[Steve D]

I've recently bought a 13 plate B-Max 1.4L that has only done 15K. I noticed that if you try putting your foot down say at 60mph in top gear, the engine dips and feels flat. However if I back the throttle off it seems to start picking up quicker. Any idea's?

 

[cianpars]

Could be low fuel octane - how long has the fuel been in your tank? where did you buy the fuel?
When was it last serviced?

Otherwise, what you describe sounds like slight fuel starvation or timing too far advanced.

 

[KeithW]

The 1.4 litre petrol version is unfortunately the slowest and least economical model. It uses the Duratec engine (originally the Sigma engine designed by Yamaha way back when) which is a 1990's DOHC naturally aspirated engine and is never going to give the sort of performance the newer turbocharged 1.0 Litre ecoboost or 1.5 litre TDi can achieve. To get the best from it you are going to need to rev it and use the gears rather more. Think of top gear as overdrive on this car as it just doesn't have the torque of the other engine options.

Torque at 3000 rpm
1.0 ecoboost 170 Nm
1.4 Duratec 124 Nm
1.5 Duratorq 260 Nm

 

[cianpars]

The 1.4 litre petrol version is unfortunately the slowest and least economical model. It uses the Duratec engine (originally the Sigma engine designed by Yamaha way back when) which is a 1990's DOHC naturally aspirated engine and is never going to give the sort of performance the newer turbocharged 1.0 Litre ecoboost or 1.5 litre TDi can achieve. To get the best from it you are going to need to rev it and use the gears rather more. Think of top gear as overdrive on this car as it just doesn't have the torque of the other engine options.

Torque at 3000 rpm
1.0 ecoboost 170 Nm
1.4 Duratec 124 Nm
1.5 Duratorq 260 Nm

Fair enough, but it still shouldn't have a flat spot.

 

[330]

EGR Valve?

 

[cianpars]

For those like me who didn't know what an EGR valve was:
The EGR (Exhaust Gas Recirculation) valve helps lower the car's exhaust emissions (gases from the tailpipe). It recirculates the portion of the gasses coming out of the engine by putting in back into the intake manifold, where the engine can burn it again, thereby reducing the emissions.

 

[Steve w]

My 1.4 accelerate does well in 4 and 5 gears but not a lot in 3rd