2000 F-150 Fuel too lean Bank 1 and 2

[stmichael]

5.4 liter

I have this causing my SES light to come on. I have replaced the (4) O2 sensors... Which was probably needed anyway(?) . But, the problem still exists. I added fuel injector cleaner, yesterday, and have only went 40 miles since adding it. (as I am assuming the problem is plugged or partially plugged injector or 2). Would this be a correct evaluation of the problem? The thing is I went to checker to use their "free" code reader and the code I believe was p0170, and there was the EVA deal flashing on the top of the reader as well, this is apparently a brand new, updated code reader? I should have written it down, but, anyway, the reader also said that on bank one and two the fuel pressure was at 10.2% and the other was at 8.4% on both banks, (I do not know why the two different psi's). Or is my problem something else? Fuel filter is about 8 months old. I can clear the SES light but it will come back on after about 50 miles.

As for now the truck is running fine with no problems, if it is the injectors can you clean them or just replace?

Thanks for any help!

Mike

[Shack]

I would think those injector reading's are with in spec... It is rare, but you could have a leaking intake manifold. The easiest way to check for that is to spray carb clean around intake and see if you idle climes up (PLEASE USE CAUSION WHEN DOING THIS. ANY SECONDARY ARCHING FROM PLUG WIRES CAN CAUSE A FIRE). If this is not the case, I would take it in to local dealership and have then tell you what is wrong. The diagnoses charge is about the same as a local garage, but the diagnoses is about 97-98% accurate. The main reason I recommend going is because it just might be a P.C.M. update. If this is the case, the diag. and repair is covered by 8 years/80,000 mile federal emissions warranty (this is new software for you trucks computer). Besides the little "blown spark plug thing", the 5.4l is a great and almost problem free motor.

I have very rarly ever replaced inj. because of clogging. The ones I have replaced were because of an "Elec. failure" inside of them. If an inj. was the cause, you would notice a runnning concern. If I was in vegas, I would bet on PCM update. If your truck is over 80,000 miles, it is a cheap fix. 9 times out of 10, you can even wait for it, if genstar,WDS or Palm Piliot are not being used in shop. I know all you dealship guys would kill me for saying "Waiter".

[Jeremy airjer W]

I'd have to second the intake gaskets/intake leak. The 5.4 is not as common as the 4.0 SOHC, but you do see a few.

Since I have started a motor on fire with carb spray and was trapped between a burning motor and a drivers door that did not work I do not reccommend or use carb spray anymore. Most shops have a smoker. It introduces a pressurized smoke into the intake through a vacumm port. Whever there is smoke there is a leak.

[Shack]

AHHH! The evaporative emissions leak detector. Most dealerships (and small garages as well) have this device. I do use carb spray in a pinch. I should add, I will “hot soak” the eng. Before doing this (this means spray water over a warm eng. While running) to check for any arching. A diag charge is a cheaper price to pay than burnt wiring repairs or your health. Good advice Airjer!

[Scott K]

I dont know the milage that is on your truck. The codes set were most likely p0171, and p0174. The fuel numbers you were refering to are the fuel trim percentages (pcms corrected fuel percentage) anything below 15 shouldnt make the ses come on. As for intake gasket leaks, they are not very comon on the f150s. I would start off by cleaning the mass airflow sensor with brake clean with key off. I would then look at the rubber elbows for vacuume hoses, they have a tendency to crack and leak at the rubber elbows, one in front and one in the back of the throttle body. I would also replace that fuel filter, you said it is only 8 mos old, but didnt say how many miles, 15k it should be replaced.Then if you dont find anything, I would then bring it to the dealership, as they see the trucks everyday and know what to look for, and can update the pcm if needed.

[stmichael]

Thank you all for the replies,

the mileage is about 134000

[Jeremy airjer W]

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I would start off by cleaning the mass airflow sensor with brake clean with key off. I would then look at the rubber elbows for vacuume hoses, they have a tendency to crack and leak at the rubber elbows, one in front and one in the back of the throttle body.

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Carb spray would be a better choice. I've seen some brake cleaners destroy parts upon contact. Most carb sprays are "sensor safe".

Any moderate vacuumm leak can cause this type of code. A good shop with a smoker will be able to find it if it exists. Typicall these show up with colder weather so there may be a chance that they will want you to leave it over night so they can check it with the engine as cold as possible. Some of these will clear up with the warmer weather and will not show themselves again until the fall.

[stmichael]

I was just looking on another site,I think I have found the problem, it is with the Mass Air Flow Sensor, I had installed a K&N air filter and one of the techs pointed out that the oil comes of the filter and will gunk up the sensor. I thank you all for the information, I might have to go back to using a OEM filter, I guess I will see if this is the actual problem and will post tomorrow. Airjer, thanks for the heads up on the carb cleaner, My first thought was break clean as well.

I suppose had I posted this little tidbit of information You guys would have figured it out as well!

Thanks again,

If this and the other possibilities mentioned it will be stopping in at the local Ford dealer. I am done throwing money away. Last week when the light came on, I looked up the code and the guy behind the counter said it was a O2 sensor, but, could not tell me which one, so, I bought both pre cat. $117., this is not going to be good if all I had to do was clean off the MAS... , Oh well, A person tries to save a buck and do it themselves... not any more for this guy... at least the diagnostics.

[Scott K]

Most carb sprays will work if they are non- chlornated, otherwise they put a film ontop of the sensor, inwhich will do more harm then good. Alot of brake clean now is electrical contact cleaner also, and wont leave this film behind. And this is what the ford hotline engineers have told us.

[stmichael]

I have to print this page... too much stuff to remember.

Thanks again guys!

[Jeremy airjer W]

AHA! The old k&n trick. You should be able to see some debris build up on the sensor if it is dirty. It is the very tiny resistor looking thingy that hangs down. Usually you will get some funky driveability symptom when these get dirty as well. Usually poor accelleration or poor performance under load. Interesting that it only showed up as a check engine light!!

Isn't everything non chlorinated now?

All I know is we had one brand of brake cleaner that will melt netrile gloves, Self destruct certain kinds of plastic, and would melt brake dust into the clear finish of aluminum wheels. We have changed brands!!!

[Scott K]

I think if you buy a known brand of either I think you would be fine, but if you find some stuff for .69 cents, I would be hesitant to use it either way.

[Jeremy airjer W]

Agreed!

[stmichael]

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AHA! The old k&n trick. You should be able to see some debris build up on the sensor if it is dirty.

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Yes, the sensor was a little dirty... OK it was very dirty. I used non-chlorinated brake clean. I could watch the build up wash away.

Well, I have driven 35 miles, since cleaning the MAS, I had to disconnect the battery to clear the SES light. Now it is a waiting game to see if it comes back. I went back to the local Checker and tried hooking up the code reader to see if it would give any information on how things are going. I guess as long as the SES light is out, you are not going to get any information out of the reader/computer(truck).

airjer, 4wanderingeyes, and, shackbash, Thanks again for the help.

[Shack]

Correct! Yes, disconnecting battery for about 10 minutes does clear memory.

[lots of luck]

Quote:

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Besides the little "blown spark plug thing", the 5.4l is a great and almost problem free motor.

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I got to deal with this three years ago, besides this catastrophy I have really enjoyed my 99' 5.4L. The warning sign was there, I didn't know what it was and it reared its ugly head. Kaboom at 70 m.p.h while pulling my boat 300 miles from home. Thank god for extended warranty.