Received ScanGauge...now for the fun..

[MisterJeeves]

Hi there,

I just received and installed the Scangauge on a 04 Ford Focus ZX3 2.3L, manual transmission.

I have a question for anyone with experience in the matter... Shouldn't the SGII read 9999 (infinite) MPG instantaneous when the momentum of the vehicle is propelling the car and the fuel injectors are shut off? I get better FE when coasting in neutral and it certainly never reads infinite.

Any ideas?!

Thanks all
-Brendan

[Funny]

Originally Posted by MisterJeeves

Hi there,

I just received and installed the Scangauge on a 04 Ford Focus ZX3 2.3L, manual transmission.

I have a question for anyone with experience in the matter... Shouldn't the SGII read 9999 (infinite) MPG instantaneous when the momentum of the vehicle is propelling the car and the fuel injectors are shut off? I get better FE when coasting in neutral and it certainly never reads infinite.

Any ideas?!

Thanks all
-Brendan

Unless your focus is a hybrid, then you won't see 9999 MPG with the engine running.
The only way you are going to get 9999 MPG on the SG on a non-hybrid is if you shut off the engine and EOC. Or if you have a car that has fuel cutoff while in gear (DFCO?), then you can coast in gear down hills and see 9999 after a few seconds. Good luck, and welcome to Ecomodder!

[SVOboy]

Yep, you need to make sure you're actually engine braking, not not just grinding along in gear.

Welcome to ecomodder

[MisterJeeves]

I was under the (perhaps) false impression that when the engine is being turned over by the momentum of the vehicle, the fuel injection system cuts off any fuel flow to the engine. Is this what happens, but isn't logged on Scangauge, or does this not even happen at all?

Case and point...going 30mph in 3rd gear with the "induced" RPM @ 2500 (or whatever nominal amount it is).....The engine will function as a source of braking, surely not consuming any fuel?

The engine is a 2.3L Duratec PZEV by the way.

Thanks guys for your help....I look forward to posting the statistics of my endeavors soon.

(My parents, back in the UK drive a Ford Fiesta 1.4L Diesel vehicle that empirically yields them about 70mpg....just a juxtaposition of what I'm working with right now).

-Brendan

[Mustang Dave]

My '07 Mustang goes into DFCO when compression braking with the engine RPM above about 1500. My ScanGauge reads 9999MPG under those conditions.
I believe that makes my Mustang a PZEV.

[MisterJeeves]

I find it difficult to believe that when engine braking there is any fuel injection in this model vehicle...I've looked at the TPS setting on Scangauge & the Open/Closed loop indicator, but the loop indicator is always closed. How does Scangauge determine if the vehicle is operating with 0 fuel injection at finite speed.

Any tweaks I can perform, or is my vehicle -really- injecting gasoline when letting having the vehicle momentum turning over the engine at >1600RPM for instance....

Thanks guys

[MetroMPG]

In all likelihood your car shuts off fuel flow when the throttle is released above a certain RPM threshold.

The ScanGauge doesn't actually monitor fuel flow. That's not part of the standardized info available in OBD-II.

So in order for it to "see" deceleration fuel cut-off, it is probably looking at a combination of factors, like throttle position, engine RPM, and loop status.

I seem to recall that there's a Throttle Position Sensor (TPS) related threshold that you can set - maybe that will fix the problem. I've never had to do this with a SG, but others have and hopefully someone will chime in. I did a quick search with no luck.

[Mustang Dave]

When mine shows "9999 MPG", it also shows "OPEN LP".
There's a section in the ScanGauge manual for setting up fuel cutoff parameters:

"MORE>SETUP>FUEL>CUTOFF
Some vehicles will turn the fuel injectors off when coasting. This will
cause the fuel economy to go to 9999 MPG or 0.00 KHL. This shows
when you are not using any fuel while coasting. This is sensed through
the open/closed loop indicator and the throttle position. To tell if the
throttle is closed, the throttle position is checked against the CUTOFF
value. CUTOFF is the value the throttle has to be below in order to
indicate a fuel cutoff and show 0 fuel flow.
< 24 >
Cutoff SAVE>
The default is right for most vehicles, but it can be adjusted by pressing
the upper left or right button. The setting is not critical, but is best if
about 4 above the no-throttle TPS value. If set to "0" it disables this
method of fuel cutoff sensing."

Hope this helps.