I believe I have, https://www.greenhybrid.com/discuss/...514#post122514

Let me know if my procedure was incorrect and I'll try it again.

 

There are sometimes spikes, errors, or noise in the CAN data bus. Sometimes, the SG will get "frozen" on a piece of data that is not changing.

You can try this for instance:
Sometimes, in EV mode I see ICE RPM on the SG, when it is clear the ICE is not running. What I think happens is, on the way down from 1000 RPM to 0, there is a frame of data at say "33" RPM. Then, the fraction of a second between real 33 RPM and 0 falls between data refresh rates. Then the CAN bus quits sending RPM data, since the engine is not running. The SG gets frozen on 33 RPM, until the CAN bus sends out new data. The 33 RPM only gets stuck for a couple of seconds, then goes to zero. So maybe with ICE running the RPM data rate is fast ( say 10 times a second ) and the RPM data refresh rate is slower ( every 2-3 seconds ) with the ICE off. Just guesses.

When driving in EV I will sometime see random numbers on the RPM also.
Just for a second. I attribute this to noise on the CAN bus.

You need some consistant data to draw conclusions.
Do you often or always see closed loop on the SG at the same time as infinate MPG? Or did it just happen once? I personally think it was a fluke, or noisey data. But I wasn't there. My car does not do that.

-John

 

Yes, it's repeatable under the conditions I described in the referenced post.
Could it be that the SG is incorrectly reporting loop status when the engine is in fuel cut-off? Or maybe loop status doesn't update on the bus under these conditions. But you don't see this in your vehicle, so I'm at a loss to explain.

Here's that post again:

"Yes, I just confirmed, closed-loop and 0 L/100km simultaneously. I was coasting down a long hill at 40mph, in D, foot off the gas completely, 1100rpm, and saw closed-loop on the SG and 0L/100km on the dash econ gauge following an econ reset. I reset the econ several more times to confirm the reading was indeed 0, and the SG continued to read closed-loop."

 

gpsman1 and econoline you really do need to try to resolve this issue of "open-loop" or "closed-loop" operation when coasting in fuel-cut mode. Ron DeLong says that this is the only case he's aware of that reports closed-loop when in fuel-cut mode. Can you come up with some tests that both of you can conduct to verify that you both get the same results, and with any luck resolve this issue?

Stan

 

That would be great. The easiest way is on long, steep downgrades. It's pretty hard to study around town, when you can only get run-up for a few seconds. Descending the Rockies, it is possible to get open loop, fuel cut coasting for minutes at a time. I'm open to suggestions. -John

 

Not to really butt in here, but is it possible that the disagreement is due to a programming/operations change in the FEH between model years?

 

Short answer is yes.

Okay, new info as of 5/18/07.

With a cold engine, like 2 minutes after a start, I was going downhill and shifted to L to capture regen. ( Habit )
But my battery was already very full.
The car did the "run up" in RPM and stayed "closed loop".

Also, Later, I was coasting downhill in EV. Open Loop on the Display. Shifted to L. Captured lots of regen for a few seconds.
Then the battery got full. The engine started, stayed in Open Loop. The engine went up to 4000 RPM, stayed Open Loop.
However, gas was shown as ~ 1 L/100 km. NOT zero.

So... this is not a simple binary If/Then senario. Open loop usually, but not always means fuel cut.
But Ford never said it did.
Ford simple stated that "Open Loop" means the fuel/air is not controlled by sensor feedback.

-John

 

New info.

 

I assume your "~ 1 L/100 km" observation is by the ScanGauge.
The ScanGauge has some limitations under such conditions.
http://www.cleanmpg.com/forums/revie...e-ii-4495.html

"Another issue has to do with Fuel Cut. The ScanGauge II has no way to tell if the ICE is in Fuel Cut or if the car is at speed running at idle as you would in a NICE-On. Although the FE calculated and shown is very high under this condition (between 130 and 250 MPG depending on speed and ICE size), fuel is still shown being consumed when it is not thus causing an ever increasing error to build in. "

Ken@Japan

 

Ken, you obviously have not read earlier posts in this thread.
Please do. The scan gauge cannot display L/km, only km/L.
So no, I'm not talking about the SG.