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Author Topic: Shakey Cold Start  (Read 4988 times)

Offline OllieVRS

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Shakey Cold Start
« on: November 17, 2023, 10:41:16 am »
Started the car this morning to have the engine running but shaking the whole car with the regs steady at 1000. Turn the car off and on again and it was still shakey, but disappeared after 10 seconds and back to normal, nice and smooth.

I parked with the car facing downhill and with a full tank, could this have been the cause?

I also occasionally get the fault code on VCDS for P0441 (charcoal can/N80, I know) but not frequent enough to throw a CEL.

Or is it the valves reminding me they'll need to be carbon cleaned eventually?

Engine on 132k miles, fuel filter changed.

Cheers
'06 Skoda Octavia vRS TFSI

Offline Octoparrot

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Re: Shakey Cold Start
« Reply #1 on: November 17, 2023, 02:31:16 pm »
For the first time ever mine ran a bit rough on first start up on Tuesday, definitely not firing right on 1 cylinder, cleared up after about 10 secs or so and has been fine since then. I just put it down to the cold damp weather.

Offline pudding

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Re: Shakey Cold Start
« Reply #2 on: November 17, 2023, 03:36:13 pm »
Or is it the valves reminding me they'll need to be carbon cleaned eventually?

That is certainly a possibility.  Cold starts/warm up is the only time the fuel injection strategy actually runs in 'Stratified' mode (the S in TFSI), so bunged up valves can interrupt the airflow enough to cause misfires in extreme cases.

Non functioning or sticking swirl flaps is another cause.  Those, the valves and the fuel supply all need to be tip top to get a dead smooth cold idle/warm up.


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Offline OllieVRS

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Re: Shakey Cold Start
« Reply #3 on: November 21, 2023, 12:51:01 am »
Just completed a lovely trip to the Cliffs of Moher and back to Dublin without any issues bar one tiny situation.

Was doing a bit of a cheeky overtake on the motorway on the way back, flooring it (in 5th I think?) and I got this this sort of judder/stutter. At the time I thought it was wheelspin as it was raining. But now I've checked VCDS and it seems at that very moment I got a low fuel pressure fault code  :scared:

What could it be?







EDIT:

Not sure if relevant or not, but had this code come up while on the dyno getting mapped a couple days prior:


« Last Edit: November 21, 2023, 01:01:43 am by OllieVRS »
'06 Skoda Octavia vRS TFSI

Offline mjmallia

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Re: Shakey Cold Start
« Reply #4 on: November 21, 2023, 08:14:15 am »
Checked your HPFP cam follower and cam recently?
Mike

South Coast

S3 8L ---- Golf Mk4 GT TDI ---- Lupo GTI ----  A4 B6 Sline ---- Golf Mk5 GTI

Offline OllieVRS

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Re: Shakey Cold Start
« Reply #5 on: November 21, 2023, 02:22:54 pm »
This is my old cam follower with 10,000 miles on it. Replaced it at the time (5000 miles ago).





And this is my cam. A bit scary looking but was running completely fine.




'06 Skoda Octavia vRS TFSI

Offline pudding

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Re: Shakey Cold Start
« Reply #6 on: November 24, 2023, 10:06:53 pm »
That cam has had it. The peaks are worn down and is why your follower looks like that after 10K. It's not critical at the moment but I would look into getting a new cam.

Is it an AXX engine? They're known for having chocolate intake cams.
« Last Edit: November 24, 2023, 10:09:10 pm by pudding »


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Offline OllieVRS

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Re: Shakey Cold Start
« Reply #7 on: November 25, 2023, 08:08:55 pm »
That cam has had it. The peaks are worn down and is why your follower looks like that after 10K. It's not critical at the moment but I would look into getting a new cam.

Is it an AXX engine? They're known for having chocolate intake cams.

Feared you'd say that. It's an BWA with 132k miles, but shoddy service history as well as a history of low oil pressure. If the cam goes then I might as well start looking at a full rebuild or replacement as the rest of the engine is pretty worn from previous owners neglect.

Does it explain the weirdness that it's only flooring it at mid RPMS in a high gear? Doing a normal 'pull' with high RPMs in each gear is no problem whatsoever, she's still running sweet.

On a side note, friend said if I give him a grand discount on the car when I sell it to him or a year or so he'll promise to rebuild the engine  :grin: so she needs to survive till then.
'06 Skoda Octavia vRS TFSI

Offline pudding

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Re: Shakey Cold Start
« Reply #8 on: December 01, 2023, 09:50:57 pm »
I usually am the bearer of bad news aren't I?  I do try to be positive as no one wants a big bill, but in this case the cam is unhappy I'm afraid! Take him out and buy him a drink to cheer him up, poor thing, he's had a hard life!

