Edition 30 - Large Carbon deposits on Injectors

[AnSGTI]

Injector test results are in - they cleaned one injector and found a 10% increase in dispersal at various RPMs. They found no leaky injectors. They also said they had not seen carbon build up like this on other GTI injectors they had tested in the past and that this may point to a combustion problem. I've had a compressions check (which was fine) so what could this mean? Or could it just be a combination of poor fuel and short journeys?

Anyway the workshop manager and I spoke for some time and he recommends getting them cleaned professionally (£30 each) and then re-fitting and running some cleaner through the car. I explained to the garage that I didn't think it was fair that I would have to pay for this, plus the work to date I'm guessing.

I now have a case (manager) with VW Customer Services after I wrote to them complaining about the quality of this car - it has FVWSH, serviced on time and is only 3 year 4 months old with 21K on the clock. Anyway they said they'd speak to the VW garage and give me an answer tomorrow after I updated my case with the info above.

Failing that I guess I try my luck with Car Plan again (who the 3 month warranty is with that I got when I bought the car), but given they turned down VW's original recommendation to replace all the injectors I'm guessing they'll just reject this claim too.

This Thursday my car will have been in the garage 4 weeks 

I can't find much information about what would cause carbon deposits other than the additives in fuel but guessing combustion/timing problems as stated previously

[Mako V12V]

Interesting stuff, keep the updates coming. I've been running on Shell V-Power for almost a year now since i've had the car but do alot of short journeys.
The confusing thing in all this though is that once normal idle has been reached the car performs faultlessly in all driving scenarios.
If the injectors were carboned up then surely performance would be hindered all the time?

[AnSGTI]

The report, which I hope to get a copy of, suggested a 10% increase in dispersal once they had cleaned an injector. Under a cold start I'm guessing the injector will be using a slightly different spray patterrn so maybe this accounts for my problem, I hope. The report did also suggest that these large carbon deposits could point to a combustion issue so I'm guessing this could be timming/spark issue - a compression check was fine so that all I can think of really.

Anyway I now have the battle on my hands of trying to get VW to pay for this work, if that fails it's back to Car Plan through the supplying dealer to see if they'll foot the bill for all this

I've searched high and low for what may cause excessive carbon deposits on Injectors - I have threads on other forums but I'm mainly talking to myself. I may try the Vortex forum

[Richn83]

All sounds very annoying mate, hopefully you will get back a working car and it can slowly re-build your faith and joy in owning it.  In an earlier post you said the previous owner was a lady doing 7-8k a year, if that was all low speed round town driving without ever stretching its legs then I am under the impression that this could cause a build up of deposits especially if she was using crap fuel.

And surely you only need to get 3 injectors cleaned since the testing company clearly cleaned one to do their testing 

Mine is only a KO3 car so has different internals to yours, on start up it catches fine and the revs head straight up to 1100-1200 but as they slowly drop down after this there is an occasional lump to the idle which transfers into the cabin which goes once the revs reach normal idle, so even when the initial fire up issue is fixed expect an occasional lump as the engine settles down 

[john_o]

ok, Id still keep an open mind as to the primary cause.

In terms of the injectors , 10% seems a relatively small variance (but depending on the required tolerance it could have no or a huge effect i dont know). Have VW or the testing company confirmed that +/- 10% would definitely exhibit your issue?
The ECU can adapt with correction as well.
(if i took injectors off any GTI would they not also show a dispersal issue at this level due to normal use?)

what oil has been used in it
(I know TT always stated poor quality oils can cause deposits on the valves etc , dunno about the injectors themselves though being DI)

deposits may have nothing to do with your problem.

bottom line get the injectors back in and see if the problem is fixed.......

[AnSGTI]

Thanks for the replies - yes I am keeping an open mind about this. The engineers report said that they 'hadn't seen this level of build-up on other GTI injectors' - they also said 'in their opinion this wouldn't have caused a miss fire at start-up' and that it  may all indicate some combustion problem.

I have no idea about the type of Oil I'm afraid - it's on time/distance and all been done by Halifax VW. I'm working away so can't get to an invoice at the moment to get the oil part number.

Problem I have is who pays for the injectors to be cleaned

[AnSGTI]

OK - well some good news.

