Although I have a 2009 1.8tdci c-max I have still suffered the above gremlin like other people when finding myself in need of power at low revs.

The fault is……when I approach a roundabout, maybe in 2nd gear around 1000 revs issshhhhh put foot down to continue because nothings in the way and……..bang…flat as a pancake until you clutch slip to 1500-2000 revs, then it will fly.

Sound familiar ?

While waiting for my wife to do some shopping, I decided to play around with the throttle pedal and try and work out the fault.

This is what I came up with.

The engine ticks over at about 800 rpm.

With the gentleness of a feather I press the throttle to try and get the revs to 900 or a 1000.

With every other conventional throttle car I have had, If I touched the throttle I could get another 100 revs or 200 revs, whatever speed I wanted that’s the control you had, however with this car it’s a different beast.

The moment that I did manage to get the revs to change beyond 800 rpm it went to 1250/1300 and nothing in between. As I say with the touch of a feather.

So it was either tickover at 800 rpm or 1300 rpm.

I tried the same coming down the revs

I could hold it steady at 1500 then 1400, but the moment it hit 1300 you could see the rev needle trying to nudge back to 1400 via the engine management then it would fall back to tickover 800rpm with nothing in between again.

So whether you are revving up or down, when it gets to the band 800 to 1300 it’s flat.

OK, so putting this into a driving situation, if you suddenly find yourself approaching a junction at low speed,low revs then find you don’t have to stop, you hit the throttle and bang…flat as a pancake, if you quickly glance at the engine revs you will find you are in this 800 to 1300 band and that’s why you can’t go anywhere without clutch slip to get it beyond the 1300 rev range.

This fault can be repeated time and time again….the problem is, whats causing it and what to do about it.

Any ideas or views.

Ford dealer couldn't see a fault.

mr rugby

I don't experience the flat spot that you describe, rather I just find the 1.8TDCi slow as hell.

Have you tried re-setting the ECU perchance?

The engine ticks over at about 800 rpm.

With the gentleness of a feather I press the throttle to try and get the revs to 900 or a 1000.

With every other conventional throttle car I have had,

The diesel throttles are not conventional. They are EDC or electronic diesel control (drive by wire) where by moving the pedal you change a resistance and thus a voltage at the ECU. This is compared to a value stored for that particular engine speed and adjusts the fuel pump quantity accordingly in order to accelerate

If I touched the throttle I could get another 100 revs or 200 revs, whatever speed I wanted that’s the control you had, however with this car it’s a different beast.

This fault can be repeated time and time again….the problem is, whats causing it and what to do about it.

Any ideas or views.

Ford dealer couldn't see a fault.

mr rugby