Intermittent Knocking Noise from Engine Idling 2013 Corsa 1.4 Ecotech

[MJG50 7]

I've noticed what seems like an occasional misfire on a 2013 Corsa 1.4 SE Automatic. I'd never buy a chocolate engined Vauxhall for stock but I took this one in PX. 

Last week,  I noticed a very occasional slight knock/bang and the revs would momentarily fall slightly and then go back to normal when idling in traffic. Now the weather is a lot hotter, I've noticed when pulling away when the engine is hot the engine bangs quite a bit with the same slight drop in revs. Whilst waiting at a roundabout today for a few seconds there was a banging / pinking sensation that I felt throughout the car. Once on the move though, the car drives absolutely perfectly with plenty of smooth power. This banging/knocking only occurs when idling and just recently when pulling away.

I've read about quite a few problems with this 1.4 Ecotec engine - I'll get it looked at by my mechanic but I just wondered what is the most likely cause?

It will be a tricky noise to show the mechanic as it's not as though it does it all the time.

The oil & water are all fine.

The car was recently serviced with 5 W 30 oil (as used from new) - I'm sure I read somewhere that using thicker oil could help but is this likely to be of help in my case?

It's a really nice car - this annoying misfire is the only thing wrong with it.

[MarkTVS 209]

Coil pack or plugs?

[MJG50 7]

I'm pretty sure the last owner had a new set of plugs fitted at the last service just before she traded it in but I'll check the service history to make sure.

[Halfpenny 114]

Correct oil would be 5W30 Dexos.  Unlikely to be oil problem.

Fault codes? Live data?

Coils and plugs normally play up under load - not idle.

Check oil filler and dipstick are seated - vac leaks cause problems like rough idle.

These engines are prone to broken valve springs.

Are you sure its not A/C cutting in? Possible noisy A/C compressor.

Edited July 21, 2021 by Halfpenny

[It's me 615]

9 hours ago, Halfpenny said:

 

Are you sure its not A/C cutting in? Possible noisy A/C compressor.

This would be my faraway diagnosis too

Hopefully my cheque is in the post

 

[MJG50 7]

Many thanks for all the replies, much appreciated.

The last owner did have a new set of plugs fitted before trading in.

The cheque is in the post 'It's me' but unfortunately I think the postman is self-isolating 

I've done some more research and if the coil pack goes it seems to make a clicking noise and I wouldn't call what I have as a clicking noise.

The only cars I've ever had with a very noticeable A/C compressor are Rover 75s when they were about 3 years old - they all seemed to have a very noticeable knock when the a/c cuts in.

This Corsa does this knock a lot though as you can see in the YouTube video and it behaves exactly the same if the a/c is on or switched off.

The misfire hasn't triggered the EML so I don't think there would be any fault codes.

I'll get the oil filter checked, as far as I can tell the dipstick is fine.

I've done my first ever YouTube video  - hopefully it shows what I'm talking about, the engine moves slightly when this misfire occurs and the revs drop slightly. I'd say the misfire happens quite a lot when idling now, roughly at 10/18/22/31/34/43/50/57 seconds and 1min 06 seconds on the video. 

 

Edited July 22, 2021 by MJG50

[Halfpenny 114]

I would not describe that as knocking or banging.  I suspect something switching in/out causing change in load or AFR - A/C, cooling fan or maybe check EVAP system. That doesn't look like coils/plugs or broken valve springs etc.  Carefully check vacuum/intake system and any solenoids etc. Check PS also.

Edited July 24, 2021 by Halfpenny

[justina3 518]

Second for the evap system heard a purge valve make similar noise before. 

Vile things

 

[MJG50 7]

Many thanks - the only car I've had that needed a new coil pack was a S-type Jag and that was losing power alarmingly on the motorway whereas this Corsa drives absolutely fine when on the move so I agree it doesn't seem like coils.

Am I right in thinking this YouTube video explains the evap system problem?

 

[justina3 518]

thats the little bugger, last one i had made a loud clicking noise when you remove the feed to it the noise went away. 

yuck did i mention i hate these things. 

[MJG50 7]

9 hours ago, justina3 said:

thats the little bugger, last one i had made a loud clicking noise when you remove the feed to it the noise went away. 

yuck did i mention i hate these things. 

Thanks again, oddly enough it's got a lot worse today. It sounds awful pulling away from idle as though it's going to pack up! I'm not sure I fancy driving 10 miles to my normal mechanic so I might get it done locally. I bet they'll say its the coils but I'll them it's the EVAP purge valve.

Do you know if it's ok to disconnect this valve to check the noise isn't there before fitting a new one?

I know some people seem to do well on Corsas but I think they are best avoided, especially when we can't hear them runnning at auction.

 

Edited July 26, 2021 by MJG50

[justina3 518]

There a doddle to change mind only two star bolts one electrical connector and a air pipe honestly ten min job with a my first tool kit.

