Why is my ICE not shutting down at a complete stop? Is that normal? I usually drive with stop and goes around 5 times at 10 minute intervals. Some days it shuts down frequently and other days not at all. Anyone know what is up?

 

Some reasons that come to mind.

The battery needs charging, or worse, reconditioning.

The battery needs A/C to cool off.

 

My '05 does that on occasion and I have yet to figure out why. There are times where I know the battery is charged, the engine is warm, I'm not using a red setting on the climate control and the outside temperature is moderate and the thing just will not shut down. It's aggravating since I know that in the exact same conditions, my '06 would be humming along in EV. I've contemplated bringing it in for service several times.

That said, I have been driving the '05 exclusively for the last couple months and I have had my best tanks yet in either vehicle. I've come to accept the non shutdown as just part of the way this car works and there is nothing I can do. My last tank was 35.3 mpg and 250 miles of that tank was 100% 65-70 mph interstate. The tank before that (my regular 24 mile each way commute) was 39.1 mpg. I'll take it.

 

Do you have A/C Max?

Is your trip less than 10min? My MMH wont shut down during my wife's ~8min commute (~4miles).

 

Or either of the defrost settings.

Should rule out the obvious first I guess.

 

I have a 2006 Mercury Mariner Hybrid with 13,000 miles and absolutely love it. I always drive in "L" and have averaged 27 MPG. I have the Nav radio and usually monitor the power diagram.

My commute changed back in April and on my new morning commute I have a few rather long down hill sections where I am costing or braking below 40 MPH. The ICE will shut off as expected for a few seconds but then with foot still on brake, kick back on and race up to 2000-3000 RPM and stay there until a few seconds after complete stop? I'm fairly certain the battery is charged at this point because most of the prior driving was with ICE on and the indicator does not show "Charging while Idle".

It's very consistent and temperature (60 - 100) degrees doesn't seem to matter . Usually the AC is in vent mode with sunroof open. I don't see this condition anywhere except on extended downhill coasts. I have experienced the battery discharge/charge cycles and don't believe this is it based on how frequently I can repeat behavior.

 

That's engine braking. When your battery is fully charged, the car will spin up the engine w/o gas to cause friction to slow you down.

 

Perfectly normal but annoying behavior. The '05's spin up to 4000+ RPM but Ford toned it down for the '06 model year. It's harmless but the first time it happened to me I almost panicked.

 

Something else you need to know is... regenerative braking is for GENTLE slowing.

You only have about 50 brake horsepower ( am I using that term correctly? ) without the pads touching the discs.

This is way over simplified, but goes something like this:

If you press the brake pedal softly, the computer turns the motor into generator mode. This creates magnetic resistance to slow you down.

If you press the brake pedal medium, the computer turns the motor as a generator and applies the brake pads at the same time.

If you press the brake pedal hard or softly for a perlonged period of time, more than a few seconds... The computer turns the motor as a generator, applies the pads to the discs, AND turns on the gas engine to act as engine brake, all at the same time. Having the engine on can reduce the pressure on the brake pads.

Maybe I give the car too much credit, but I THINK the car is being proactive, and turning on the engine on purpose to slow you down, to prevent you from dragging the brake pads for more than a few seconds and heating them up.

 

Hi All

The term "engine braking" when the ICE runs up in RPM's, I believe is misunderstood here. As most of you know, my roads are pretty much flat here in So. FL and I didn't experience this situation till I began the use of charging the battery in "L" when reducing speed.

It has always been my opinion that the run up in RPM's was due to the HV battery overheating or is at it's full capacity stopping additional charging. The Traction Battery Control Module (TBCM) and Powertrain Control Module (PCM) determine battery condition, and prevent these conditions.

While there is minor regen still going on as you are going down hill or slowing with the ICE start up and run up in RPM's due to overheat or full battery, the RPM's has nothing to do with the drive axles. The only connection is the energy produced by regen or traction motor that's driving the burn off of that energy with the starter motor (generator) turning the ICE. Many times I reach a complete stop as this burn off occurs.

When I think the battery is full and cannot accept additional charging, I shift to "N" to prevent an ICE restart and run up in RPM's. The Scangauge reads Mast Air Flow as MPG even though the fuel injectors are shut off. This all effects the Navi average and the SG average.


In short, just shift to "N" at this point and use the brake pads to slow down when the battery is overheating or full.

GaryG