Discuss confusion around "calibrated" MAF's on AllFordMustangs.com, the place for Mustang enthusiasts.
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Now how does it make this voltage in the MAF? It is made by a small wire that heats up when air passes over it. The more air, the more heat, the more voltage it sends to the ECU.
This isn't accurate, or at the very least not written properly. The wire is heated to a constant temp, 200 degrees C above ambient air temp. Please notice that it's constant relevant to ambient air temp. It's not a constant temp And there are two wires not one. One wire is not heated and this gives the ambient temp of the air passing through the MAF. The other is heated and it the comparison between the two that gives the data needed to send the proper signal to the EEC.
Some early fords and some mazda used a vane type maf and other mazdas used a heated resistor but what I wrote is true for most fords and their relatives.
As for the voltage output. The max voltage the MAF can output is 5volts but it never reaches that level in normal operation. For example at 60 mph an MAF will output about 2 volts.
If one really wants to understand how Ford EFI system function one should buy, and read, "How to Understand, Service and Modify Ford Fuel Injection & Electronic Engine Control" by Charles Probst. It's a great book and covers everything you might ever need to know about ford EEC-IV EFI systems. And this book does state that when you change the injectors you need to calibrate the MAF for that injector size. This means that the voltage that is returned to the EEC is a factor of the change in air temp and the size injector the MAF is calibrated for. This is why you need to have a calibrated MAF. Yes the voltage that an MAF produces just effects the pulse width to the injectors. But it does not mean that all MAFs will deliver the same voltage for the same amount of air flow.
Am I clear? I'm not sure if everyone understands what I wrote.
hey guys. im new to the site, so bare with me. i just bought an 88 gt that supposedly has a 347 stroker in it. it is still speed density though and i am in the process of the conversion. it also still has 19# injectors, but a sizable cam. the car runs like crap and i was advised that it needed it done. i have an A9L comp. lined up and a buddy of mine gave me a MAF from an 01 gt. now, will i be able to use this when i finish the wiring if i get the OBD1 to OBD2 adapter? and does anyone know if this MAF is calibrated for 19's??
thanks shaker. now my next question. the MAF i have from the 01 GT has a 4-pin sensor also. so am i good to go? and does anyone know what size injectors 01 GT MAF's are calibrated for?
Hi,
You are correct in stating that your explanation is an over simplification of the communication process between the ECU and the MAF. Not wanting to be disrespectful, I would like to say that your explanation isn't that far off the mark, and I hope that I can be as thorough as possible without presenting useless jargon that will have eithe little or no impact on helping the Mustang community to increase their performance level.
First of all, I've made it know that I'm one of the old gizzers in this forum. What I haven't stated is that I'm an electrical design engineer; in fact, one of my designs currently is in the AWAC's. My specialty is microprocessor design within the high tech community. Enough about my credentials, because the purpose of this thread is to add to the knowledge base of what as been presented by the author that started this discussion. I will try to make my comments as brief as possible (starting to fall asleep).
The author is correct about the signal that between the MAF is voltage based; however, what is significant in his explanation is that a "pulse" is sent from the MAF to the ECU. Within this pulse is intelligent information that both components understand, based on the feedback from the MAF, the ECU compensates how much additional fuel is needed to optimize the fuel to air ratio. However, a stock ECU has been programmed to limit the amount of fuel that can be delivered to the injectors, because of emissions requirements.
Sorry to say guys, I'm just too tired to continue, but will pick up this thread as soon as I can. However, before you get the idea that I'm one of these wealthy engineers, I can assure you that isn't the case, since many jobs like mine have been move overseas. Another point that I would like to make is that, in a past life (pun indented) , I worked as an auto mechanic, and was known for my ability to tune carb based engines by ear. Then affordable EFI came along, and the rest is history. The author of this thread (still too new to the forum to figure out who's who) spoke of a 90mm MAF? This would be a perfect upgrade for my 408cui motor running 120 lb injectors, which still passes emissions in the Denver area (running E85), and pulls wheelies in 1st and 2nd gear with street slicks.
More to follow.
UBie
Last edited by UBie; 04-27-2008 at 05:37 AM.
Reason: Gramatical errors found after posting
I spoke with a tech over at mass-air.com and he told me as long as i am running the 93 cobra computer that having the 24# injectors and a stock mass air sensor for 19# injectors (except ones starting with an E8 in the model number it is from a cali emissions car) would work fine.
He stated that ford programed the 93 Cobra computer for 24# injectors and for the Cobra computer to use the 19# mass air to do it, so for example i took the mass air modual out of a 91 gt, put it in a 70 mm mass air and connected it to a 93 cobra computer and installed my 24# injectors and he said that that would work perfect. and it does run well.......
it i believe is still a little rich and thats from the B303 cam...
thats all i know.......
hope it helps some one
__________________
1988 GT Hatchback, 5 speed, BBK Headers, BBK H-pipe, Flowmasters, 3:55's, Subframe Conecters, Underdrive pulleys, BBK Cold Air, 65mm throtle body, 70mm TB spacer, 70 mm Mass air, 93 Cobra ECM, Mass-Air Conversion, 24 lb injectors, B303 cam, ported and polished upper and lower intake and ported and polished heads, heads shaved, total rebuild.
this was the old time....
1/4 mile..... 14.10 @ 95 MPH before i went into the motor.... on street tires.......
I spoke with a tech over at mass-air.com and he told me as long as i am running the 93 cobra computer that having the 24# injectors and a stock mass air sensor for 19# injectors (except ones starting with an E8 in the model number it is from a cali emissions car) would work fine.