Yeah if it's holding back with heavy throttle inputs in the mid rpms, it's lean. That's when the engine demands the most fuel. You only need to wear the cam down 0.5mm to start screwing with the fuelling. With all that wear on the follower and cam, it could be as much as 1mm short in pump lift. I think the pump lift is only about 5mm or so with a healthy cam, so it's a pretty tight margin.

Neglect definitely doesn't help unfortunately!

You could pop a used S3 intake cam in there in the meantime which has a touch more pump lift than the GTI/ED30 cam.
« Last Edit: December 01, 2023, 09:52:57 pm by pudding »


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Offline OllieVRS

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Re: Shakey Cold Start
« Reply #9 on: December 02, 2023, 04:59:58 pm »
Yep, looks like I'll be going back to my factory map then at least until winter ends.

Have missed being able to do 40mpg  :grin:
'06 Skoda Octavia vRS TFSI

Offline OllieVRS

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Re: Shakey Cold Start
« Reply #10 on: January 15, 2024, 11:40:04 am »
I usually am the bearer of bad news aren't I?  I do try to be positive as no one wants a big bill, but in this case the cam is unhappy I'm afraid! Take him out and buy him a drink to cheer him up, poor thing, he's had a hard life!

Yeah if it's holding back with heavy throttle inputs in the mid rpms, it's lean. That's when the engine demands the most fuel. You only need to wear the cam down 0.5mm to start screwing with the fuelling. With all that wear on the follower and cam, it could be as much as 1mm short in pump lift. I think the pump lift is only about 5mm or so with a healthy cam, so it's a pretty tight margin.

Neglect definitely doesn't help unfortunately!

You could pop a used S3 intake cam in there in the meantime which has a touch more pump lift than the GTI/ED30 cam.

Looking at my options, would you by any change have the part number for both the GTI and S3 cams? I saw a video on youtube of a 'Golf R' cam install, does this mean installing the cam from the MK6 R?

Also for this job does the timing belt gear on the exhaust cam need to be removed if just changing the intake cam?

I'm considering just doing the cam in the coming months rather than a full rebuild like I previously mentioned, but I need to weigh in my options. There is a lot of potential for things to go wrong with a job like this, like poor @dazza has been having.
'06 Skoda Octavia vRS TFSI

Offline dazza

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Re: Shakey Cold Start
« Reply #11 on: January 15, 2024, 11:50:12 am »
Don't let my troubles put you off. My engine was completely foobared, it runs fine and the wife is using it for the school run  :driver:.

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Offline OldGTI

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Re: Shakey Cold Start
« Reply #12 on: January 15, 2024, 06:22:40 pm »
Shoddy service history as well as a history of low oil pressure makes me think you should also be thinking about getting the oil pick up cleaned.

BTW: So happy Pudding is still about, I have never needed him on here but it makes me feel better running about in my old gti knowing he is around. Kinda like the AA does.

Offline breeze

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Re: Shakey Cold Start
« Reply #13 on: January 16, 2024, 09:17:43 pm »
If it is a K03 GTI you can probably get away with replacing the follower and fitting HPFP internals. Not the ideal solution but fast and easy to do at home. Then just monitor the cam follower.

Alternatively, new cam is a good time to do cam belt and cam timing chain.

Edit: BWA engine so I guess the same applies. Definitely fuel cuts.
« Last Edit: January 16, 2024, 09:24:43 pm by breeze »

Offline OllieVRS

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Re: Shakey Cold Start
« Reply #14 on: January 17, 2024, 07:02:10 pm »
Thanks for the replies guys.

Shoddy service history as well as a history of low oil pressure makes me think you should also be thinking about getting the oil pick up cleaned.

BTW: So happy Pudding is still about, I have never needed him on here but it makes me feel better running about in my old gti knowing he is around. Kinda like the AA does.

Appreciate the tip but everything on that end has been sorted. Not only was the pick-up change twice, but the oil spray jets (aka oil squirters) and even the connecting rod bearings have been changed too.

Always a joy to see Pudding on here  :smiley:

If it is a K03 GTI you can probably get away with replacing the follower and fitting HPFP internals. Not the ideal solution but fast and easy to do at home. Then just monitor the cam follower.

Alternatively, new cam is a good time to do cam belt and cam timing chain.

Edit: BWA engine so I guess the same applies. Definitely fuel cuts.

She's a vRS that prefers to identify as a GTI, in a country where 95% of our sporty Octavias are diesels  :grin:

Would HPFP internals alleviate the fuelling issue, at least temporarily? Not to keen on them, considering their hefty price tag.

Unfortunately only did the cam chain last year. But timing belt's on three years. Would changing the intake cam even give you any advantage when doing the timing belt? I don't think I have to remove the exhaust cam for the intake cam right?

Cheers
'06 Skoda Octavia vRS TFSI