I talked to my salesperson this evening and learned that our new MMH has left the Denver rail yards and is now in their possession. They are still waiting to receive/install the EBH and then we’re looking forward to becoming a two hybrid family!

I’m stoked to visit this side of the forum and learn that it’s just as active as the HCH side of things! I read the FAQ and some great stuff on engine block heaters, but would love to read anything I can about how to get the best FE I can with this car. Are there any other “recommended reads” I should know about? More importantly, does anyone have any specific advice on mountain driving with the MMH/FEH?


Thanks in advance!

 

If you are going downhill and gravity is enough to pull you down, pop the car into L gear, let your foot totally off the gas. In 2-5 seconds, the engine RPM will Rev up, but all fuel will be turned off.

Now, keep your foot off the gas, and shift back to "D".

You can now coast down the entire hill without using any gas.... even at 75 MPH. This is called "fuel cut mode".

If you shift to "N" the car will burn fuel at an idle rate.

There's a tip you won't find in any manual!
-John

 

John - That is a wonderful FE tip. I've only had our 08 FEH AWD for 2 months, and didn't realize this one. Slightly confused though. I thought that shifting to Low Gear w/ICE running forced the engine RPM to ~1000, enabling EV mode if all other conditions were met? You said that "In 2-5 seconds, the engine RPM will Rev up, but all fuel will be turned off." If the ICE is still running at say 75mph, how can it not use fuel (a tiny bit)? Or does this sequence enable EV mode regardless of speed? This "fuel cut mode" sounds intriguing!
Thanks for the MANY good posts. Enjoy reading them when I can find time.

 

My experience down hill is that when you shift to L it will charge the battery up to some level, then hook up th ICE for compression braking. That is more than 2-5 seconds, but still a desirable effect.

Thanks, John, for the tip an all the great posts.

 

P.S. I would lose the "Debunking Global Warming" graph though.

 

I picked it up tonight and am pretty stoked! I got "30mpg" on the way home from the dealership and "34mpg" on a round trip version of my daily commute. After driving the HCH, it was a little weird to drive in stop and go without the ICE spinning! I can't wait to spend some more time behind the wheel so I can get used to the car.

 

Sorry, there are so many conditions, is it hard to describe them all.
At speeds over 40MPH you cannot have EV, so this is almost always going to REV the engine up to about 3500-4000 RPM when you shift to L going fast. But the "speed" is being "spun" by electricity only. All gasoline is turned off. But the "Rev" creates lots of slowing, so by shifting to L for just a few seconds to shut off the gas, ( you need to see ~3500 rpm to shut off the gas ) and back to D, you send Rev's back to idle, but keep fuel cut as long as you don't touch the gas pedal.

Set your MPG display to Metric instead of gallons.
It will read liters per km which is upside down of MPG.
Coasting downhill without this trick, you may see 0.1 or 0.2 liters per 100km. Using this trick, it will show exactly 0.0 L/100 km. ( no gas )

You can't have gas cut over 40 and power the vehicle ( EV power ), but you can have 100% of the gas cut off and just coast at any speed. I've done it at 75 MPH coasting down I70 in drive. You get a little bit of regen drag doing this, so really it only works well on hills 5% and steeper.

Below 40 MPH a shift to L will lower engine speed to ~1000, and soon go into EV. ( 0 engine RPM ).

Just like variable displacement V8's can run on 4 cylinders on the highway, your FEH can run on 0 cylinders on the highway.
-John

 

Very cool, that is great info!

 

GPSMan1

John, Thanks for the great explanation of 'gas cutoff'. Can't wait to try it when wife lets me drive her FEH . Slightly unrelated, but now if I could only get the SGII-xgauge (or SGIII, whatever), to read Battery Traction Temp (BTM), I'd be pleased. Unlike some of the others, I can read SoC perfectly, but NEVER the batt temp. Not a big deal with winter here in KY, but spring/summer is never far away. Obviously there is an addressing difference with the 08 FEH AWD compared to the 05 FWD (and later models).

 

I also have trouble reading the HV battery Temperature.
I thought it read once per key cycle, but now that is not even true.

It just read once here, and once there.
I have not found a pattern, rhyme or reason for this.

I always get a number, just not the CURRENT number.
The number, say 37.4 from yesterday will stay there for 3 days and a dozen key cycles for example. Then, all of a sudden, it will update.

I am becoming suspisious to the real possibility that no one is getting correct HV battery temp numbers, but since they get SOME number, they are unaware.

I monitor the HV battery temp on my trip ODO, and that one is trustworthy. The one the SGIIxG is not trustworthy. I suspect there are two paths to retrieve this data, and we don't have the correct way figured out yet.