Hi,
New to me, 2009 Fiesta 1.25L Edge 84bhp model.

Still under dealer's 3 month warranty.

When air con is on, the car has a flat spot, e.g. at about 2200 rpm I can feel it (in all gears I think).

If on flat or downhill, it will get past the flat spot and when get to 2900 the torque really kicks in as it should on these cars (still feels weird to me after my old escort and puma), otherwise I simply change down a gear.

With air con off the little engine behaves as it should.

Any ideas?

Thanks in advance.

 

I expect this is mapped in for something to do with emissions / co2 Mpg bollox. Worth asking the dealer to look and ask them if there are any updates / technical bulletins.

I bought a Rover BRM brand new years ago and I was amazed that on a 145bhp VVC K series you could feel the power drop with the aircon on.

 

Thanks.

Will do that.

A correction maybe...

Just took it for a drive and noticed that there was no pulling power as I pulled out into a roundabout, turned Air Con OFF and immediately I had more power. As opposed to a "flat spot".

So I tried it a few more times on a straight and at a constant speed and sure enough, turn air con on and car actually slows, turn air con off and car picks up speed; blooming dangerous.

Voltage remains constant (only drops from 14.5V to 13.8V when radiator cooling fan comes on)

Oh, and only 37k on the clock. So that means it was driven by some old granny on short trips most of its life (in fact reading the past MOT docs, one year it did 1k and the next less than 200 miles ! - Surprised the air con still works after such lack of use)

 

Don't forget that the air con probably pulls 2 to 4 bhp when working hard, that is a fair chunk on an 84bhp car, you would notice it in the same way that if you remapped the car and saw a 10% increase you would feel it, that would only be an 8 bhp gain.

My TVR Cerbera used to switch off the aircon if you hit full throttle...just to give that extra power....I think it was probably to stop the belts coming off but they claimed it was for full power.

 

It's pretty common on most modern cars to cut the ac at wide open throttle.