Removing the MAF without a CEL (ODB-II)
#21
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it's my understanding the the MAF signal is a 0-5v signal. the voltage drops as air passes over the heated sensor. As long as the ecu sees a signal on that input, it shouldn't throw a code. but it's a guess. im assuming it would want to see something less than 5v as well, then it would know the sensor is failed.
#22
I can test this out for you guys on an NB.
Though I need a O2 simulator to trash my rear O2, it's throwing a CEL right now.
EDIT: Might try this http://www.mkiv.com/techarticles/oxy...sor_simulator/ unless you all know of something easier.
Though I need a O2 simulator to trash my rear O2, it's throwing a CEL right now.
EDIT: Might try this http://www.mkiv.com/techarticles/oxy...sor_simulator/ unless you all know of something easier.
#26
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all the stim does is send fake signals to the megasquirt so you can make sure it's operational. that's it. it requires removing the db37 harness, in that case it will not manipulate any of the signals to the car.
#27
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Why cant I make a megastim like device, maybe even use the megastim itself, to provide the factory ecu with the proper signals? Lets make it even simpler, we can use a real MAF and EGR Valve to simplify the whole emulation procedure. Why cant I build a computer program for example that will emulate the car, after all the ECU is just another computer.
I am sure im not the first to think about this.
#29
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According to arkmage, the only other problem he see that may be a problem is the second O2 sensor which calculates a differential from the first O2 to judge health of the catalytic. Now, we are providing the ECU a fake signal that the car is always running properly. The computers calculations would theoretically be off if the second o2 is still providing a true signal.
Two big question though, which will silence me if answers are right.
Just because a car is turbocharged, or supercharged that doesn't necessarily mean that it works outside the normal emissions parameters. Therefore we dont have to worry about the second o2 sensor no calculating properly. That would also mean that the LC1 isnt being programmed to display untrue readings.
Is there anyone, anywhere, passing inspection on a modified OBD2 car who is using a standalone to run fuel and spark?
#31
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I meant in tandem with the factory ecu.
But for the sake of this thread lets discuss a way to emulate the car so the ecu can pass without it.
If I had a wiring harness out of a miata I would already be trying to test this on a bench.
But for the sake of this thread lets discuss a way to emulate the car so the ecu can pass without it.
If I had a wiring harness out of a miata I would already be trying to test this on a bench.
Last edited by Saml01; 11-02-2007 at 03:47 PM.
#32
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if your two problems are the MAF and rear o2, i dont see why you're making it so hard on yourself. test with the cat and MAF installed.
the rear is just there to simple verify the cat is working, so it's probably making sure the voltage stays within .02v-.08v. something like that.
and you know my thought on the MAF signal.
the rear is just there to simple verify the cat is working, so it's probably making sure the voltage stays within .02v-.08v. something like that.
and you know my thought on the MAF signal.
#33
I borrowed an oscilloscope from work today, so if I get time Sunday I'll verify if the OBD2 MAF is a simple linear voltage, or a PWM output. Most OBD2 air meters output PWM so I'd be surprised if it's linear.
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