I'm not worried about people calling me names and crap. That's about as childish as it gets. I'm here for discussion of facts. If I wanted their crap, I'd just go argue with my 12 yr old cousin.

 

No code hunh... How do you know it went into limp mode because of that then? Your truck could have been missing because of ANYTHING! And you know it! Why are you trying to make a fool of me by posting this nonsense? Marc, I have known you to be very knowledgable, but come on. It isn't very complicated, how these trucks work, and I think ya'll are writing WAY too much into it.

Yeah, my truck went into limp mode once too, and it was right after I installed the EDGE. But it wasn't the edge, and it wasn't lean. It was because of wet COP's. And I found out a little while later when I got a code.

 

Hi Chester;

I'm not calling you out, nor calling you names.

But, Marc's right - you just don't listen.

I think the concept of a transfer function is beyond your grasp. Because if you understood that, half of your misconceptions would disappear.

The link I posted on intakes was germain - I asked you to glean the facts, and the importance of transfer functions were part of that post - sorry you missed the significance and the relevance.

Oh, and the PCM is enormously complex - you got that wrong too. To get all the functionality into so (relatively) few lines of programming is a profound achievement.

Thank God I know one guy who does understand it ! My tuner Maestro!

Cheers
Bubba

PS - Hiya, Dad

 

Whatever. Just because it can't accurately read the ammount of air entering the engine doesn't mean it can't set a CEL for a lean condition. I don't know what you're getting at.

It's also a shame that all these intake companies are selling this product that is apparantly ruining the machines of all who own them, and neglect to purchase a custom tune.

All along, everyone has been saying, "it flows better, so it lets more air in the engine, and it runs lean". And that's crap.

But you're saying that the MAF sensor cannot accurately measure the quantity of air entering the engine, because the tube diameter surrounding the MAF sensor is not the same as stock? Is that right? So you have to modify the programming to account for that?

That's really poor design in my opinion, and I find it hard to believe that they did that. But I don't have one, so I can't go out and measure the diameter. I have to trust you on that!

I still fail to see how the computer wouldn't notice the fact that it was running lean. That one escapes me. And the way Marc's engine knew that it was lean enough to go into limp mode, but STILL neglected to throw a code...

 

Hi Chester.

Okay - let's try this by using an analogy.

Familiar with flowmeters for fluids? Well, for the ones that use physical sensing elements (not the ones that use other non-invasive sensing methods) the sensor sits in a predetermined location inside a venturi of known properties ( cross-section, laminar linearity, flow vs.pressure, etc).

That sensor is not very bright - it knows nothing with regard to it's environment, only that it puts out a signal that changes when the flow changes. That signal, coupled with a transfer function that is based on the physical properties of the tube it's in (and the specific gravity of the fluid being measured), results in a meaningful & accurate representation of the flow. Change one thing, anything, and it's accuracy is gone. A small leak, type of fluid, debris on the element, dynamics of the tube etc, and it cannot be corrected for.

Lesson 1: - the sensor is DUMB. It depends on the engineered characteristics of the tube it's in ( as described solely by the transfer function) to provide useful data.

In a MAF - it's the same principal at work. EXACTLY the same. Change the type of gas (i.e, it's specific gravity) without supplying a modified transfer function for that gas, and it's output is useless, as the MASS of the fluid (a gas is also a fluid, y'know) is different.

- Get the MAF dirty - same problem. It doesn't know it's got caca in it's pants, but the output will be skewed.

- Put the MAF in a different place, in the same tube - same problem.

- Put the MAF in a different tube - same problem.

- Change the dynamics of the gas upstrem of the MAF (e.g. Ram Air) - same problem.

You need a transfer function to account for the deviation or you are toast. The PCM cannot correct, because that sensor is DUMB.

Lesson 2: - the PCM, although complex, is also DUMB in this case - it's only going to provide acurate outputs based upon the accuracy of it's inputs - it does not, in this case, have the sensing or capability to infer that the conditions it cannot possibly sense have changed. Unlike the density of the fluid changing with temperature - it has sensing for that & can correct accordingly.

