Thanks Carl. I set fuel cut to 15 per your original recommendation. Good explanation too. Very complex vehicle.

 

DesertDog — Perhaps you can clarify something for me concerning the updated ScanGaugeII (I haven't had mine updated yet). If one sets the ScanGauge "CUTOFF" setting (or whatever it's called) to say 16, then when the TPS reading is 16 and the ICE is open-loop, will ScanGauge treat this as indicating fuel-cut? Or, must the TPS setting actually fall below the CUTOFF setting (say to 15) before ScanGauge will treat this as being indicative of fuel-cut?

Stan

 

Maybe Carl can clear this up, but here is my take on the subject. Ron Delong set the default Fuelcut at 24 I think because the SGII would read Fuel-cut at most TPS readings at idle. This setting would give the SGII time to confirm Open-Loop so that 9,999mpg could be close to the time the fuel was cut by the PCM.

I took my idle TPS reading in "D" at decel which was 14 in my '09 FEH. Some people have suggested setting the Fuelcut on the SGII 4 above the idle TPS reading, so I set my SGII Fuelcut down to 18 from 24 the default setting. At 18, it takes about 2 seconds after decel for the SGII to display 9,999mpg and open-loop.

I've never experienced any of this in my '05 FEH, so it's weird seeing 1,100rpm's and getting 9,999mpg at the same time. If I accelerate to 50mph, I can go fuel-cut at 9,999mpg in "D" and shift to "N" and coast till I get to 40mph and go EV from there. This is like doing a key-off FAS without doing anything but letting off the gas pedal and restarting by just pressing on the accelerator. My concerns about the EV threshold being at possibly 50mph are even better with fuelcut. In effect, the '09 FEH/MMH can get the same 9,999mpg as EV from the highest speed the FEH will go.

SOMEBODY STOP ME!

GaryG

 

GaryG — My question for DesertDog really concerns whether the fuel-cut logic in SG uses a "less-than" or a "less-than-or-equal-to" test before deciding that the ICE is in fuel-cut. In my TCH, the TPS reading is 16 when the ICE is in fuel-cut. Suppose that I set the SG "CUTOFF" value to 16. Then, the question is: Will SG interpret an open-loop condition together with a TPS reading of 16 to be fuel-cut, or not? If a TPS reading of "less-than" CUTOFF is the test, then I would have to use a CUTOFF setting of 17 and not 16 to have it work properly. If a TPS reading of "less-than-or-equal-to" CUTOFF is the test, then it will work properly with a CUTOFF setting of 16.

Stan

 

It is less than the number you enter. Even though TPS is displayed with no decimal point, it has steps of 100/255 (.392) so it is possible to have cut-off with seemingly identical TPS numbers. If you program an xgauge up for TPS you can show a decimal point and verify this.

 

Thanks DesertDog! That answers my question.

Stan

 

As I said, I set the SGII Fuel Cut at 18 and I noticed TPS seems to always read 17 during EV and Fuel Cut. I'm wondering if the SGII will always read the next number below the Fuel Cut setting if it is above idle?

Also, I confirmed the SGII shows 9,999mpg and open-loop even below 40mph to almost a stop when using decel in "L" in the '09 FEH. The RPM's go to ~2,000 no matter the SoC. This is nice because you can get the same MPG as EV when the HV battery is still to low to go EV. In addition, your getting regen from "L" to charge the HV battery.

GaryG

 

GaryG — Corresponding values for my TCH are as follows:

• In pure-EV mode (ICE not spinning) — TPS = 15
• In fuel-cut mode (ICE spinning) — TPS = 16

So a SG setting of 16 (or possibly 17) would seem to be the proper value to use to get correct fuel-cut detection in the TCH.

Stan