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I would be most concerned with the rather low kW readings, and some of the other issues (like poor MPGcs and friction brakes engaging sooner than required) could be related.

When you step on it, the Volt should be able to pump out over 100kW from the battery to the traction motor (MGB). And max regen should be ~55kW (which happens to be the rating of the generator MGA). If you are not seeing this, I think there there is definitely something wrong. I regularly see 100+ kW draws and 50kW+ regens on my 2013 Volt .. You can say I am a spirited driver.
 
One thing that concerns me is your discrepancy of fuel consumed to fuel added. My 14 Volt was never more than .1 or .2 gallons different. I would try different gas station.
 
It sounds like an accelerator problem to me.

If the car thinks the accelerator is even slightly depressed, it disables regeneration on the brake pedal and goes straight to friction.

If the car thinks the accelerator is slightly depressed, you'll have less regen in both Low and Drive.

I'm not sure how a depressed accelerator can figure into the lower maximum power, but if the car thinks it is depressed because of a problem with the sensor or pedal, that same problem might keep it from thinking the pedal is pressed down all the way, too.

Have a close look at the pedal, make sure there aren't mats or anything else in its way. If everything looks normal, try lifting the pedal with your foot while you're slowing down and see if it matters.
 
I would be most concerned with the rather low kW readings, and some of the other issues (like poor MPGcs and friction brakes engaging sooner than required) could be related.

When you step on it, the Volt should be able to pump out over 100kW from the battery to the traction motor (MGB). And max regen should be ~55kW (which happens to be the rating of the generator MGA). If you are not seeing this, I think there there is definitely something wrong. I regularly see 100+ kW draws and 50kW+ regens on my 2013 Volt .. You can say I am a spirited driver.
*nodnod* That, plus the worn brake pad, plus the poor hill-climbing performance, just smells like there's something Very Odd going on in the braking system,
 
He should still get more kw showing when he floors it even if something is dragging. It almost sounds as if one of your motors isn't working or the clutches are malfunctioning. Odd that it wouldn't show a code or anything.
 
Discussion starter · #27 ·
Op, do you only drive your car in MM?
I have only used Mountain Mode three times "for real" beyond testing purposes.

(1) Engaged in Chattanooga with zero bars before going up Monteagle 45 minutes later and after the Reduced Power message, stopped at the truck stop and left it in MM while eating

(2) Engaged in Knoxville with zero bars before going up to Clingmans Dome TN and after the Reduced Power message, left it in MM while at the top.

(3) Engaged while parked for about an hour while eating in a small town in Northern Alabama after getting the Reduced Power message after going up a hill with zero bars and left it in MM for the rest of the drive.
 
Discussion starter · #28 ·
It sounds like an accelerator problem to me.

If the car thinks the accelerator is even slightly depressed, it disables regeneration on the brake pedal and goes straight to friction.

If the car thinks the accelerator is slightly depressed, you'll have less regen in both Low and Drive.

I'm not sure how a depressed accelerator can figure into the lower maximum power, but if the car thinks it is depressed because of a problem with the sensor or pedal, that same problem might keep it from thinking the pedal is pressed down all the way, too.

Have a close look at the pedal, make sure there aren't mats or anything else in its way. If everything looks normal, try lifting the pedal with your foot while you're slowing down and see if it matters.
Good thinking but I had already checked the sensor range with a scan tool and it reports something like 3% to 100%.

I had experimented with Sport mode but when I realized that I could reach 59 kW in both modes, I kinda ruled it out, as well.
 
Discussion starter · #29 ·
He should still get more kw showing when he floors it even if something is dragging. It almost sounds as if one of your motors isn't working or the clutches are malfunctioning. Odd that it wouldn't show a code or anything.
I agree, but there definitely no codes for anything and have never seen a check engine light. I had to turn the car on a few times to even find it!

Also what is weird is the number 59 kW. That doesn't correspond to anything. If I recall correctly, one motor is 55 kW and the other is 110 kW.

In MyGreenVolt, it shows both motors working while under wide open throttle.
 
I would say your evidence for something wrong that you can take to the dealer is right there. That 59kW.

For kicks and giggles I'd be interested in what your 0-60 time is. Sounds like it could be way slower if you are in fact getting only 59kW.
 