 

[MJG50 7]

Thanks for your help justina3, much appreciated.

One last question, can I just double check this is the right part?

https://www.ebay.co.uk/itm/302256182199?epid=14034592235&hash=item465fdf53b7:g:ssgAAOSw4CFYzRLi

 

[justina3 518]

Thats the little bugger, good luck hope it solves your problem.

[MJG50 7]

I've finally got the EVAP purge valve replaced today and unfortunately the slight misfire at idle is still there! 

I don't think it's the coil pack as it still drives fine under load but I guess it's worth me getting the coil pack looked at - if there are signs of corrosion to it I'll get it replaced. The bolts on the engine as shown in the YouTube video above are pretty rusty so it is possible the coil pack is corroded too.

I've checked the service history and the last owner who traded it in had new spark plugs fitted just being trading in so this was probably done to try and cure this problem.

As far as I can see, the oil filler and dipstick are seated fine. 

It it isn't the coil pack, I may have to sell it as it is, declaring the misfire.

[BHM 994]

For the lack of a helpful answer all I can say is if you sell it cheap the sort of person who buys a cheap Corsa won’t give a toss, tbh they probably won’t even notice it. As far as I can tell most Corsa owners run them into the ground anyway, thinking tyres, brakes & general maintenance are optional extras not worth bothering with.

[MJG50 7]

22 hours ago, BHM said:

For the lack of a helpful answer all I can say is if you sell it cheap the sort of person who buys a cheap Corsa won’t give a toss, tbh they probably won’t even notice it. As far as I can tell most Corsa owners run them into the ground anyway, thinking tyres, brakes & general maintenance are optional extras not worth bothering with.

You're right there BHM! It always amazes me how fussy buyers are when looking at car, checking every single detail, previous work carried out etc etc yet once they take on ownership they usually run them into the ground with very little maintenance and very little care for the car. I've occasionally seen cars I've sold to fussy buyers a few months down the line and I could never believe the state they were in! One particularly fussy 3 year old BMW buyer (the car, not the buyer) had managed to wreck it within a few months with almost every panel scuffed and she was mega fussy when buying it.

I've just found this video which points to changing the coil pack but having said that, I still doubt my problem is the coil pack as the car still runs 100% fine under load once on the move. 

 

That clicking noise he describes above is quite similar to mine so I guess it's worth me having the coil pack looked at and if it looks rough, I'll get a new one. 

Some people reckon it could be the rocker cover housing - I'm not sure if this is likely though?

As you say BHM, if all else fails I maybe better just selling it cheap and declaring the misfire at idle - in the past, I've got rid of PXs with the odd niggle at the block but maybe in future I should do a brutally honest video description. I remember there was a bloke on here who did long videos showing every fault. The sort of buyers I get would normally be put off by the slightest imperfection but at least a brutal video would weed out any fussers from viewing the car.

[Halfpenny 114]

If you think its a coil pack then buy a cheap one for £25 and drop it on. They are dead easy to change. The £25 cheapies are not built for the long term, but they do work and it will prove a point.  Count the number of connector pins because there are two styles (7 or 6 pin, IIRC). Takes about 5 mins to swap these out.

[It's me 615]

1 hour ago, Halfpenny said:

If you think its a coil pack then buy a cheap one for £25 and drop it on. They are dead easy to change. The £25 cheapies are not built for the long term, but they do work and it will prove a point.  Count the number of connector pins because there are two styles (7 or 6 pin, IIRC). Takes about 5 mins to swap these out.

not built to last is a very polite

[Halfpenny 114]

33 minutes ago, It's me said:

not built to last is a very polite

Yes, but putting one on will satisfy his curiosity one way or the other. If it were me I'd be looking at fault codes and live data. Would nail it fairly quickly.

Edited August 14, 2021 by Halfpenny

[MJG50 7]

Many thanks, I didn't even know it was possible to get a coil pack that cheap! 

It's not throwing up an EML so I don't think there will be any fault codes?

[MJG50 7]

Its taking a while to get the Corsa looked at again as the workshops I use are all ridiculously busy at the moment.

I've had a look at it again today and it doesn't seem to misfire until the engine is warm and the hotter the engine is, the more often it misfires.

I'm no Corsa expert (as no doubt you can tell! ) but is it possible that misfire could be caused by a timing chain issue or even a head gasket issue? As far as I can tell, the timing chain doesn't rattle at start up and the head gasket is ok but I did once have a Jag with a misfire and that was caused by a stuck injector that lead to a head gasket failure. I doubt it's the case here but just trying to consider all possibilities before embarking on the game of parts darts!

It's a bit frustrating as I've done nearly 200 miles in the car and it drives 100% apart from the misfire at idle.

[BHM 994]

FFS, just sell the fucker as it is. 

[Tony911 79]

1 hour ago, BHM said:

FFS, just sell the fucker as it is. 

Thought he would have sold it by now