rduclos
Posts: 10
Joined: Sat Jul 08, 2017 9:17 pm
Delivery Date: 03 Jul 2015
Leaf Number: 336420
Location: Nova Scotia, Canada

Brief torque loss during acceleration, a potential life-threatening event.

Sun Dec 30, 2018 11:26 pm

While similar events were described four years ago at http://www.mynissanleaf.com/viewtopic.p ... 9&start=10 , my recent experiences have seriously upset my faith in the safety of EVs. I have owned and driven a 2014 Leaf 39000 Km over nearly four years, during which its quick and reliable acceleration had given me confidence in performing certain maneuvers, such as quickly merging into a traffic stream, or turning left through a gap in opposing traffic. Now I am experiencing occasional random total loss of torque during rapid acceleration, occurring usually one or two seconds after applying the increased power and lasting about a second, and sometimes repeating, then resuming full normal acceleration. I normally drive in Eco mode and often also in B mode. I live in eastern Canada with temperatures near freezing.

This is, as I said, occasional and random, and is hard to replicate. A dealer might never encounter it, so I am starting to take it seriously enough to try to analyse the circumstances when it does occur. I am also starting to drive more conservatively when in traffic (sort of spoils some of the fun of driving an EV).

Edit on Sun Feb 24, 2019 2:41 am:
Two months and two thousand kilometers later on the same car and driver this has not happened again!
So why it happened (about five times) last December is still a mystery. The last time was particularly bad as it occurred twice during the same acceleration while moving into a traffic stream ahead of another vehicle --- very upsetting at the time and leading me to post this notice the same day. I continue to drive more cautiously in traffic as a result.
Last edited by rduclos on Sat Feb 23, 2019 11:44 pm, edited 3 times in total.

cwerdna
Posts: 9390
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 12:46 am

It's possible it's normal and that it's traction control and/or stability control cutting power when it detects wheel slippage. What tires are you running? Are the front tires nearly worn?

You say "rapid acceleration" and "full normal acceleration" and "eastern Canada with temperatures near freezing." Also, you mention Eco. The responsive of the go pedal is really sluggish feeling for much of the travel in Eco (I almost never use it) and then perhaps you're making a sudden sharp increase when floor it or nearly floor it.

If it happens only on wet road or road that's snowy or slushy under hard acceleration, that's probably your problem. Do you have other FWD cars w/non-snow tires and with traction control or stability control?

Remember that on FWD cars, when you accelerate, the car squats and weight is transferred to the rear wheels, which provide no propulsion. And, weight is coming off the driven front wheels so there's less downforce on the fronts and more potential to lose traction and have the front wheels break loose.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

lkkms2
Gold Member
Posts: 339
Joined: Wed Jul 20, 2011 8:10 am
Delivery Date: 30 Dec 2016
Leaf Number: 302025
Location: San Diego/National City, CA

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 3:50 am

rduclos,
Understand your concern 100%. That would be very unsettling if the acceleration wasn’t there when you expected and needed it.

Traction control could be part of the issue. (As cwerdna mentioned.) I remember (vaguely) that my 2002 Prius had an issue similar, but I think it was related to the breaking suddenly wouldn’t work over certain bumpy road conditions. Toyota had to replace the electronic components that sensed the road conditions. (Sorry at the moment can’t recall exact name of components).

Another possibility is the extreme cold temperatures (and aging) affecting the connections of the electrical components. Have dealer check all the connection. Also maybe the component controlling the acceleration needs to be replaced.

Besides contacting the Dealer I would also call customer service to see if there is any technical bulliten related to this kind of condition.

Because this is definitely a safety concern be sure to get resolved as soon as possible!
2011 Leaf SL purchased 6-22-2011, sold 1-18-2017 with new battery.
2017 Leaf SV with Premium Package purchased 12-30-2016

User avatar
Nubo
Posts: 5187
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 4:15 am

cwerdna wrote:It's possible it's normal and that it's traction control and/or stability control cutting power when it detects wheel slippage. What tires are you running? Are the front tires nearly worn?

You say "rapid acceleration" and "full normal acceleration" and "eastern Canada with temperatures near freezing." Also, you mention Eco. The responsive of the go pedal is really sluggish feeling for much of the travel in Eco (I almost never use it) and then perhaps you're making a sudden sharp increase when floor it or nearly floor it.

If it happens only on wet road or road that's snowy or slushy under hard acceleration, that's probably your problem. Do you have other FWD cars w/non-snow tires and with traction control or stability control?

Remember that on FWD cars, when you accelerate, the car squats and weight is transferred to the rear wheels, which provide no propulsion. And, weight is coming off the driven front wheels so there's less downforce on the fronts and more potential to lose traction and have the front wheels break loose.


