Engine RPM not crossing 3000... Superb 2.5 V6 TDI

[vprasanna]

Hi all, 

 

This is my first post in this forum. I am from Bangalore and we do not have a dedicated skoda forum here, so posting this question at UK forum where the car models are same like India.

 

Bought a used Skoda Superb 1, 2.5 TDI V6 engine( odo reading 17600 kms) recently. Noticed a problem in high way that occasionally the car is not going beyond 85 KMPH, and the RPM gauge is not crossing 3000, and the RPM drops slowly.  I tried to press the accelerator in ' knock down' method, and even then neither the RPM increasing above 3000 nor the car speed above 85 KMPh.

 

Took the vehicle to skoda authorised service centre, the customer relations manager has taken a test drive and confirmed that the car is not crossing 3000 RPM and there is a problem. He wanted the car to be tested ( electrical circuits + sensors + Turbo+ engine diagnostic) on Monday.  Since this is my first automatic car i could not understand the problem. My past cars were stick shifts and never had any impact on Engine because of electrical/electronics. 

The question here is, has any one faced this problem in your V6 Engine? Any suggestions/ advice from your end will be more  helpful for me to discuss with the mechanics here. Right now the car is at service centre. 

 

Note: In empty highway this car is reaching 120 kmph within the 3000 RPM, i could feel that the turbo kicks in at 1800-2000 RPM also. 

Edited 28 September, 2013 by vprasanna

[Cown]

It's in limp mode. You need VCDs to check what the fault is. Would be my best guess. 

[vprasanna]

Thanks for the feedback, will wait for Monday and see how the diagnostics go! Will keep every one posted!!

[Sheldon.Cooper]

I had this on a Passat 2.5 TDI V6.

 

Felt like turbo wasn't working, wouldn't rev beyond 3000rpm.

 

Put it on vag-com and maf readings and turbo boost were half what they should be.

 

Basically the VNT mechanism on the turbo wasn't moving.  The cure was to remove the air tubes going to the VNT and blow them out (Especially any plastic pipes joining rubber pipes together).

 

Worked perfectly after that. 

 

Apparantly a 2p plastic connector gets gunked up, stops the small vacuum air flow and is diagnosed as a faulty turbo.  So £1000+ later and you have the same problem.

 

Try the above, simple to do and check afterwards.

[vprasanna]

It's in limp mode. You need VCDs to check what the fault is. Would be my best guess. 

 

The Good news after today's engine analysis test is that the car is not in limp/safe mode. The problem seems to be on the vacuum hose. The problem has been identified, but the technician who did the test could not locate the exact hose. He needs more time, so more tests tomorrow.

[vprasanna]

I had this on a Passat 2.5 TDI V6.

 

Felt like turbo wasn't working, wouldn't rev beyond 3000rpm.

 

Put it on vag-com and maf readings and turbo boost were half what they should be.

 

Basically the VNT mechanism on the turbo wasn't moving.  The cure was to remove the air tubes going to the VNT and blow them out (Especially any plastic pipes joining rubber pipes together).

 

Worked perfectly after that. 

 

Apparantly a 2p plastic connector gets gunked up, stops the small vacuum air flow and is diagnosed as a faulty turbo.  So £1000+ later and you have the same problem.

 

Try the above, simple to do and check afterwards.

Sheldon, thanks for providing this info. The technician with whom i have spoken to in Skoda service centre is also aware of this point(probably this may be a standard problem here i suppose), and he wanted more time as he has completed the MAF analysis and confirmed to me that car is not in Limp mode. He has checked the vacuum hoses, and told me that he will zero down on the problem if i provide him with one more day. I will keep the forum updated.

