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Fuel level sensor


steven91

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Hi guys 

Looking some info for wiring up and fuel level sensor. Using link g4+ storm and the fuel sender make is speeding parts fuel level sensor  Resistance full: 90 Ohm and Resistance empty: 0 Ohm. I have an input 5 free on the ecu and can splice into ground out. Would anyone have a diagram of where to  place the resistors and what resistors are required. 

thanks 

Steven 

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  • 1 month later...

Just jumping on the back of this - I'm assuming it would then be possible to get the ECU to drive an external fuel gauge from this?

Wonder how well a 0-5v style digital gauge would respond to a PWM signal from the ECU.

Context: The AE86 digital cluster (and probably other digi dash Toyotas of the era) use a 0-5v input for the fuel gauge. The cluster itself outputs a 5v reference and dedicated gnd for the sender unit and depending on the wiper arm position the sender unit returns an analog voltage to the cluster. The cluster itself has the damping circuit built into it that works by reading the voltage input every 4min and 15sec (255 seconds), and if the voltage has changed from the last update it will move the gauge one segment in the direction of change. So if you instantly go from full to empty the gauge wont indicate this - it will just keep ticking down 1 segment every 4min15s until it reaches empty.

The problem is the sender units that are specific for the digital cluster and are no longer available to buy. You can't just connect a sender unit that was designed for a resistor style analog fuel gauge either without passing it through some kind of converter.

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1 hour ago, DerekAE86 said:

Wonder how well a 0-5v style digital gauge would respond to a PWM signal from the ECU.

Having made a false TPS signal to the 4wd computer in my Stagea I would recommend using an injector drive output with a pullup wired to the 5V as I used a standard Aux which pulls up to battery voltage and so the actual output voltage would vary with battery voltage (engine not running, engine cranking, engine running).

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4 minutes ago, Vaughan said:

I would recommend using an injector drive output with a pullup wired to the 5V

Ah smart. I'd love to do this but I already built a converter box for myself and I don't have any free inputs/outputs on my ECU anymore.
But it's nice that it'd be a viable option for others facing this situation.

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54 minutes ago, DerekAE86 said:

What PWM frequency did you find worked the best for this?

I didn't try different frequencies, just went to as high a frequency as possible (10kHz), same for when I was controlling an MX5 dash oil pressure gauge and MR2 dash temperature sensor. In the Stagea I did also use a low pass filter but I suspect you won't need one for your application given the internal filtering

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  • 9 months later...

So I have come into this issue of voltages moving around more than i would like, I am going to try the capacitor and 18kohm option what voltage would the 1000uf capacitor be 16volt or closer to 5volts.. i only got it working recently so while im back there might aswell get what is needed to make this filtering circuit..thanks 

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