Note that pre-2008 vehicles or engines without CAN-BUS will have slower communication (about 2-3x per second), so fast updating gauges like RPM will be slow to respond and the user will have noticeable lag. There are many workarounds for this, however, so please don’t hesitate to reach out and discuss options with us. CAN-BUS enabled OBD-II ports can communication many times faster (50-100x per second, at least) so lag is not an issue.
There is a long list of sensor data that is transmitted by OBD-II, but this varies by year, make, model, and engine. RPM, Coolant Temp, MAP (boost/vacuum), IAT, fuel trim (short and long term), TPS, and MAF are standard, but most vehicles transmit much more information. We can only guarantee that the readings in the previous list are transmitted to OneGauge; since other sensors often require manufacturer- or engine-specific codes (called PIDs) to be able to read the data, it can be difficult to access these readings. Other companies and apps that develop gauges typically pay expensive licensing fees to the major auto manufacturers for the rights to these codes, though they can occasionally be found on the internet. We have had some success in getting GM and Ford specific PIDs to work, but these are not guaranteed since they can vary by year/engine/make/model.