Smokey Xsara

[PC2CV]

My mums Xsara is a 2.0 HDi 90, recently it started to produce more black smoke than normal. It also seems to have lost some of its already limited 90 horses to the point where setting off from a junction in 1st feels like its in 4th and the car chuggs out black smoke until it builds up momentum.

What might be going wrong?

[Hell Razor5543]

I would first check the fuel filter. It might be somewhat clogged.

[Bick]

as said fuel filter but also air filter then go from there - 2.0hdi can get maf sensor problems if you unplug this and it gets better you have your problem. But start basic as said by above ^

[PC2CV]

I tried to open the fuel filter housing, and the holt head turned circular.
Eventually after opening it the filter looks like new, id say the same about the air filter as i serviced the car about christmas time and it has not covered many miles since.

The maf sensor has aways been disconnected

My mum doesnt drive it particularly hard so i knew to try blow out the cobwebs, ive done thisand they really should be long gone at this rate.

What are the next things to check? Its at the point where the car is dangerous it puts out that much thick black smoke behind it especially when setting off, it is also slow to build up revs as it does so

[Zelandeth]

Too much fuel or not enough air.

Have a good look around in case a hose has blown off between the turbo and the inlet manifold (often evidenced by oil mist having sprayed out of the respective joint), a collapsed air intake hose before the turbo or if you have one, whether there has been any damage to the intercooler. Any of the above will cause the symptoms you have.

Failing those, we might need to get the car on Lexia to see what live data we're seeing.

[Gibbo2286]

Does the air filter pick up from a plastic tube under the wing like the C5? If so has that tube collapsed and restricted the air inflow?

[Gibbo2286]

I tried to open the fuel filter housing, and the holt head turned circular.
Eventually after opening it the filter looks like new, id say the same about the air filter as i serviced the car about christmas time and it has not covered many miles since.

The maf sensor has aways been disconnected

My mum doesnt drive it particularly hard so i knew to try blow out the cobwebs, ive done thisand they really should be long gone at this rate.

What are the next things to check? Its at the point where the car is dangerous it puts out that much thick black smoke behind it especially when setting off, it is also slow to build up revs as it does so

Just noticed that, surely that's the first thing that needs sorting.

[PC2CV]

Ill need to check the inner wing tube, i replaced the broken fuel filter housing, poured some redeem into the housing, and the rest in the tank then started it up.

Regarding the MAF sensor, what exactly do they do? For talks sake if the car runs fine in the absence of the MAF sensor why is it needed? I ask as my 406 also has it's MAF sensor disconnected.

Nonetheless Lexia gave the following:

Engine ECU – EDC15C2 fitted to RHY

Permanent Faults
- Inlet air temperature signal. Short circuit to + or open circuit
- Inlet air temperature signal. CAN value not plausible
- Flowmeter signal. Short circuit to earth or open circuit Flow too low
- Pre – post heating relay circuit. Short circuit to earth or open circuit

Temporary Faults
- Fuel pressure regulator. Stop requested but regulator still active
- Fuel high pressure monitoring. Fuel high pressure regulator blocked

Remote Faults
- *Permanent fault Brake switch signal. Communications fault
- Temporary Fault CAN Communications. Fault: BSI communications.

BSI

Intermittent Faults:
- Transponder identifier not received
- Alternator
- Battery Charge
- Brake contact – no press
- Intermittent fault vehicle speed information incorrect value received
- Vehicle longitudinal acceleration information incorrect value received

Here are some parameter measurements:

[Gibbo2286]

I could describe in detail the MAF function if I had time but maybe here will give you what you need to know.

https://www.yourmechanic.com/article/sy ... low-sensor

[PC2CV]

I tried some EGR cleaner in the car as it did seem quite like a clogged EGR valves symptons. The cleaner made it smoke even more, and it briefly ran away. Yet still was down on power and smoked after the cleaner. I then removed the vacuum line for the EGR put a bolt into it, and a cap over the other end.
It actually fixed the problem, there is no more smoke and plenty of power again.

[white exec]

Another one that doesn't like breathing its own exhaust?

[Stewart(oily)]

It was sounding like an EGR fault to me too.