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Hi guys am new here. I am at my wits end with my 406 HDi 110. Starts fine everytime but soon notice it has no power when try accelerate. Becomes worse when going uphill even on gentle slopes. Has also started belching out black smoke when rev the engine :

Strange enough, after driving for a distance it sometimes drives normal but thats only sometimes. Its a big problem when i am on the motorway and end up holding traffic because sometimes stuggles to go past 40 miles per hour.


Really desperate guys as i use the car to travel from Edinburgh to Glasgow for univeristy.


Please help

Split in a rubber intercooler /turbo pipe?

Air flow meter?

Fuel filter blocked?

Fuel pump fault?

Fuel pressure regulator?

jasper5 wrote:Split in a rubber intercooler /turbo pipe?

Air flow meter?

Fuel filter blocked?

Fuel pump fault?

Fuel pressure regulator?

Thanks for your response Jasper but all the above confuses me even more. Where is the most basic place to start to detect possibility of any of the above

Darkchild101 wrote:

jasper5 wrote:Split in a rubber intercooler /turbo pipe?

Air flow meter?

Fuel filter blocked?

Fuel pump fault?

Fuel pressure regulator?

Thanks for your response Jasper but all the above confuses me even more. Where is the most basic place to start to detect possibility of any of the above

I'd get yourself a Haynes to familiarise yourself with the components and locations
Welcome btw!

If there is no power between 2-3k rev range then it is possibly a fault in the turbo. But if there is no power in the 1-2k range it is most likely the Air Flow meter.

I would start with the Air flow Meter. Its attached to the black box to the right of the engine with a large pipe coming from it. A wire is plugged into it. There are two screws holding it on and a metal band securing it to the pipe that needs to be screwed loose. Once you have the air flow meter out, check to see if its clean. If not, It can be sprayed with carb cleaner and dry itself. DO NOT TOUCH THE CONTACTS INSIDE. If its not the air flow meter, i'd check the air filter which is housed in the box mentioned above.

I wouldn't worry too much about the black smoke when accelerating as every second HDi with a bit of mileage under its belt pumps out a bit more than its fair share of smoke. (Unless your making massive clouds of smoke behind you of course)

I believe a leaky egr valve will give similar symptoms, (not experienced it myself, but hopefully someone will confirm or otherwise).

The EGR would explain the smoke. My EGR isn't right but it sure isn't that bad that I'm losing loads of power

The black smoke and lack of power are symptoms of either a split turbo/intercooler pipe, or a faulty airflow meter, of course check the air filter first to see if it is blocked.
Don't mess with the airflow meter if you don't know what you are doing, as Eoin says, you could damage the wire inside.

The turbo/intercooler pipes are in front of and below the radiator, about 3"/75mm in diameter, and connect to plastic piping. Squash them to see if there are any splits and look for any oil dripping from them.There could also be a strange noise coming from under the car where the split is.

The symptoms you describe could also relate to the turbo or quite a few problems, if you don't know what you are doing, have it looked at by a reputable garage.

I, personally, have had this type of fault quite a lot recently on different cars, the faults have either been down to split turbo pipes or airflow meter faults.

Thanks guy, you are a god send. Now i will go to my mate who tinkers with motors a bit with the suggestions you made and start trying isolating the problem that way. Funny thing is just this Friday the car was going like the clappers on motorway, next day was off and on with the problem and they today was just really bad


Whats an EGR by the way

Exhaust Gas Recirculation I believe. Something to do with burning the exhaust gas maybe?

EGR valve is Exhaust Gas Recirculation valve.

Usually if this is faulty or dirty, you get misfiring, hesitation, bad starting when warm, and engine stalling.

The EGR valve can be cleaned using special EGR cleaning fluid, similar to carb cleaner.You remove it and give it a good clean.

On the HDi, there is an electronic box mounted on the rear of the engine compartment that controls the EGR valve, there could be a fault with that if your EGR valve gives trouble, cleaning them out usually sorts them out, however.

Hi there and welcome , the symptoms you describe are exactly the same as happened to me,
split intercooler pipe .Looking at the engine bay from the front of the car look at the radiator
and on the right hand side of the radiator you will see another little one that is attatched to it,
this is the intercooler it has one big black pipe coming out of the top of it and another one
coming out of the bottom of it. It was the bottom one that split on mine close to one of the bends .

puggy wrote:Hi there and welcome , the symptoms you describe are exactly the same as happened to me,
split intercooler pipe .Looking at the engine bay from the front of the car look at the radiator
and on the right hand side of the radiator you will see another little one that is attatched to it,
this is the intercooler it has one big black pipe coming out of the top of it and another one
coming out of the bottom of it. It was the bottom one that split on mine close to one of the bends .

so basically inspect the interccoler to see if the pipes is split. Was yours experiencing the same power loss as mine. I mean there were times was crawling at speeds of 40 miles per hour and would go higher even when tried floor it. Especially going up inclines and the turbo just never kicked in, you know that whooshing sound when its powering away. Thought was gonna die on me on the motorway and you can imagine the number of beeps i got from other irate motorists

Darkchild101 wrote:Was yours experiencing the same power loss as mine. I mean there were times was crawling at speeds of 40 miles per hour and would go higher even when tried floor it. Especially going up inclines and the turbo just never kicked in, you know that whooshing sound when its powering away. Thought was gonna die on me on the motorway and you can imagine the number of beeps i got from other irate motorists

Yes it was, huge clouds of smoke, seriously stuggling on inclines, hardly any any power... (much to the amusement of the rest of us ). Yours sounds exactly the same as what happened to Puggy's car, I'd take a good look at the intercoler pipe if I were you.

Welcome by the way

When my intercooler hose went it made such a loud 'air blaster' noise you couldn't mistake what was wrong.

This guy's trouble sounds like the car is in limp mode most of the time. I would firstly suspect one or more of the solenoids/vac lines on the bulkhead are faulty and disabling the vacuum control to the turbo/egr - ask your friend to try swapping them around to check (there's 2 of them).

To be fair a faulty egr doesn't normally make that much difference to performance but they do leak and can cause blockages/crud in the inlet manifold when it gets really bad.

Similarly a faulty Air Flow Meter will reduce performance but not dramatically like this.

The HDi has quite a lot of components controlling it and it's a case of working through stuff to find the problem. I can reassure you in some way by saying that the turbo itself never fails really (at least it's not something we would call common) some people assume the turbo has failed and replace it (expensively) when the problem was only a sensor for a few quid!