PCV Valve / Oil Filler Cap

[E13ADD]

Following on from my thread here regarding changing my rocker cover gasket after finding oil on top of one of my spark plugs.

I ran into a few further issues of misfiring on Friday (first since changing), enough that i could hardly drive the car. I popped some new spark plugs in as they were looking pretty rough and it started up and drove without issues.

I now can’t tell if i have a rough idle or not or if it’s how it should be and i’m over thinking. It’s not fully smooth but it also does not jump erratically at any point (i’ll try and get a graph reading if i can)

After some searching i found a few posts regarding the PCV valve although these describe fluctuating revs when idle.

On a running cold engine i went to remove the oil filler cap, there was quite a lot of suction which i’m not sure indicates a faulty valve or not?

It could be fine but after all the work i’ve done to get things right again i wouldn’t mind making sure this is fine too! The car does eat through oil more than i expect. I’ll replace OEM if it needs it rather than any type of delete.

Leon Cupra 2008 1P

Cheers.

 

[380bhpdaily]

Hi out of interest what were the gaps set to on the spark plugs before you fitted them?

 

[E13ADD]

I left them pre-gapped as they came.

(just to note the slight off idle was the same before any of these main issues i’ve changed)

 

[Leeoncupra]

Hi

If your oil cap is sucking in then your pcv valve needs changing

Good little test for the pcv is just loosen the oil cap , if the idle changes and goes rough but then goes back to normal once the cap is tightened back up then that's the sign of a good working pcv

If no change and idle is still lumpy wether the oil cap is opened or closed then pcv valve is knackered

Hope this helps

Sent from my SM-G950F using Tapatalk

 

[E13ADD]

Hi

If your oil cap is sucking in then your pcv valve needs changing

Good little test for the pcv is just loosen the oil cap , if the idle changes and goes rough but then goes back to normal once the cap is tightened back up then that's the sign of a good working pcv

If no change and idle is still lumpy wether the oil cap is opened or closed then pcv valve is knackered

Hope this helps

Sent from my SM-G950F using Tapatalk

Thanks for that,

When i turned the oil cap and lifted slightly there was a big range of suction against it and the engine started running really rough, as soon as i closed the gap again it smoothed back out.

Not quite sure now as that goes against both things you’ve said haha,

I’ll do another test in the morning to confirm.

Planning on calling the local Seat dealership, if they happen to have on in stock tomorrow i might end up just changing it to make sure.

 

[Leeoncupra]

Any fault codes showing up?

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[E13ADD]

No fault codes. I did have some misfire ones but i think changing the spark plugs has now sorted it however i’ve not really been able to go on a decent drive since i did them.

 

[E13ADD]

Here’s a video of the engine currently

YouTube Link

I actually don’t think it’s what i think, the RPM just over a minute is around 760, there’s the odd tiny blips that you can’t make out on the graph, goes to around 780/90 for second and i can feel it slightly jump sat inside. It’s probably normal haha.