If you were to increase the flow across the MAF sensor what effects would it have over the numerous interlinks (injector volumn, EGR valve position, timing etc.) in the PCM?
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If you were to increase the flow across the MAF sensor what effects would it have over the numerous interlinks (injector volumn, EGR valve position, timing etc.) in the PCM?
Surely someone has some idea of what would occur.
It will defuel sooner. The actual air volume would be less than the perceived, so it would "think" it has too much air for the fuel/power output. EGR position would not likely be effected much, if any, but could go nuts 'cuz the output doesn't match the input. It's a delicate balance, and if you lie to it w/o computer intervention, it'll throw a fit (SES, limp, etc.).
Bad idea.
It is not clear to me what you mean by 'increase the flow' across the sensor ? ?
Do you mean that you would somehow 'trick' the sensor into sending the same signal it does now at higher flow rates? Why would you ever want to do that?
The MAF is a Mass Air Flow sensor - it corrects for changes in air density due to humidty, altitude, and temperature to give an accurate measurement of the mass of air flowing [Kg per minute, etc.] in order to meter the proper amount of fuel through the injectors to maintain the correct air-fuel ratio.
If what you mean is to physically increase the flow by removing restrictions, etc. then there should be no problem as long as you do not exceed the range of air flow that the MAF sensor was calibrated for. Not all sensors are universal - many have upper and lower limits, too high or too low and you will not get accurate readings.
The MAF is one of the crucial inputs to proper fueling of any engine - it would be the last thing I would ever mess with.
I don't understand how if it is reading more air that it would defuel, that sounds backward but that is why I'm asking------I don't know how it all interacts, but would like to learn.Quote:
Originally Posted by DmaxMaverick
Does it not effect the timing?
This post actually stems from another "LBZ Hot and Loss of Power", in which there were some good responses but not a lot of direction for what to do to find out what was causing such a loss of towing power.Quote:
Originally Posted by jmoser
One response from a Banks Tech led to a phone conversation with same; and the basic recomendation was to relocate the MAF. He said that Banks had had some problems with their intake system in developement and found that when they located the MAF in the bend just before the turbo tract, and on the outside of the bend that they found good power gains and also found that the EGR valve pretty much stayed closed all the time.
Fact or not I though it was something to check out and try; if I could get any other insight that seemed favorable.
The position of the MAF on my LBZ (others too I assume) is on the inside of the first bend past the filter box. In this position the main velocity of course is on the opposite side of the intake tube; as with any hydraulic action the inside of any bend has a lower velocity than the outside. Depending on the configuration a vaccum can actually occur on an inside of a bend at some flow rates. (In chill water systems sometimes to the exent of air pockets and pump cavitation given the right proximity.)
In any case it seems that Banks by their repositioning has increase the flow at the MAF dramatically. How does that work?----and is it possible that this could actually effect the EGR. Seems that the consenses here is that it could not.
I'm still looking for the power loss----Killer Bee says I'm on a ghost hunt!!! But this ghost sure has some real power drawbacks---hot too.
MAF is one the better inventions for a motor. The old speed density computers back when fuel injection first came out where a table of set values that couldn't take into account environmental conditions. Those motors were hard to add performance to since back then it was hard to rewrite the ECU tables. (OBDI was the only game in town).
Now, MAF is much better because it allows the motor to dynamically change to the environment. Messing with that signal will either cause a LEAN or a RICH Condition. More Air = More Fuel, so if you trick the MAF to report more air than is going in, then you will have RICH condition, although the 02 sensors will rat out the MAF and the motor will DEFUEL to compensate for the mixed signals. This can cause a surging motor because the MAF and other sensors are battling each other.... Same thing can happen if an onxygen sensor is going bad.
