Speeduino is now on Github Sponsors (Rather than Patreon): https://github.com/sponsors/noisymime
Any questions you have before you begin buying, building and installing.
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By GregK
I'm excited to have found this project!

has anyone had success in replacing their North American OBD2 California Emissions ECU with a speeduino?

Also - can speeduino be used to turn my factory relay-based radiator fan setup into a PWM control based on coolant temp sensor signal?

I'd love to be able to sign in here using my github credentials...

By dazq
Speeduino like almost all(if not all) aftermarket ECU are not recommended for use on vehicles needing to meet emissions checks especially any vehicle readiness type monitoring via obd/2.
This is why they most always say for off-road or race use only.

That said many do meet emissions testing requirements, but as I say NOT the readiness tests.
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By GregK
Emissions testing is no longer mandated in my jurisdiction for road cars.
Don't most people want to squeeze as much go as possible out of every drop of juice in the tank? I suspect -even without Readiness in places that still do tailpipe testing- a speeduino probably beats an OBD machine in the emissions dept pretty handily.
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By Chris Wolfson
If you are a top tuner with a rolling road and a lot of time, you may come near a OBD stock cars emission, but only after reconditioning the whole engine and renewing all emission relevant components. The OBD tune is not for best economy or maximum performance, but for a narrow window of emission components.
Your "max power, max economy" tune will in any case have worse NOx emissions, making the 3-way converter run less efficient.
Take a look at the ignition map of an OBD car and you will see my point.
User avatar
By Chris Wolfson
You can use the standard ECU connector of your car with Speeduino and install a second connector with additional engine components if needed. That way you can return to the stock OBD configuration in 10 seconds.
No need to rip out the stock parts and wires. Most are needed by Speeduino anyway. Just read your cars schematic for engine controll. Any wideband lambda controller, for example, has an emulated narrow band output. If you fit an additional cam position sensor, the OBD ECU does not care if it not connected.
There are even people that run stock and aftermarket ECU in parallel, but only one of them injecting and sparking. The second one running without managing any engine functions.
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By GregK
Thanks for your kind and mindful replies, Chris.
The ability to swap from Factory to Speeduino is an interesting possibility I hadn't considered!

I appreciate your NOx emissions concerns - I'd have no idea how to read an ignition map even if I could find one. :lol:
BUT - what I know of the science behind water injection makes me think it would help keep temperatures low enough to prevent and increase in NOx...I take it people around here are electronics-savvy enough to have tried pull-up/-down resistors on MAP sensor signals to ECU/Speeduino?

I suspect it might be in my best interest to see if I can replace the narrowband o2 sensor on my car to a wideband without making the ECU go crazy BEFORE getting deeper into Speeduino.

Thanks again!
By JRockland
Narrowband to wideband, your original ecu won't like it.
BUT on my Harley I had a welder add 2 bung so I had both narrow and wide for a similar reason (faster to connect on my dyno)

If you can get the original ecu model, and find a connector, it is not such a hard task to modify a board to make it fit. OR someone can make you an adaptor harness. If you need an inspection just swap it out, drive the car +/- 30 min to clean it out, clear the codes then you should be fine.
By theonewithin
Most wideband controllers actually have a narrowband output BTW so you can run just 1 sensor.
By dazq
What would the point of this be with speedy?

..I take it people around here are electronics-savvy enough to have tried pull-up/-down resistors on MAP sensor signals to ECU/Speeduino?

Tricking an OEM is one thing but doing that to an aftermarket is a silly exercise, simply calibrate and tune it correctly to begin with .

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