Cupra TDI loss of power,lots of smoke

[coco g]

I am about to trade my Seat Cupra TDI in and it has developed a problem.

A couple of weeks ago it suddenly lost power when pulling away and smoke starting to billow out of exhaust which I guess was unburnt fuel.

When I pulled over I found that the flexible pipe connection from intercooler had come free where it connects at bulkhead side of engine under engine cover.Refitted spring clip and gave the engine a blow through and away it went.Also I noticed some oil lying around filler cap which wasn't there previously.

Car appeared to be running fine until Saturday when it started playing up again.
Same connection had come free again,reconnected but engine was not idling smoothly with loss of power and lots of smoke billowing out of exhaust.

Got the car on a ramp to look for any obvious pipes that had split or come free but could not find anything.No fault codes were coming up either.

Took car back home but smoke still belching out of exhaust and could do no more than 40mph no matter what the revs.On the way home the car suddenly got power back and smoke stopped belching out of it almost like the turbo had not been working and had then kicked back into life.However there was a more definite whistle/rattle coming from turbo after this.

I am now running out of time before trading in and am thinking turbo may be gubbed.

Any suggestions on what may be the problem?

 

[diddles]

What colour is the smoke?

 

[Muttley]

If it has blown the boost connection the hose needs replacing. One of the locking lugs will have sheared off.

It will not be holding boost no matter what you try. A temporary repair can sometimes be made with cable-ties but it will not last. The connection will move around as the engine rocks backwards and forwards, so flexing the joint. It may have made the connection good for a short while, though this is unlikely, unless you were keeping to a light throttle.

Which joint is it?

 

[coco g]

What colour is the smoke?

Black smoke,smells like unburnt fuel to me

 

[n11tht]

Black smoke,smells like unburnt fuel to me

if its black smoke it'll more than likely be what muttley suggested. If it was blue smoke it would mean your turbo is knackered

 

[coco g]

Looks like pipe number 7 in diagram.It is a flexible rubber hose with a metal end on the pipe where it connects.It is the top pipe in diagram running round from intercooler via plastic pipework.

This joint originally had sprung apart a little bit causing initial problem. Joint remade and spring clip tightened so the joint was tight with no movement.This joint was still good when engine started playing up again.

Engine was still unhappy down on power and smoking when idling so joint was not causing problem at idle as there was no movement.

Car drove for around three miles only getting to around 40mph smoking constantly out of the back and then all of a sudden the power came back and the car literally took off.All smoke cleared and it was driving normally although there was definitiely a more audible noise coming from turbo when spinning up which made me think a problem with the turbo.

 

[Muttley]

The only way those joints can fail is if the locking lugs are worn down or sheared off. The spring clip should click audibly as you force the pipe into the joint, to signal that the joint has locked. Check both sides.

If the joint has opened once it's also possible that the seal has become kinked or just not seated properly, causing a constant leak.

Check the other joints in the system to see if another has failed. The joints next to the intercooler are common points of failure, they flex more. The design of the joint and clip is only barely adequate for the TDI 150 engine, and they will fail with age, it seems.

Take the joint apart and check the lugs. If either is worn or sheared the spring clip has nothing to bear against. The joint is not held together by the tightness of the clip (like a jubilee clip would do) but by positive mechanical engagement of the lugs behind the clip.

If the lug is worn or sheared then only a new pipe will fix the problem. I'd replace the seals as well, and indeed did just that when my lower intercooler hose failed recently. It made a big difference to the car, improved the low end torque and response noticeably.

If you are sure that the boost pipes are all OK, then I'd suspect sticky turbo vanes,

 

[coco g]

The only way those joints can fail is if the locking lugs are worn down or sheared off. The spring clip should click audibly as you force the pipe into the joint, to signal that the joint has locked. Check both sides.

If the joint has opened once it's also possible that the seal has become kinked or just not seated properly, causing a constant leak.

Check the other joints in the system to see if another has failed. The joints next to the intercooler are common points of failure, they flex more. The design of the joint and clip is only barely adequate for the TDI 150 engine, and they will fail with age, it seems.

Take the joint apart and check the lugs. If either is worn or sheared the spring clip has nothing to bear against. The joint is not held together by the tightness of the clip (like a jubilee clip would do) but by positive mechanical engagement of the lugs behind the clip.

If the lug is worn or sheared then only a new pipe will fix the problem. I'd replace the seals as well, and indeed did just that when my lower intercooler hose failed recently. It made a big difference to the car, improved the low end torque and response noticeably.

If you are sure that the boost pipes are all OK, then I'd suspect sticky turbo vanes,

I have checked over all joints and they appear ok locking it place with no movement.

The way the engine behaved made me think it was something sticky in turbo.The car was running rubbish smoking everywhere and then suddenly kicked back into life like the turbo burst back into life but was much more noisy than before which made me think turbo is on the road out.