Measuring Gas Used
 

Is there an aftermarket way to attach a measuring device to measure fuel used by attaching it to somewhere in the fuel line (e.g. fuel pump, fuel line itself, somewhere around the manifold, etc.) that can display instantaneous fuel used and fuel used for trip either directly or through something like an Arduino?

Thanks!

I dont know about aftermarket devices, but you can read the whole thread and make an opinion how to build one yourself:
http://ecomodder.com/forum/showthrea...gine-1123.html
Easiest could be to use flow meters combined with MPGuino, in my opinion.

I read through that thread. I would like to use an Arduino, which I am planning on installing soon anyway. My Arduino project will already include tapping into the VSS, so just the flow meter reading and a way to measure time would be necessary. Any ideas on what kind of flow meter to get and how to attach it, without impeding the the flow of fuel? Also, would a meter right after the fuel pump suffice, or should I attach it somewhere else like the injectors for a more accurate reading (e.g. to account for things like fuel return, which I do not know if my car has)?

Thanks!

If your car has digital injectors . . .
 

. . . just use the arduino to tally the total time the injectors are open. You can then equate this to a volume flow of fuel for a unit time - assuming constant rail pressure.

Exactly as RustyLugNut said, the best way to do this would be to use the method the MPGuino uses. Instead of measuring physical flow, the MPGuino measures how much time the injector is open for. By knowing your injector size, it can then compute how much fuel you have used. It then takes that information and with speed calculates your MPG.

If you don't have fuel injection then of course this would not apply.

Umm... Then.. buy one?

That was going to be my suggestion; buy an MPGuino....

Yes

From what I have seen these projects end up getting shelved because the lack of a cost effective, accurate metering device, and often, the need for two of them to measure the flow on the return as well. You can get them in the aviation and marine markets but they are spendy and often inaccurate at typical automotive flow rates.

On a carbureted engine it is tough because instant flow at the fuel line does not necessarily=instant flow into the engine. As flow into the carb is a function of float valve and vacuum and flow into the engine is a function of airflow past the venturi.