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Mk3 Mondeo Tdci Problem

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just brought a mk3 tdci euro 4 engine 55 plate mondeo

the problem is really wierd

if u drive it hard after 3000rpm it will go into limp mode ... but if driven sensibly it will go all the way round the rev range ????

when i brought it the guy said it has had a second hand turbo actuator on it . as the old 1 failed .. . and he was told sometimes they need recoding ??? is this true ?? or not ???

also today i unplugged the MAF Sensor ( airflow meter ) and the car didnt run no different ..... but im sure it should of ran lumpy and smokey with out that connected ?????but the engine management light did come on ??? but went off when reconnected MAF Sensor .

it starts first time in a morning . no smoke from cold when started . and no smoke when driving .... engine is a little knocky but put that down to a diesel knock

the things i have tried is

Clean EGR Valve

Unplug MAF Sensor ( Changed MAF Sensor as it brought code p0100 up )

Changed Boost Pipe As it was split

Changed Airfilter As it was black ....

checked for a power feed to MAF - All Workin Fine

What else could it be ????

its got 148k on clock ....

Im still getting 40mpg combined ....which i think is good ???? and around 35mpg round town .....

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I have exactly the same car (assuming yours is a 130 6-speed).

I wonder if the turbo vanes are sticking when you just bang the revs up to the top? Thing is a 2nd hand one might not be much better than the one it replaced. 'fraid I can't really help much, beyond saying that I get almost 50mpg just moochin about, and almost 60mpg on a motorway run.

Do you have a code reader? Force it into limp mode and check for stored DTCs.

Also, did you clean the MAF or just look at it then put it back? Clean the metal wires (very carefully) with a cotton bud dipped in carb cleaner, also clean inside the little tube bit as well. If it's caked up in filth it won't be working properly.

When you cleaned the EGR valve did you have a go at the inlet manifold too? Because that can get just as bad.

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Is the tube coming up too the egr split you wont see unless you take it of and inspect it also when was it serviced last my guess is a while ago change the fuel filter for a gen ford one ..........

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Fuel filter any service history at all ? You described the air filter as pitted with this being an easy item i doubt any of the nuts bolts and spanners servicing has been done

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If you change the EGR, get it from Jaguar. Identical part and half the cost of the same thing from Ford.

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Good idea to blank the EGR, some Mondeo owners are on their 4th valve, a Mondeo TDDI runs better with a blanked valve than a "perfect"ly working one - solid,(no holes to let gasses through) stainless steel ones ate best

As you have a Euro 4 the EML is liable to come on with the blanked EGR (but limp home mode should not be triggered)

Worth cleaning out your inlet manifold as well

There must be a reason the car goes into "limp home" mode when you drive hard and not when driven "sensibly"

One possibility is the variable vanes in the turbine are coked up / not moving to their fullest extent, the vanes control the boost pressure via the control rod and actuator, if these items are not attenuating boost enough it may cause exessive boost triggering limp home mode when driven hard and when driven "sensibly" not enough energy in the system is created to generate enough boost to trigger "limp home" mode

the vanes sticking can cause actuator failure, as the SWR on the motor goes up, that may be why the actuator was changed

Other things can cause this eg, fuel delivery / injector problems (sufficient flow/ preesure for moderate driving, not enough for hard driving etc)

Not everyone achieves 60mpg, it can depend on road conditions, driving style, outside temprature, duration/ length of each run, tyre size/ type/ make/ pressure, weight in the car etc etc, 35mpg round town and 40mpg isnt too bad and results an ST220 driver could only dream about

The engine is quite low revving, peak power may only be at 3 to 3.5k (euro4 Mondeos tend to develop peak power at lower revs than euro3s, in my experience ) and peak torque much lower (typically 2.2k, depends on exact model)

so changing up at 3k may make the car accelerate faster anyway - if you are "mooching about(cruising?)" you probably want to change up earlier, 2 to 2-1/2k car will probably pull better/ return a better MPG

No point in "booting" it round town/ in 1st/ 2nd, these cars are rubbish 0-60 / through gears anyway, once your in the higher gears/ in the midrange its a different story, if you use the available torque, again you will make better progress, and get a better MPG

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ive had it on a reader .and the egr is the only thing comming up . got 1 comming tomorrow to try ..... still gunna blank it anyway ..


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I blanked mine and made hell of a difference also cleaned out the egr and the inlet manifold it was full of black carbon crud

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well i changed my EGR and still going into limp mode ... am gunna blank it off and see what happens ... gunna change a boost hose i taped up cuz of a little hole ...


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