Ok, I replaced my cabin heater pump, so now my CHT actually drops while I sit at a stop light. I always thought the ICE didn't re-start until the CHT dropped to 150 F. Mine is kicking back on when the CHT drops to 188 F. This is with outside temps around 10-20 F. This really limits my EV time as the CHT temps drop faster than the SOC.
I'm pretty sure my ICE used to not re-start until 150 F during warmer weather. I wonder if the re-start temp changes below a certain outside temp.

Can anyone from a cold weather area verify at what CHT their ICE re-starts from EV mode?

 

There have been problems with stuck open thermostats in earlier FEH. That may have been you're problem in the first place. In the '09 FEH, Ford had new sensors installed to detect this.

Gary

 

I just had the thermostat replaced about 2 months ago. The FEH heats up just fine to about 220-235F (CHT) depending on my speed.
Again - is there anyone from a cold weather area that can verify at what temp their ICE re-starts when sitting stopped in EV mode?

 

From the gpsman1 sticky thread on top of this forum:
-CHT was at 168 degrees when FWT was at 138 during electric drive mode when ICE fired up because SOC fell below 40%. The outside air temperature was 35 degrees-sunny-no wind at 4:15pm 12-18-07
12-25-07 2:30pm 36 degrees able to sustain electric mode at CHT of 158 and FWT at 142 before ICE came on when SOC hit 40%.
12-26-09 5:40am 29 degrees outside--driving the short (<1mile) distance from home to the YMCA for an early workout when I slowed for a stop sign, shifted into L and "popped" the vehicle into electric mode. CHT was 188 and FWT was 154. This happen two more times in the next 90 minutes--the drive back home and the drive to work. Both times at the same 188 CHT reading.

Maybe this isn't as cold as what you are experiencing in the Twin Cities but it is a reference. I'm curious on what your CAT temperature is (it drops fast in EV) when you ICE fires up.

 

I suspect something might be amiss then.

I'll set up my scangauge to read the CAT temp so I can monitor it. Any idea at what temp the CAT cooling off to would cause ICE start-up?

I can't sustain EV mode below 190 CHT with SOC at about 48-52%. Yesterday we had slightly warmer temps (about 35F) and still saw the same ICE start-up at 188 CHT. This is with completely warmed up vehicle after about 20 miles at highway speeds (and normal 225-230 CHT seen while on the highway)

 

If my memory serves me correctly, normal CAT is like 1250-1300F. I believe I have seen sub 900F before the ICE fires up.

 

Thanks. I set up CAT on my scangauge last night. I'll watch it when I go out today.

 

Checked my CAT temps today and they never even reached 900, even after vehicle being warmed up and a short stint (2 miles) on the highway. Doesn't seem to be any correlation between CAT and ICE restart. But when CHT cools down to 188F the ICE starts up, every time. Temps outside today are just below zero F.

 

A too cold hybrid battery will cycle between "charging" and "discharging" in an attempt to warm itself and thus will make EV bout very short or not possible. Monitor the TAV and AMP values on the scanguage for details.

 

I know about this behavior and see it when the battery is very cold.
Tonight the HV battery was above 52F and SOC above 50 but as soon as the CHT hits 188 the ICE starts up, every time. AMPS don't matter as it will even happen sitting still, drawing no motor amps.
I know you can't get into EV mode until you've initially hit 190F CHT, but during warmer weather (above 40-50F) I know I could run the SOC right down to 40 and/or the CHT down to 150F before ICE startup. I wonder if there is something in the programming that won't allow the CHT to cool down anywhere as much when the outside temp is so cold.
I wish we had someone from Ford who could verify exactly what is 'normal' in cases like this.

- EDIT -

OK, I started searching through the Scangauge Data Depository 'sticky' and found in a GPSMAN1 post:

"Required CHT for EV in below freezing conditions is 216'F, and stays EV until 190'F.
( engine comes on at 188'F ).
EV is possible in warm weather with CHT at 150'F or warmer. ( Engine comes on at 148'F )"

So, maybe my FEH's behavior is 'normal'. Will continue to investigate.