Ok here is the question, when going down hill, after regen and the motor revs the nav unit shows max fuel efficiency, while the scII shows fuel consumption. I am under the impression that fuel is cut when this happens so whats the deal.??

 

The SG bases fuel on x fuel per cycle. With more RPM this = more fuel used.... usually.... The older SG had no way to measure fuel cut mode.... EXCEPT... you can look at "loop" status.

If you are "coasting" you will have zero fuel used in "Open Loop".
( you can also have open loop at wide open throttle... but I have to believe you will know the difference! )

Thus, you are correct, and MPG will be worse on the older SG during these fuel cut times, but these fuel cut modes are usually rare, and short lived.

The Navi, being Ford specific, is smart enough to know when fuel is cut.
EDIT: Thanks to Carl and Ken, we now know how to adjust the fuel cut settings on SG v3.15! See newer posts!

-John

 

The SG has a fuel cutoff parameter you can set. It is the throttle position sensor value that under which the SG will cut fuel when in open loop. I forget the default number, but if you set it to zero it will disable this feature, which means it will not cut fuel. I think it is under setup -> fuel -> cutoff.

 

Ask that nice Ron fellow if he can update the user's guide to version 3.15 as well!

 

I commonly experience Fuel Cutoff in my Ford Ranger 3.0L 5sp Manual. On SGII-Xgauge Ver 3.15, Horsepower (HPR), FP1 or FP2 (Fuel Pump pulse count), & GPH, all go to Zero. MPG goes to max, 9999. This only happens when coasting in 5th gear starting from a higher speed, and foot naturally off the accelerator. Touching the accelerator or depressing the clutch cancels fuel cutoff and HPR, GPH, & FP1/2 start registering low values. When speed decreases to abt 20mph Fuel Cutoff ceases. I have never monitored Loop when this happens to see if it goes to OPEN loop? Fuel cutoff is never enabled if clutch is depressed, so now I coast with left foot on the floor for better FE in the Ranger.

I also would like to read the manual's description of Fuel > cutoff. The default value is 24, but don't really understand it.

 

In the Ford Escape Hybrid (2005) when in EV the throttle position sensor goes to 12, which I think means 12 degrees throttle angle. It is never zero, and it is never 100% nor 90 "degrees".

So since my car is never lower than "12" I set my value to 12, now that Carl brought it to my attention. I was unaware of that feature before.

In your Ranger, turn the key to "run" without starting the truck, and see what the SG says for throttle position ( TPS ). Then try that in the fuel setting menu for cutoff.
-John

 

If the TPS never goes below 12 and you set the cutoff to 12, it will never do fuel cut. Fuel cut occurs when open loop and TPS is below the threshold you set.

 

So set it to 13 then. It that were you set yours?

 

I checked Fuel Cutoff parameters again this morning in Ford Ranger, since I had never monitored Loop in this condition. See below, Loop does transition from Closed to Open.
HPR = 0
GPH = 0
MPG = 9999
FP1 (Fuel Pump Pulse count) = 0 [value is 563 with truck stopped and engine at idle]
Loop = Open

Fuel Cutoff is still at 24, default value, because until this moment, I didn't know what it meant. I’ll reset it to the TPS Run value this afternoon, and check results on way home.

Carl, I assume that if Fuel Cutoff value on SG is set at or below TPS Run value, SG will never display values indicative of Fuel Cutoff, but in reality, cannot actually control/force/inhibit actual Fuel Cutoff? If that's really the case, then why not just leave the value SG value set considerably to ensure that Cutoff mode is correctly registered?

 

Open loop happens at any throttle value during cold start up.
Open loop happens at WOT.
Open loop happens at minimum throttle when the car is warmed up. (and Fuel is cut)

Thus, it has to be an "and" command.

Fuel Cut = minimum throttle AND open loop at the same time.

Minimum throttle is different in each make of car.
That's how I understand it.
-John