# Tricking the MAF?



## JSK (Oct 15, 2003)

A friend who used to have an older (91 or so) gen Eclipse turbo told me he messed with the MAF sensor. Forgot exactly what he did, but it supposedly tricks the motor into feeding it more air?? I don't exactly know how it works or if i'm saying it right, but he's not only the only person i've heard from who does it. I've seen it here on vortex not too many times.
Is there anything we can do or is this all bs?


----------



## 94jetta~~ (Feb 22, 2002)

*Re: Tricking the MAF? (JSK)*

i think it has something to do with sticking a resistor in line somewhere with the MAF so that it thinks the air comming in is colder than it actually is, so it bumps up the fuel a little. not exactly sure though


----------



## Checkpoynt Charlie (Aug 4, 2004)

When you do that, you're going to be running rich on fuel. That will lead to some bad things happening, such as destroying your catalytic converter, fouling your spark plugs, and bad gas mileage.
Intake manifold sensors are usually the ones plugged with a resistor, but I'm sure the MAF could be done also.


----------



## tdogg74 (Mar 1, 2002)

*Re: Tricking the MAF? (94jetta~~)*

You two need to stop listening to your friends and stop shopping on Ebay. You're gonna wreck your engine....
The MAF sensor converts the amount of air drawn into the engine into a voltage signal. The computer needs to know the intake air volume to calculate engine load. Our MAFs have a thermistor that maintains the sensor at a specific temperature. The rate of incoming air is measured by how much heat loss occurs withing the sensor as the intake air charge passes over it, and the ECU compensates by sending more voltage to the sensor to maintain "nominal" temperature. 
Now, for arguments sake, I can see what putting a resistor online with the MAF and ECU would do, but you have to take into consideration the downside would be. By tricking the ECU into thinking its running colder, it will add more fuel. So now if its like 85'F + degrees outside, and under your hood is even hotter (running an open element CAI) you engine will be "tricked" into thinking that its drawing in colder air, which leads to richer A/F condition, which also leads to a more advanced ignition timing, which then leads to pre-detonation because its not really colder out. Hot air is less denser than cold air, therefore hotter air has less oxygen in it. See where Im going with this? 
The only way to safely "Trick" the MAF is to have a true cold air intake that is away from the hot engine. Trus me, the minimal gain is NOT worth the damage that results. 


_Modified by tdogg74 at 11:37 AM 1/23/2005_


----------



## bearing01 (May 27, 2004)

*Re: Tricking the MAF? (tdogg74)*

Listen to tdogg on this one.
The MAF is actually a self-contained unit that has feedback to control itself. The incoming air mass cools a hot-wire and the circuit feedback increases the current in the wire to increase it's temperature - keeping the temperature relatively fixed with respect to the ambient temperature. The voltage the feedback circuit is using to create temperature is the signal that goes back to the ECM and this voltage is proportional to air-mass that cools the wire.
If you are experienced with electronics then you could design an op-amp circuit with variable gain to condition the MAF output voltage to vary more than the MAF signal voltage actually varies. However, I believe any performance gains may not be worth the reduced drivability you will get during other conditions like cold start for example. It's not really worth it.
There is no simple trick like putting a resistor in series with something.
AND there is no trick to get the MAF to pass more air. To do that you need the engine to pass more air... or you need a forced air system.


----------



## tdogg74 (Mar 1, 2002)

*Re: Tricking the MAF? (bearing01)*


_Quote, originally posted by *bearing01* »_
Listen to tdogg on this one.
The MAF is actually a self-contained unit that has feedback to control itself. The incoming air mass cools a hot-wire and the circuit feedback increases the current in the wire to increase it's temperature - keeping the temperature relatively fixed with respect to the ambient temperature. The voltage the feedback circuit is using to create temperature is the signal that goes back to the ECM and this voltage is proportional to air-mass that cools the wire.
If you are experienced with electronics then you could design an op-amp circuit with variable gain to condition the MAF output voltage to vary more than the MAF signal voltage actually varies. However, I believe any performance gains may not be worth the reduced drivability you will get during other conditions like cold start for example. It's not really worth it.
There is no simple trick like putting a resistor in series with something.
AND there is no trick to get the MAF to pass more air. To do that you need the engine to pass more air... or you need a forced air system.

http://****************.com/smile/emthup.gif 
BTW, I like your sig.....


----------



## greyhare (Dec 24, 2003)

*Re: Tricking the MAF? (tdogg74)*

Resistors across the MAF are used to "trick" the ECU into thinking the air mass flow is higher or lower than it actually is.
This is normally used as a band-aid for larger injectors. Some people think it is cheaper than proper ECU tuning.








It is a fixed offset value that may allow the car to idle and may work at part throttle but, will probably be detrimental at WOT.


----------



## 94jetta~~ (Feb 22, 2002)

*Re: Tricking the MAF? (tdogg74)*


_Quote, originally posted by *tdogg74* »_You two need to stop listening to your friends and stop shopping on Ebay. You're gonna wreck your engine....
_Modified by tdogg74 at 11:37 AM 1/23/2005_

whoa, whoa... i never said i did this or that i plan to, or even that i agree with it. I heard it mentioned on here a few times, so i thought i'd let him know what i have heard.