So how does that relate to what Banks is doing in their relocation which obviously places the MAF in a much higher flow area and their claim of the improvement in power. That said, Banks is pretty well known for being effiency minded which would be contridictory to the more fuel added equation that should play a major role adversant to that end.Quote:
Originally Posted by Dakster
If I recall, BANKS is more than just "messing" with the MAF. It is just part of the whole equation in how it relates to the engine management system (stock or not) that creates "more power." Since, I do not know about the Banks system you are talking about it is hard for me to get specific as to why/what they are doing. Although, knowing Banks kits, I would assume that it is more involved then just moving a stock MAF to a better place - although I could be wrong.
Easiest analogy I can think of help you. On a gasser with a distributor. The factory sets a specific timing that is realiable, dependable. You can gain a few HP (5-10 depending on motor) by advancing/tweaking the timing. Advance too far and you get denotation and pinging. Take that to MAF, you can gain some HP by tweaking it tricking the motor to squirt more fuel. However, tweak too much and you get driveability and computer issues.
Actually that is what Banks recommended that I do. After talking about my intake modification (stock air box with and additional 3" air source that draws thru the recovery hook hole) they said that I was probably getting as much air as what their cold air intake kit was getting. They said that their original design had the MAF located just past the air box as with the stock set up. They were having problems with the EGR staying open so started trying other MAF positions. When they located it in the bend just before the turbo tract they found that the EGR valve stayed closed most 100% of the time and they also dyno'd a very good gain in power. I can't see why they would have any reason to be less than honest about it. I feel that they were just trying to help me out because of the higher temps and loss of power that I experienced after installing their exhaust system---good customer support in my estimation.Quote:
Originally Posted by Dakster
Okay; from what input that has be generated here it seems that what Banks has done with the MAF, and what they suggested that I do with mine; is 180 degrees from one another. Now I hope you can see why I asked what effects that increased flow rates have on the MAF. I can't see going to the trouble of making an additional MAF port in my intact if the exercise is overtly futile; not to mention that by doing so with out some sembilance of understanding of the ramifications of the experiment. It evidently works for Banks but how in the world does it work if it is so contradictory to what I have been hearing here on this site. Need some help here!!!
The problem is that in your first post, I assumed that you were talking about messing with the MAF on a STOCK motor. Now that I realize you have "modified" the intake of the motor, you have created a new condition that the motor is running in. This is my fault... Sorry for any confusion I may have caused; however....
If Banks says to move it because their intake likes it there and the motor runs better, what have you got to lose by trying it? You have issues that you are trying to correct and won't know if it works until you try it...
What banks expereinced falls directly in line with what I have been saying all along. Change the amount of air flow or the metering of such and you could have driveability problems. Here you have driveability problems, possibly due to the aftermarket components being more (or less?) efficient than stock. GM is only gonna test and make there systems work on a stock truck, which makes sense.
To compensate for the aftermarket components, Banks, found a spot to mount the MAF that works well... If it was my truck experiencing problems I would be relocating the MAF. Worst case is I either need to buy another intake piece or I have to plug it.
I also understood your question to be about a stock system, and your wanting to shortcut a performance mod.
In your case (and Banks), what likely happened is their intake with the MAF relocated (originally) was decreasing the OEM efficiency of the MAF. Relocating (correcting) it likely replaced what was lost, and it is again more efficient and within its operational window. Taking it outside of it's operational window will wreak havoc with the PCM, as Banks discovered.
Sorry but I think I am more confused than ever. If the MAF is relocated from a position that is in a very low flow area of the intake tract (even possible decreasing flow with tract flow rate increase due to the probable vacumn effect that I pointed out) to a position that is obviously in a much much higher flow area, it would seem that all speculation of the MAF's reaction is out the window. I think that I heard that a de-fueling would be expected with flow increases. Also from what was offered herein I would believe that a very high injector flow rate would be seen if; 'higher flow = more fuel', my feeling is that the flow has to be near doubled over the inside the bend position. There has to be more to it than what is speculated or thought to be fact. Sure seems that the understanding of the MAF must only be within the grasp of the designers-----it sure has this country boy baffled.
Hmmmm.
OK. Consider this.
