Oh bugger, Ithink the turbo's died :cry:

[Welly]

Wouldn't a failing vacuum pump make itself more apparent by a lack of assistance in the braking department?

Apparently the brakes just about survive (unless you go mad pumping) but the auxillary air lines suffer the most. I think it was Tux2006 or someone had this and they replaced the vac pump and his turbo came back!

[Welly]

he said nothing because we haven't fixed the problem

More like - "we charged you enough last time, don't know what's wrong and daren't ask you for anymore"

[Longintooth]

Hi there
Are you sure they changed the Turbo - did you get a warranty card from the company that supplied or reconditioned the Turbo? Do the little test I suggested and post back the result - if the turbo is pressuring up and swelling the pipe you know it's working up to the manifold. Other things you need to check is the air filter clear ( I'm not being funny). If all is well move on to the injectors - is there any black smoke at any point in the RPM range - there should be absolutely none - they do not ever smoke unless the injectors are really knacked. The common rail pump has a device that reduces the pressure in the line when at idle - it does this by holding off one of the pumping plunger stages (There are three of them) If this does not release then there will be insufficient pressure to deliver enough fuel when you demand power. The 406 gives a short erratic idle just when it operates but then smooths out. This PSI HDI is one of the most advanced engines you will ever drive it is state of the art and I cannot praise the performance enough. Warning - if you are not familiar with common rail keep your fingers away from any part of the injection system when it is running - The pressures are huge and though it injects at low volumes any leak can put enough fuel the size of a needle into your blood and you will die before you get to hospital. Oh another peculiar thing about the 406 is the dual mass flywheel - it slips under certain conditions and can seem like loss of power. When cruising at about 70mph you can feel it slip when accelerating hard after a good distance but if you do a stall test it will not slip - very strange - I had one apart and could not find a visual reason for this phenomenon - the plate was good and clean, no distortion and only a little more rotational play than a new one but after replacing the flywheel,Cover,plate and thrust bearing the problem disappeared and the performance was/is stunning - very expensive.

[steve_earwig]

AFAIK there's no point in giving a turbo-diesel high revs, it kind of defeats the object of all that torque. Wait for the turbo to spool up? Is this the good ol' days when everything had massive amounts of turbo lag? I know mine's dead low down but I couldn't really say when the power comes in, nor wherwe it peaks: it's not like the 2.1, it never kicks me in the back, the power just comes in and peters out (must take more notice when I go out in a bit)...

Power band - 1800 to 2800 is best, but never 'floor' the throttle, no use.

...but I don't have to play with the loud peddle to make it happen (more stand on it, hey, it's only talking to the ecu, there doesn't even appear to be anything in the way of a throttle butterfly)

That 3rd piston Longintooth speaks off, on mine it's obvious as mine rattles like crazy up to about 3,000, then the 3rd one starts and it changes to a more uniform, slightly quieter, worrying noise.
So, what stops the turbo spooling up? Those solenoids on the bulkhead, are they messing with the wastegate? I think that's quite possible. How? Hey, my name isn't James... What else? Blocked air filter? Blocked cat? An air leak somewhere? Hmm, I like that one too.

As for the b/f, a relationship without trust isn't a relationship, in my meagre experience it's either true or it says bad things about yourself (I'm not saying you're an evil suspicious cow or anything, it's just that this person isn't bringing out the best in you in this particular relationship). I don't know how much your lives are intertwined and how difficult it would be but I'd think you'd be better off kicking him into touch...

[STALLED]

Have you tried swearing at it? I find that works when working on Peugeots?

Outta interest - how many miles has your HDI done? Thinking of possibly swapping mine over for a HDI if the sums add up...

[steve_earwig]

How about giving it a sound thrashin, Basil Fawlty style

Just back from a trip around town. Unfortunatly I couldn't give it so much of a test as the future Mrs. Earwig was on board (world's most nervous passenger...) Anyway, it starts pulling at about 1300, pulls well from about 1500 to 3000 where it starts running out of steam and it seems like a good time to change up.

"There you go, you're not giving the turbo chance to spool up, it needs to be at least 3000 rpm before it will really start to pull. In fact, it should still be pulling at the 5000 rpm mark"

The man's talking out of his tailpipe, he's trying to tell you your malfunctioning car's meant to be like that so you'll go away and leave him to play with his woggle.

[Nicodemus]

Absodefolutely has. Stick 'Throttle Pot' in the forum search and you'll get quite a few hits

Just cleaned the connector on mine yesterday afternoon to see if it would help with intermittant varying engine idle speed. Didn't.

