Hi everyone... I am experiencing an occasional monumental loss in acceleration with my 2008 Ford Escape Hybrid. I seemed to have stumped my Ford mechanic.

First, I should give you a baseline description of how the vehicle usually performs off the line. Usually, if I put the pedal to the metal (as they say) it jumps off and accelerates they way it should. It is no race car, but if I was sitting in an intersection trying to turn left and noticed someone about to run a red light and t-bone me, I would have time to scoot out of the way.

Occasionally, however, I experience a total inability to accelerate with any umph whatsoever. When things are running as usual, it usually takes 9 or 10 seconds to do 0-60. Once this problem happens, though, it takes 17 seconds instead. From 0-20mph takes the longest time... and then after I hit 20mph, it acts a little more normally, but I can still feel a loss. I might add, when this happens, I have never gotten a check engine light, and no code is generated.

I brought it to the local Ford service shop and had their mechanic drive around with me while this problem was actively happening. He plugged in his fancy computer and had me drive around. Although it was obvious to him that there was something majorly wrong with the acceleration, his computer program told him nothing out of the ordinary. All systems, from his findings, were running normally.

I told him it would be a tricky thing to try and fix because usually, if the car sits overnight, it tends to correct itself. On average this happens once or twice a month.

The mechanic had it for a week, and apparently "reset modules and loaded newest firmwares, etc (yada, yada") and told me to come pick it up because it was running just fine for him. So, I picked it up today, drove it on city streets for 12 mins and it was running fine. Then I took it on the freeway and a few mins later, I could tell the problem was back. So, I exited and stopped at a red light. When it turned green, I confirmed... no change to the problem at all.

Now, when does this tend to happen? I have really been thinking about my driving style / situations when this problem happens... and it is hard to pinpoint one situation that throws it into this mode. Sometimes it happens when I am on a freeway with the A/C on... sometimes it happens when I drive up a hill, or reverse up my steep driveway. Sometimes it happens after I accelerate quickly. It feels like it happens more when the A/C is on... but I am not totally sure about that.

Another thing... once it goes into this "mode" it will NOT ever go into full electric mode. Usually I go into full electric mode and stay there below 20mph. If I am sitting at a red light or something, the gas engine shuts down and I sit in battery mode. But, once the acceleration goes, so does the hybrid mode.

I would love any advice you all have. It is sitting at the dealer now.

2008 Ford Escape Hybrid. 90k Miles.

Thanks!

 

I have a bit of the same problem with my 2007, 85k miles, although I only experience it when accelerating from a stop. Several times now I've been in mid-intersection waiting to turn left, in EV mode, and then barely accelerated when I floored the gas pedal. It's a scary feeling seeing oncoming traffic with little power to move quicker.

I'm not getting any codes or other symptoms that could explain this. The a/c was off and I was in EV mode with ICE off when it happens. For now I'm just being more conservative in my driving while I wait to see what this develops into.

 

The Atkinson cycle engine is gutless off the line. It relies on the electric motor to compensate.

As you speed up and the rpm rises, you get most of your power from the ICE.

What you describe sounds very much like a hot battery - not necessarily dangerously hot, but hot enough to where the system dials back the utilization.

 

Do you have a ScanGage or other app to monitor battery temp, SOC etc?

 

Here is a frustrating update.

I told the dealership about this forum and showed him everything everyone said. He then tested the battery temps and they are all normal. He ran every other sort of test he could... and they were all normal as well.

They brought it to the transmission dept and they pulled a d7000 code. They reset this code and told me to drive it for a few days.

I left the dealership and 5 mins later the problem returned.

Not sure if this is related... but about 5 months ago I got a STOP SAFELY NOW warning. When I took it in, they told me they had to replace the fuel pump. Ever since then, this happens way more often.

Thanks for the continued advice.

 

Sounds exactly like a hot HV battery, cold battery, depleted (low) battery, or otherwise deactivated battery.

 

How is your air conditioning functioning? If the a/c system has developed a leak and lost enough refrigerant it could cause the problem you described. I think the battery temperature cutoff is rather low, ~100 F if I remember correctly.

 

I wonder as these FEH's high voltage traction batteries age (irregardless of mileage), they may not be able to charge/discharge very well. Suspect the Ford diagnostic computers were not designed to evaluate the HV battery's overall performance, only a failed battery (i.e. no start condition).
Maybe someone could go in cell by cell and rebuild/rebalance battery packs like they do for old Priuses and Insights. Haven't heard about this happening for FEHs but it could be about time (if there is any interest).

 

I would check on your scangauge and see if you are getting high module delta voltage right before it happens. An imbalanced pack will do what you're describing and you'll see high delta right before the software cuts off allowing assist.

 

@thatjoerussellguy This is EXACTLY what is happening with our 2008 Escape at 86,500 miles. We also stumped our Ford Mechanic at the Dealership. They had it for 5 days, the mechanic took it home overnight and he experienced the failure but had no true fixes. The first problem I suspect is that the mechanics are no longer able the think through as well as in the past. They are reliant on the read outs and codes. This trouble produces no codes or alerts in the system.
I have noticed a correlation with this trouble and no/low 'green' in the HV battery icon on the Energy Screen. I shared a Video of it happening with the dealer. I also suspected the A/C use correlation, but I have proved that theory wrong over and over. This is so very random, but it is happening mostly every time we drive.
As described in this thread, (and how I describe ir every time) it really feels as though the HV battery just drops off. With no HV assist this thing is so powerless to dart out. I live in an urban area and that is 95% of our driving.
The mechanic 'suggested' cooling fan replacement per code (sorry not in my hand) from the Ford Website. He placed a call to Ford Hotline for help and I have not heard back. I will call again Monday.
Thanks for this thread. Good to have proof I am not crazy...about this