MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: flashp on February 15, 2014, 11:37:03 am
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Had these sorted out the other week. Not as bad as some but not great either. Installed a Forge catch can to hopefully alleviate some of this. The oil ingress via the valve stems is intentional so that will have to be lived with. The overlapping cam timing won't help either since it bakes in place deposits. I'll get a borescope image taken in a few thousand miles or so and see what's going on.
I can say though that I am certain that the engine is smoother at idle and under throttle.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi326.photobucket.com%2Falbums%2Fk438%2Fflashp%2Fimage3_zps4604d7d9.jpeg&hash=1d6e05b45433100a7c0f7e8743ded167e70cd75e)
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Found this from VW via another post:
"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve.
Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter.
Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle.
A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible
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Very impressive, what sort of method did you use to get it all out?
Simon
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You will get some oil past the turbo seals so you can never prevent carbon build up.
IIRC VRSAlex cleaned his valves, then fitted a catch can and checked the valves after 8k and they were coked up again :sad1:
May take a little longer without the PCV system blowing oil in though.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
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A catch can only stops the oil vapour recirculating when off boost but when under boost the oil vapour recirculates through the rear pcv. So the catch cans do very little to prevent it from happening.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
You will more then likely find it will be the injector on the cylinder that's causing the misfire on idle..
Common fault that also causes poor idling,and poor hydro carbon results.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
No, JKM cleaned mine up for me. Took a while I believe.
Limited options for taking care of this, water/methonal also a contender but maybe a PITA to live with longterm.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
You will more then likely find it will be the injector on the cylinder that's causing the misfire on idle..
Common fault that also causes poor idling,and poor hydro carbon results.
When it's idling it doesn't bounce up and down you can just feel the miss through the car, there is no fault codes either on my car. Would the injector fault flag up as a fault code if I had a problem?
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
You will more then likely find it will be the injector on the cylinder that's causing the misfire on idle..
Common fault that also causes poor idling,and poor hydro carbon results.
When it's idling it doesn't bounce up and down you can just feel the miss through the car, there is no fault codes either on my car. Would the injector fault flag up as a fault code if I had a problem?
no it won't show an actual fault on vcds, but if you do a live miss fire count using vcds, it will show you .I had this very same issue and spent ages ruling out everything else before giving my car to JKM to get them to confirm that they too agreed like me it was injector 4 causing my idle misfire.They replaced it and car is spot on still 8 months later.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
You will more then likely find it will be the injector on the cylinder that's causing the misfire on idle..
Common fault that also causes poor idling,and poor hydro carbon results.
When it's idling it doesn't bounce up and down you can just feel the miss through the car, there is no fault codes either on my car. Would the injector fault flag up as a fault code if I had a problem?
no it won't show an actual fault on vcds, but if you do a live miss fire count using vcds, it will show you .I had this very same issue and spent ages ruling out everything else before giving my car to JKM to get them to confirm that they too agreed like me it was injector 4 causing my idle misfire.They replaced it and car is spot on still 8 months later.
Think it's time I invest in Vcds , need it for a few things now. How much was the new injector just out of interest ?
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Thinking about it I had a slight misfire on my Focus Ecoboost and changed the plugs etc. I put a full bottle of redex petrol injector through and it runs fine now. I have even picked up 3mpg extra on fuel economy. The bottle said will do 4 full tanks of fuel but I thought what the hell and poured it all in. The engine hasn't misfired since so I wonder if its something to do with carbon build up around the injector with direct injection and causes the incorrect spray pattern so it doesn't ignite properly. For the sake of £8 its worth a try.
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Did you do this yourself? Was the intake mani a hassle to remove? I haven't had a close look to see how it removes yet. Mine has a miss on idle and wondering if it's this.
You will more then likely find it will be the injector on the cylinder that's causing the misfire on idle..
Common fault that also causes poor idling,and poor hydro carbon results.
When it's idling it doesn't bounce up and down you can just feel the miss through the car, there is no fault codes either on my car. Would the injector fault flag up as a fault code if I had a problem?
no it won't show an actual fault on vcds, but if you do a live miss fire count using vcds, it will show you .I had this very same issue and spent ages ruling out everything else before giving my car to JKM to get them to confirm that they too agreed like me it was injector 4 causing my idle misfire.They replaced it and car is spot on still 8 months later.
Think it's time I invest in Vcds , need it for a few things now. How much was the new injector just out of interest ?
I think an injector is around £90 quid, but labour and vat done by a reputable garage like Jkm cost me £275 approx.
Thinking about it I had a slight misfire on my Focus Ecoboost and changed the plugs etc. I put a full bottle of redex petrol injector through and it runs fine now. I have even picked up 3mpg extra on fuel economy. The bottle said will do 4 full tanks of fuel but I thought what the hell and poured it all in. The engine hasn't misfired since so I wonder if its something to do with carbon build up around the injector with direct injection and causes the incorrect spray pattern so it doesn't ignite properly. For the sake of £8 its worth a try.
I tried redex and wins EGT spray down the inlet track and it made zero difference, my hydro carbon readings were up near 185 ppm, (200max for Mot testing) the injector was replaced and my recent mot last month, it's now 23ppm. That's a tuned car with Sports cat so she's running spot on since Jkm changed number 4 injector.
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Thinking about it I had a slight misfire on my Focus Ecoboost and changed the plugs etc. I put a full bottle of redex petrol injector through and it runs fine now. I have even picked up 3mpg extra on fuel economy. The bottle said will do 4 full tanks of fuel but I thought what the hell and poured it all in. The engine hasn't misfired since so I wonder if its something to do with carbon build up around the injector with direct injection and causes the incorrect spray pattern so it doesn't ignite properly. For the sake of £8 its worth a try.
Yeah I had plugs in mind and Il be changing the plugs soon as it'll need servicing soon and il see if that changes anything. I nearly bought some of that redex yesterday actually as I was thinking it'll be worth running some through, think it was 5th gear that put some in and it regained some ponys back 'apperantly'. Like you said its worth running some in it can't hurt anything
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Cheers saintsteve though it'd be more tbh :happy2:
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You will get some oil past the turbo seals so you can never prevent carbon build up.
IIRC VRSAlex cleaned his valves, then fitted a catch can and checked the valves after 8k and they were coked up again :sad1:
May take a little longer without the PCV system blowing oil in though.
Yep.
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You will get some oil past the turbo seals so you can never prevent carbon build up.
IIRC VRSAlex cleaned his valves, then fitted a catch can and checked the valves after 8k and they were coked up again :sad1:
May take a little longer without the PCV system blowing oil in though.
Yep.
So would you still say it's worth fitting a catch can to slow down the build up? Or I'm I better off not to bother
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There isn't really any catch cans that work well enough.
I use a combination of a huge forge r32 baffled can, 42dd plate and larger hose. Had to remove the carbon canister to get it all to fit.
Ideally you want all the vapours to release to atmosphere, but the vapours stink and will give you a headache.
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So, basically there is no permanent solution to this problem?
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So, basically there is no permanent solution to this problem?
No
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So, basically there is no permanent solution to this problem?
No
Wrong, just don't run the engine... :evilgrin:
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Take it apart and clean it every month :signLOL:
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A few guys on here have messed around with catch cans and found the car runs better with the OEM PCV system :surprised:
Coked up valves is inevitable so why waste £300+ on a catch can :stupid:
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How much is it to have them cleaned
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Probably a few hours labour and a small cost for materials.