&N kept assuring me that it wasn't.
-There was a broken bolt where the K&N mounts to the manifold/engine. It appears to happen if someone leans on the CAI while working on the engine. It puts a lot of pressure on the bolts (kind of like a seesaw effect). I was able to get the bolt removed and got a new bolt put in. Everything is secured now and I tested for air leaks.
-I disconnected the battery terminals several times to let the computer system re-learn everything.
-I checked for vaccuum leaks with starter fluid on all hoses and connectors on the top of the engine. I have not made it to any connectors/hoses behind the engine.


I have attached some pictures as well as a Data log file from Dash Cmd. At row 8695, the fuel flow goes from 2.452 down to 0.84 then sputters out at 0.178.

If anyone can help me resolve this/point me to the next step, I would GREATLY appreciate it. I have been beating my brain outs trying to figure this thing out. Thanks in advance!

F150Torqued

@inimicaljords you have certainly provided lots of data, but if we are to get you some help, we gotta' grab you by the shirt tail and slow you down a bit. I took a look at the file you attached and - WOW, 1.1 MB of so much it would loose the best of IT guys. Respectfully, your altitude, GPS latitude/longitude, GPS accuracy, vertical and lateral acceleration and on and on simply obscures the important elements. If I wasn't an IT type and HEAVY user of Torque Pro myself, the wall of numbers in your Log File would have stopped me immediately. I'll come back to that later.


For now, I have a couple of relevant questions (focusing on specific statements YOU made that may already have answered your question). You state "I checked for vacuum leaks with starter fluid ..." etc. etc. Exactly How did you do that? Since you use Dashcommand, you should have set up a screen displaying 'Short Term Fuel Trims', and 'upstream O2 Sensors' - and actively monitor those signals WHILE spraying a 'flammable' - EVERYWHERE. If you hit a leak point, STFT will react - though you will NEVER notice any difference in idle. (BTW I prefer/recommend using an 'unlit' propane torch instead of starting fluid or flammable liquid. It is safer, and not as hard on rubber components).

It is true, many with K/N CAI experience lean codes, but I presume you can't go back. SO, the important thing here is your DTC's and symptoms ALL point to AIR/FUEL problems exactly as you suggested. You've got lean code on BOTH banks, so the unmetered air is entering the system common to BOTH Banks. You've got BOTH bank O2 sensors stuck low (lean) screaming for MORE fuel because there is TOO much air (post MAF) and the PCM has already increased fuel trim(s) to - +50% you say - ???.


Therefore, I would focus on the CAI system - between the MAF location and the IM, then underneath the IM / rear of IM, Valve cover gaskets, Oil Filler Tube, Power Break Booster, EVAP solenoid, IWE vacuum lines, and particularly where the power break booster connects to the belly of the IM way down behind the head by cyl 8.


I'm not forgetting about the Fuel side of the equation. You need to start somewhere and eliminate one thing at a time. (Narrow down your data Log File). Based on what you have done and parts you have changed so far, raises these questions in my mind first. If it proves negative, next - is your exhaust BLACK / rich smelling with fuel, and I would monitor fuel rail pressure, Fuel Pump duty cycle, and FTP, etc.

inimicaljords

First off, I just wanted to say that I greatly appreciated your input.

I know that I probably provided too much info, but I always hate to deal with scenarios like "it just doesn't work." I get those a lot at my work, lol. I wasn't exactly sure what was useful or not in that log file so I just left it in the raw format that dash command saved it in.

When I checked for air leaks, I specifically was going on the "noise method" where I was listening to rpm changes. I did not think about looking at the STFT or O2 sensors while doing it. I will give that a shot to see if I can find something that way.

After posting, I did some more research on K&N website and started looking at the parts diagram for the CAI. I know the gasket that went to the throttle body was not original. It looked like it was made by hand. I went ahead and ordered the proper gasket for it as well as some cleaner and oil for the air filter. Currently waiting on it to arrive.

I didn't notice any rich smell or excessive black smoke coming from the exhaust, but I will pay closer attention to it.

F150Torqued

Yeah many don't give the computer enough credit. It is MUCH to quick on the draw for RPM or anything to change when spraying combustibles looking for leaks. You would have to totally flood it or choke it completely down. Damn computer is checking the O2's about six times a second for changes and can adjust throttle, fuel injector pulse widths in a fraction of a second - way to quick for us to pick up on.


But fortunately, you can "SEE" that all with your dash command.


ALSO, after posting before, I noted that that engine bay is WAY TOO CLEAN for an '04 no matter how many miles it has on it. Blowing up the photos I can see evidence of pressure washing on the felt across behind the IM, and even perhaps steam cleaning on the alternator white corrosion spots. Also some rusted bolt heads. Assuming that it certainly might have been washed before you bought it at an auction - I was going to suggest you be on the alert for flaky electrical connections.