Now, S&B claims, for example, that they have specifically engineered thier intake's MAF location & tube properties such that the original transfer function that is fixed in the factory PCM will work. The AF1 3" also does not alter the paradigm. But the 3.25" and 3.5" does (as does the JLT) - as has been determined empirically - hence the need for tuning changes. I can't speak to this - the respective experts will need to provide additional input on this state of affairs. If you believe the pundits, it's apparently possible to design it such that no changes are required - I'll rely on the data to support this, speaking for myself, which is why I stated elsewhere that I'd like Mike Troyer to independently test.

Hope this helps.

Oh, and try to watch your manners - I have never told you to 'shut up'.

Ahhh RP, another Windbag response ( damn those solder fumes)

Cheers
Bubba the Winbag

 

I concur with MGDFan. You also have to take into account costs. It's cheaper to install a MAF that is set to specifically monitor specific airflow parameters than to install an adaptive sensor that accurately measures airflow and air temperature. Warmer air is denser than cooler air, which is why a vehicle running in cooler temperatures runs better than one in warmer temperatures, not to mention heat and other things. An adaptive sensor would allow the ECU to make adjustments for air density, which just plain doesn't happen in the real world.

Chester's theory would be correct if these were adaptive sensors that provided accurate feedback to the ECU so that the ECU could accurately change the fuel mapping. Our trucks, while sophisticated in some regards, are not THAT sophisticated.

Now, take into account the number of F150 owners that play with the performance of their trucks the way we do. That further propagates the fact that the MAF sensor is designed for only one set of parameters. 90% of the trucks sold today will die the same way they came into this world; completely stock.

So, back to the issue at hand. Can you drive your truck with an aftermarket intake kit without doing damage to your truck? Short-term, yes. Long-term, no. Should everyone who installs an aftermarket intake and filter have custom tuning done to correct a lean running state? Yes, of course. Do they? No. Why else would companies like K&N among others have a disclaimer that their product MAY void your vehicle manufacturer's warranty and that installing their product is at your own risk?

Face it, the general public tends not to follow procedures too well. Oil changes, tire rotations, wiper blade changes among other things are things that are far too often overlooked by the general public. How many of the general public follow their maintenance schedule to the letter? Surprisingly few. It would be silly to assume that the general public, in "hopping up" their vehicles would take the time to properly research and do the correct things for their vehicle, let alone read the instructions provided by either the manufacturer of the vehicle or the manufacturer of the aftermarket intake system.

 

Hi Unclebuck;

A couple corrections, if I may.

Cold air is denser than warm air.

The MAF has the capability to adjust for density change ( = mass change), by the fact that the cooling effect on the MAF hot wire is affected by the Mass (density) of the air flowing past it, Hence the voltage changes reflect the actual Mass of the air, giving you the reason it's named such. There is also an IAT input. Other than that, yup, it's a pretty simple-minded sensor, knowing or caring not a whit about the orifice in which it resides ;-)).

I'll chaulk these up to simple typos . Happens to me all the time.

Thanks for the support.

Cheers
Bubba

 

Duh.. warm air rises Is it Monday?

Thanks for the correction!

 

I understand. I wish they would mention that.
I don't agree with this. To my knowledge, it CAN correct for these erroneous readings to a point. And when you pass that point, THAT'S when you get your CEL. "Limp mode" is different for different problems. I'm not exactly sure what the computer would decide to do in an extremely lean situation. I know that it can shut off an injector if the missfire threshold is broken, and it might do something to that effect. But I don't know about that.
Let me first say that I don't know everything about these vehicles, but here's how I understand it. I don't think it's that dumb. I think that it CAN sense that the conditions have changed, such as a new intake. Because under closed loop conditions, it would recognize the deviation from stoich, and it would adjust the fuel trim corrections table. That's why I suggested that you remove the battery cable for a while to allow the PCM to forget its long term fuel trim corrections, and hopefully build a new table that would account for his intake. But if the new intake caused a lean condition that exceeded the acceptable values (25% or 20% or whatever for fuel trim corrections) it would set P0701 or P0704. I don't see how it could be lean and not detect it. I also don't see how it could go into "limp mode" and not set a code for something.
If I remember right, the computer can detect rapid deviations from the fuel trim corrections table, (maybe 5 or 10%) and recognize those as a malfunction. (such as an intake change) even though they don't surpass the calibration threshold. That's why I suggested removing the battery. By deleting the long term fuel trim corrections table, it gives a greater range of "short term adjustability"...