The OEM system has a known intake pipe diameter, and the MAF sensor is located in a known position within that pipe. Therefore, with some logic, it can calculate the lb/min of air traveling through the pipe. The PCM monitors the air intake volume and temp, MAP, engine load, fuel temp, TP, among others. The PCM calculates what each value should be under given circumstances. If you change one parameter, the PCM will expect to see corresponding changes in others. If any of these parameters are outside of what the PCM considers normal, it will try to correct the perceived problem. One of the first things it will do is defuel. If you operate outside of the PCM's envelope, it will defuel. An increase in air volume alone, without the presence of a corresponding fuel, MAP, or engine load change will be perceived as a problem the PCM will address. Fuel is not metered according to air intake volume alone.
I think that possibly there is still a misunderstanding of my intake; lets give it another try so there can't be any doubt of what it is.
The intake tubing and billows from the air filter box to the turbo is completely stock, no change in any way.
The air filter box is stock, with the exception that forward upper quarter around the deflection vanes is removed to provide a more direct route for the added 3" supply to flow thru.
A 3" aluminum dryer vent is used to transfer air from the air dam hole (where the recovery hook was removed) running up and thru an enlarged hole behind the headlight and then entering the air filter box enclosure.
The original air breathing holes into the fender well cavity were enlarged and provided about 3 additional square inches of breathing area.
Additional sealing was done around the air box to prevent any air from the engine compartment from entering the air box.
Thats it, a pretty basicly stock system; and really, sans the air filter box the Banks intact tract routing and size is pretty much a mirror of the stock system also.
That cleared up--I hope; it seems a very DRASTIC change moving the MAF from an inside bend location (relatively shielded) to a point where it is getting a direct hit, if you will, from the incoming air charge. From what I have learned here that would seem to really drive things bonkers, no? That is why there would seem to be much more to the system than meets the eye or common conception of its scope.
I notice that there are five wires at the MAF so I presume that it is sending out four separate signals to the PCM.
1. Air flow
2. Air temp. ?
3. ??
4. ??
1. More air flow=more fuel -----provided the criteria is met?
If more air flow is detected but load is light what happens?
In a gas engine a lean mixture equals more heat many times, is it the same with a diesel?
2. Air temp ??? what does the PCM do with that, if indeed that is one of the MAF signals?
3. & 4. Can't ask the question because I don't even know what they are or if they exist.
Bottom line is, I don't mind modifing if I've some grasp as to the workings of what I'm modifing----but in this case it is evident that I don't have a clue. Also it might even be entirely on the wrong track toward correcting my elevated EGT's, water temps, and loss of towing power.
Still need help guys!!!!
5 wires. 1 ground, 2 each for the temp and velocity, or something like that. Maybe 1 and 3. I could dig up the diagram, but it's pointless.
If the PCM "sees" more air passing through the intake, it WILL NOT add fuel because of this. It may expedite fueling from idle, if it detects the airflow sooner than OEM. Still, several other input values have to be "seen" before more fuel is added. If the PCM "sees" more air, and can't make sense of it (no other input values changed), it will assume an error.
Changing any part of the intake system can (not necessarily will) change the dynamics of the airflow. Making more air available to the intake by modifying the tract can increase the perceived MAF. It won't, however, increase fueling in and of itself. More fuel is "requested" when you increase TPS input, but you won't get it if all the other input values aren't in line.
Great input that, thanks! Don't know what TPS is though, help.
Another question; what effect do you think that the MAF's orientation to the the direction of flow has on its readings. That is that Banks recommended that the MAF sensor be rotated 90 degrees from its original orientation to the flow in the intake tract. Could that be something that would offset the drastic change in the amount of flow with the new location in the intake tract?
Also does it seem possible that the relocation could make the EGR stay closed?
And one more does a lean mixture in a diesel create more heat as it does sometimes in a gas engine?
TPS - Throttle Position SensorQuote:
Originally Posted by moss6
;)
I guess that makes sense in the relation to the loss of power, as load is increased throttle position has to be linearally greater to maintain a given speed. If flow across the MAF does not correspond then additional fueling is not provided????