Cable from accelerator comes up into engine compartment and is partly wrapped around a wheel or drum at the top of the engine. That assembly contains the throttle pot. Not convinced this will be your prob but serpently worth having a bash at. Might be worth getting one from a scrappy to substitute/test with before coughing up for a new one. Certainly worth making sure connector clean and contacts not mating poorly.

ttfn

[Nicodemus]

Nope the D9 does not have anything under the pedal - it just pulls the cable IIRC. Deffo either a VW thing or over enthusiastic desk op b@llocks (do you see that neat diplomatic swerve there? 'over enthusiastic.' Might have spoiled the effect with the b@llocks though... hmmm - yeah ok I'm over tired and taking painkillers).

Nonetheless - for ten mins fiddling with the connector and a can of contact cleaner (Maplins is your friend) you've nowt to lose. Speculating on whether the various numpties who've worked on the car are trustworthy is really a waste of your time and energy in spite of the seriously infuriating, bile inducing, ire raising, anger fanning frustration and aggro of having spent so much time, money, energy etc without a fix so far.

If I was going to try and fault find your car in an attempt to limit further expenditure, right now my rough list would go:-
Do some of the simple easy double checks first -
Check air filter element and check for any soft hoses or blockages in air inlet pipery. You've had a new MAF sensor haven't you? The one that goes in the outlet pipe from the air filter housing to the turbo? Check connector on that is sound and clean.
Clean throttle pot connector contacts.
When was the fuel filter last changed?
Bung some Forte Diesel Fuel treatment in to clean injectors etc. It could just be a sticky injector valve ball.
Do a reset on the fault code thingy and reset adaptives - can't remember how to do this offhand - disconnect battery for a while then reconnect and drive around for 20 mins at varying speeds and loads - use engine more around 3000 rpm IIRC.

Then onto some thoughts for longer term:-
Follow longintooths suggestions;
I'm not sure about being able to see or feel hose swell since if the hoses are in good nick they may not respond to the few psi increase in pressure but worth a try - you're getting some boost at higher engine speeds IIRC so you could test that the test works if you see what I mean.

Monitor the ACTUAL boost pressure:
On the 2.0 hdi IIRC the turbo output pressure is mechanically controlled with a traditional wastegate, ECU does not directly control turbo. I've no doubt Niz or someone can suggest a way to monitor the boost pressure - don't some people buy and fit boost gauges? Might be worth a try bodging something up, that way you could see if boost is actually coming in at the right engine speed as you're driving around. If the wastegate isn't working properly it could give these symptoms.

Stuff to do later 'cause it would cost money:-
It could be the high pressure fuel pump as longintooth suggests - But then why does it work at higher engine speeds? Sticky valve relieving third piston pressure?
- The only conclusive way to check this is get the fuel delivery pressure properly measured IIRC it should be something just over 1300 bar at higher engine speeds - but this does need specialist fittings and does mean disturbing the fuel pipery. Expense. So put that one on the back burner for now.

Can't think of anything else for now - going to try and get some kip.

[ianst28]

i thought that the d9 was fly by wire which means no conventional throttle cable
if i'm right then that means that it must have a throttle position sensor somwhere i guess that's possibly the prob but i really don't know

on another wild thought and its an open q to all would having it remapped do anything one of the guys at work had a d9 that had bags of bottom end but no top end speed it would pull the earth into a new orbit but could only do 90mph and would only get 35-37 mpg he had it remapped and now its a completly different car

dont know if this would help

[Longintooth]

Hi all,
Don't listen to the crap about revving the nuts off - a diesel works its best at maximum toque (about 1900 - 2200 rpm) and will follow a longer more flatter torque curve than a petrol engine. The HDI does have a very very small hesitation if you stab the throttle but the PSi HDi is the best performer on this subject you will find - so much so Jaguar chose it for their motor. It just pulls and pulls without a gear change for longer a real long legger. Now back to your problem - the turbo will always spool up with RPM but the ECU will control the out put at specific points to control the emissions without affecting performance as much as possible unlike a petrol it does not have an over boost discharge simply because it has no throttle butterfly (the throttle is a simple electronic reho that tells the ECU when you want to go) it is always full bore pressure as much as it can push in - that's why on a diesel it uses EGR to control the oxygen content to cool the burn. If you can run to the expense get a OBD2 scanner it will give you a constant readout of your MAP, MAFF and other emission related data, I use PCMscan from Palmer Performance - the manufacturers are only allowing some of the data through because of the US emission laws but used with a laptop when you are on the road is invaluable for fault finding especially with petrol engines - less with diesels. I can graph all the parameters over all the range and pick out faults. You can do drag tests for performance etc. Trust me on the little pressure test, mine is showing good on the scanner and does just expand the hose when you take the revs up to just 2000 rpm on no load. You know the 406 is quite a heavy motor but it should drive and feel very nimble and light. Somewhere I read on this site that someone heard some clonking on the steering - it is a common problem and easily rectified - its the macpherson strut upper bearing sticking and winding up the spring which tends to release with a clonk but that's another story.

