which would benefit me more?

[azraelswrd]

tips:

When you fill it up, make sure it's around 1/4 of the tank (or less). The first few tanks may be wonky for tank calculations -- for me it overestimated my MPG by a massive degree which is why my fillup adjustment was +12.2%. My last refill the SG was off by +0.1gal so now my adjustment is +13.3%.

If you intend to do any forced autostops or engine-off-coasting, use HYBRID mode but that may not work all the time. The SG prefers the engine running than not to function properly.

Deceleration fuel cutoff (DFCO) is calculated when your engine loop is OPEN, the rpm's are above the cutoff limit plus above the idle throttle position selector*. You know if you have DFCO when your MPG = 9999 or the GPH = 0.00 and most modern fuel-injected vehicles do have it

*idle throttle position selector = when car is idle, the current TPS value

I followed the manual's recommendation and set the "FUEL CUTOFF" value to 14, which is 4 above my idle TPS (10). I note this because I've seen a lot of people confused by this over on CleanMPG so I figure I'd kill the beast before it got loose.

You can make your own customized gauges called Xgauges.

[Brian03cav]

azraelswrd,

so you're saying i should let my tank go to 1/4, then fill up completely, then plug in my sg2? im just trying to understand so i get the best possible results.

i dont plan to turn my car off while driving it, but i have been wondering about the Deceleration fuel cutoff (DFCO) as you called it. does my 2003 cavalier have that? so i should stay in 5th gear when coasting instead of putting the car in neutral? i figured only more expensive cars would have this feature. my car is manual so i was putting it in neutral on long downgrades.

as for the adjustments, did you make those by using the sg2, and keeping track of your mpg the traditional way? then setting the difference in the sg2?

im excited to use it, but nervous im going to mess up the settings. i expect it to arrive on wensday!

[azraelswrd]

Got ahead of myself. Plug in your SG, then fill up the tank but don't make any adjustments for that FIRST TANK. The next time you refill, wait until you have 1/4 left in the tank and then you can make your fillup adjustments. Adjustments at the fillup are based on the ACTUAL amount of fuel I pumped into the tank at that time so no need for traditional tracking.

ex:
I pumped in 8.747 gallons today. I turn on the Scangauge, go to FILLUP and it says I used 8.6 gallons. I then adjust it to agree with the actual fill amount (8.7) and note the adjustment percentage (+13.3%). That's it.


When you first plug in the SG, you need to calibrate your car info such as engine size, tank size, fuel type and car type. The instructions for the installation are pretty clear.

***
Your Cav should have DFCO. What you do will depend on what you need to do -- if you need to stop soon, I'd coast in gear. If you have a downslope or no stops in the near future, neutral is better. This is where having a SG is really useful but it sounds like you already know what you're doing.

***
I still use traditional tracking of odometer difference and tank amounts to determine my ACTUAL mpg (plus I use that to plug into the [garage]) because the SG is not perfect when it comes to tank calculations. It's close but I rely on it for instant feedback on the road.

***
Don't worry about messing it up.