You might even disconnect the battery, use some good spray electrical contact cleaner on plugs at the PCM and other components - plug & re-plug them several times to burnish contacts and try to insure good contact as part of your overall efforts. Just a thought.

inimicaljords

You have a good eye....

The truck was nearly spotless on the engine when I bought it so I do agree with you that it had been cleaned. I'm just not sure how. BTW, the truck has 143k miles on it.

I do have some CRC electronic cleaner that I got, but haven't used yet. I have never tried to clean any of the connectors before. Am I suppose to just unplug them and spray the cleaner inside the connectors and let it dry? (with the battery out of course)

I plan on working on the truck some this weekend so I will post some more results as I find them.

Also, the electrical connector lock on my MAF was broken... I went to a pull-apart yard and got a new connector for it. I was planning on cutting the old one off and just splicing the new one in. Do you see any problems with that? I plan on using solder and a heat shrink wrap to make sure its secured properly. However, the connector appears to make a good solid connection, it just doesn't lock anymore.

techrep

iTrader: (1)

Looks to me .. that the MAF has been moved to the down stream.. close to the fender draw hole side of the CAI.. you can see a bolt in place up by the throttle body RH side where my MAF is on my 08. Maybe the 04 is different..IDK Have you checked the condition of your FPDM ?

F150Torqued

@techrep makes an excellent point. I had noticed a significant distance between the MAF sensor location and TP, but my '04 has a stock intake and MAF is right there about where @techrep's is.

Someone may have moved it looking for a IAT nearer ambient. Mine IAT will rise dramatically sitting at a red light (sometimes near 120º in the hot S. Texas sun) but settle back down near ambient when crusing. **IF your's is 'moved', would make me extra suspicious of an unmetered air leak - or question prudence of feeding the PCM a lower IAT temp.


SO - all this sent me back to your big block of data that I had slammed you for (lol). I notice (while your engine RPMs fluctuate quiet a bit, too much! - (between 570 & 616) your MAF reading at idle seems to average a higher than mine. //Not saying to replace MAF - yet, but stay aware// Mine will idle very steady right around 600 RPM at average of 4.5 to 5.0 grams/second.


Can't tell from your profile or prior posts where you're located, but IAT indicates 90ºF when you cranked up (probably from solar load), but declined to avg. of about 82 - and when you revved it up around 2300 down to 1600 R's pulled in ambient that registered 79ºF, so I presume IAT sensor is working. Some of the calculated values look OFF, (including stoichiometric air/fuel ratio @ 14.64), but it looks like engine displacement (183.071/ 3L) may not be correct in the vehicle setup - throwing all that calculated stuff out of whack.


Your Fuel rail pressure (39.4 lbs) looks fine and even held after RPMs went to zero (Don't know if ignition shut off or it died, but IAT changed after that point ??). However, I agree with @techrep RE: check FDPM. I do not see FPDC in your data file, but I think you can input custom PIDs into DashCommand. If so, you can monitor Fuel Pump Duty Cycle (the output from the FDPM driving the fuel pump) at PID # 1672 known as FPDC, Units %, Min 0 Max 100, produces a 2 byte response, formula (A*256+B)*(100/32767) will yield % duty cycle.


As for the CRC electronic cleaner, I just spray both ends good to displace moisture / dissolve corrosion deposits and plug/unplug the connection while wet - leave unpluged to dry then plug/replug a couple of times to burnish pins/contacts. It's basically a preventative effort/crap shoot but definitely replace those (expensive) little broken clips because the little rubber seals tend to push the plugs back apart -leading to unwanted poor connections.


Good Luck

techrep

iTrader: (1)

Splicing a new MAF connector on like you mentioned will work just fine.

inimicaljords

I am not sure why the MAF is located closer to the filter, but it appears thats the way its suppose to be with the CAI. I did see some other trucks at the junk yard that had MAF in a similar position. I attached the installation pdf for the CAI.

When I got home from work today, I tried checking for vacuum leaks again with dash command. I sprayed and sprayed, but couldn't narrow down any leaks. At least, not on the top of the engine. The truck does a lot of random small revs up and down on its own and the fuel trim fluctuates as well. The starter fluid didn't seem to have any impact.

I then went through and cleaned all of the electrical connectors I could see. I waited for it to dry and then tested. It is still getting the same rough idle/dying.

I had not checked the FPDM yet. I will try to get under there tomorrow to see what it looks like. I will have to get the spare tire off, which looks like it could be some trouble considering the key doesn't turn on the back right of the license plate and the jack is also missing from the truck.... lovely

Also, I live in Knoxville, TN, but the Truck appeared to come from North Carolina. Its a pretty moderate climate here (62 degrees right now), but we do have some high humidity days with maybe 1-2 small snowfalls a year.

Christianwalker023

I have been getting a p0171 code for quite some time now. I already changed all 4 o2 sensors and checked for vacuum leaks. It's driving me crazy. I already cleaned the MAF sensor. I don't know what to do can someone help me. The engine revs up when idling on its own. Not sure where to go from here. Also getting terrible gas mileage.