Hey guys!

Recently purchased an Octavia VRS 1.8t 2001.

 

its only done 49K and seems in good condition, however it has been sat for a few months. had an mot and service in April and flew through.

 

Symptoms:

Bad MPG - around 25-27 MPG driving carefully!
Flat spot around 1500 to 2000 RPM - with a sudden surge every now and then with light acceleration. as if theres a sudden slight hit of boost.

 

Before the MOT the EML came on with the same code P0130, they decided to go ahead and replace both the O2 sensors.

 

However after a drive of about 15-20 minutes (after buying) the EML has come back on with the same code. (previous owner knows and is willing to help).

 

due to the sensors being replaced I'm guessing unless the wrong part was installed its a different problem. 

 

 

I have looked at what i believe is the voltages for the 1st O2 sensor, i saw somewhere its meant to flick between 0.1 and 1 in voltage? from rich to lean? or something like that? 

on my dash command app, the Wideband equivalence ratio (lambda) hovers around 1 and +/- around 0.05. another showing the Wideband Current (mA), shows between -0.1 and plus 0.1.

 

I checked the MAF and gave that a clean but there was no difference. could it be as simple as a vacuum leak?
Any previous experience would be greatly appreciated to see if i can sort it before taking it to the dealer.

 

Many thanks, i don't have much experience but i know a little bit and don't mind trying things.

 

Tom.

How did you check the MAF? VCDS logging?

I didn't check the MAF sorry bad wording i just meant physically and cleaned it as i have done previously with other cars and its helped sometimes. 

Ive just got an OBDII dongle and dash command on my iphone

Edited 14 May, 201610 yr by TEJenkins1995

If the MAF is goosed cleaning it won't help.

Try running without it plugged in, if it runs the same your MAF is ok, but if it runs better unplugged your MAF is dead.

Edited 14 May, 201610 yr by pauldazzle

ill give it a try!

There will be a MAF fault code after running with it disconnected so just clear it.

Wre the replacement sensors genuine VAG parts?

yep will do.

They were replaced before my ownership but it was done at the local skoda garage 

So i went for a quick dave without the maf. no real difference i could see immediately. 

however my MPG dropped again to around 18...

Unlikely to be MAF related then.

P0130 does seem to be only caused by Lambda Bank 1 sensor. http://wiki.ross-tech.com/wiki/index.php/16514/P0130/000304

If the wiring has continuity I would expect it to be sensor failure. If the previous owner is being helpful I would ask if the replacement sensors were genuine VAG parts.

When it comes to VAG engine sensors genuine replacements are a must. There are many many stories of aftermarket pattern parts not working correctly, & my own experience has confirmed that to be fact.

Edited 15 May, 201610 yr by pauldazzle

All he could tell me was that both the sensors were Bosch.

You need to check for vacuum leaks as that can really screw things up. If unmetered air is getting into the system after the MAF it can cause real problems for the Lambda. With the engine at idle have a good listen for hissing in the engine bay, particularily around the inlet manifold.

All the small braided vacuum pipes around the inlet manifold mounting plate are known to fail with age, & there's a pipe under the inlet manifold commonly referred to as the S pipe, which is notorious for splitting, & can only really be checked properly by removal, which is a bit of pita as it's secured with crimped clamps.

Edited 15 May, 201610 yr by pauldazzle

okay looking now and sounds very slightly hissy, but not sure if thats just other components working or not.

ill probably take it in on monday and get them to have a look a it and just tell them what i know so far. thanks!

See if you can listen any strange sounds from the exhaust manifold (before turbocharger) till the second lambda sensor like exhaust leak or something similar. Try to tighten bolts from turbo and manifold even if you don't hear anything strange.

Edited 15 May, 201610 yr by ThomasItis