Over revving at 70mph

[Dean3452]

Hi. I bought my MG HS PHEV 4 weeks ago.
I started to have trouble when driving on a flat or slight decline where the engine in HEV mode would sit a 3000rpm.
Even when letting go of the accelerator the engine would not change gear.
I have since taken the car back to the main dealer who reconfigured the software. Who immediately informed me the gearboxes are very lazy and not much good.
This didn't install me with much confidence about the MG Brand.
They have informed me that the car now, will have to learn my driving style ??, and that the car would perform even worse for a short while.
This was over a week ago.
Now when driving at 70mph the car in HEV is revving at 4000rpm constantly without changing gear, and I am averaging 18MPG.
I am driving down to Newquay in a couple of months in a car I have no confidence what so ever in.
I had a doubt in my head about buying a SUV that was 10k cheaper than other leading brands.
My doubts are becoming my nightmares.
Has anyone else experienced anything similar?

 

[salty]

Dean, sorry to hear about your new motor, giving you problems. It's well documented on other threads on here, about this problem. Same problem with the MG3 and ZS Hybrids. Have a look at them.
You've found out quickly that MG dealers are next to useless. Good luck.

 

[BoJoUK]

Hi. I bought my MG HS PHEV 4 weeks ago.
I started to have trouble when driving on a flat or slight decline where the engine in HEV mode would sit a 3000rpm.
Even when letting go of the accelerator the engine would not change gear.
I have since taken the car back to the main dealer who reconfigured the software. Who immediately informed me the gearboxes are very lazy and not much good.
This didn't install me with much confidence about the MG Brand.
They have informed me that the car now, will have to learn my driving style ??, and that the car would perform even worse for a short while.
This was over a week ago.
Now when driving at 70mph the car in HEV is revving at 4000rpm constantly without changing gear, and I am averaging 18MPG.
I am driving down to Newquay in a couple of months in a car I have no confidence what so ever in.
I had a doubt in my head about buying a SUV that was 10k cheaper than other leading brands.
My doubts are becoming my nightmares.
Has anyone else experienced anything similar?

TBH I think that the engine is running at that speed only because it is charging the battery, it will not be driving the wheels, they are being powered by the electric motor.
There are other entries in this forum that explain how the drive system works on the new HS PHEV. It only gets power from the ICE when applying full acceleration. At other times the engine just acts as a generator.
Very clever and very good.

 

[Dean3452]

TBH I think that the engine is running at that speed only because it is charging the battery, it will not be driving the wheels, they are being powered by the electric motor.
There are other entries in this forum that explain how the drive system works on the new HS PHEV. It only gets power from the ICE when applying full acceleration. At other times the engine just acts as a generator.
Very clever and very good.

I believe that is the case with the ZS, not in the HS PHEV.
I can not possibly accept that in HEV mode on a motorway cruising at 70mph, the engine should be screaming at 4000rpm to charge a battery.
This is constant and my fuel economy drops to 18mpg. This is neither economical or effective.
Its going back in on Monday as in the last half hour its also developed an engine management fault due to emissions.
Oh and I am now unable to scroll through my navigation, tyre pressure and Mileage info.
By the way I would be most grateful if you could point me in the direction of an explanation on how the HS PHEV engine works that would be amazing.

 

[Dunkie59]

The Roewe D5X-dmh is the Chinese version. They have an interesting video about the PHEV on their web page (https://www.roewe.com.cn/vehicles/d5x-dmh/#) Try visiting it via Chrome browser and letting Google translate the page for you. I believe it uses the Miller petrol engine cycle (as opposed to Atkinson or Otto)

 

[Dean3452]

Thanks. I have done a bit of research on Parallel and Series Hybrid set ups.
I agree, very clever. But do other HS PHEV owners experience such high RPM's at cruising speeds?
I could live with the engine firing up at 2000rpm to charge the battery, which would be far less intrusive than thrashing away in the background at 4000rpm for over an hour.

 

[BoJoUK]

I believe that is the case with the ZS, not in the HS PHEV.
I can not possibly accept that in HEV mode on a motorway cruising at 70mph, the engine should be screaming at 4000rpm to charge a battery.
This is constant and my fuel economy drops to 18mpg. This is neither economical or effective.
Its going back in on Monday as in the last half hour its also developed an engine management fault due to emissions.
Oh and I am now unable to scroll through my navigation, tyre pressure and Mileage info.
By the way I would be most grateful if you could point me in the direction of an explanation on how the HS PHEV engine works that would be amazing.

I do believe that this is how the HS PHEV works, and there is quite a good posting from user “aerofurb” called:

2025 MG HS Trophy PHEV v 2020 Skoda Superb iV Sportline PHEV​

As the title describes, he is comparing the 2025 HS PHEV to his older Skoda, but he explains quite well how the drive train works.
However, you are now getting more problems and it is booked into the garage next Monday, please keep us updated as I am sure that you are having more problems with your car now.
I tend to only use the EV mode so haven’t seen if the engine revs are much higher when using the HEV mode. Mine normally starts at about 2200 revs, then 2400, sometimes higher and then down to 1400 revs before going back to 0 revs. The other thing I have noticed is that mine runs the available mileage on battery, down to Zero before the engine starts up. As I say, this might be because I use it in EV mode.
Good luck and I hope they get it sorted for you.