1.6 tdci Underboost problem

Hello everyone

I have a 2010 ford focus 1.6 tdci with 109hp.



The problem:

The car is very slow and it is very clear than it is lacking power. I have recorded some graphs while i were driving the car where the boost pressure is very low i have attached these.
EDIT: I forgot to say that the fault code is P0299 Turbo underboost



What i have tried:

I have had the underboost problem for a while now and have tried nearly everything to fix it.

I have changed the Turbo, DPF, Actuator solonoid valve, Airfilter and Egr.

I have also blocked off the EGR,

I have checked the turbo actuator which pulls down when engine starts and releases when engine is stopped. The actuator moves freely.

I have tried to check the hoses freom the turbo through the intercooler and up till the engine intake and i can't find any cracks or oil build up there.



Do anybody have any idea what can be wrong? i have tried almost everything. if you need some extra data or graphs i will gladly do so.

Did you check or clean MAF...it does not need to came a dtc from MAF!

I have tried to measure the signal from the maf with a multimeter and i can't get any values to change eventhough im giving it gas. But if i look at the reading from my scanner it changes. I have also checked the codes and when i remove the plug for the MAF it gives 2 errorcodes one for the maf and one the the IAT so it seems like it is getting the signal.

I have also tried to remove the sensor plug, and drive around and i cant feel any difference from driving with or without the sensor.

I'm confused how the scanner can read a signal from a sensor that is disconnected? But i have already ordered a new sensor which will be here between friday and thursday.

Have you checked for a restricted exhaust?? Oh what does oxygen sensors do wide open throttle?

What does map sensor and turbo charger boost pressure sensor read key on engine off? Should be a reading of about the same psi

Under boost is lack of airflow into the engine,ok thats the obvious statement,nowwhat causes lack of air flow into the engine?a restriction either into the inlet side or the outlet side into the exhaust,as Cheryl has pointed out,also correct to check the corrolation of the map/tbps they should agree.
The air flow is measured in hz on a ford,look at desired verus actual, should agree,When you unplug the airflow it runs on a substituted value,@ idle around 4000hz and at wot 8500hz,if there is a problem when checked best to use scan data if your multimeter desnt do hz,
The wastegate is held closed by the turbo boost solenoid by a pwm signal,not unusual for the pipes to the solenoid to get damaged when the oil filter is changed,check for splits and soft hoses at the oil filter,when the turbo boost is excessive the solenoid is fully grounded to open the wasgate,check the grams /second at idle through the scan tool,1.6-2.0 gps,also check fuel desired against actual,using live data through eobd perhaps would be best.

Cheryl:
How can i check the exhaust for restrictions? I have changed the dpf but can the exhaust be clogged further down?
I have checked the DPF differential pressuresensor which measures 1.2-1.4 kPa while idle and 4,2kPa at wide open throttle in neutral. which i think is good
I can't see the oxygen sensor reading with my tester it seems (Delphi DS150e)

I can't find a sensor called turbo charger boost pressure sensor? But i have compared the MAP sensor with the BARO sensor at key on engine off and they read the same.

Landroverman1958:
How would i check for intake restrictions?
I have not been able to find a desired MAF reading on my scanners datalist so i can't compare it to the MAF.
The car uses a Variable Geometri turbo so no wastegate, but the actuator moves down when the car starts and holds steady until i give it gas so it seems fine.
The MAF reading at idle is about 9.5gram/sec.
I can't find the fuel usage on my tester.


My scanner is a Delphi DS150e i will attach all the data i can get out of it in the attachments, maybe i am using the wrong datasets?
I also have a Forscan scanner and i will also attach the datalist i can measure with it.

Remove front oxygen sensor install back pressure tester in oxygen sensor hole. Shouldn’t see more than 1 psi at wide open throttle

Differential pressure sensor values are ok but are you sure the sensor is ok?

MAP sensor or turbo pressure sensor, whatever you want to call it, is very important that he is in good health and giving the correct values!? I had almost the same problem and changed it for a chinese one and I noticed that is not 100% correct!
If you don t have a leakage same where give it a try...

Good evening,A diesel engine gets its power from diesel fuel being injected into compressed air,which is heated by being compressed,it may pass through an intercooler to cool the air charge down after travelling through the turbocharger,
the amount of power produced is directly proportional to the amount of fuel injected by the injector,the air charge does not alter as it it is determined by the size or cc of the cylinder,so it is vital that the fueling is correct which is dependant on good low pressure supply inc volume to the high pressure pump,
Now the air mass,,,, multi functions: measurement of air travelling into the intake,measurement of smoke opacity-will not over fuel, causing black smoke if the amount of air being measured is too small for the given amount fuel demanded by the driver,throttle position wide open,egr monitoring looking at air flow if egr open,perhaps sticking reduced clean air entering the cylinder causing a low flow condition the engine ecu see,s a corrolation flow problem,also air mass meter is used as a check on dpf flow believe it or not,,,,, so check the amount of fuel delivered is correct for power required,not necessarilly an air flow issue....if this is too advanced please advise,
i have just attended a diesel training course which was extremely informative.

Hi, have you by any chance managed to solve the problem?
I have the basically the same issue and can't find any solution