Air leak

[Ibizatime]

Hi, i seem to have an air leak and could really use some help. If i tap the accelerator sharply, just before the engine revs, i can hear a puff of air coming from the back of the engine. At low rpm the engine isn't very responsive, and when it does get going the engine sounds rough, and i can hear what sounds a bit like a turbo whistle sort of sound. I have a 2007 Seat Ibiza 1.4 DAB SE.

Any help or advice would be greatly appreciated.
Thanks

 

[Ibizatime]

Anyone?

 

[R3k1355]

Probably an exhaust leak

 

[RUM4MO]

Probably an exhaust leak

If so, probably at the front flexi-joint, it is a weakness on that exhaust!

 

[Ibizatime]

Thanks i think you are both right. I have just ordered a new flexi-joint. I had no idea that the exhaust would affect the performance so bad, i was expecting to be told that the problem was on the intake side of the engine.

I will let you know how i get on.
Thanks

 

[RUM4MO]

Normally the correct flex-joint is a weld on only part due to its position, is this what you are planning to do with it?

 

[Ibizatime]

I ordered this from ebay, it wouldn't let me post a link:

"seat cordoba OR ibiza exhaust flexi flex cat repair pipe 1.4 16V stainless"

 

[R3k1355]

If it works like they say should be alrite, but I've no idea the position of the flexi on your system so you're just going to have to see what happens.

 

[RUM4MO]

If it works like they say should be alrite, but I've no idea the position of the flexi on your system so you're just going to have to see what happens.

The exhaust on the 1.4 16V 75PS at least, is really nasty as it passes above the cross member and there is a hanger just where the flexi ends, so, unless the flexi is exactly the correct length and the repair tails are cut correctly, that job will never work very well. Trust me, I've been there done that and yes I went to a proper professional exhaust fabricator and they just fitted the best they could find - which was too big a diameter flexi and too short a flexi section, so it caused booming with the bonus that it touched the underside of the car during reversing up a steep slope (engine flexing on its mounts). So, I got someone on a VAG forum to measure their original flexi, then I ordered a proper and proper sized one - at that position it needs to be the higher temperature rated version as it is next to the manu-cat, and got that same exhaust fabricator to fit it - " it will not make any difference, trust us, we design special exhausts!" - well it did and last for many years!

 

[Ibizatime]

The flexi joint was a total waste of time. I ended up buying a whole new exhaust. Unfortunately this did not fix the problem. The car still makes the puffing noise when i tap the accelerator, whistling under fast acceleration, and feeling majorly under powered under 2k rpm. I have the engine management light on, which my VAG says is down to the lambda sensor.
I took the car to a mechanic about the air leak problem, he said that these engines make bit of a puffing noise anyway, and that he didn't think it was an air leak as it would affect the engine through the whole rev range (Which it kind of does?!), he said i should replace the lambda sensor as it may be causing the engine to go in to limp mode, potentially causing the symptoms that i described. So i splashed out on the new sensor, which i fitted today, but frustratingly the EML came straight back on after clearing the codes, and the same symptoms persist.
Which now has me thinking that the lambda sensor was working fine all along, and was doing it's job in telling me that something is a miss in the air/fuel ratio.
I have now spent more on this car then what i paid for it (I paid £550), and am now incredibly frustrated and pee'd off with it.
Anyone have a clue as to what the problem is? I tried spaying some easy start around the back of the engine in the hope that it would expose a leak, but i didn't notice any difference to the idle speed.

Any help would be greatly appreciated!
Thanks

 

[R3k1355]

Which lambda did you replace?
Often in a 2 lambda system the one closes the engine does all the work and the other does ****-all.

You used a genuine OEM sensor and not some tripe off eBay right???

 

[RUM4MO]

Which lambda did you replace?
Often in a 2 lambda system the one closes the engine does all the work and the other does ****-all.

You used a genuine OEM sensor and not some tripe off eBay right???

And, the above translates into:- "only ever buy a VAG part from a dealer or the exactly the same item direct from an NGK dealer which gets sold under the NTK brand name", it should be B1 S1 .

Not trying to rub your face in it, but did you check if that flexi was leaking before changing it, ie limit the exhaust tailpipe and check if any gasses were coming out at the flexi?

Edit:- exactly what fault codes are being logged?

 

[Ibizatime]

The the whole exhaust system was pretty rotten, and needed to be replaced anyway really.

The current codes are: P0402, P0030, P0135, P1183, P1180, which i think is more codes then i got with the original sensor. I'm going to swap back to the original sensor for now..

It's not a genuine sensor, it came from ebay, cost £60, and came with a 2 year warranty, so i figured i would give that a go rather then pay twice the price for a NTK one, I don't plan to keep the car for 2 years anyway, after all the agro that i have had with it, i just want to fix it then get rid of it.. I would buy a genuine one if i was sure it would fix the problem, but at the moment i'm not even sure that the original one is faulty.
Couldn't an air leak throw off the air/fuel ratio reading taken by the sensor, causing it to flag up the fault codes? Or are the two not related?

Thanks

 

[Ibizatime]

I would buy a genuine one if i was sure it would fix the problem, but at the moment i'm not even sure that the original one is faulty.
Couldn't an air leak throw off the air/fuel ratio reading taken by the sensor, causing it to flag up the fault codes? Or are the two not related?

Anyone?

 

[Ibizatime]

So know one knows??

 

[R3k1355]

Looks like the sensor you bought was total crap, most of the fault codes you're getting are Lambda sensor codes.

but a new, genuine sensor fitted and get someone with VCDS to pull fault codes for you.

 

[Ibizatime]

I have switched the sensors back, and the missus hasn't been out in it since, but once she has i will recheck the codes. And i will replace with a ntk one once i get the refund for this aftermarket one. However I'm not convinced this is my main problem.

Surely a faulty sensor would not cause the puffing sound when i tap the accelerator, or the poor acceleration at low rpm, or the turbo whistle sort of sound that it makes under hard acceleration?

The engine doesn't sound great when driving either, it sounds a bit like there is a small hole in the exhaust, which i know there isn't.

Thanks

 

[R3k1355]

Until you fix the obvious problem you can't really go about fixing the others as it's just a stab in the dark.

 

[Ibizatime]

This is my problem, is a faulty sensor the obvious fault that would cause these symptoms? Or would an air leak cause a working sensor to throw up fault codes? For all i know, the sensor is just doing it's job. £130 is a lot of money for a part that i may not need, so i hope you can see where I'm coming from.

 

[RUM4MO]

If you can't work out if that exhaust is still leaking, then get it to somewhere that can sort it for you. After that deal with the Lambda probe faults if they still exist.