Power Loss / Turbo loss on VW Passat 1.9TDI

[dreadnoughts]

Having a similar problem with my 2000 reg 1.9TDI. Putting the boot down produces nearly nothing with frequent clouds of black smoke. Car chuggs when taking off in 1st and 2nd gear also. Had 2 faults from scan - camshaft position sensor (g40): signal out of range and also Charge Pressure Control: negative deviation. I have cleared the codes and it the problem seems less apparent.
will be taking a look at the pipes from the intercooler as per other instructions here as well as checking out the MAP sensor.

This is a really good forum everyone! Learning lots and hopefully will be spending a little less time and $$$ dealing with the garages!

[cazyp]

Take a look at the small 3mm vacuum pipes & braided hoses as well. Blow/suck them to see if they are leaking.

[mubsy812001]

CrazyP/Crasher,

Sorry guys been down south for few weeks as my grandma was ill.

Didn't take my car and cars just been stood there on my drive since.

Now that I've come back I will try and get a diagnostic done (if I can pulll the money out!)

Following your post carzyP regarding all the techy terms ( as I am a complete novice with cars) can anyone show me a diagram (haynes manual diagram ) of where exactly the N75, MAP, turbo vane springs are so at least I can have a look at this myself? and where all the 3mm vacuum pipes you mentioned in your post are? you've also mentioned the black plastic actuator arm and the diaphragm, where is this - diagrams would be excellent! or else everything is going over my head as i don't know where anything is in my car.

PLEASE PLEASE SORT THIS OUT FOR ME PEOPLE, AS I NEED SOME MONEY AND AM LOOKING TO GET RID OF MY CAR TO FINANCE MYSELF AS THE CREDIT CRUNCH HAS SERIOUSLY HURT ME REAL BAD!!!

[Crasher]

Mubsy, without doing a fault code read you do not know in which way you car is going into limp, i.e. code 17964 or 17965. Without this information you are chasing your tail around and could waste money trying to repair the wrong things.

[ChillOut]

I would say think hard before putting good money after bad - I have started down this route and perhaps its time to bail out and get the pro's to diagnose. I had two faulty AMM's (MAF) from GSF - luckily the faults were blindingly clear on the first two, but I am advised that even now I have one that seems to work, it could still be dodgy.

I have heard that Bosch service centres only charge £40 to diagnose and won't charge you for parts unless they cure the fault - if that's true, it will be well worth taking that route. VW typically charge £80 for a diagnosis - you can insist they don't change anything until they get your agreement. eg they will rob you for a new turbo, so you'd want to stop them doing that and take stock if they recommend that.

[Crasher]

A VW dealer will not “rob you for a new turbo”, if the car needed a new turbo (which is a significant possibility) they would advise and quote, saying that VW dealers are thieves really winds me up…

[scotty33]

Hi

If this car is rarely boosting, it seems likely the problem is underboost?

Even if not, it costs nothing to check a few things out.

Check this link out, it shows the insides of the type of turbo used. Also how to strip it down and clean it if necessary..

http://www.technologie-entwicklung.d...t15-turbo.html

You can see the vacuum actuator attached to the side of the turbo. It needs vacuum applied to the actuator to make the VNT mechanism move into 'boost' mode. On the car, you should be able to see/feel the actuator rod move upwards approx 1/2" when the engine runs. After the engine stops, you should see the rod drop back down.
If this is not happening pull the small hose off the vacuum actuator, see if there is any vacuum when the engine is running?
See if you can get another pipe onto the actuator, suck the pipe, see if the rod moves.
The vacuum capsule could have a torn diaphragm which would mean a new actuator is required, or the mechanism could be coked up and stuck. If you unbolt the actuator from it's bracket (2 x 10mm nuts) you will be able to see if the vnt mechanism moves freely..

There is a vacuum pump on the back of the cylinder head, it has a large (approx 1/2") pipe running off it which goes to the brake servo. Branched off this pipe is a smaller 3mm vacuum line which is the 'source' of the vacuum in the boost control system. Try sucking or blowing through the small pipe, this will give an idea of whether there is a vacuum leak. This pipework runs forward to the airbox area, some pipes go under/behind the airbox and connect to a solenoid valve at the front of the engine in the area in front of the turbo - this is the N75 (boost control valve). This valve is also connected to the turbo 's vacuum actuator.
The vacuum lines also run across the back of the engine bay to another solenoid valve which is mounted below the hard plastic intake piping (on the coolant expansion tank side of the engine) - This controls the Exhaust gas recirc.
There may be another vac feed to a device on the coolant hose nearby?
All of these small vacuum hoses need to be airtight, the vac hoses are mostly covered with braided cloth, but some by the airbox are plastic, these often wear until holed.
The N75 solenoid could be dead, you could check it's continuity with a multimeter, i dont know what the value should be but guess it would be approx 40 ohms? Over say 200 would be trouble I think..
The Map sensor is mounted directly into the hard platic intake pipe - just above the egr control valve. Somebody good with Vag com could check it's function and your maf's function before you replace them.
Have a look in the Vag com section, see if there is a user near you?

Good luck with it!

[GRAHAM.C]

A very good post scotty33,very informative and well presented so that even a novice could understand.Good on you mate.

[Crasher]

Yes but I do think that it is easier to have a £30 fault code read done first rather than removing and stripping the turbo and finding you have a rubbed through vacuum hose.

[ChillOut]

A VW dealer will not “rob you for a new turbo”, if the car needed a new turbo (which is a significant possibility) they would advise and quote, saying that VW dealers are thieves really winds me up…

Apologies to you and most probably to VW dealers in general because you/they can't set the prices of the parts. However, I will explain. I am not suggesting they will mis-diagnose the fault, but you can get an exchange turbo, full warranty, for well under £500 + fitting, VW set the price, also for an exchange at around £1250 + fitting. If you want to get your own re-furbished if its not too badly failed (no damage to blades I think mostly), you can get that for £250, again with a full warranty, but your car off the road for a week. Yes, this is much more hassle for you, but you are saving between £700 & £1000 so its really worth a thought isn't it? Clearly anyone can call into question the quality of those exchange units and any refurb, but there again, my OE one appears not to have lasted too long either.

I will put my hands up, I am pretty hacked off with VW right now - car fully VW serviced and owned by me from new and just 4 years 66K. It is now facing (at VW main dealer prices) up to £4,000 worth of work if I want to get it fully back to spec. Its the most I have ever had to spend on any car even if I added the entire life service bill for those previous cars; and I have taken cars to well over £100K/10 years with nothing more than a waterpump and wheel bearing fail.

Crasher offers a lot of help on here, so this is not directed at him, but I hope this explains where I am coming from.

And VAG speciliast indpendent mech I have spoken to confirms that VW are very good for his business these days - not the cars they used to be. He does still recommend and use OE parts though.