econoline — Since I don't own a FEH, I'll have leave it to gpsman1 to provide you with clear and explicit instructions as to how to check this out. I'm sure he'll be happy to do so. Thanks to you both for being willing to do this!

Stan

 

Okay Stan. That was a very clear and concise description of what you seek. Before it was in bits and pieces.

Unfortunately, at this time I can't help you.

econoline thinks he has seen fuel cut and closed loop more than once.
I personally have never seen it, but will also admit I've spent fewer than 5 days looking. I will keep looking.

-John

 

econoline — The vehicle is in the fuel-cut mode of operation that we're interested in if:
(a) the ICE is spinning, and
(b) there is no fuel flowing to the ICE.
The former can be ascertained from a tachometer rpm reading (e.g., using ScanGauge). The latter cannot be furnished correctly by ScanGauge. [In my TCH, ScanGauge reads fuel consumption at a rate of ~1 L/h instead of zero when in fuel-cut mode.] But you can apparently use your FEH's trip consumption readout (as explained previously in this thread by gpsman1) to verify that no fuel is being used, by resetting it at the beginning of a high-speed, run-up coast in 'D,' and seeing if it still indicates zero fuel usage at the end of the coast. Further instructions or clarifications will have to come from gpsman1.

Stan

 

Stan, everything you've put down sounds correct.

 

Stan,

I understand and agree with everything except, "by resetting it at the beginning of a high-speed, run-up coast in 'D,' and seeing if it still indicates zero fuel usage at the end of the coast."

Why are you bringing in engine run-up here? I thought the test you were interested in is whether or not we EVER get "both fuel-cut and closed-loop indications at the same time." My earlier observations were that I saw fuel-cut (per John's use of dash econ gauge) and ICE rpm >0, and closed loop, and NOT run-up simultaneously.

Please clarify what you want me to look for.

 

econoline — You're quite right! It's not necessary (at least in the TCH) to have run-up (meaning an increase in ICE rpm above its idling rpm). In my TCH in 'D' I get fuel-cut with ICE rpm ~1000 (idling speed) and no run-up; in 'B' (= 'L') I get fuel-cut and run-up to ~3000 rpm. In both cases my FE gauge on the dash correctly reads precisely 0 L/100 km, showing that I am indeed in fuel-cut mode. And ScanGauge says "open-loop" — this is what you need to check when you are in fuel-cut mode. I understand that you can switch the FEH display to metric, so that you also get a display of instantaneous fuel consumption rate directly in L/100 km, and can also read the fuel used since the last reset.

Stan

 

Stan-
Sounds like Don's car has broken the "rule" you are interested in.
Mine has not. I also have the original ScanGauge, version I.
If Don has the ScanGauge II, then this is another variable perhaps.

I know you are eager to get an answer Stan, but the best way for me to do reliable tests is on sustained, long, downhill coasts. During ski season, I was doing this every-other weekend. It may be a while before I get to experiment more with this. -John

 

gpsman1 — Okay. I can wait! I have a ScanGaugeII. I would expect that the ScanGauge I and II rpm, open-/closed-loop, and fuel consumption rate (L/h) readings should be identical, since these are just standard CAN bus data outputs — no data interpretation is needed.

Stan

 

I just did somemore testing. I can easily and repeatedly get the following indications by simply letting off the gas to coast to a stop:

RPM = 1100
LOOP = closed
Fuel Flow = 0.0 L/KM (as indicated on dash econ gauge following repeated resets during the coast)

I'm using a SG II, although I don't see how that would affect anything. My guess is that the 0.0L/KM does not actually indicate fuel-cut mode, but I can't prove that. We need one of those tail pipe sniffers to actually determine if fuel is being burned.

 

Don- last question, then I'm going to go out and try it some more.

Was your engine completely hot during your test(s)?
Or was it pretty close after a start-up?