MG4 Restricted speed - weird

[bowfer]

You are aware that the 150kw isnt a constant rating and continuous power is 68kw?

If the motor is overheating it might cause throttle back.

Picture from manual View attachment 15653

Not overheating, impossible.

 

[tsedge]

Not overheating, impossible.

68kW is still 91bhp, which should enable gentle acceleration. Plus people have seen this without any hard driving.

But this isn't the fault bowfer and others are seeing anyway, the car doesn't lose power, it hits a brick wall of speed and the speed changes from occurrence to occurrence.

Some have said this might be the way the motor responds to overload, by refusing to spin faster, which might be true but it is mighty strange that there's no warning given or indication of a forthcoming overload.

I don't think it is either or these things, I think it is a bug that is being triggered somehow, likely related to hard work / acceleration.

 

[Xiao Wazi]

This isn’t power being ramped back and then speed suffers accordingly.
It’s the other way around.
The car decides what speed I’m being allowed, then stops at that speed and the power is ramped back to a level that holds that speed.
For example, last night the car decided 71mph was all I was getting.
So up to 71mph I got full power, then once it stopped at 71mph it decided 38% power was all I needed to hold that speed and the power meter tumbled accordingly.
Stamping on the throttle or coming off gently and reapplying gently makes no difference.

It kind of sounds like some sort of EV version of rev limiting. Perhaps the battery in the SR doesn't cope very well with being asked to give out max power?

Has anyone reported this issue on an LR or Trophy as this uses the older battery technology?

I’ve not checked but if it’s true there’s a lot of low mileage examples for sale already it’s perfectly reasonable to suggest it’s cars that have been handed back.
They can’t all be ex-demo and it’s far too soon for them to be motability.
There’s no doubt in my mind plenty have been handed back for less than I’m experiencing, people will have rejected over oil leaks alone.

Don't forget the lock-in issue as well as an owner even went to The Sun newspaper about it which might have caused some owners to reject the car before the fix was issued by MG Motor UK to dealers.

Experienced my first power loss yesterday in my SE SR, similar to others.
Left on a short trip with 38% battery, but on the return leg it was down to 18% about 3 miles from home on a 70 mph dual carriageway.
Going up a long hill just before my exit doing about 70 mph, I started overtaking a slower truck. Pulled into the outside lane, got half way past the truck, put my foot down and..... nothing! Worse still, my speed started dropping and another car came up behind me in the outside lane! Fortunately, the truck slowed down more than I and I just managed to creep past him and cut in to make my exit in time.
I call that DANGEROUS!

This car needs an EV equivalent of a Nitro boost button to get you out of sticky jams or even a DRS mode.

 

[bowfer]

This car needs an EV equivalent of a Nitro boost button to get you out of sticky jams or even a DRS mode.

Or just make it work properly.

 

[Xiao Wazi]

Or just make it work properly.

This sounds like beyond what is possible with the current people in charge of SAIC in China.

Some car manufacturers have an EV boost feature:

https://www.kbb.com/car-advice/what-is-ev-boost-button/

 

[stevegus]

68kW is still 91bhp, which should enable gentle acceleration. Plus people have seen this without any hard driving.

But this isn't the fault bowfer and others are seeing anyway, the car doesn't lose power, it hits a brick wall of speed and the speed changes from occurrence to occurrence.

Some have said this might be the way the motor responds to overload, by refusing to spin faster, which might be true but it is mighty strange that there's no warning given or indication of a forthcoming overload.

I don't think it is either or these things, I think it is a bug that is being triggered somehow, likely related to hard work / acceleration.

The reason i suggested its overheating is Bowfer has multiple times indicated hes a fast driver. And it does it on a fast stretch. So ifvits been booted for a bit then arrives at that fast stretch perhaps it’s overheating by then.

The car shouldn't do that obviously.

But it could be that most here dont have the issue, perhaps they are not driving it as hard?

Perhaps i can experiment if / when mine arives in a couple weeks. But its an ER not a SR as Bowfer has

 

[Ian Key]

Just a random thought. Could it be a glitch in the road sign recognition software and the car is picking up a speed limit sign and preventing the car going over that speed?

 

[tsedge]

The reason i suggested its overheating is Bowfer has multiple times indicated hes a fast driver. And it does it on a fast stretch. So ifvits been booted for a bit then arrives at that fast stretch perhaps it’s overheating by then.

