Golf 5 TDI Engine wont rev, no power lots of smoke

[Swinissteve]

Hi, I hope someone will be able to help me. I have a serious problem with my Golf 5 1.9 TDI (1K5024 BLS).

Last Friday the car broke down and needed to be recovered to get it home. The car does start but wont rev above 1500rpm and produces huge quantities of black smoke from the exhaust, and barely has enough power to drive at all.

I have looked all over the engine and cannot see anything obvious. I have also removed the intake flap and EGR valve, both were cleaned and the EGR was checked for operation by connecting directly to a battery. I looked at all of the hoses and vacuum lines, boost pipes and cannot see any leaks / spits or disconnected pipes.

I have found 2 potential problems but do not think that they would cause such a poor running, they are:-

1:- I checked the VNT actuator and it seems to be faulty as it will not hold a vacuum. The pipe feeding it is okay so i guess the internal diaghram is faulty. I removed the tube to the VNT actuator and plugged the tube, this means the VNT actuator will not work but more importantly it will stop the vacuum drawing in excess air. This made no difference to the cars running so I do not think that this is the major problem causing the engine to run so badly.


2:- I have also removed the camshaft cover to look at the camshaft as this seems to be a common problem. I looked at all of the lobes and found that one lobe seems to be worn, it has a sharp burred edge. The other lobes still show the small chamfer. The position of this lobe was the third valve lobe from left while looking at the car from front (cylinder 2). Would this be enough to give this problem?



A diagnostic scan only shows code P0698 voltage C low, however that code has been there for a few months with no noticeable problems.

Also a few months ago a scan showed 3 of the 4 glow plugs were faulty so all were changed. The car was okay before and after the glow plug change.


I really need some help to identify what the problem is.

Thanks in advance for any help you can give me.

Regards

[zollaf]

well if the vnt actuator doesnt work, there is your problem...

[Swinissteve]

Hi zollaf,

Thanks for your reply. Will the VNT really cause such a serious fault?. With the vacuum line plugged (to stop it sucking in excess air) I moved the VNT shaft with a screwdriver but moving it did not appear to make the engine run any better. Also do you know if the VNT actuator is available as a spare part, it seems hard to source in the UK.

[zollaf]

with no vacuum to the turbo then the turbo is on zero amounts of boost. full vacuum gives it full boost which is where it is for most of the time, until you hit about 3k rpm where it then starts to drop off.

[FLAPPERJACK76]

Plenty of actuators available. I would try and get a good new one such as Garrett not a no name item. Its just 2 bolts and a clip. About £30 delivered. Set it to the same length as the old unit. To get it set perfect you something like vcds and to find out what the n75 duty cycle percentage is at rest ie full boost request and what the duty cycle should be at around 3500 revs. You can find these from trawling through other posts.

Sent from my SM-G930F using Tapatalk

[Guest 2]

For the actuator to be changed on my BLS the turbo had to be removed due to the design (upside down turbo).

I wasn't getting any smoke etc, just noticeable lag below 2000rpm.

Drives like a new car now 180k going strong.

[Swinissteve]

Hi again,


I think that I am making some progress. I worked on a few more items and wondered if the DPF / Exhaust may be blocked. So I decided to undo the clip that connects the turbo outlet to the DPF, I also loosened the DPF mounting bolts so it could be moved slightly away from the turbo to leave a gap for the exhaust gasses to flow out, therefore bypassing the exhaust and DPF.


I then put everything else back together and gave the engine a start. It now seems to rev freely so it seems the DPF or exhaust is blocked. I didn't drive the car as I don't think it should run for long like this.


Has anyone ever had a problem with the DPF or exhaust being blocked and what were the symptoms?


Also can anyone give me any advise on the best way to fix this problem.


Thanks

[Swinissteve]

I have now fixed this problem. It was a totally blocked DPF. I have managed to clean it using a steam / hot jet washer !!!. Not sure how long it will last, but at the moment is is okay.

I hope that the information in this thread will be useful to someone else.

Regards