[vprasanna]

Update as of today :

 

Rectification work that has solved the 3000 RPM problem :

 

1) VCDs show low MAF

2) Turbo not working ( Turbo hose found loose)

3) Vacuum hose cleaned connecting to engine and turbo( real reason for the problem)

 

some Additional work done :

4) Glow plug rewiring done ( wiring found to be bitten by rat)

5) Engine wire rewiring done ( same as above)

6) Minor correction like Air bag ( top left above passenger got disturbed when i fitted the GPS sensor for Blaupunkt New york recently)

 

Root cause for engine RPM not exceeding 3000 as per Service Engineer : The  hoses connected to turbo (VNT) had some built up and needed cleaning with compressed air. Post that Turbo started working well and MAF shown correct readings.

 

some additional info :The bottom skit ( Bottom surface rubber/plastic cover) found to be open leaving stones in the road entering and hitting the hoses. One of the vacuum hose needs replacement but, unfortunately the stock is not available at service centre and i have been told to wait. 

 

2) Wires were bitten by Rat ( since i bought this car only 10 days ago, it must be at the previous owner's location!!)...

 

 

Test drive : Took the car in a highway where speed restriction is not there, tested up to 190 kmph and no problem noticed, zero to 100 found to be faster than my Honda civic stick shift ( this is the only reference point available with me) and i could not use a stop watch...

 

Additional info : I have fitted Blaupunkt new york ( double din) in the car by removing the existing one and also the tray below that. It's working fine.

 

Total cost for rectification : Rs 2850 ( approximately 50 Pounds) 

 

Initial symptoms : If any one facing this problem of RPM locking at certain point and further dropping, try this solution than expensive replacements.

 

Thanks for the Briskoda members... i would love to answer questions if any!

 

 

[oh_superb]

You managed to reach 190 km/h in India????      HOW?  Where?

I remember it being a very jammed up place last year...  And I saw a couple of Superbs in Mumbai

Edited 3 October, 2013 by oh_superb

[vprasanna]

You managed to reach 190 km/h in India????      HOW?  Where?

I remember it being a very jammed up place last year...  And I saw a couple of Superbs in Mumbai

It's possible in NH 7 connecting Bangalore to Hyderabad, and you are right..these speeds are not possible in India, but during the test drive we did it for a short empty stretch to test max speed of the car. 

 

Superbs are not in vogue in India now, the star for Skoda in India is Octavia and Laura... yesterday Skoda India has officially launched the New Octavia 2013 model. Saw the test car at service centre, and it was really nice....

 

I am going on vacation for next 2 weeks, thanks for your post.

Edited 4 October, 2013 by vprasanna

[mahesha5]

Hi Prasanna

 

I have SKODA Superb 2.5 AT and I am having similar problem. RPM doesn't cross 2000 and when we run the diagnosis, it gives a Manifold Valve not working error. Do you know how this could be resolved? Also, Could you give me contact details for this mechanic that you tried? Superb service centres here in Pune are not able to resolve my issue.

[vprasanna]

Hi Mahesha, I was out of country and came back just now. Could not check messages or login to Briskoda earlier.

 

I can connect you with the Vinayak Skoda Service center, located here at Okalipuram, Bangalore.

 

They are well aware of this problem in 2.5 V6 TDI, and can guide the Pune team to resolve this problem.

 

Message me at [email protected], I will provide you with phone numbers.

 

Cheers...

[Phil-E]

I can't believe all that work only cost £50!!! Very cheap (compared to our prices anyway!)

 

Phil

[Parag]

I've got a similar issue if not exactly the same.

I've got a Superb 2.5 V6 TDI 2007

If I gradually accelerate the car touches 130 kmph and the RPM drops or gets stuck at around 3000 rpm intermittently.

If I go with the kickdown, it goes all the way to 180 kmph without any issues.

The kickdown also has a delay.

 

The engine revs go high but I don't feel the same power being transmitted to the wheels.

The fuel economy is also extremely low, it goes around 6.6 kmpl (15,5 mpg) in Mumbai traffic, 10 kmpl (23.5 mpg) on highway runs.

The Skoda dealership says everything seems fine there is no problem  :S

 

Any suggestions on what could be the problem and a possible solution?