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516 Posts
Discussion Starter · #1 ·
Car 307 SW HDi 110. Year 2002 The car is standard.
Location not in the UK
Since last September my car has been getting worse and worse. It acts like the turbo would only "kick in" from @3000rpm not any lower. At first this was an intermittent fault and is now permanent. It makes for hard work going up hills or overtaking. It was also acting very lumpy when the car was moving slowly in first and second gear sort of like it was in too higher gear, but that was not the case.
The car passed all the emission tests during the local roadworthiness test last December. It also does not bellow any smoke, no matter what the temperature of the engine or climate.
There are no odd noises coming from the engine.
I went to my local garage he had the car two days so that he could start the car cold to see how it performed and used is "generic" diagnosis machine. Found the could not read any errors. He then took the car to another garage used a different generic diagnosis machine and obtained the same result.
There has been a mechanical inspection and test drives. Again nothing untoward found.
I then took the car to my local dealer who is an hours drive away.
To be far they have been very good and patient with me and the car. Three hours of looking around test drives playing around. Only thing found so far was a gasket missing from the mass air flow sensor. (This I changed some years ago)
The readouts do not have codes as the dealer says my car is too old. I have got no idea id that is true).
Translated the faults are.
Fugitive defect. Admission air temperature signal to Short circuit positive or open circuit
Fugitive fault. Turbo pressure signal Coherence with atmospheric pressure
Fugitive defect. Turbo Presion. Turbo pressure measured too low
Fugitive defect. Air flowmeter signal. Short circuit open or short to ground. Flow rate too low. (PO l00 This is the only one with a code)
Fugitive defect. Default. Relay circuit pre-post-heating Relay blocked
This is the order of them from a printout.
I now have had the errors erased.
The fault where the turbo did not kick in quickly returned. The lumpiness has not and the car certainly runs smother.
I am thinking this is going to be a case of having to remove the turbo to see what the condition is like, removing all feeds to and from the turbo and checking the condition of it. But ultimately this could be an electrical issue.
Any suggestions as to what the read out mean?

Sorry for the long post and for the google translate of the faults.

12,806 Posts
Those faults (although missing the vital P codes) are all pretty standard.

Check wiring to MAF. If OK, replace the MAF.

Turbo fault codes well documented on here too.

And, considering the age of the car, check all air piping.

15,376 Posts
It is most definately NOT the turbo

That list has all those readings BECAUSE its not working right it could possible be the MAF again but my bet is you have a vacuum leak on the turbo control system this will not show on diagnostics and causes the symptoms you describe

Check the vac levels with a vacuum gauge at idle and when revving it should be stable

516 Posts
Discussion Starter · #4 · (Edited)
Thanks for the tip about the possible leaks.
A little update:
I had arranged to return to the dealer to allow them to rescan the car.
This time a code showed up PO246. As far as I can tell after searching the web that points to the wastegate solenoid not functioning correctly.
Print out reads
Engine revs: 3919rpm
Flow: 38mm3/ impulse ( no idea what that is, the amount of air going into the turbo?)
Turbo pressure: 1576 millibars
Turbo pressure setpoint: 1953 millibars
RCO on EGR, 88%

None of this means anything to me.
I went back to my "normal" garage for him to check it over. He had the car two days. I doubt if the mechanic was working on it all the time. But he said he could not find and broken vacuum line and that the solenoid (rod) does open and shut. But as I write this he did not say when the engine was working. So I will have to check that with him.
The grand total of the garage bill so far is 35€ for the first scan and erasing the fault codes.
The four days the normal garage had the car nothing. The second visit to the main dealer nothing.

Some how this points to either an electrical fault, or the garage failed to spot something when the vacuum lines were inspected.
I am return the car back to the dealers for hopefully some solution. Not begin so rich I have to limit them to a budget.
I will report back if anything is found.

1,140 Posts
The readings show that the turbo is not providing the pressure the ECU wants. ECU wants 1953mb, turbo supplying 1576mb.

You need to check the vacuum AT the vacuum pump inlet by disconnecting all inlets to it and connecting gauge directly to it, and then reconnecting the vacuum pipes to the pump and then checking vacuum at the turbo valve by connecting the gauge to the vacuum pipe that connects to the valve.

Both readings need to be the same and steady at all rpm. If there is any difference between the reading at the pump and at the turbo valve, you have a leak somewhere, maybe in the pipes or maybe another faulty valve/vacuum tank etc.

It may be electrical, leaks in the inlet tract, or even mechanical issues with the turbo, but vacuum issues are, in my experience, the most common issue with a lack of turbo boost, and are easily checked.

516 Posts
Discussion Starter · #6 ·
Thanks everyone for the helpful replies.
I had the solenoid changed. a small vacuum pipe had to be changed due to the age of the car (it was on the verge of splitting). Also had a minor correction done to the MAF readings.
The main dealer undertook the work for me as I run a business where the outside of the property cannot look like a repair shop.
In all I am pleased with the service and the price.
Labour was only 54€ per hour.
Why the main dealer? because the local garage could not find any fault!
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