I don't know why it would improve a situation by rotating the sensor. Not enough info. I will guess that Banks encountered some turbulence not otherwise persent, and it may present the MAF to the thrust of the turbulence. The MAF design is directional. It could be that the position that makes the problem occur may be too high a volume, and turning it could reduce the perceived volume. Goes back to what I said the first time. I could tell you what the EGR is supposed to do, but can't tell you why it does what it does when it doesn't do what it's supposed to do.
A Diesel engine can't run lean. It can be too rich (excess fuel it can't burn completely), but that's the black smoke that gets expelled. Lean a Diesel, and it slows down. There is no "mixture". There is no controlled restriction in the intake to control the air, other than the later models, but that's for the EGR and DPF, not mixture. #2 does not require the 15:1 like gas. It's variable according to the fuel properties (which varies from kerosene to bunker oil), available heat, injection and combustion chamber design.
Your last statement sounds like you are getting closer to understanding. At the same time, the PCM tracks the air volume trend as well as the given known volume values.
All that said, the engine will run fine with the MAF disconnected. It will be sluggish off idle and lack power, but will still run near normal. Try it. The SES will show up and you'll get a MAF code, but it will still run and respond to pedal input.
Yesterday I bought another intake tube and today installed the MAF as per Banks suggestion. Tube was $75 and a PCV grommet $3 so not to expensive an exercise if it doesn't work.
What I have found:
1. Intake temps. appear to be about 10 degrees lower; at first this made no sense but if the EGR is staying closed it would seem reasonable/possible.
2. EGT'S don't seem to be effected much---if anything I would have to say they are higher??? Again is it possible the EGR has changed; we have heard that the regurgatation of exhaust lowers EGT's.
3. Any black smoke under heavy throttle has disappeared; this is in any setting of the EDGE. Big change from before where you could see black smoke when heavy on the throttle.
4. No perceptable change in power; I'm not surprised at that but surely hope there is a decided change percieved when I hook back up and tow heavy. Before the loss of towing power was experienced I did not experience any feel of loss of power when unloaded.
5. No codes were set.
I'll have to hook up and tow to see if this has worked. As of now my expectations aren't real high if indeed the EGT's are a bit higher; the first thing I noticed along with the resistance to pull the normal gears after the Banks exhaust was installed.
Need someone to tell me what wire and what voltage on the EGR valve to see if its open, closed or in between.
do you have some way of measuring plenum temps? This whole thread, and the other sure has me wanting to go out and by a new set of lawn darts. Are you sure you were talking to a Banks rep? So far, nothing that you refer to banks makes sense to me. Are you referring to IAT? If so, that is measured at the MAF sensor, not the intake, and yes, of course that will change if you mess with MAF orientation (the nuttiest idea yet IMO). But more importantly, is has nothing to do with EGR. Your IAT is the temp of air entering the box, way upstream of any egr interaction.Quote:
Originally Posted by moss6
Lets go back.
If you have the stock tube, and the MAF is in the stock location, NOTHING that you do to modify your intake upstream of the element is going to change your MAF reading. I repeat, nothing.
This whole idea that a free flowing intake will change your MAF reading for a given boost and rpm setting, is TOTAL BS. That is what the idiotic intake manufacturer morons want us to believe, and believe you me, there is no truth to it. "flows more air"? Not a chance.
I'll help clear up MAF tuning in a diesel. If your MAF is down (significantly), whether it be because of a boost malfunction, or MAF sensor degradation, or any other mishap, fuel will be limited in proportion according to a histogram matrix that sees to it. Very simple, not complicated. Oil coating the sensor could be such an event. Oxidation of the hot wire, another.
If you want to check it, just get onto someone with EFILive and log it. You should see 48-58 lb/min airflow (stock MAF location) in 90 degree weather, near 800 ft above sea level, using stock WOT boost settings and 3200 rpm. I will bet you fall into this category.