My manners?!
I thank you for your kind explanation of you sentiment. I also thank you for you kind explanation of the intake diameter, and the transfer function. Which I was not aware of. I don't know that much about custom tuning, so when facts are put on the table, everybody can learn. Oh, and I assure you that none of my knowledge of these trucks/tuners came from wikipedia.

I will not refute facts. If I'm wrong on anything I said, please correct me, as I am working on old knowledge...

 

Hi Chester.

OK - I think we should just stop here & agree to disagree.

You are lacking a fundamental piece of conceptual understanding, and it's a hole I've failed to fill.

In a nutshell - the PCM cannot make accurate decisions based upon bad data.

The transfer function is fixed in the pcm - it can only be changed by programming & it is the key to it all - EVERYTHING follows from that. If it no longer represents what the intake looks like, if it is outputting incorrect A/F's, then it's producing bad data, which the PCM still believes to be true, but isn't. There has to be a trusted reference, and that's a big one.

Sorry, but I'm done. Lord knows I've tried. Perhaps the collective brain trust of real experts who frequent here would care to take up the cause. What do I know, anyway?

Me? I'm gonna go solder something - I need a hit of those fumes Then I'm gonna go out and kill another chebby.

Chester - I wish you well & remember, anything can be taken out of context to twist it into something it's not. You are not an idiot. And 'The Disclaimer' was in the spririt of a joke, nothing more.

Cheers
Bubba the Windbag

 

I know it may have seemed like argueing to some, but I found it to be very informative. Thanks.

Am I right in assuming that during normal driving the pcm adjust the fuel air mixture accordingly, (assuming all sensors are working properly). Yes?

During WOT, the PCM is set to a particular fuel air mixture that is not adjustable regardless of inputs received from the various sensors. Yes?

Thus the problem with aftermarket intakes is that not only are the sensors not placed properly in the tube (in some cases), but the PCM has not been adjusted accordingly for the increased air flow during WOT. True?

Sorry to drag out the thread, but just trying to make sure I understand what being said here.

 

Yes. To a point. And at if you cross that point, you get a CEL.

Not exactly sure. The mixture is supposed to go very rich, which *might* be ford's way of taking all variables into account. Also, a lean condition might not be of consequence over the short duration of a WOT run. As I understand it, the main reason that the PCM commands rich on WOT is so that it can safely advance spark without fear of pre-ignition. But I'm not sure about that. Not to mention the fact that it keeps down EGT's. I don't remember reading anything about the PCM adjusting WOT fuel delivery based on "modifications".... It might, or it might not....

We're gonna need Mr. Troyer for this one....

According to them, the MAF mounted inside a sensor housing that is larger than the stock one, so the MAF readings are erroneous at all rpm's. That's the part that I don't understand.

ME TOO! Argumentative or not, a lot of info has passed hands here.

 

O2 sensors. They don't care what kind of intake you have. The PCM adjusts the fuel tables from the O2 readings..... It's only when you exceed it's "margins of safety" that you get a CEL. Or at least that's how I see it.
We need Mr. Troyer!

 

well for the most part. even though most will believe that it is not true. i think that all cold air intakes should be able to be installed without having to tune the truck for damage not to occur. if it were true then it should state so on the website or the box. as for the CEL;s. all trucks even though created equal are not. every truck out there even with the same mods is going to run a little different.

 

Ya nailed that one. I agree.

Just talk to anyone that races. 2 identical vehicles will perform differently under different conditions. Soooo many variables.

The bad thing is that we read about a few people having trouble with a mod, and myself included, assume that all the mods of that type are bad. could just be bad production, not enough r&d, the altitude, or any number of weather conditions. I'm sure that thousands of intakes have been installed that have not thrown a code. Same with exhaust. some say you lose low end torque, some say not. Again I think it depends on how the vehicle is driven, other mods, tire size, gear ratio, etc. Ya just never know.

But it sure is fun playing around with it. That's what it's all about.