Day 2 below freezing, and I had some errends to run today. spent 99% time in ICE mode, as expected. I did notice some odd things if you will. the tach spent a majority of time at 2500 regardless of pedal pressure. It was like a on/off switch vs a pressure switch. Foot off = 1500 foot on = 2500 yet SG at times was showing 30-40 mpgs! not complaining, just mentioning something strange I noticed, and I needed an excuse to play with my new treo!

 

Where do you live?

 

thought it showed to the left, but in OKC. Grew up in central PA.

 

I have a 2007 FWD and noticed the same thing with RPM today in very cold temps (< 20 degrees). It was very hard to accelerate between say 1600 and 2400 RPM. It seemed to jump right up into the 2400 range even with very light pressure on the accelerator.

Anyone know what this is?

Thanks,

Rick

 

I don't know the answer, but my 08 did the same thing last weekend when it was < 20 F. Foot off pedal, 1500RPM. Touch it lightly, and jumped up to around 2400RPM, like a switch. The other noticable thing was EV mode rules about cyl head temp, state of charge, etc, all seemed to change. Sitting at a traffic light one time, my SoC was 52%, fWT was 155F, and the ICE kicked on. Outside air temp was about 12F. Normally, under warmer ambient temperatures, the ICE wouldn't kick back on until fWT dropped to ~125F. Yesterday, with temperatures back in the mid 30s, it started behaving normally.

I'm starting to think the ICE on/off algorithm is more complicated than I thought.

 

Yes. My 2005 does the same thing. I had hoped Ford did some software ( or harware? ) refinements by 2008. So on one hand, I feel better that mine behaves just like yours. OTOH I feel worse that Ford has not smoothed this out over the years.

In addition to what you describe:
At one point ( in winter of 2005-06 ) I came to a stoplight after the car was somewhat warmed up already in -10'F weather. The RPM slowed as the car slowed to near 1100 rpm when I about reached zero MPH.

Then, with my foot on the brake, car still in drive, the RPM on it's own revved up to to something over 2000, as I sat there for 20-30 seconds...

I got in contact with Ford engineering. ( I had an "in" at the time.) The reply I got was "This is not part of the design. Please have it taken to a dealer if it is convienient for you. However, understand this may not be reproducable in shop conditions, and in warmer conditions, so don't be surprised if nothing is determined."

 

It's that 98% of the answers ANY shop ever gives for a problem?!

I should add tho achieve the outstanding 17mpg, I was sitting in the school parking lot with the engine on for like 20+ min! I tried turning it off, but it got too cool quick, then I turned it "on" but not running to suck off the engine heat, it quickly droped from like 150 to 120 in like a min, so I said $crew it & just let the engine run, I'm old and a wimp now!

The only reason I was able to get it upto 17 (was sitting at 13ish) was 1/4 mile from home there was road work, so it was stop, then crawl for almost 1/4 mile, and luckily something changed to allow me to EV through it!

Apparently this is normal for <=20 air temps, just thought it odd, more like a switch than an acceleration. Not complaining, not wanting a fix, just odd.
I too at one stoplight had it go EV, for 20-30secs then ICE kick in even tho SOC never dipped below 53% (maxed at like 57%) and FwT was like 145-155 can't recall now.

 

Mine did that a few weeks ago. It was kinda annoying actually. I was going about 20mph on a long downhill in electric drive but was still only getting about 30-40mpg and the engine was pegged at 2500rpm. I understand that the car needs to heat up but I was surprised at the low MPG since I was in electric drive. After about 20 miles of downhill, it finally started acting normally. Next time, I'm going to let it warm up while I take my ski boots off!

 

For the last 2 days it's been almost impossible for me to go EV (temps 20 or below). SoC always over 50%, fWT 160 and above. In heavy traffic on the interstate this morning I came to a standstill and went EV, then accellerated and the ICE came back on. Next time I slowed, it would not go back to EV. I see the same thing at stop signs.

-- Rick

 

Rick... it is just soooooo hard to keep things hot enough in winter to meet EPA standards, etc. Driving with gas on the HIGHWAY will not get my car hot enough.... if it's really, really, cold, like sub-zero, to enable EV when I come to that off-ramp and stop.
The wind-chill at 65 MPH takes away the heat faster than the car can make it. Part of that is a good thing. Unlike most cars, the FEH does not waste gas, so there is no "waste heat". It makes less heat ( by using less gas ) year round. So this really becomes apparent in winter.
-John