A simple way to find my fuel balance
If your vehicle (you didn't mention model, make, or year) has an ECM/PCM, it is calculating and trying to deliver a ratio of 14.7 (plus or minus .05) to 1 of air and fuel. It does this by measuring the air flow (with MAF and/or MAP sensors, coolant temperature sensor, IAT sensor, and TPS sensor), and controlling fuel injector pulse width and spark timing to meter the proper fuel delivery for the conditions.
Using the OBDII tool, you can see either the actual ratio (few vehicles) or the fuel trims that your ECM/PCM sees. If the fuel trim (combined short term and long term) shows a positive number, the engine is tending to be lean and the ECM/PCM is compensating for that. If the fuel trim is showing negative, the ECM/PCM is compensating for a rich tendency. The ECM/PCM gets its information from the heated O2 sensors located before the catalytic converter(s) that monitor how much residual oxygen is in the exhaust flow.
The only other way I know of is to somehow measure how much air is going into the engine, calculate its weight, and compare that with the weight of the fuel used in the same time period.
I guess the answer to your question is that the simple way is to rely on the engineers who build the fuel delivery system, and the caution light to advise you when things get out of whack.
Nov 30, 2016 |
Cars & Trucks