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Bob, UK Car Mechanic
Category: UK Car
Satisfied Customers: 2046
Experience:  Nvq Level 3, ATA tech, Ford tech,6 years with Ford, 4 years with MG Rover
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fiesta diesel 1.4 tdci. We had a problem with the engine having

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fiesta diesel 1.4 tdci. We had a problem with the engine having a slightly sluggish pick up. Found that one of the foils was broken on the MAF sensor. Change the sensor but now have an intreging problem, EAC Fail comes on intermittently for the first 2 minutes of the day holding the revs to below 2000rpm. After 2-3 mins the flashing of the fault slows down to not at all. When the display is normal the car is perfect. The reduced power is like throwing a switch, no fade of power just "off" above 2000rpm.
Put old MAF back in but fault remains.
Once car has started and cleared fault once on the day the car seems to be ok all day.
Help please, I think it has to be somthing to do with the warning up, the temp gauge works fine but is there another temperature sensor for the ECU to reduce the overfuelling for the initial start period "the choke on a petrol".

Hi there hope i can be of assistance.


Just to confirm, the original fault is, sluggish pick up and performance?


The EAC warning came on AFTER the new MAF sensor was fitted?


Many thanks, Bob

Customer: replied 7 years ago.
Yes, the EAC fail came on the first instant the ignition was switched on to test the car following the fitment of the new MAF sensor.

Hi there thanks for the reply.


When the EAC warning comes on car will go into 'limp home mode' not letting the engine rev above 2000rpm.


Its strange how the new MAF sensor brought this light on, which makes me think the PCM (or ECU) needs to have its calibration updated. Often with an update to the PCM the values for fuelling/sensor ranges can be different which may cure your sluggishness and EAC fault.


If a calibration isnt available or dosent relate to your fault then i would check the ECT sensor on a real time display (there is only one for gauge and PCM), as well as fuel pressure for checking injectors.


This way you will be able to physically see if the ECT sensor is working in range in relation to the gauge and your estimation. Also with the fuel pressure displayed, while the car is sluggish, you will be able to pick out any faults or at least eliminate the fuelling system from your investigations.


Fuel pressures:


With just ignition: 6-8Bar

Cranking: 250-320Bar

Idle: 220-250Bar


Anything vastly different indicates a problem.


I would also inspect the hand primer and fuel filter for any signs of leaks. Check the clear pipes leading to and from the hand primer for any signs of excessive air in the fuelling system. Note: a small amount of air is acceptable.


Also check the operation of the glowplugs. These dont just come on with the ignition. They come on when the cylinder temperature is low to maintain a perfect temperature for lower emmisions. If the glowplugs arnt working properly this will cause the performance to be less as the cylinder temp isnt what it should be.


If you need any further help, let me know, cheers Bob


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