Discussion starter · #31 ·
One thing that concerns me is your discrepancy of fuel consumed to fuel added. My 14 Volt was never more than .1 or .2 gallons different. I would try different gas station.
I agree. My cars have always been very close to what the drivers information center reports. Or at least close enough.

As for gas stations, while I have a favorite Shell station, I've been all over.

Now consider this. As I stated in my first post, I got into a situation where I could not find premium unleaded and went ahead an put in a tank of regular remembering that some people had success with it. The car ran fine, and while I heard no audible preignition, I cannot discount events the sensor picked up that I didn't.

The interesting point is that I got noticeably better economy in CS mode confirmed with my calculator. It was definitely over 34 mpg.

If this were a flex fuel vehicle, I would wonder if the module didn't detect the correct rating or when the vehicle starts up the ICE that it didn't correctly pick the right table. As I recall there is one for premium fuel and one for lower octane.

But then again, why the poor MPG when that is a completely different system than the electric drive?

(Visualize someone banging their head against a concrete wall)

I keep pondering what could possibly be in common, what could be in common that wouldn't generate an error code.

How could the car think the power output is proportional to the inputs? For example, in a modern automatic transmission, there transmission controller compares input shaft RPM and output shaft RPM versus what ratio is selected to know if there is slippage.

I'd better quit thinking. My brain is starting hurt. Or at least something between my ears is hurting.
 
Discussion starter · #32 ·
You know, I think this might be a good excuse to get my stopwatch out.

The other Volt I saw in Atlanta was DEFINITELY quicker than mine.

And, to update everyone, I have an appointment for Tuesday the 23rd and she said they will need the car for at least the rest of the week.

On my way there, I used the Interstate in electric mode. The on-ramp has a bit of a hill on it and can say that it is about as fast as an S-10 Blazer to 70 MPH.

I'm putting a charge on the car right now because I've been driving the wheels off it. Did over 100 miles on electric yesterday alone. After I fix something for lunch, I may put that stopwatch to good use...

And, to all, thanks for your replies! All these little bits of info is useful and helps me think through what could be going on.
 
Discussion starter · #34 ·
Wild guess: are you running with something plugged into your OBD port all the time?
No. While I do have various scan tools and a Bluetooth reader, I do not believe in leaving them plugged as I do not want to add any unnecessary data on the buses.

I had a Malibu Maxx that bought a ScanGauge II for it and knew such devices could cause unexpected consequences when, just by plugging it in, caused several solenoids to activate with the engine off and key out.

Good question.
 
OK. Let’s boil down the facts to define the problem. In essence, you don’t have excessive drag because your efficiency in CD is good (4.4 miles per kWh, for example). Things causing drag such as brakes, tires, alignment, etc. go away.

Historically, the car in CS mode averaged 36.8 mpg, slightly less than advertised. Maybe the previous owner had a heavy foot on the go pedal, maybe not. Your experience is worse; 34 mpg going by what the car declares; 27 mpg if you use the gas pump figure. You may have a heavy foot on the go pedal, the car is lying, the gas station pump may not be calibrated. We have too few data points to accurately define efficiency in CS mode. At this point it is just an indicator.

BUT…

The car seems to lack power in CS mode and seems to be limited in regeneration when observing the driver’s information display. We do know that in CS mode available power is not as great as when in CD mode. That is by design. However, the OP sees a maximum of 59 kW. IIRC, in CS mode the maximum should be 80 kW – someone correct that figure if need be.

Monteagle's 4–6% grade seems steep. I drove in CS mode west toward Bolder City from Hoover Dam on US 93 with CC set at 65 mph and the Volt produced the power needed without any curtailment over about 7 miles. I mention that as the ICE was wailing like a banshee. I haven’t been able to find a published gradient for that section of road. Your experience in driving from Chattanooga to Monteagle seems suspicious.

It would be nice if Customer Care monitoring this forum would offer to help the OP with this problem.
 
Just for a comparison, I have a 2013 in the Shenandoah Valley of VA and I just clicked over 50k miles this week.
Assuming fairly ideal conditions of temperature, wind, and so forth.....
  • Generally 39mpg running the REX (Range Extender) at even highway speeds of 70-75 mph
  • Full power that I can get from just the REX tops out at 54kWh
  • 39-41 miles BEST EV range (37 is typical)
  • Running on battery tops out at 110-114 kWh
  • My Regen tops out at 59kWh and seems to dump to just hydraulic brakes at about 5-7mph.
  • Regen alone (car in "L") will not bring my car to a stop even on a flat, at 5-7mph regen stops and the car just rolls
  • 0-60 in about 7.7 sec

My car has absolutely NO problem climbing and accelerating on the 10% grades of route 33 through Shenandoah National Park while on battery, and will also "hold it's own" though not accelerate if I'm doing the same drive on just the REX although the REX howls like a banshee when I push it that hard.
 
