Input Impedance of Analog Pins on RusEFI Proteus

[coolantbongrips]

WARNING: THIS THREAD WAS BORN OF STUPID IDEAS
Is the input impedance on the analog in pins on a proteus high enough that it and a car's stock ECU could be connected to a sensor output without the use of a buffer amp? My plan is to share Crank, coolant and air temp, MAP, TPS, and maybe Knock sensor outputs between the two ECUs.

[AndreyB]

Looks like four separate questions and we would have to wait for Matt for the best answer

CLT and other temperature sensors have a few K of pull-ups you would probably want to remove those. All analog inputs have op-amps so there is hope for piggy back.

I recall that MAX992x piggyback was a NO in case of VR?

No idea about knock

I assume you had a chance to glance at https://github.com/mck1117/proteus/blob/master/export/v0.5/proteus_0_5_schematic.pdf

[mck1117]

Analog volt inputs have a 500k pulldown, so they're effectively not there at all.

Like Andrey mentioned, the analog temp inputs have a 2.7k pullup to 5v. You could always wire your coolant sensor to a voltage input instead, which would probably work.

Knock and VR sensor are a different story.... less likely to work super well.

I assume you're trying to run Proteus as a piggyback ECU, why?

[coolantbongrips]

Analog volt inputs have a 500k pulldown, so they're effectively not there at all.

Like Andrey mentioned, the analog temp inputs have a 2.7k pullup to 5v. You could always wire your coolant sensor to a voltage input instead, which would probably work.

Knock and VR sensor are a different story.... less likely to work super well.

I assume you're trying to run Proteus as a piggyback ECU, why?

Mostly laziness, my plan is to swap a EZ30R into my Outback with an EZ30D and ideally not take much more time than simply pulling and reinstalling the engine. My idea is an almost plug and play harness that goes between the engine and the bulkhead that lets the RusEFI control all engine stuff while keeping the stock ECU happy enough to maybe not throw CELs while also running things like the cluster and auto HVAC. A bonus that most people wouldn't care about is this would also keep EGR and evap intact. I also plan on eventually adapting this design to more subarus if this works out so other people can easily H6 swap their cars without a lot of downtime, annoying wiring, or harvesting of ECU connectors. As for the VR crank sensor, I have to convert the hall effect cam sensor signal on the new engine to one the stock ECU can read anyways and can just add another channel to that for crank if I can't share it.

[Simon@FutureProof]

Is this a case where getting engine info over CAN would be useful?

[AndreyB]

@coolantbongrips hope to ship your unit tomorrow feel free to share any amount of your plans in a Hello World thread