FSI EM light comes on after refueling

Hoomart

Member
For the 3rd time in a row after refueling , within 10 km of running, the EML comes on for no apparent reason, with no loss of performance, idling stability, consumption increase (or decrease ☹️) etc & I've no idea why.

I'm using Aral 98 & various refill amounts ; 30 litres, then 25 & the last time was only 15 & different stations, so no common explanation there.

The light does go off without me doing anything, but again, with no repeatability on time, distance or frequency of restarts ; all very strange - even for an FSI !

I know the 'official' answer will be do a VCDS, but my question is ; has anyone else had a similar issue with a definitive answer on what is going on ??

I'm a mechanical engineer, but hate electrical problems & all l can think of is something related to cold fuel being drawn into the fuel lines & injection system, but apart from that l've no idea what's going on. I recently changed the fuel filter, which was not showing any excess contamination, given that l have no idea when it was last changed, so don't think it is related to sediment in the fuel tank being disturbed during refueling.

Over to the experts who make this such a great site for solving all things A2 related.

Martin
 

PlasticMac

Member
Inspired guess🙂. Renew the petrol cap.

No time to say more at the moment.

Andy
Here's the link:
Mac.
 

Hoomart

Member
Inspired guess🙂. Renew the petrol cap.

No time to say more at the moment.

Andy
Hi & thanks for this suggestion ; l have read that airleaks via fuel cap can cause issues ; mine looks ok, but can try to find another.

Not being ungtateful in any way, but was hoping to find someone else who has experience this same issue with their own car & solved the problem.
 

audifan

A2OC Donor
Well it is cheap enough to replace the cap regardless. It is the most likely source of your problem. You are twisting the cap until it ratchets I take it?


Another issue could be to do with the charcoal filter..

You should never brim the fuel as there is no room for it to expand. Once the fuel clicks off that is enough in a petrol engined car.
 

Hoomart

Member
Well it is cheap enough to replace the cap regardless. It is the most likely source of your problem. You are twisting the cap until it ratchets I take it?


Another issue could be to do with the charcoal filter..

You should never brim the fuel as there is no room for it to expand. Once the fuel clicks off that is enough in a petrol engined car.
Agreed, this is a cheap, quick item to change & see what effect it makes ; l'll source one & report back on any changes.
Will also look at the charcoal filter as well, but think my Webasto heater may make that more difficult to get to.

Re over filling ; l am aware of this & only do a one click then stop.
 

steve54

Member
hi there, always with the FSI you need a code reader, i use a an xtool vag401 at around £50, i've kept my FSI sweet for a long while,
it will tell you enough to put you in the right direction. an FSI guess is generally an FSI shed load of money.
hope this helps
 

Hoomart

Member
Webasto heater on a 2005 petrol FSI. That must have taken some doing, not least the diesel fuel supply it needs.;)
Hi there ; don't want to be contentious, or go too far off topic, but here it is ; Webasto in a 2005 FSI & was not a retrofit. Reading the booklet, it is a multifuel unit.
I have used it over last winter, but now, with the price of fuel everywhere (ours is up by more than 70% in a year !), running a Webasto unit on 98 oct does not seem a good option vs wearing an extra jumper, if this carries on - and it will !!
Webasto.JPG


@steve54 , thanks for the reader info - will get one & keep it in the car all the time. Have to say, apart from changing coil packs & plugs to smooth out the tickover, the engine is really performing fine for nearly 2 years of ownership, apart from the EML after refueling issue, which was the subject of my initial post.
Martin
 

Hoomart

Member
What's the cars history
Possibly an Scandinavian spec for extreme cold climate?
Bought new in Potsdam, Germany (suspect as a company car as has so many options added), 4 previous owners before I bought it near Dusseldorf & personally imported it to Luxembourg.

All Webasto documents supplied with the car have print dates (if any) before or in 2005.

This type of heater is (or was) a factory option on many pertrol & diesel cars on mainland Europe, but possible not so many UK specs. & different variants will run on almost any fuel you can get your hands on.

Martin
 

Proghound

Admin Team
Bought new in Potsdam, Germany (suspect as a company car as has so many options added), 4 previous owners before I bought it near Dusseldorf & personally imported it to Luxembourg.

All Webasto documents supplied with the car have print dates (if any) before or in 2005.

