I was pulling out of work today, and after pulling onto the feeder, I noticed I had very little power initially. I didn't think much until I got to the light. From a dead stop, I push the accelerator, and have almost nothing ...I am barely coasting. So of course I push the accelerator down all the way. very slowly, I build rpm and speed, until maybe 1600rpm or so...at which point it revs pretty quickly past 4000 rpm.
Now I know I have a problem...I have absolutely no power assist. I guess the FEH engine really needs the electric motor to help it spool up. I soon realize that as long as I don't come to a complete stop, I am ok, but I am no longer charging in braking or coasting or getting any help from the electric motor on acceleration. I don't have a scan guage, but the built in system check shows that everythig is fine, and no error codes or lights. About 5 miles into my trip home out of 6, I finally noticed a little electric assist, but not much. AC was on high and cooling about the same as usual....ok given the 103 temp, but nothing to get excited about. I made it home fine, but am really concerned about the possibility of a very expensive repair. My first thought was that it must be the heat. Maybe the battery was too hot and it shut down the electric assist until the ac could cool it down. Today was hot, maybe the hottest of the year, but it has been hot all summer and I have never had anything like this happen before.
I waited until the evening, and took it on a short run around the block. I had electric assist from the start, but it seemed a bit weak...rather than giving me everything on full acceleration, the guage was showing 60% or so. Still, this was much improved from my trip home. I am hoping it will drive normally in the morning.
Facts:
2006 Ford Escape Hybrid
80,000 miles
The wiring harness has been replaced
Any thoughts on if it could really just be the heat, or something else? Cooling Fans? failure imminent? any ideas? Thanks in advance. This is my first post, but I've been reading you guys for years.
-Richard

 

This part of your experience matched the one I had this summer. My FEH sat in the sun for 6 hours on one of the hottest day of the year. Then, when I went to leave, it was very weak with no regen....like you saw above. Got it going on the highway for about 15 mins with the A/C on full blast and it finally came around in about 20 minutes....as I drove stop and go around town. Never happened before and never since. I am at about 70,000 mi. I believe the traction battery was over temp.

 

Morning Update: So I drove to work this morning with no problem at all. It drove like it was brand new... I hope this was a one time thing due to the extreme heat we are having, but we'll see if I head out for lunch or on my way home this evening.Still...that doesn't really make much sense because as I stated, it is always hot in houston in the summer. Maybe yesterday was 103 instead of 99, but that doesn't seem like enough to push it over the edge. Thanks for sharing your experience Glennb.
-Richard

 

I had something very similar happen to me while driving across country in mid July. I crossed over into Port Huron, MI and had the temps climb quite a bit while there. By the time I hit Chicago it was up to almost 100f, driving across the country (through Wisconsin, Minnesota, South Dakota and eventually Montana) I had poor electric assist for the first 30 mins until the AC could cool the battery and cabin. After that everything was fine.

 

I have a 2005 FEH and this summer developed a slight leak in rear air conditioning lines to hybrid battery and found that if the hybrid battery got to 100F it wouldn't go into EV. I didn't have any issues of power loss though. I have a scanguage and 1 of the guages is hybrid battery temp

 

You took the ferry ride over from Sarnia to Port Huron?

 

No, I drove across the bluewater bridge

 

So it has been a couple days, and the problem has not repeated itself. It's been just as hot, so who knows. It is still getting over 100 here in houston, so the inside of the car has to be getting over 120 if not higher. My AC performance seems fine, so I doubt I have a leak in an ac line, but I will continue monitoring. Thanks to everyone who has replied. Hopefully this was just a one time fluke.
-Richard

 

I took the ferry one time. Darn thing left the dock but every time another car appeared with Canadian plates it returned to get it. It did that 3 or 4 times! Never again for me.

 

Richard- sounds 'normal' and heat related. For sure a rare event.
The peak battery assist actually occurs at 95°F. Warmer than this and assist decreases by about 3% per degree. A hot parked car will give the battery an over-temp condition before you even start. Going the other way (colder) you lose about 1% per degree, so it is even more gradual.