He stated that ford programed the 93 Cobra computer for 24# injectors and for the Cobra computer to use the 19# mass air to do it, so for example i took the mass air modual out of a 91 gt, put it in a 70 mm mass air and connected it to a 93 cobra computer and installed my 24# injectors and he said that that would work perfect. and it does run well.......
it i believe is still a little rich and thats from the B303 cam...
thats all i know.......
hope it helps some one
You should have used a 70mm 93 Cobra MAF Meter to match the Cobra EEC and the 24# Injectors.
ok, so i have a C&L 73mm Mass Air Housing and 24# injectors, i will beable to take the stock senor off the stock housing and put it on the C&L and not have a problem?
ok, so i have a C&L 73mm Mass Air Housing and 24# injectors, i will beable to take the stock senor off the stock housing and put it on the C&L and not have a problem?
that is the idea.
__________________
Sr. Master Ford nerd.
saludos caballeros del ovalo azul
Ok I now have a better understanding how the MAF works but still does not answer a few of my questions. I have a 1990 Mustang GT with DSS Pro Bullet 331 Stroker, aggressive cam (I do not know the #, have to look it up) and Kenne Bell Supercharger @ 12# of boost. Now I have 42# injectors, Trick Flow Fuel Rails, Aromotive Fuel Regulator, and Vortech 42#/80mm MAF. I was thinking that I still needed to get a new chip for the car to recognize my configuration because if I mash on the petal, she spits like not getting enough fuel. But if I gradually get into it, its fine. So my questions are:
1: Do I have a bad MAF (I called JPC Racing and they told me to get a P&M MAF and that I should not need the computer to be reprogrammed) 2: How much pressure should my Fuel Regulator be at idle vs peak RPM? 3: Should I get a new chip so it can be configured for my application? (Summit can build one to your application) 4: Not sure this is related but if I try and increase the pressure on the Fuel Regulator, one of the L adapters that connects the braided hose to the fuel rail comes loose and i get a small fuel leak. It is back near the firewall under the supercharger.
__________________
1998 Mustang GT, 5.1 Stroker/311cu in, Fordged Internals, Alumium block, Patriot Heads, NX Plate system with 100 shot, Trick Flow plumium, long tube headers, Xpipe, SLP Loud Mouth exhaust, coil overs, sub frame connectors, upper and lower controls arms, Ashburn Locking Dif, 3.73 Weilds, M/T street slicks, M/T skinnys up front, Pro Motion T45 Tranny, Zoom Stage 3 Clutch and Custom Tune laying down 600RWHP.
Last edited by 90 Stanger GT; 06-03-2008 at 03:21 PM.
Reason: updated with updated info
The C&L meters have sample tubes that can be swapped. The different sizes allow more air to pass over the wire, cooling it. The computer compensates and uses that to correspond to the injectors.
So if I bought the C&L kit for 24 lb injectors I don't need to buy a calibrated mass air flow sensor? I can use the stock sensor that was designed for 19 lb injectors?
__________________
1979 Pace Car – Use to have a bunch of goodies......sold them all to buy a house. She'll be alive again.
1989 GT - DSS 331 short block, Eibach Sport line springs, Magnaflow CBE, Pypes Headers/mid pipe, Trick Flow Twisted Wedge Heads & 1.6 rockers, Cobra upper/lower, 24 lb inj......so on and so on...
Ok I now have a better understanding how the MAF works but still does not answer a few of my questions. I have a 1990 Mustang GT with DSS Pro Bullet 331 Stroker, aggressive cam (I do not know the #, have to look it up) and Kenne Bell Supercharger @ 12# of boost. Now I have 42# injectors, Trick Flow Fuel Rails, Aromotive Fuel Regulator, and Vortech 42#/80mm MAF. I was thinking that I still needed to get a new chip for the car to recognize my configuration because if I mash on the petal, she spits like not getting enough fuel. But if I gradually get into it, its fine. So my questions are:
1: Do I have a bad MAF (I called JPC Racing and they told me to get a P&M MAF and that I should not need the computer to be reprogrammed) 2: How much pressure should my Fuel Regulator be at idle vs peak RPM? 3: Should I get a new chip so it can be configured for my application? (Summit can build one to your application) 4: Not sure this is related but if I try and increase the pressure on the Fuel Regulator, one of the L adapters that connects the braided hose to the fuel rail comes loose and i get a small fuel leak. It is back near the firewall under the supercharger.
My issue was that I had my fuel lines crossed...LOL!
__________________
1998 Mustang GT, 5.1 Stroker/311cu in, Fordged Internals, Alumium block, Patriot Heads, NX Plate system with 100 shot, Trick Flow plumium, long tube headers, Xpipe, SLP Loud Mouth exhaust, coil overs, sub frame connectors, upper and lower controls arms, Ashburn Locking Dif, 3.73 Weilds, M/T street slicks, M/T skinnys up front, Pro Motion T45 Tranny, Zoom Stage 3 Clutch and Custom Tune laying down 600RWHP.
, I worked as an auto mechanic, and was known for my ability to tune carb based engines by ear. Then affordable EFI came along, and the rest is history. The author of this thread (still too new to the forum to figure out who's who) spoke of a 90mm MAF? This would be a perfect upgrade for my 408cui motor running 120 lb injectors, which still passes emissions in the Denver area (running E85), and pulls wheelies in 1st and 2nd gear with street slicks.