This type of heater is (or was) a factory option on many pertrol & diesel cars on mainland Europe, but possible not so many UK specs. & different variants will run on almost any fuel you can get your hands on.

Martin
Wow, you learn something every day. I suspect like many UK A2 owners, I had no idea that Webasto could be fitted from new with anything other than the TDI. Sometimes we just don't think outside the box enough in this country :)
 

audifan

A2OC Donor
So being built as a cold climate car, there may be other items or functions we in non cold climate countries are not aware of. As such we may be of limited help on this issue. If it is not the fuel cap nor charcoal filter AND a full scan that preferably gives Audi fault codes and not generic ones does not highlight the fault you may be better seeking help from owners in the same region. Not being unhelpful but unless someone here has a cold climate region car ( and I doubt all the 1.2TDI owners here are included in that ) we probably can not help further.

Good luck and please post back your results and cure.
 

Andrew

A2OC Donor
Webasto in a petrol car - the new upgrade! Interesting what will be required but I assume it is covered in the workshop manual.

What a surprise.

Andy
 

PlasticMac

Member
So being built as a cold climate car, there may be other items or functions we in non cold climate countries are not aware of. As such we may be of limited help on this issue. If it is not the fuel cap nor charcoal filter AND a full scan that preferably gives Audi fault codes and not generic ones does not highlight the fault you may be better seeking help from owners in the same region. Not being unhelpful but unless someone here has a cold climate region car ( and I doubt all the 1.2TDI owners here are included in that ) we probably can not help further.

Good luck and please post back your results and cure.
I think (famous last words 🤞) the EML is unlikely to be related with the Webasto, or other, unknown in UK, cold climate options.
Mac
 

PlasticMac

Member
In the end, I couldn't resist a guess.
When the petrol cap sensitivity came up originally, we found out that there is a solenoid valve between the carbon canister and the inlet manifold, that opens occasionally to relieve the build up of petrol vapour that is temporarily stored in the cannister, when the pressure in the petrol tank rises. The tank is not vented to atmosphere, only via this controlled circuit. The fuel that is delivered from the forecourt dispenser is cool, so it will expand as it warms, especially the vapour. So this control valve should open and purge the cannister, and relieve the intank pressure. Whatever routine in the ECU controls this valve must (pure supposition) be aware of the need to open. Maybe if the purge process is too slow, the EML is triggered, but clears as the pressure drops.
So, my suspect is the carbon cannister.
I'd go with a VCDS scan, or OBD Eleven, to ensure those VW and FSI specific errors are correctly labelled.
Best to clear codes prior to the next fill, then scan post fill, 🤞that the EML comes up on cue.
Mac.
 

Hoomart

Member
So being built as a cold climate car, there may be other items or functions we in non cold climate countries are not aware of. As such we may be of limited help on this issue. If it is not the fuel cap nor charcoal filter AND a full scan that preferably gives Audi fault codes and not generic ones does not highlight the fault you may be better seeking help from owners in the same region. Not being unhelpful but unless someone here has a cold climate region car ( and I doubt all the 1.2TDI owners here are included in that ) we probably can not help further.

Good luck and please post back your results and cure.
Will do !!

I'm 110% sure it will not be Webasto related, but I was just following up on your @audifan , original doubts over my car having a petrol powered Webasto pre-heater.

I prob will try 1) new filler cap, 2) locate & clear charcoal filter & pipes & in parallel, 3) order an xtool vag401scanner, to keep in the car & catch the guilty item causing the EML to come on redhanded, 4) stock up on thick jumpers, ready for the coming winter ........ BTW we have 29c today, going upto 33 on Saturday, so no rush on that final item 🥵

Martin
 

steve54

Member
hi there, solenoid valve that's spoken about is the N80 evap purge valve, worth a bunt for the money, i changed mine in the early days (bought mine running like a dumper truck, ha ha) no fault code, ha ho FSI guessing again.
only trying to help
 
The carbon canister is meant to be a lifetime item, it shouldn't need changing. Having said that, I have changed one on an A2 1.6 FSI, when I was getting petrol smells while driving. That didn't fix the problem, then I changed the evap purge valve - that didn't fix the smell - then I finally found a tiny leak in a hose where it was clipped!
 
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