----------



## D4V3 G60 (Jan 22, 2005)

*Re: Tricking the MAF? (94jetta~~)*

yeah, stay away from those EBAY resistors... no go0d


----------



## bearing01 (May 27, 2004)

*Re: Tricking the MAF? (greyhare)*


_Quote, originally posted by *greyhare* »_Resistors across the MAF are used to "trick" the ECU into thinking the air mass flow is higher or lower than it actually is.
This is normally used as a band-aid for larger injectors. Some people think it is cheaper than proper ECU tuning.








It is a fixed offset value that may allow the car to idle and may work at part throttle but, will probably be detrimental at WOT.

I can see how this could work on a vane air-flow sensor since the vane sensor is just a variable potentiometer (variable resistor) that changes value as the vane swings open. Putting a resistor in parallel with the potentiometer would have an effect. I'd be suprised... very suiprised... if you put a resistor in parallel with a MAF you'd get a difference in signal. Maybe you'd load the driver in the MAF and cause it to burn out -> $300/down drain.


----------



## bajan01 (Nov 26, 2001)

*Re: Tricking the MAF? (bearing01)*

I have a question then. Suppose you want to run a larger throttle body...say one from a VR6 on an ABA. Do you run the stock 2.0L MAF within the now larger intake tubing from the VR or run the VR MAF in the VR tubing? The goal would be to not have to switch over to stand alone


----------



## JSK (Oct 15, 2003)

*Re: Tricking the MAF? (bajan01)*


_Quote, originally posted by *bajan01* »_I have a question then. Suppose you want to run a larger throttle body...say one from a VR6 on an ABA. Do you run the stock 2.0L MAF within the now larger intake tubing from the VR or run the VR MAF in the VR tubing? The goal would be to not have to switch over to stand alone










I believe the VR6 throttle body does not fit. I would have done it already if so.
Let's just end this thread.










_Modified by JSK at 12:04 PM 1-24-2005_


----------



## diablo7877 (Feb 11, 2004)

*Re: Tricking the MAF? (bajan01)*


_Quote, originally posted by *bajan01* »_I have a question then. Suppose you want to run a larger throttle body...say one from a VR6 on an ABA. Do you run the stock 2.0L MAF within the now larger intake tubing from the VR or run the VR MAF in the VR tubing? The goal would be to not have to switch over to stand alone









Well, I would think that with a larger throttle body, and I'm assuming a larger intake tube (a big bore or somethin else), and a higher flow filter you would want a larger MAF just so that it flows better and can detect more air flowing in... And when you do that, might as well get a high flow intake manifold too and then you'll be golden, ha ha. http://****************.com/smile/emthup.gif


----------



## Fast2.0L (Oct 12, 1999)

*Re: Tricking the MAF? (diablo7877)*

I used to run a MAF sensor from a Mustang GT, they have the same voltage range but you must build an adjustable amp circuit since your voltage will be a lot less. I hooked up a scope watched the stock MAF in a few different temps and then hooked up the Mustang MAF and matched it up as close as I could.
The throttle body swap isn't too hard either, you just need to cut the mount or make your own off the VR6 manifold. The TPS has the same range but really you'll be feeding almost the equivalent of full throttle at like 3/4 open on the VR6. When I used a ported throttle body on my engine I ended up with an On/Off switch, there was a very small range for partial throttle.


_Modified by Fast2.0L at 1:16 PM 1-24-2005_


----------



## bajan01 (Nov 26, 2001)

*Re: Tricking the MAF? (JSK)*


_Quote, originally posted by *JSK* »_I believe the VR6 throttle body does not fit. I would have done it already if so.

You are correct in saying that the VR6 TB won't fit on the stock ABA intake...but my intake won't be stock for much longer
















Just want to know how to go about tuning without having to choke the intake back down to the stock diameter with the stock ABA MAF










_Modified by bajan01 at 9:00 PM 11-25-2005_


----------



## CL111583 (Mar 21, 2003)

*Re: Tricking the MAF? (JSK)*


_Quote, originally posted by *JSK* »_A friend who used to have an older (91 or so) gen Eclipse * turbo * told me he messed with the MAF sensor. Forgot exactly what he did, but it supposedly tricks the motor into feeding it more air?? I don't exactly know how it works or if i'm saying it right, but he's not only the only person i've heard from who does it. I've seen it here on vortex not too many times.
Is there anything we can do or is this all bs?
 
everyone here seemed to miss the key word, that being turbo.
So in his application it works fine, he does it to attempt to prevent the car from leaning out at higher than stock boost settings.
In our 2.0 NA settings (or Vr, doesnt matter, as long as its all NA) then you wouldnt have or need a reason to run any richer than what your chip is set at.


----------



## vdubstreets (Apr 26, 2004)

*Re: Tricking the MAF? (ChadMk3)*

My MAF is running rich, i get shi*ty gas milage, its running hott and NO extra power. so no thats a bad idea and im looking to get it replaced with oem soon.


----------

