I find it very interesting to read how Ron DeLong eventually dealt with the fuel-cut issue in ScanGaugeII. I had a lot of e-mail communications with him on this issue back in April. This is what I find in my Toyota Camry Hybrid (TCH):

• Before the first start of the ICE, the TPS reads 18 (open-loop of course).
• When the ICE first starts up in really cold weather (well below freezing), it initially stays open-loop for some seconds. During this brief period, the TPS appears to read between 15 and 17. On going closed-loop, while still at idle, it rises to 19 and then drops slowly to 16 as it warms up.
• When fully warmed up, and idling, it reads 15-16 (closed-loop).
• When fully warmed up, and in pure-EV mode, it reads 15 (open-loop).
• When coasting in pure-EV mode, it reads 14-15 (open-loop).
• When coasting in fuel-cut mode in 'D', it reads 15 (open-loop).
• When coasting in fuel-cut mode at high speed in 'B', I have seen it read 19 briefly, before dropping to 15 (open-loop).

This last observation seems to correspond to what gpsman1 has just reported in post #20. I trust that he'll communicate with Ron about the aberrant behavior of the new SGII when operating WOT! I shall monitor the cold-startup TPS and open-/closed-loop behavior of my TCH a bit more over the next little while, and report back if I need to modify the statements I made in bullet #2 above.

So, for my vehicle, a setting of 16 or 17 would seem to be appropriate. My TCH always reads open-loop when it goes into fuel-cut. However, it seems from some of the earlier fuel-cut threads on the FEH/MMH forum, that not all FEHs actually indicate fuel-cut during fuel-cut operation! This could cause a difficulty in getting proper indications from SG in such vehicles.

Stan

 

My wife drives the 08 FEH AWD while I drive my 02 Ford Ranger, of which I have posted findings abt Fuel Cutoff. It was others on this thread that informed me that Fuel cutoff even existed. For that I am appreciative.

Throttle Position (TPS), as displayed on my SGII-Xgauge when connected to the 02 Ford Ranger, ALWAYS shows 18 when the throttle is not depressed. This is a constant, regardless of engine temperature, speed, or even Key-on/Engine-Off. Whenever my foot leaves the pedal, TPS drops to 18 everytime. So for the 2002 Ranger, 3.0L, 5sp Manual, the fuel cutoff setting on the SGII is simple -> just one number higher, 19, always works on this vehicle. It's interesting that other vehicles don't always display a constant value for TPS when foot pedal is at rest!

I'm certain that when any vehicle goes into 'fuel cutoff' mode, Open Loop occurs simulatneously. Horsepower is zero, GPH is zero, and Fuel Pump pulse count all go to zero. I have several opportunities to coast in FCO mode on my daily commute, vs. coasting with the clutch depressed (at idle), but the braking action does cause me to come to a stop a bit earlier than in neutral

 

KenE — The hybrids use electronically-controlled throttles ("drive by wire"), and so the actual throttle vane's position is determined by the engine ECU, and it need not always read its minimum value when your foot is off the accelerator pedal. The ECU determines how much total torque (i.e., acceleration) you're requesting, and then determines the correct amount of gas to feed to the ICE and the amount of NiMH battery power to use, before moving the throttle vane to the appropriate position. This is certainly the case in my TCH, as the data given in my post above show. The same holds true for the FEH/MMH. This makes choosing an appropriate number for ScanGauge's fuel-cut setting more difficult than simply using a number 1 more than the lowest observed TPS reading.

Some FEHs appear not to go open-loop when in fuel-cut mode. (My TCH always goes open-loop when fuel injection ceases.) This was discussed ad nauseam in the thread "Fuel Injector Shut-Off", but I believe never conclusively resolved. These FEHs will presumably not correctly trigger fuel-cut detection on the latest ScanGauges either. Moreover, at least in the Toyota hybrids, the engine ECU continues to generate fuel-injector pulses even during fuel-cut, and this causes faulty fuel usage readouts on previous ScanGauges. Correctly determining when fuel-cut is actually occurring was a major headache for Ron DeLong. It was to resolve this problem that Ron has apparently added the adjustable TPS setting to the XGauge version of ScanGauge.

Stan

P.S. I've added additional information to my post #21 above.

 

I just did a drive from Denver to Los Angeles.
There are quite a few long mountain grades along this route.
I have two SG plugged in, in series.
ONE has the fuel-cut feature, one does not. ( set at 24 )
After 20 or 30 miles of downgrade on a tank, the SG with fuel cut had 0.5MPG higher for the tank average than the other one.