Peugeot 407 SW HDI depollution and hot starting problems.

[Agile]

About a month ago on a Sunday morning after 2 miles the car cut out and showed the EMR fault light and failed to start for about 5 minutes.

Exactly the same think happened two weeks later on Sunday morning after 2.1 miles!

Now the problem is occurring several times a day.

Regular depollution fault light.

Limp home power reduction seems operating although no indication of this inside the car.

Starts fine when cold but when hot virtually always does not start until left for at least 5 minutes. These MAY not be related.

The classic cure for the depollution fault is to add cataclean. None in stock so I used a clean the carbon filter additive which is also suggested. Next solution is to but Shell or BP fuel for a tank or so.

Have had the carbon clean in for three days now and rarely get the depollution fault warning but I can clear it when it does.

But seemingly being stuck in limp mode is annoying! Should there be any indication inside?

Alternatively what fault could cause poor HOT starting and limit the power output?

It was stated to have had a new turbocharger within the last 20k by the seller!

How can I know if the turbo is working? I never feel that I can ever hear it on this model. Until recently car worked fine and could reach 95 easily!

Tony

 

[Burnerman]

It could be worth investigating the EGR system Tony.....the source of many diesel evils.
If the turbo isn't working properly, the car will accellerate like a snail -pop off the pipes at the turbo and see if you can spin the vanes with your finger.
John

 

[Belle427]

Im guessing its a dpf problem but know very little about the pug system, i know they use an additive to help with the dpf regeneration so it may be worth checking this system out first.
Short journeys kill these dpfs, have you tried a motorway journey for 15 mins or so with the revs at or above 2000rpm?
Its probably snake oil but i throw a can of dpf clean in and fill up with ultimate diesel twice a year when we do a long journey.

 

[Burnerman]

Just looking at this again......if the engine shows no sign of starting from hot at all - but goes fine from cold - I'd gamble on the crank position sensor. Its on the top of the bell housing, one allen screw holding it in place. The genuine item is around £16.
John

 

[Peter.N.]

If it uses the 8 valve 2.0. engine it could be the pressure regulator on the HP diesel pump.

Peter

 

[Agile]

I think that its a 16v and 1600 diesel HDI engine.

When hot it fires at first but not enough to keep it going. But its such a contrast to the cold start which is immediate as it always was.

It will never start again without waiting when hot such a contrast.

So what do you think could be wrong with the sensor to cause this John?

Is the sensor a Hall effect device?

 

[Burnerman]

All I can say is that your symptoms are typical of the position sensor failure (that's sticking my neck out, I know!) It is a Hall effect device and is sometimes affected by the clutch dust that gathers upon it......obviously with the heat involved down there it is working in a somewhat hostile environment.
Presumably to get the car going again, all you have to do is wait - no fuel priming or anything?
High pressure pump problems could also be an issue of course, but (only) in my experience I've noticed the engine has a tendency to stall.
John

 

[Agile]

It happens when I stall the engine, presumably more often now because of the reduced power, and has been at embarrassing places like traffic lights on busy London bus routes! Why do people behind just hoot when I have put the hazard lights on?

All I have to do is wait! Then it starts. Makes no difference if car is pointing up or downhill. Previous fuel line air leak caused problems on first starts when pointing uphill on my sloping drive.

I will be checking to see if turbo is free to turn later.

Thanks

Tony

 

[Burnerman]

At this point I would expect EGR valve problems.....if it is stuck open with carbon then sometimes there's so much ingested exhaust gas then the engine just can't start. A popular move is just to blank it off, at least to see if there are any changes.
This engine also uses air 'doser' valves which live in the inlet tract....these slam shut when the engine is turned off to give immediate stopping. Peugeot know all about issues with these as they also affect the EGR system and DPF. All somewhat useless inventions which will hasten our return to petrol.
John

 

[AlanE]

All somewhat useless inventions which will hasten our return to petrol.
John

That plus what I heard on the news today that they are intending to pass a law to stop diesel cars entering some towns!

 

[Agile]

Right, the bad news! Then the worse news!

As rather expected, I checked the turbo and found that the bearing is well worn! Some leaking oil around it too.

But a little while later while driving the low pressure oil light came on!

Does the turbo oil feed bleed back into the sump and if this flow is excessive could that possibly be causing the LP oil light to come on? Or is this just yet another annoying fault?

If that could be the possible case then presumably if I could find some way to block the oil feed into the turbo then it would solve the LP indication until I can deal with the turbo?

If unlikely then what is the most likely cause of a LP oil fault? Pump? Bypass valve jammed? Anything else?

Tony

 

[Burnerman]

Hmmm on this engine, I didn't want to hear this!
The turbo oil feed pipe has a filter within it, which is prone to blocking. Oil failure wrecks the turbo big time.
If the turbo is to be replaced, it's vital that the sump is dropped to clean the oil strainer within and the oil feed pipe replaced too. (This comes from Peugeot, incidentally.)
It's usually irregular oil changes and/or inferior quality oil that causes all of these problems, and the oil quantity is low anyway.
As per the low oil pressure issue, I would suggest the sump strainer is partially blocked, but it's possible the pressure relief valve may be stuck open too.
One point.....on some turbos, the bearings 'float' and rely on oil pressure, but there's no way the vanes should ever contact the turbo body.
John

 

[Agile]

Thanks

he impellor vanes are not contacting the body but are showing a lot of play and there is oil around it too. Just like one on youtube!

I have not felt it with engine running.

But do you think that the low oil pressure is likely to be caused by worn turbo bearings or another cause?

Tony

 

[Burnerman]

If the turbo bearings were worn to that extent, the whole system would be full of oil, producing clouds of smoke and with a high possibility of the engine running on its own lubricant - totally out of control and revving to destruction.
I don't think yours is that bad, and all turbos pass some oil - even when they are new.
Obviously, shell bearing wear anywhere will cause a reduction in oil pressure - as would a blocked pick up strainer, blocked oil filter or a stuck open pressure relief valve.....the latter I haven't seen since my early Mini days.
John

 

[AlanE]

Just looking at this again......if the engine shows no sign of starting from hot at all - but goes fine from cold - I'd gamble on the crank position sensor. Its on the top of the bell housing, one allen screw holding it in place. The genuine item is around £16.
John

John not certain about the 1.6HDi but the larger versions also have a cam position sensor.

On that engine, from memory, the ECU compares the output of both with respect of each other but only at start up. The position of the cam sensor is highly critical with respect of distance it is sited from the cam shaft pulley. So critical that the sensors come with a pre-moulded pip that is set to touch the pulley and which is then ground away when the pulley starts to rotate the first time.

Failure, or intermittent working, of either crankshaft or cam position sensors would prevent start up. Diagnostic device would no doubt show if pulses from either were missing.