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C Max Not Max Power

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#1 Pontylad



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  • Name: Terence
  • Ford Model: C Max 1.8 TDCI Titanium
  • Year: 2007
  • Location: RhonddaCynonTaff

Posted 13 December 2012 - 11:14 PM

I've read a few strings on this but as others have described, and a common problem it seems, my 07 plate c max 1.8 TDCI is ok at low speeds but loses power when pedal is floored as on a hill or at speed or trying to pass a slower vehicle as if there is fuel starvation but returns when i ease off. I've had sensors cleaned and EGR valve replaced (on this car it comes with the manifold) - big bucks.

I don't know what to believe, as several answers have been given.... MAF, pedal sensor, Fuel line weakness, etc.. It starts ok, as new starter motor, battery, alternator and glow plugs have just been fitted. It also had recent fuel/air filters and oil change.

Anyway, may be a waste of time and money but I'm booked into Fords for a £75 diagnostics check which may not show any codes, or may open a big can of worms. If no codes come up what next. Anything positive welcomed.


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#2 Navarro93



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Posted 14 December 2012 - 05:39 AM

check your vacuum hoses. Sometimes they split, but under normal load the air still flows through okay, and it's only under acceleration that the pressure drops (usually because when you accelerate hard the engine rocks a little, which can cause the vac hoses to move and the splits open up)

#3 Pontylad



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  • Ford Model: C Max 1.8 TDCI Titanium
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Posted 14 December 2012 - 10:46 AM

Thanks navarro93.
I'll see what comes up on Diag now that I've booked in but I'll get garage to look at hoses as It's worth a try.




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Posted 15 January 2013 - 01:38 PM

Not sure what to reccomend. I have bought the 1.6 Ghia model and it's really nippy.



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  • Ford Model: Mondeo Mk3 Sleeper 194 flb.p.t.
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Posted 18 January 2013 - 11:13 PM

Another thing worth checking is the lift pump - it only comes on at high demand on the Mondeo (i know its a different car to the c-max) or another fuel supply problem

Perhaps the turbo is not boosting as it should, or the engine is clogged/ restricted in some way (eg - the DPF or cat)

You can obtain a code reader online for about £22 (F-super) that can read your fault codes (much cheaper than a garage- boes the same job)

Is this the PSA engine or the old Ford engine as used in Focuses etc and does it have a DPF and is it euro 3, 4, or 5?

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