I have an AEM Brute Force intake for my '04 F150 5.4L, and my Edge unit (along with the check engine light) is reporting a lean condition in both banks (codes P0174 & P0171).

The MAF sensor is clean, so I thought that I might have a leak somewhere; so I took the truck into the dealer to see if they could find any leaks or a bad PCV. Everything checked out ok (no leaks); and the tech told me that there is 'too much air flow going through the MAF sensor' causing a lean condition. Running the Edge at level 2 has not compensated for this either.

So, other then the options of going back to my stock intake or a different intake or custom tune, I was wondering if an aftermarket MAF sensor like the one from Granatelli would help my problem? I'm under the assumption that the stock MAF sensor can't read the high air flow that the AEM intake has, and thus a higher-flow MAF sensor should help.

Am I wrong with that assumption? What do you guys think? Thanks in advance!

 

I have a volant intake with EDGE and get no "CEL". Did the CEL come on after the AEM install? I know of several others on this site running AEM aftermarket intakes without any issues... hopefully someone has more knowledge of this error. So sorry I could not not help. Good Luck! BoB

 

Yeah, I had a K&N FIPK intake previously, and had no CEL come on. I switched to the AEM, and have had a lean condition ever since. I'm pretty sure that the AEM short tube intake is less restrictive then the K&N long tube intake; thus the increased air flow. The dealership has confirmed that there are no leaks; they say that it is just too much air flow for the MAF sensor; which to me, suggests that the stock MAF sensor cannot handle the increased air flow.

 

Sounds like you need a custom tune, its not worth destroying your motor.

 

I figured that might be the case. So, a higher-flow MAF won't help? I'd rather not get a custom tune, but I will if that is my only option.

 

I can't tell you if it'll help or not but I'd start with the custom tune. I'd give Jusnes or Troyer Performance a call and they'll be able to help you out.

 

Yes, your assumption is wrong. Unless the meter is pegging at 5V, its not flowing too much air. It's simply flowing more air than the computer can compensate for. I am not familiar with the Edge programmer, but I know with my X-Cal2 I can add fuel with it. If this is possible with the Edge, then that should be all you need to do to fix a lean condition. If it's not possible, then you will need a custom tune. Since you are getting a CEL for a lean condition, your truck is running EXTREMELY lean. Stay out of WOT operation until you get this situation resolved.

 

If you have "to much air" going thru your MAF, Ford has a serious design flaw on their hands.

(based on what I learned on supercharging my '88 Mustang)
The MAF takes air and translates it into DC voltage, 0 to 5V to be specific. That voltage is then compared to a table in the PCM (MAF transfer function) to determine how much air is actually flowing in kg/Hr. With everything stock you shouldn't be anywhere over ~2/3rd's of the MAF's capability to measure air. Although you get better drivability by utilizing as much of that table as possible, it's not feasible. The truck has to be able to account for hotter & colder climates, and production variences in motors (among a million other power effecting factors). I was running a 90mm LMAF and pegging it out. But then again I was pushing 18psi from a Vortech SQ trim (flowing 1,000 cfm) down that little 302!

I'm running the Edge on Level 2, and sometimes play with it's settings. I also have a K&N intake setup, and Roush street legal exhaust kit. So far the only DTC I've thrown is one saying a fuel circuit has low voltage or something like that -- which randonly pops up after fuel ups with different octanes.

If a dealer told me I was pegging my MAF with just a CAI I'd take it to another for a second opinion....

 

"Too much air through the MAF" is right, sorta, the guy at the dealer is thinking about it the wrong way though.

A better description is "too much air for the PCM to compensate for adequately." The stock PCM calibration is pretty sensitive in regards to air/fuel, maybe a little too sensitive. I do not run an aftermarket intake myself, but from what I've read on here, some intakes may make the engine run a little leaner than it should, turning the CEL on. A custom tuner like the XCal2 is the answer you need.

 

As Badcobra and weasled said, unless the MAF is pegged at 5V, then air is getting in behind the MAF, thats what the computer can't adjust for. If you can datalog the MAF voltage, do it. Otherwise check for a leak between the MAF and Heads.

 

Thanks for the info guys, I really appreciate it. I'm going back to my old K&N intake to see if it still goes lean; as I never had a lean condition with that setup before the AEM. If I still get a lean condition, then I know something fishy is going on; ie leak somewhere or even the lesser chance that I have a faulty O2 sensor.

 

It has more to do with the proper design of the intake than it does with the MAF sensor. The problem is some intakes don't get the placement of the MAF sensor correct and air bypasses it making the engine run lean.

 

That's exactly what I'm thinking the problem is.

 

Yeah, but you guys are forgetting the 04's are very sensitive regarding lean conditions compared to the 05's and up. The intake isn't designed poorly, it's fine. The af1 intake does the same thing on 04's. Custom tuning will cure the lean conditions. Do a search and there is tons of info on this site regarding this exact issue.

 

If that was the problem, his K&N should have thrown codes, too. It didn't and I believe the only thing he changed was the intake. That pretty much supports the conclusion that the intake is the problem. I never have liked the excuse that you need to buy product X in order to make product Y funtion properly. Product Y should have been designed to function properly by itself.