[Welly]

I think a Global test is a good idea, and I also bow to these new guy's on here knowledge - very impressive

[Longintooth]

Hi
Here's another little test you can do without any gauges (HDI only) - at idle put your hand over the exhaust it will feel very weak for a 2 ltr engine - as if the exhaust is leaking somewhere - check that it isn't externally. It is in fact leaking intentionally through the EGR valve in the Turbo but when you rev her up it should blow out the exhaust as normal, this is because that EGR valve is shutting as it should.
Incidentally during an MOT test the emission probing on a petrol is different from a Diesel so should not be confused with the two. The petrol measures the CO2 content etc remaining in the gas as determined by the various O2 sensors and the CAT it is affected by any leaks in the exhaust system but a the probe test for a diesel has to allow for the fact that there is no O2 sensor - just the CAT and the EGR and so the parameters are not as easily controlled. When you go for an MOT test always ask to wait for it to be done and go for a good hard drive - get it really warmed up - try and keep the motor running until it's your turn. The MOT testers are a not as well trained in emission testing as they should be and don't realize how crucial it is to get the CAT really warmed up well before the test on a diesel and they leave them standing in the yard for hours - then have trouble getting the the pass readings often leading to an unnecessary CAT replacement - the petrol has the benefit of the O2 sensors to adjust the oxygen levels to compensate for a cool CAT . Oh and the clonk on the steering is not the lower ball joint it is the upper strut bearing housing sticking - it holds the spring so that it does not turn when you turn the steering as it should and then goes with a twang. The lower ball joint locking nut should be replaced with a new one every time it's removed so you can check it easily. But if you are not sure of your ability to check it over do let a competent person have a look, don't ever mess with things like steering or brakes unless you know what you're doing and never tender advice to anyone unless you are sure it is good. My advice assumes people have a good knowledge of basic engineering.

[Longintooth]

Hi
Well I'm trying very hard to help you and to save you money - you've suffered enough. I chuckle when I hear statements like "kicking in" the turbo is always blowing, it never kicks out or switches off,it just changes speed. Further the basic simple tests I have given you are enough to start eliminating the things that can cause your problem and I've tried to explain the fundamentals so that you can begin to figure out where to start looking. After that you have to write down each action in a form of "if" "yes/no" you get what I mean. Now the last test I set was feel the exhaust because what's happening here is that when exhaust gas enters the induction pipe the gas being inert cools the burn and reduces the NOX and co2 emission because at idle there is an over whelming amount of oxygen in the cylinders and the burn gets very hot and that's when nitrus oxide is created as it combines with other gases. That is why the speed of the exhaust gas with Turbo and EGR is at it's slowest ( I mean really slow, slower than a naturally aspirated engine of the same size at idle) and is the opportunity for the exhaust gas to be taken in - otherwise the compressed air would stop any admission of exhaust. So the result is a weak exhaust out the back. Now as soon as the ECU senses a throttle and MAFF demand it shuts the EGR the cylinders get charged with more fuel the turbo spins faster the exhaust proves this by the sudden increase in output. Now as the engine falls back in the cruise with lower throttle demand the ECU senses that there is this higher ratio of oxygen than fuel being injected and the process of EGR is introduced again. The task of the turbo is to increase the volumetric efficiency of the engine ie, help it breath easier and accept more fuel than a naturally aspirated engine essentially when you demand power. But in fact it also helps in creating more fuel economy if driven correctly. If you want to see all this happening with all the sensors going full belt you need a scanner.
I'll keep trying for you
as I suggested earlier.

[Welly]

There you go see poppy, as the old saying goes..."if it ain't fixed don't break it"..oh wait..."if it's broke don't fix it"..err,

I'm currently in talks with my dropping MPG-o-meter depite THE most rediculous max economy driving it refuses to budge from 40.9 (was on 42.2) not sure if it's cos the engine light's on or the Tesco's finest in the tank

[Longintooth]

Hi guys
Just to clarify - I,m real glad it's ok supa. I'm a stickler for getting meanings and detail right to be consistent. When you refer to the kicking in of the turbo your actually feeling the maximum torque whether it's a naturally aspirated or turbo. It can be simulated on a push bike for easy understanding. You push down hard and of you go but there comes a definite point at which you can't actually accelerate anymore although your little legs a going like mad - that's the bikes maximum torque for you falling off. However, if you continue to pedal faster you increase the work done /min for maximum BHP until your chain comes off.