no power octavia 1.9tdi pd

[Mstretch]

hi, im a diagnostic technician and am having a lot of bother with an octavia taxi

The first thing i must mention is there's 250k on the clock

so the problem with the vehicle is that its got no power and its very smoky (black smoke) under high revs. I have plugged the vehicle into a snap on solus and I get 3 codes, 1 being intermittent they are

1. 19557 Motor for Intake Manifold Flap (V157): Short To Ground
2. 19558 Motor for Intake Manifold Flap (V157): No Signal
3. P1556 Turbo pressure not reached (this is the intermittent one)

Going into the data reveals that the turbo pressure is a lot less than what is desired by the ECU (according to the solus.) The actual reading at idle is 1000-1010 mBar and the desired amount should apparently be 1040 at idle. If i rev it (up-to/below 5000 rpm) the turbo pressure builds slightly but is always hundreds of mBar below the required amount of pressure, when i rev it above 5000 rpm the pressure then exceeds the required pressure.

Things I have already done:
1, Replaced the Turbocharger
2, Replaced the N75 Valve & the 2 valves beside it
3, Replaced all vacuum pipes
4, Cleaned the intake manifold & EGR Valve

The Vehicle has been to the local Skoda dealership to be diagnosed 3 times ant the 3out of the 4 items above are the only diagnosis' that they can reach - it was my decision to try the 4th

As i run an garage that is independent of VAG i only have the information that the autodata cd3 can give me (which is very limited on component testing for this particular vehicle)

Any suggestions would be greatly appreaciated

[martin1810]

Sounds like the manifold flap is stuck part shut or is closing slightly as the engine revs. Have you replaced the EGR with manifold flap. This is a common failure.
I would replace the EGR with flap and check all the fuses as these often blow when the flap jams. The idle turbo pressure is ok. If the EGR etc are not working correctly the turbo figures will be distorted.

[Mstretch]

thanks for the reply Martin1810 - ill try that today and let you know how i get on

[Mstretch]

Replaced the manifold flap and 1 15A fuse that i found to be blown and it cured the engine management faults meaning there is no codes listed now but the no power fault is still there

going to check the timing and the mechanical condition of the engine as i (just today) found out the timing belt was replaced 6k ago and hasent been right since

any more suggestions would be greatly appreciated & thanks for reading

[martin1810]

Perhaps the cam belt was put on without the locking tools. You only need to be one tooth out to lose power. Have you looked at the cam lobes for wear.

[Mstretch]

thanks for your interest again Martin1810

reset the timing with the locking kit that i borrowed from another mechanic but had no success, unfortunately the timing was correct. I have heard about the camshaft fault but the camshaft was replaced 1 year ago, are they really that bad of a fault for the possibility that it could be worn again in about 30k.

Other than that im thinking about getting the injectors and the fuel pump (on the back of the engine) tested unless there is something else more obvious that someone can think of

[yeh yeh]

Hi, have you try checking the breather pipe for blockage,and also the catylist could also blocked considering the high miles.

[martin1810]

If you use VCDS you can check engine measuring blocks for egr, maf, ijectors etc. That would give you a good clue. Cam could wear in 30k if the wrong oil is used.

[Mstretch]

i removed the cat and replaced it with a straight pipe - still no luck going to check for cam wear over the next few days (work is piling up so i apoligise for any late replys) once again thanks for your interest

[Mstretch]

Removed the rocker cover and the injector shaft only to reveal the cam had worn lobes everywhere. So replaced the camshaft and checked the tappets while I was in there for wear - they were ok. After I rebuilt the cam/injector system and got her going again I took it for a test drive and it had loads of power..... for about 5 minutes. Then after 5 minutes (roughly) the EML came on and it lost power again. So i plugged it in again and got the fault "17964 - Turbocharger (TC) Pressure - Control Limit Not Reached" which is similar to the p1556 fault that I mentioned about in my first post. So because I have replaced the Turbocharger, the N75 Valve, the 2 valves beside it & all vacuum pipes I don't know where to go next as its only done a few miles since that work was done

My head is melted lol any suggestions would well be appreciated and thanks for your interest