If you are frustrated try to put yourself in my shoes; and now I have to avoid being impaled by lawn darts! Really if it were your truck, which towed really well with only an Edge Juice with Attitude, and you read all the attributes of adding a performance cat back system and adding some cooler air on forums like this; then put them on your truck only to find that it didn't pull nearly as well and ran higher water and EGT temps. ,what would you do. I came to this forum to try get some help in fixing the problem; plain and simple. I may not be any very good at conveying my thoughts or questions; we all have our limitations; but I try to do the best I can. I don't know what else to offer other than if contributors here really want to help, please try to tolerate some of my lack of expertise.Quote:
Originally Posted by killerbee
Anyway to try to respond to your post:
Yes the person I talked to was a Banks representative and when we spoke he consulted others at Banks for support of the discussion.
As for where the air temp sensor is I don't think that the information is in the Edge literature. One thing is for sure it is not in the intake tube and taken by the MAF because the temp is always at least 25 degrees (a bit less now) higher than the ambient and I have seen it 100 degrees higher than ambient when pulling hard with the current setup. I do not have data on the highs before the cold air and exhaust install.
I am not sure I agree with your statement that nothing you do with the MAF in the stock position can change the MAF reading. I would think that if modifications have in some what hurt power in a high load situation (ie excessive throttle opening position vs normal MAP) some odd things could occur, doknow.
I really don't think the intake flows more air nessesarily, but it is cooler and I have tested on other vehicals and found that modifications can actually lower water column readings in the air box and intake tube locations.
Nearly forgot; I installed the MAF with the orientation the same as stock and have not rotated it to see if there was any percievable change in performance.
Also after stateing that I got no codes my wife got a Mass or volum air flow circuit range performance code yesterday and today. Not sure but something like P0101?? It's cleared now so I can't access it anymore.
I had cleaned the MAF with MAF cleaner after removing the K&N.
I don't have access to EFIlive.
Amazeing to me that you can place the MAF in such a high flow area and see no change in performance; worse or better.
I'd still like to know if you can check the EGR valve position with a volt meter to see if what Banks said is correct about it staying closed.
I'll rotate the MAF tomorrow for grins to see what havoc that provokes.
I'll also call Banks with the results and see what their take is.
I haven't got to call Banks yet, got in too late, but I did get to do some testing on the effects of rotating the MAF sensor. To be honest I really expected this to be a inane exercise so my expectations were pesimestic at best. However the results were highly surprising as well as encourageing.
When I rotated the MAF in an orientation such that the plug in was down stream of the air flow there was a noticeable increase in throttle response and acceleration. The EGT's also showed a decrease and the intake temps were still lower as when the MAF was relocated. Now in spite of all the negative input my hopes are up. At this point I let the computer do a MPG check and that shows that we are doing pretty good there also.
That done I pulled over and rotated the MAF sensor 180 degrees for another try; in that position (plug in end facing upstream of air flow) response and acceleration was futher enhanced and I'm feeling better about things than I have in a good while. I let the computer do it's thing again and MPG still looks good. EGT's are also still noticeably lower as in first position, and didn't even have to let it idle a bit after pulling into the garage to let it get below 400 degrees as has been the norm.
I realize at this point that this is not substantial evidence that the problems are cured, but I am encouraged. It remains to be seen if this will bring back the loss of towing power which was accompanied by the high temps. but I must be optimistic that I'm on the right track. Only the tow will tell.
It is so strange that these results are so contradictory to most of what I have heard. And of course the Jury is still out, with the adapability of the PCM things could go down hill in a hurry; I prey they don't and that I once again can be one happy camper when towing the fifth wheel!
In the mean time I hope that smell that I think I can sense in the air is baked crow.
same as the rest of us. Believe it or not, the MAF is the site of that readingQuote:
Originally Posted by moss6
While im not an expert nor do I claim alot of knowledge relocating the sensor should help because there is more intake air, as has been said if you had a stock system an you tried it the O2 sensor would foul you up by reporting a rich condition, however with more air then normal an it not getting reported correctly the O2 sensor is still fouling you up by now reporting a lean condition? I dont know if that would hold true for a diesel engine or not but that would be one reason I think relocating the sensor would work.
