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Mazda 6 GG Facelift ECU to Throttle Body Wiring

1623 Views 1 Reply 2 Participants Last post by  jovanzac
I have a strange issue with a throttle body. The communication with the ECU may suffer somewhere. Why i think like that? The input is ok and the body gets all the signals to control the valve but the return data is incomplete. It returns only two stages of voltage eather it gets 10 percent (5 with the old body) and 80 at slightly increase.
So there were a thery and i already gathered the wiring diagrams for it and i think i will get the connectors for it to. Planning to do full rewire to the ECU directly and eliminate possibility of wiring harness where hacked somewhere in the middle.
My old friend before i do that told me to to just use the ecu pinout and try to messure the voltage comming to the ecu in general and see maybe there is a problem with the ecu not the body or harness. That is a wise suggestion and when i will get a chance i will try to messure that.
I have an older question about that, wanted to get any suggestions but i see this is a rare problem and it is uncommon in here to talk about the wiring and diagnose problems.
I am a IT engineer for more then two decades and comming to a problems from diagnose>analize>fix perspective and this is how i do everything. I bought a car that had weard problem with the power loss so i diagnosed whole injection system and what signals is used to messure the fuel mix. There is two main components: air and fuel. The fuel injectors works perfectly and the fuel delivery works good while the fuel pressure on the fuel rail is enought to maintain good pressure. Then it goes to an air. The MAF sensor is showing that the fow is ok and that there is no restrictions. So there is a good air and fuel. ECU mixes mixtures by messuring the return sygnals from the injetors, fuel rail and MAF. To increase the power in needed stages from 1800 to an 3500 rpm is a turbine that creates extra air pressure during that stages and that is controlled by vacuum system and the vacuum pump. The pump has no sensors and the only one has is one sensor that messures vacuum or boost. The stage has to be precise and activate the turbine precisely by opening it graduately step by step not all at once.
Now imagine you are an ECU and you have all that data and no other things to decide what to do. If you get normal air and normal fuel pressure good RPM's then you will see the data from throttle body comming feedback that it is opened 10 percent and then bum 80. So you whinking o f... i need to push more pressure, bum to vacuum to open whole turbine and wish for the best? Yep? And what if the data is wrong then the mixture is wrong and the pressure is created on low RPM that is not needed and is not efficient.
So this is the problem i have with this system. Strange? not at all . This is just a voltages that is increasing or decreasing while moving the valve. This is only a resistance added to the voltage. Simple. Now i just only need to find the ecu, pick it up and messure the voltage comming from teh body sensors (both of them).
In this case i see how the older system that is activated and works with a vacuum is more reliable that the electronics.
I am still not rejected the possibility that there is burnt ECU and that one needs fixing or repracement. But that one would be whole new history.
I am waitin' for any ideas suggestions corrections if i am wrong.
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