Discussion starter · #37 ·
OK. Let’s boil down the facts to define the problem. In essence, you don’t have excessive drag because your efficiency in CD is good (4.4 miles per kWh, for example). Things causing drag such as brakes, tires, alignment, etc. go away.
Agreed. 4.0 miles per kWh is easy enough to hit.

Historically, the car in CS mode averaged 36.8 mpg, slightly less than advertised. Maybe the previous owner had a heavy foot on the go pedal, maybe not. Your experience is worse; 34 mpg going by what the car declares; 27 mpg if you use the gas pump figure. You may have a heavy foot on the go pedal, the car is lying, the gas station pump may not be calibrated. We have too few data points to accurately define efficiency in CS mode. At this point it is just an indicator.
I only consider fuel economy on long trips, such as 100+ of CS mode. Short trips vary wayyy too much.

Easy driver. Usually exceed ratings. In my pickup, I exceed the highway rating by 2 or 3 mpg most of the time. Even towing a 16,500 lb trailer in the company truck (Duramax), I get 11 mpg and I see others getting 7 to 8 mpg.

I have data on 13 trips, all but one showing in the 20s using pump data, all showing 30s using car data. (One in the 30s using pump data and that anomaly was after using a tank of regular unleaded.)



The car seems to lack power in CS mode and seems to be limited in regeneration when observing the driver’s information display. We do know that in CS mode available power is not as great as when in CD mode. That is by design. However, the OP sees a maximum of 59 kW. IIRC, in CS mode the maximum should be 80 kW – someone correct that figure if need be.
Your numbers seem logical as one motor gets reversed into generation duties.

I see a maximum of 59 kW in both CD and CS modes.

Monteagle's 4–6% grade seems steep. I drove in CS mode west toward Bolder City from Hoover Dam on US 93 with CC set at 65 mph and the Volt produced the power needed without any curtailment over about 7 miles. I mention that as the ICE was wailing like a banshee. I haven’t been able to find a published gradient for that section of road. Your experience in driving from Chattanooga to Monteagle seems suspicious.
Maybe this is a clue: I can barely hear the ICE. I can feel it buzz but overall, I think the little engine is very quiet. Definitely quieter than the engine in my truck by a long shot. (Well, especially when the ICE doesn't need to run!)

When I bought the car, I was curious about the RPM range and used a basic Actron scan tool to watch it for a little while. I didn't document it but most of the time, the engine stayed below 2000 rpm and cannot recall it ever exceeding 3000 rpm.

Under what condition could I get the ICE to reach maximum RPM ? I'm thinking about putting it into MM and drive up a 1.5 long hill. I wonder if the root generation problem is that the ICE isn't being instructed to go to the highest RPM range.
 
Discussion starter · #38 ·
Considering the range of problems, could this possibly be a defective 12 volt battery situation ?

I was thinking that the electronics are driving from the 12 volt system, would be instructing the inverter as to how much power to produce, how much to generate, etc.

My guess is that the battery is original but I haven't looked at it.

The only anomaly beyond drivability issues is that the back door push buttons don't work very reliably. However the rear hatch has never failed to release. I replaced the button battery in all three of my remotes because one was weak.
 
There are cellphone apps that will log 0-60 times. Or cheap race computers that will do it. They start when the car moves.
Charge the car up, powerbrake it, hit START, and let 'er rip. Should be in the 8.x second area IIRC. If it's 60kW, it will be about 12++ seconds.

60kW is the max regen rate. 109-113kW is the max WOT rate.

It will generate full regen rate in drive or low with the brake. Take the car up to 75mph and brake assertively but not to the ABS (pedal pulsing) level. It should stay frozen at 60kW for awhile since you are past max regen.

The ICE engine is only 84hp so 63kW peak once fully warmed up.
 
I thought I posted the 2013 0-60 times on this board, but I've never been able to figure out how the search engine works here.
 
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