FiestaMk7.com Owners Resource

Hy,
Firstly, I know there are topics concerning both the issues above in the subject line, but there hasn't to date as far as I can see, a link between the two, I'm an aircraft engineer myself and pretty sure this is a sensor (either fuel/fan) or ECU problem.

Driving along at any speed, usually less than 60, there is usually a very slight surge or misfire momentary, followed by fuel computer reporting decreasing consumption numbers, ie car using more fuel...stopping at the roadside, the cooling fan remains on (a/c off). I've checked this on several occasions, and the sequence of events is always the same; very slight misfire, fuel cons. dropping, fan on.

The only way to return the car to "Normal" is to disconnect the battery.

If it were a sensor, the sensor wouldnt react to battery disconnect/reconnect, more likely a relay for the fan at least, but what about the consumption? thats got to a function of the ECU ie temp/press/throttle position/boost etc etc..

Anyone with any ideas, I'd love to hear, btw, no fault warnings or else illuminate.. any ford specialists on here? 09 model, 32k miles

Thx in advance ,,,Dov

wondered, if anyone with coolant fan issue, ie coming on by itself/for no reason, could observe their mpg at a steady throttle and see if they too have a link between the 2 symptoms?

cheers

dov

I think, I may be answering my own question here; it would appear that DPF filter egeneration uses a built in fuel additive AND extra fuel to generate enough heat to cleans the DPF. This process generates lots of heat in the CAT/DPF and as its mounted behind the radiator, the engine coolant fan is used to disperse the heat, preventing local hot spots?? Some research has led me to conclude that the engine management system initiates this every 250 or so miles and more frequently if the car is driven on shorter journeys.
Conclusion; driving small diesels economically results in DPF regeneration more frequently, which results in more power being required to run a relatively power hungry coolant fan, which absorbs power, as does pouring fuel in to the engine/exhaust to raise Exhaust Gas Temp to levels sufficient to cleans the filter....So my fuel efficient little 1.6 "ECONETIC" guzzles fuel to keep the environment clean ?????? Plus the filter needs cleaning at 50k and fuel additive (built into the car) requires replacing at 100k...

Anyone want an econetic that does 74mpg some of the time and 52mpg when it feels like it?

All euro car engines (think it's up to euro 5 now) use more fuel to achieve the emissions levels required by law due to the amount of restrictive filters they have to use (dpf, cat, egr and so on), same as the lorry i drive, my old R reg volvo FL10 320 used to do 18mpg at 32 tons, 06 plate FM9 340 only does 11 mpg at the same weight, don't know how they can say that its better for the environment to burn more fuel!

unreal eh? At least I have an explanation for it all ie it's not because there is a crossmember in front of the rad. Were it not for the coolant fan running, the bonnet paint would blister at 550 !!

52 and 74 are awesome! i get 38 and thats rly good, and im going into the twenties soon...ur still lucky!! lol