MAF Question
Hello Guys, I have a small embarrassing question about my Car's MAF.
I have a 99 miata and i need my maf to work properly for my ECU (Ecumaster DET3). Short story about it: It's a ECU that can make a conversion from MAF -> MAP. I installed the MAP and cut the MAF wire going to the ECU, down (LG/B Wire colour (i guess)). Now the problems. With the MAF connected to the ECU, when i measure the voltage it's all alright ( 1.7v at IDLE -> 4.8V at full 7k RPM ). Now.. if i unplugg the wire from the old ecu and measure the voltage of the sensor it says 7.2 V. At this moment i thought that the wire is broken or something and i removed the MAF from the car. My MAF has 3 wires, GND SIGNAL and 12V. I added a battery to the GND AND +12v, all ok, and when i check the SIGNAL comming from the maf it says 7.2V. Even if i blow on it or put a fan on it, that damn thing does not change... For my ecu to make the conversion i must have the maf working good outside the car becouse the MAF signall will enter in the ecu (DET3) and DET3 will output a given voltage to the original ECU. The Question is WHY? why does my MAF have a good output only when connected to the OLD ECU ? What is simulating the ECU ? How can i make it work normal outside the car (not connected to the ECU). I made a lot of research and i couldn't find a answer. I want to make it work like this: MAF FORUM POST Why that MAF is working outside the car and mine not. I guess my MAF is not broken becouse it would not start without it, and it's values are ok, i guess (car running good, maybe a little rich). Thank you in advance and sorry for my language. P.S. I don't want to change it unless it's truely broken and please don't tell me that the ECU will change IGNITION timing if i change the maf, the DET3 will handle it, i know this :) I draw a scheme: MAF DRAW *Could it be a frequency MAF ? |
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@Joe Perez any idea?
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* here i connected it to a +12v supply and the signal wire (middle) shows 7.2V :) https://cimg8.ibsrv.net/gimg/www.mia...33d56b102.jpeg |
I found the same thing. I believe there is a pull-down resistor inside the ECU that scales the signal. Haven't tried it myself but someone mentioned that they did that to get it working on another forum. Was a 1k resistor from memory.
You could always probe the OEM ECU to work out if there is one and what the value is. |
Originally Posted by Barton
(Post 1527137)
I found the same thing. I believe there is a pull-down resistor inside the ECU that scales the signal. Haven't tried it myself but someone mentioned that they did that to get it working on another forum. Was a 1k resistor from memory.
You could always probe the OEM ECU to work out if there is one and what the value is. Thank you. *but the thing is that the 7.2v does not change and i know that a resistor it pulling out the voltage. But if for example i pull down the voltage from 7.2v to 1 or 2 it will not change if o blow air on it either. I guess. |
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Originally Posted by Barton
(Post 1527139)
Damn, thank you very much. I will try this today. Thanks a lot. I posted on the other forums and nobody knew anything about it. Will return with feedback |
Originally Posted by Barton
(Post 1527139)
I've just tested, it works very good. I don't know if the values are good, if anybody have a table with the voltage of the maf on a given RMP will be very nice for me. Thank you again! |
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