My injectors are being cleaned, I have received a gesture of goodwill from VW of 70% costs - I accepted this meaning all work to date will cost me £75. Considering everything that's been done I don't think I can grumble and at least I don't have to try and argue it with the warranty company.

I'm going to try and get the supplying dealer to cover the remaining costs, but I'm not holding my breath.

The injectors will be cleaned and tested and sent back to the VW garage and re-fitted. They are also going to inspect the intake valves for carbon deposits after I spoke to them about it. They want me to run a fuel cleaner once I get the car back.

Hopefully they'll get the injectors back on Friday

[stealthwolf]

Mate, reading through this thread there's been some horrific news. But at least it's getting sorted finally.

I think sometimes it's more fortune. I know someone who bought a Ford Fiesta and hasn't had a problem with it. I've heard about people who've had issues with brand new Aston Martin DB9.

[AnSGTI]

Yeah I know these things happen, just never had it happen to me before  

I am feeling generally happier about it now - especially as I just had a curtsey call from the workshop manager and he said he'd given them the 'all go' to get them cleaned and he expects them back Friday, maybe Saturday. Something interesting he told me was that the injectors were tested at 400RPM pre/post clean and at this level they saw a 14% increase, the 10% increase was at a higher RPM. It's around 400RPM that my golf splutters on start-up, anyway as JOHN_O has rightly stated I shouldn't get ahead of myself and we need to see what happens when the injectors are re-fitted.

I have also asked the garage to check the intake valves while the intake is off - if carbon levels are high here, rather than getting them to clean them would I be right in thinking a good thrash with V-Power (over 3K RPM) for a long drive may help loosen these deposits? Or is a manual clean the only way?

[AnSGTI]

Well, 5 weeks 1 day and I have my car back 

The judder on idle has gone, it picks up smoothly and seems to be a better drive but it's only had 30 miles put on it and I'd imagine the battery has been disconnected for a fair while so the ECU will still be adapting.

When I first started it there was a slight hesitation in picking up revs but it didn't stutter like it used to. The head tech told me this is what he'd seen on a similar Ed30 that they serviced and said he didn't think it was anything to worry about. I'm going to stick some Forte in it and give it a good run. I'm not completely convinced to be honest but I can't argue that it's as bad as it was prior to taking it in. I guess all I can do is run it for a few days and see how I get on.

I'm still annoyed that a car supplied with a warranty has cost me money - VW have agreed to cover 70% of costs but I still have to find the other 30%. I think the supplying dealer should cover this

[john_o]

now get out enjoy the car, if it were me Id be making sure I used Shell 98 for a few tanks, let it warm up and fully exercise the car 
then remap it 
glad its better than it was 

[RedRobin]

.
Glad to hear it's getting sorted 

Frankly, it's not worth saving 10p per litre by not using a good petrol such as V-Power - The FSI engine much prefers such fuels and especially if you remap.

[danishmkvgti]

Yeah I know these things happen, just never had it happen to me before  

I am feeling generally happier about it now - especially as I just had a curtsey call from the workshop manager and he said he'd given them the 'all go' to get them cleaned and he expects them back Friday, maybe Saturday. Something interesting he told me was that the injectors were tested at 400RPM pre/post clean and at this level they saw a 14% increase, the 10% increase was at a higher RPM. It's around 400RPM that my golf splutters on start-up, anyway as JOHN_O has rightly stated I shouldn't get ahead of myself and we need to see what happens when the injectors are re-fitted.

I have also asked the garage to check the intake valves while the intake is off - if carbon levels are high here, rather than getting them to clean them would I be right in thinking a good thrash with V-Power (over 3K RPM) for a long drive may help loosen these deposits? Or is a manual clean the only way?

As your injectors spray directly into the cylinder under the compression stroke and the v-power doesn't get anywhere near your intake valves a manual clean or water/meth injection is the only options for cleaning of the intake valves 

[AnSGTI]

I friggin give up with this car - I've managed to make a video of it starting this morning - I'm told this is a characteristic of my car. Yet if the car is warm, or has been running it starts silky smooth.

I'd be extremely gratefull for any comments please about it:

http://www.flickr.com/photos/16099319@N03/5053369573/

[Mako V12V]

That's not quite as noticeable as mine! Sometimes mine holds at 400-500rpm for longer and sometimes stalls.
Characteristic my arse!!!!