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Need help with an automotive circuit

techenthusiast

Apr 7, 2017
2
Joined
Apr 7, 2017
Messages
2
This is my first post here, I'll try to make my question as easy and simple as possible

So I made a crude drawing uploaded of my task and here's a crude explanation first followed by background and detail if you're interested/if it helps

Basically one end of the circuit sees a potentiometer voltage. I need to switch it off at a certain point and substitute it with a different voltage while the other end of the circuit still sees potentiometer voltage. This needs to happen constantly over and over again depending on how I press the throttle pedal

Throttle position sensor sends a signal to ECU, potentiometer type, sending .5-4.5 volts from closed pedal to wide open throttle

I have a fuel controller tapped into the circuit, my fuel controller reads throttle voltage but doesn't intercept and change it - it just uses it as reference when I make changes in fueling

I want to wire in a grounded pressure switch that activates at a certain pressure. The ground will run a relay that pulls battery voltage, with a voltage regulator to drop it to 4.5 volts. That needs to be sent ONLY to the ECU side of the circuit while the fuel controller side still reads normal potentiometer voltage at the same time

So I basically want the ECU to see wide open throttle earlier than the circuit is designed to, while the fuel controller part of the circuit still and always will see a normally operating throttle position

I want the ECU to see only the wide open throttle (4.5v) when the switch is activated, the fuel controller part of the circuit to still see normal potentiometer voltage, and I need it to be able to happen back and forth instantly depending on how much gas I give it

(ecu must jump into normal operating mode, jump into WOT mode, back to normal operating mode, and so forth)

The only experience I have with automotive circuit modification like this is adding diodes for other purposes. But I can't see how diodes will make this work. Is there a different type of hardware like a diode to do something like this?

Thanks
 

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Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
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6,901
Sounds like just the job for a microcontroller like Arduino. Fairly cheap all around as far as I can see. The hurdle for you is the programming. If you know someone preferrably local that can help you there then all ok.
 

techenthusiast

Apr 7, 2017
2
Joined
Apr 7, 2017
Messages
2
I was hoping more for something like my last project where I researched what diodes are, soldered them in for a few bucks and was good to go,

Sounds like finding someone to program this might get expensive
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
If you take the time to learn how to program these devices then it's basically free. Everything you need to learn is open source and help when you get stuck is freely available from experienced people on the forums. Pretty good offer I'd have to say. In our day it was a small fortune for text books alone.You just have to motivate yourself as they will not write programs for you. Welcome to the world of reality.
 
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