Another thing that can trigger traction-control is having differently-sized tires between front and back. I replaced 2 tires (due to puncture) on our 2012 and even though they were the same specs, the difference in diameter between the new and worn tires was enough to cause the car to hunker down, especially around turns. Dealt with it temporarily by swapping front/rear. I forget which tires ended up where.
I noticed you're still working with polymers.

garsh
Posts: 1173
Joined: Sat Feb 12, 2011 5:27 am
Delivery Date: 05 Apr 2012
Location: Pittsburgh PA

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 5:17 am

Nubo wrote:Another thing that can trigger traction-control is having differently-sized tires between front and back. I replaced 2 tires (due to puncture) on our 2012 and even though they were the same specs, the difference in diameter between the new and worn tires was enough to cause the car to hunker down, especially around turns. Dealt with it temporarily by swapping front/rear. I forget which tires ended up where.

I ran tires that had a larger diameter than stock for a while (235/50R17). What I found was that the size of the rears didn't matter. But having front tires with a larger diameter than stock really confused the traction control system. For the most part, there was no issue. But for whatever reason, taking a sweeping bend at around 40 mph would cause the traction control to kick in like crazy. I'd lose all forward momentum and slow down as the traction control kept pumping the brakes. It was very disconcerting.

rduclos, if you've installed tires with a different diameter as well, and you suspect that this might be what you're experiencing, then disable traction control. That "solved" the problem for me, at least until I wore out those front tires and replaced them with a smaller diameter tire.

Even when I replaced them, I went a little larger diameter than the 16" OEM tires (but should have been the same as the 17" OEM tires that Leafs came with a few years later, 215/50R17). And even with those tires, I had a problem when I kept the air pressure in the 40s. At that point, lowering the air pressure to 30-35 prevented the issue from happening. So that's another thought - even if you have the OEM 17" wheels, make sure you don't have the air pressure too high. The traction control doesn't like the little bit of increase in tire diameter that the increased pressure causes. The traction control is unnecessarily finicky.
2012 Black SV, bought 2012-04-04, sold 2019-05-10. 7 bars, 101,850 miles.
Current rides: 2018 Tesla Model 3 Performance, 2018 Chevrolet Volt LT

SageBrush
Posts: 4255
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 7:10 am

Time for new tyres I suspect. Or at least a rotation.
Last edited by SageBrush on Mon Dec 31, 2018 7:23 am, edited 2 times in total.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

DaveinOlyWA
Posts: 13880
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 7:15 am

turn off traction control and see what happens
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

rogersleaf
Posts: 255
Joined: Sun May 18, 2014 7:50 pm
Delivery Date: 22 Mar 2019
Leaf Number: 307726
Location: Kent, Ohio

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 7:30 am

rduclos wrote:While similar events were described four years ago at http://www.mynissanleaf.com/viewtopic.p ... 9&start=10 , my recent experiences have seriously upset my faith in the safety of EVs. I have owned and driven a 2014 Leaf 39000 Km over four years, during which its quick and reliable acceleration had given me confidence in performing certain maneuvers, such as quickly merging into a traffic stream, or turning left through a gap in opposing traffic. Now I am experiencing occasional random total loss of torque during rapid acceleration, occurring usually one or two seconds after applying the increased power and lasting about a second, and sometimes repeating, then resuming full normal acceleration. I normally drive in Eco mode and often also in B mode. I live in eastern Canada with temperatures near freezing.

This is, as I said, occasional and random, and is hard to replicate. A dealer might never encounter it, so I am starting to take it seriously enough to try to analyse the circumstances when it does occur. I am also starting to drive more conservatively when in traffic (sort of spoils the fun of driving an EV).

The problem and link you referenced are from my posting a few years ago. Unfortunately I no longer have the car or the service paperwork describing the repair. The skinny on the malfunction is the power control system thinks the brakes are applied, thus blocking acceleration. I do remember it involved replacing an insanely expensive brake system module and some software updates.
2014 SV - Brilliant Silver - returned 1/2017 at end of lease.
2019 SL - White - w/Tech Package

rogersleaf
Posts: 255
Joined: Sun May 18, 2014 7:50 pm
Delivery Date: 22 Mar 2019
Leaf Number: 307726
Location: Kent, Ohio

Re: Brief torque loss during acceleration, a potential life-threatening event.

Mon Dec 31, 2018 7:42 am

If my memory doesn’t fail me, that module was north of $2k USD at the time. I do remember it was enough to convince me that I never want to own one of these outside of full warranty protection.
2014 SV - Brilliant Silver - returned 1/2017 at end of lease.
2019 SL - White - w/Tech Package

DaveinOlyWA
Posts: 13880
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Brief torque loss during acceleration, a potential life-threatening event.

Tue Jan 01, 2019 9:38 am

rogersleaf wrote:If my memory doesn’t fail me, that module was north of $2k USD at the time. I do remember it was enough to convince me that I never want to own one of these outside of full warranty protection.


So not an EV specific issue then...
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Return to “Problems / Troubleshooting”