The car shouldn't do that obviously.

But it could be that most here dont have the issue, perhaps they are not driving it as hard?

Perhaps i can experiment if / when mine arives in a couple weeks. But its an ER not a SR as Bowfer has

LR you mean? I thought the ER wasn't launching until later in the year?

It isn't just bowfer, others have seen it and he has seen it lots of times without any long periods of hard driving beforehand.

I think it may happen more often with hard driving but it doesn't seem likely to be a cause, this isn't lack of cooling capacity on a track like the early Teslas.

Just a random thought. Could it be a glitch in the road sign recognition software and the car is picking up a speed limit sign and preventing the car going over that speed?

Haven't seen any 63mph signs around here! It is certainly behaving like it is applying a speed limit but hard to know what triggers it.

 

[bowfer]

Just a random thought. Could it be a glitch in the road sign recognition software and the car is picking up a speed limit sign and preventing the car going over that speed?

No because that would mean the car never going over 70mph.
I’ve had mine apply the speed restriction at more than 70mph.

 

[OhmMy]

At the point your foot was down but the speed wouldn’t rise, the power meter will have tumbled.
I don’t suppose you noticed what it went down to?

Sadly no .... too busy panicking!
Going to replicate the trip tomorrow with more charge in the battery to see what happens.

 

[bowfer]

Sadly no .... too busy panicking!
Going to replicate the trip tomorrow with more charge in the battery to see what happens.

Understandable.
It will do it again, trust me.
Indications it’s going to happen are regen braking disappears, and the car feel a bit lethargic and ‘lumpy’ in power delivery.
When I get these symptoms I know to get the passenger ready with their video camera.
I never know what speed I’m going to get limited to though, that’s alway a surprise.

 

[Eber]

I never know what speed I’m going to get limited to though, that’s alway a surprise.

It's so frustrating that it's not logical and it doesn't make any sense.

 

[bowfer]

Well that’s the rejection made formal.
Email sent to MG finance (Santander) and the dealer.
Should just be a matter of time now, when the car has easily spent 50% of its time in the dealer you shouldn’t get any arguments.

 

[tsedge]

Well that’s the rejection made formal.
Email sent to MG finance (Santander) and the dealer.
Should just be a matter of time now, when the car has easily spent 50% of its time in the dealer you shouldn’t get any arguments.

Hope that sorts it out for you and you get a replacement car of a new make that is trouble free.

Thank you for sharing your experiences here.

 

[bowfer]

Hope that sorts it out for you and you get a replacement car of a new make that is trouble free.

Thank you for sharing your experiences here.

I’ll be back to report on the progress of the rejection ( might help others ) and to say bye.
Good forum this, good sense of humour.

 

[Deleted member 10041]

I’ll be back to report on the progress of the rejection ( might help others ) and to say bye.
Good forum this, good sense of humour.

Totally agree

 

[jon0881]

Im one of the few that reported this too. Im the early days of ownership i was getting 1m pkwh according to the GOM but a couple of balance charges sorted that. The limit i still get occasionally for sure feels like a protection thing as the power goes very quickly down to 40% regardless of speed as you can be going up or down hill which effects that.

After its 'triggered' i can easily recreate it by putting my foot down at higher speeds, Normal and sport mode for the rest of the journey. Mine will be on its 2nd visit back to the dealer for other things so this is added

 

[TheHypnoToad]

Im one of the few that reported this too. Im the early days of ownership i was getting 1m pkwh according to the GOM but a couple of balance charges sorted that. The limit i still get occasionally for sure feels like a protection thing as the power goes very quickly down to 40% regardless of speed as you can be going up or down hill which effects that.

Can I ask, do you have the SR or LR battery?

 

[jon0881]

im driving an SE SR. today i was able to repeat the issue and im convinced this is due to a cold of <40% charged battery. i started the day at 50% and coming out of work i had about 33%. Work to home is about 10miles. i got home with 11% whilst it was limiting power to 20% at motorway, then 80% on normal roads. it chewed through the battery so im convinced this is a poor battery or bad software protecting the battery. I videoed it too.

 

[TheHypnoToad]

Thanks, sounds like a bad battery to me, or one that wasn't tested properly before leaving the factory.