Faulty MAF ?

[GazM]

I've only had my 2001 Leon Cupra for 3 weeks, so I don't really have a feel for it yet or know what I'm doing under the bonnet.

It idles really rough on cold start and searching the forums I see other people have had that too, but 3 days ago the engine warning light came on. It seemed to drive as well as before the light except occasionally it would feel like it was stuttering at steady speed.

Last night it got worse. It would struggle picking up if I gave it too much gas.
Again after searching the forums, today I intended to check for air leaks and also clean the throttle body. When I started it from cold with the engine cover off it looked like the engine was trying to jump out of the bay and sounded like a diesel.

After it had gone off fast idle it was so much better, but after 3 or 4 minutes the revs would drop and it sounded like it was struggling every 5 seconds or so, like it was being starved of air.

There was a noise which sounded like it was coming from somewhere around or under the manifold but I couldn't tell if it was an air-leak type sound or not, it could just have been a pulley or something else.

When I revved the engine it was ok, but would almost cut out when the revs dropped back to idle again.

Remembering the searches on here, I disconnected the MAF (if its the thing sticking out sideways off the big hose top left of the air box) and it ran ok for at least 5 minutes, including when revving and going back to idle again.

Was I right in guessing that was the MAF, is 5 minutes long enough to be conclusive, and could it mean something else is wrong or is it the MAF for sure.

Sorry for the long post but I'd rather give too much information than not enough in case something I think isn't important actually is.

Thanks

 

[cupra-c_ya]

if it drove much better with the maf unplugged then that would suggest a faulty maf, I never got the stalling bit when my maf went it just went flat and would not drive properly. maybe coil packs?

where abouts you from, maybe someone could help with vag com?

has engine management light come on at all?

 

[GazM]

if it drove much better with the maf unplugged then that would suggest a faulty maf, I never got the stalling bit when my maf went it just went flat and would not drive properly. maybe coil packs?

where abouts you from, maybe someone could help with vag com?

has engine management light come on at all?

Yes, I have the engine management light on. I take it a faulty MAF would throw the light?

I'm just out of Leicester, about half way to Melton.

Is it ok to drive it with the sensor unplugged? I have to go out in it soon, so I could try unplugging it if it happens again while I'm out.

 

[traumapat]

it wont always throw a dash light but be aware that unplugging the maf will light it up.

mine wouldnt settle at idle... it struggle to maintain constant revs. ok when driven tho.

id guess your maf has died or is dying. easy to replace on an exchange basis if youve no warrenty

 

[traumapat]

i wouldnt drive far unplugged as you could damage your cat

 

[GazM]

Thanks for the replies. I'm off out now so will see how it goes.

When you say 'exchange basis' it that with a dealers?

Any other advice or suggestions welcomed also.

 

[traumapat]

Thanks for the replies. I'm off out now so will see how it goes.

When you say 'exchange basis' it that with a dealers?

Any other advice or suggestions welcomed also.

yep. take unplugged sensor sitting in its tube to dealer and he`ll give you a fresh one and relieve you of about £80.

 

[GazM]

Just come back. Before I left I plugged the sensor back in with the intention of unplugging it if it became bad, but I couldn't even pull away without the engine almost cutting out so I unplugged it again.

I tried plugging it back in again to come home after the engine had colled for about 1.5hrs and it was awful again, and was worse with the lights on.

Unplugging it again made it idle smooth with or without lights but it was very difficult to pull away (but possible) until the engine had been running for a minute or so.

Do you guys think that's enough proof to shell out for a new MAF, or could it mean something else?

If I get an exchange MAF, can I get one at any VAG dealer or does it need to be a SEAT dealer?

Thanks again.

 

[cordobabrendy]

gaz borrow one from someone here, im sure theres a monthly meet near you!

 

[GazM]

gaz borrow one from someone here, im sure theres a monthly meet near you!

That's a great idea but my problem is I have no other way to get to work which is 16 miles away, and if driving with the sensor unplugged is bad for the cat or car then I need to get it sorted as soon as I can really.

If there's anyone near Loughborough who'd lend me one for 10 minutes I could get there in my lunch break?

 

[GazM]

Just remembered something else from the way home.

I didn't really welly it but gave it a couple of short bursts of pedal, and it didn't pull anywhere near as well as last week before all this happened. That's with the MAF disconnected.

I hope that means something to someone.

 

[traumapat]

whatever it is get it sorted as un maffed is bad on your cat. any vag dealer should have one . i got mine from vw. phone 1st.

 

[GazM]

Cheers, will try the local VW place in the morning. Fingers crossed it will sort it.

It's such a nice car to drive but it is doing it's best to put me off it big time!

 

[GazM]

I got an exchange MAF today after having to give the part number to the VW dealer as they said they couldn't look it up from the car make.
I fitted it parked on the road so I didn't have to go back to get a refund on the surcharge for my old one.

At first I didn't think it had cured the problem as it was very lumpy at tickover, but I held it at about 1500rpm for a couple of minutes then managed to pull away.
It was a bit iffy driving it at first but it's gradually got better and now it seems fine so thanks to all who helped.

The radio reception even came back when the engine was running smooth, before it was garbage. Good job I beleive in coincidences!

Last question just as a benchmark to test my now apparent smooth running car, has anyone recorded times between 2 speeds in a certain gear for a standard 180 LC? I'd just like something to compare against because I don't know how well it should pull.

Thanks

 

[traumapat]

glad it seems better. try doing a search on here re gear times/speeds. or better still fit a boost gauge or get it to a rolling road.

hopefully youve sorted it

 

[CupraSteve]

if it plays up again could be coil packs (jeez thats two i the space of 5 mins lol)

 

[Lionsio]

Mate: definately it´s a coil pack, no doubt about it.

All the symtoms you´re describing corresponds to a failed coil pack

Let me ask you: have you noticed a strong fuel smell when accelerate?.

It´s very known the VAG coil packs on certain 1.8T models are deffective, and sooner or later will fail.

I have the bad experience around 3 weeks ago, I was out of the city and one coil pack failed, I drove a 90 km distance from the town where I was to Mexico City. Next day do the vagcom to my car, knew the coil pack 4 failed, when to a spare parts dealer, bought one (45 usd) and replace it, turned on the car and problem solved.

 

[GazM]

For now it seems fine - that is it runs smooth enough with no hesitation or apparent misfires, including from cold.

I do appreciate the suggestion though. Just another example of how helpful this site can be.

I'd like to get vag-com soon so if I do I will check the coil packs just to make sure.