Help - New Turbo - Boost/Lag Issues.............

Wheely

Full Member
Nov 19, 2003
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The Sou' West
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Hi All

My turbo recently made a new whining noise for about a week before dying completely -- zero boost followed by dense smoke out the back.

I have had a new genuine turbo installed, but now having trouble with boost/lag. The turbo :

1. Cant feel kick in (boost) until around 2100 rpm. Then boosts normalish and appears to rev through ok

2. If you change gear at higher revs (such that the next gear is >2100rpm) there is a big noticeable lag in turbo power.

3. Turbo noise (the normal high pitch whistle you can hear as it spools up - especially with windows down in built up areas) is very very quiet.

And today I also went into limp mode with 17964 - Charge Pressure Control Negative Deviation. Limp mode cleared after restart.

Car went back in today - they tried a new MAF but the same. They checked for leaks and none obvious. They checked the VNT operation and looks ok !!

HOWEVER when I was initially rescued from the turbo dying by Seat Assistance, the AA towed me >20 miles. THEY recommended I keep the engine idleing as they said it would do no more damage (but would be warmer for me and easier with p-steering on) ! When the garage inspected the faulty turbo they found the turbine shaft had snapped -- thus the oil being pumped from the engine into the turbo bearings had gone down the exhaust (for 30 minutes whilst I was being towed) !! Garage said on restart (with new turbo fitted) there was in excess of 2 litres of oil in the exhaust. It took them >1 hour of driving to burn it off !!

They are now stating a likely cause of the lag may be a very blocked cat. Backpressure in exhaust would slow down turbo spool-up and quieten any turbo whistle.

Now yes I may have to go back to Seat and ask why I was givin such naff information that has possibly screwed my cat. Or to save the hassle I would just get a Powerflow cat-bypass for £60 (as right now I just want my otherwise delightful car back to normal).

Do you think this much oil through the exhaust could cause similar symptoms ??? Possibly causing the 17964 error too (or would this one be unlikely).

Please give me your thoughts here -- I love my car, always maintain correctly - and the garage have said sometimes turbos to go like this even if cars have been taken care of correctly. So far this has cost me £1200 for the work/parts/labour.

Cheers

Mark
 

UncleFester

Grumpier by the day!
Apr 30, 2006
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Milton Keynes
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Have they checked the vac pipe to the turbo actuator? I only ask as mine had split/ worn through and the car felt flat in the higher gears. The cat will be filled with oil - however you don't need the cat so it can be replaced with straight pipe if that's an issue - unless SEAT / AA are paying for it :)
 
Feb 1, 2007
1,602
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Nottingham
I would suggest that this is your problem. My turbo failed and I drove it home, a stupid thing to do! I did not damage the engine but succeeded in filling the exhaust with oil! I have had a new turbo (hybrid) and the boost is sometimes normal sometimes very laggy and smokey. No problems on part throttle. Getting a decat from THS performance as I have replaced everything else trying to cure this intermittent problem. There is only the cat left to try!
Glynn