fuel economy reading?? is it possible

This is the place to ask general MegaSquirt® questions if you are just getting started.
Please read the FAQ and MegaManual before posting. Also see the Forum Rules. Click this link for Purchasing information.
If you are looking for MS-extra or MS-3 information, please post here: www.msextra.com
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
Mx73
MegaSquirt Newbie
Posts: 29
Joined: Fri Apr 24, 2009 5:29 pm
Location: chicago illinois

fuel economy reading?? is it possible

Post by Mx73 »

anyway for a output to show current fuel economy etc.?
1986 toyota cressida
5m-gte 2.8 L6
MS-2 3.57 edis 6,
trakkies
Super Squirter
Posts: 1162
Joined: Tue Dec 30, 2008 3:06 am
Location: SW London, UK

Re: fuel economy reading?? is it possible

Post by trakkies »

You need to know distance travelled for that. If you wish to have an MPG readout.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
msiddalingaiah
Helpful Squirter
Posts: 68
Joined: Fri Oct 09, 2009 7:39 am
Location: Maryland, US
Contact:

Re: fuel economy reading?? is it possible

Post by msiddalingaiah »

A simple solution is to integrate injector pulse output over a fixed time interval. That will give you average fuel flow rate. An RC filter with a sufficiently long time constant will produce a voltage proportional to injector ON time, which is more or less the same thing. As suggested above, you will have to do your own calibration, but some measurement a little math should do.
Madhu
1990 Suzuki DR350S EFI Conversion
Returnless, adjustable electronic Fuel Pump Controller requires less power
trakkies
Super Squirter
Posts: 1162
Joined: Tue Dec 30, 2008 3:06 am
Location: SW London, UK

Re: fuel economy reading?? is it possible

Post by trakkies »

My car has a factory fit OBC which gives an MPG readout, both average and instantaneous, by measuring how long one injector was open and a feed from the speedo sensor. The original injection didn't use PWM.

MS stopped this working properly. I tried various filter circuits to replicate the original pulsed DC, but got nowhere.
The answer was to time the current flow in the +12v feed to one injector.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Post Reply