Think about it, 100 degree rise from point of entry thru the filter box and then thru a portion of the intake tube; not a chance.Quote:
Originally Posted by killerbee
Seems 180 from those who know eh.Quote:
Originally Posted by 93GMCSierra
think again. How about a 150 degree rise? Yes. Before the air ever reaches the airbox. I have logged over 240 F.Quote:
Originally Posted by moss6
I am not trying to make this hard for you. I am always trying to help. But if you don't want to hear what is being said, then there is nothing more I can suggest.
This must be a joke; if not I think you just shot down any credibility of your posts.Quote:
Originally Posted by killerbee
Quote:
Originally Posted by killerbee
good luck. As a parting tidbit, consider what happens to MAF when IAT gets to 100 over ambient. I tried.
after reading this I can agree with alot of your points, However from my reading of the posts he has cooler outside air coming in the air box, it should be able to pull enough air to keep that particular problem at bay, an he is not running a lly engine, but a lbz I dont know the difference in them really but I believe that would also make a difference.Quote:
Originally Posted by killerbee
I can't see what Moss6 has, there is no signature despite suggestions to create one. If it is an LBZ, it has an additional IAT reading pre-plenum, IAT2. But who knows which one is being referenced here?
The LBZ stays somewhat cooler, but still gets up to 180 or so at IAT1 (airbox) in this neck of the woods. I have a IAT2 sensor in my LLY, and have documented 240 F. That is under very stressful conditions. Normally it stays under 200.
If there is anyone out there who knows the voltage readings for the EGR valve and what wire to tap on to I'd still love to have the info.
Also I think its good for all of us to know that if we are in need of some good hot water while out in our trucks (for coffee, tea or whatever) all we have to do is stick a cup in the filter box, and bingo you get boiling water!! Whoops, almost forgot, this only works in "extreme conditions" like er driving thru Hell; and I guess you wouldn't be needing that boiling water there anyway---sorry.
Although the truck is running much better now I am still getting MAF codes which I would like to take care of, other than letting the Edge cancel them with each start up. Wonder what effects the Finger Stick would have on that or if it can only be taken care or by remapping which I don't want to go to that alternative. Probably need some help from Kennedy or Finger here. Still need some info in order to monitor the EGR valve position to evaluate the need or not for the blocker plate.
This post seems interesting to me especially since it involved discussions around Bank's recommendations. I installed a Banks Ram Air Intake system and noticed a loss in off the line throttle response. I was wondering if relocating the MAF as required with the Bank's system was the cause of this. I spoke with a Bank's tech and they claimed I should have noticed an increase in throttle response. They have not offered much of assistance in troubleshooting my problem. I was thinking of trying to modify the Bank's system to relocate my MAF closer to where it originally was. If this doesn't work, I plan on removing the Banks Ram Air intake and going back to stock with the K&N. Has anyone had this experience or can give me some advice?
DieselMax403
If you want to try relocating the MAF to a more stock position on the Banks system it is very easy. Just opposite of what I did with the stock setup. Take a 1 3/8" hole saw and on a bench grinder grind down the outside area of the teeth until the OD is about 1 11/32"; this makes a cleaner and tighter hole. Drill the hole where you want it in the air box housing and install a grommet in the hole that will accept the MAF and provide a very tight fit; with this set up you can actually rotate the sensor into any orientation you want in relation to the air flow. I found this orientation thing to change performance pretty dramatically. The grommet I used was by Spectre Performance for 1 1/4" filler hole, I think it was for used as spark plug wire guides???? Sorry I don't have enough of the package left to provide a part #, think the Guy got it from the dress up section at the Auto zone I was at looking for a grommet with an ID hole that was big enough. The fit will bevery tight but that is what you need. Good luck, I'd like to hear about the results.Quote:
Originally Posted by DIESELMAX403
My problems aren't solved yet----still looking and have another Edge on the way---my MAF back to the stock position even though it ran so much better ---I didn't like all the constant coding, and no-one seemed to acknowledge how or why in regards to the power increase, much less have any ideas on fixing the codes with the MAF in such an unorthodox position. Oh well.