Of course a faulty injector could easily produce lower compression on that cylinder due to carbon build up on the valve seat

We talk about the problem and everybody loves a good technical discussion. We have that advantage that some of us know more some not so much about engines etc. I know something but I do not profess to be an expert by any means! I also respect the years of experience you guys have.

Engine diagnostics is not easy granted. Still, every problem, given time for diagnostics and a strict elimination regime can be diagnosed without doing completely unnecessary work. Compression test, leak down test, fuel trims, CO2 and HC, injector oscilloscope and old fashioned spark plug reading will be able to confirm or eliminate most of the combustion chamber related problems. Proper service is a must and a first thing to do BEFORE any work is done - could be blocked fuel filter doing all that!! Scan tool will show anomalies with sensors if any. Bore scope for valves (

). And so on and so forth...

I basically have an impression from what OP wrote that only one of those things was done (compression test with no values to show for btw) and the mechanic simply went with attitude, oh well, worn valve guides, lest refurbish the head and see... totally unacceptable in my book!

 

If I had a problem like that I'd first do proper engine flush, put all new filters and run full tank of fuel with injector cleaning agent added. Perhaps do it twice even! Give it a chance to clean itself first. Waaay cheaper than head refurb . Then see where we are with things.

In layman terms why do lungs transplant without trying a course of antibiotics first

 

After that start searching for things based ALL the test results. I am pretty sure even them would be able to narrow it down to one or two things before even one bolt was undid on the motor...

I think the fuel/injector cleaner additive is certainly worth doing. Fuel filter, not really, because of the low mileage, these filters are usually for life on petrol engines, and the fault seems restricted to one injector/cylinder.

As compression is now healthy, not really any need for an engine flush.

After trying injector cleaner, which will take some time, a diagnostic scan with the right equipment and someone who knows what he's doing is likely to narrow down the fault. Pappafox needs to talk to a Skoda tech - not the receptionist - to see what they can offer and talk costs.

Edited 15 October, 201411 yr by xman

^ Sounds good to me considering everything.

Evening all,

 

Had friends staying over last night and today so this is the first chance i've had to see your replies. Injector cleaner ..interesting. Need to talk to the Skoda garage re options.

 

Watch this space

Hello

 

Is there a particular brand of injector cleaner which is recommended for the VAG engine? 

I think you will find that VAG don't recommend additives, if I had a faulty injector it would be replaced with a new one.

Injector cleaner won't sort out a blocked /poorly atomising injector .

Well, if it is really coked then no, but this is a very cheap first step. Might be just there, within the realms of additive action. Worth a try. Since injectors have to be changed in calibrated sets all of them would have to be replaced really...

Bang in whatever you can get at max concentration. I'd use the Millers product, but most products in halfords, your local garage etc, will probably be OK. Then go give her some welly, initially lowish speed/flooring pedal to avoid limp mode, gradually building up. Remember that results will be gradual, maybe even over 2 tank fulls. It should also clean the pistons up a bit.

 

Its worth a go at £5-£10. As car goes OK up to 3.2k, I think that the problem maybe the injector nozzle is partly clogged, restricting max flow, probably because of lack of welly in the past.....

Edited 16 October, 201411 yr by xman

Well, if it is really coked then no, but this is a very cheap first step. Might be just there, within the realms of additive action. Worth a try. Since injectors have to be changed in calibrated sets all of them would have to be replaced really...

No you send them off for a clean and service

It's a waste of money but certainly won't do any harm , modern quality fuels come with cleaners in them anyhow, adding more is pointless

Now something like Terraclean may help

Modern fuels at supermarkets have only a minimal amount of cleaner, Tesco fuel seems particularly prone to contamination problems that hit the news from time to time. (due to them sourcing fuel from the open market on occasion). I would say that these injector cleaners will work, but bear in mind they are attempting to clean from inside out,  they rely on flow alone, don't have any assistance i.e. someone physically scraping or brushing the injector, and they have to be compatible with all the fuel system and the fuel itself, so their action tends to be somewhat gentle and slow.

Worried about having to have all three injectors replaced!  Skoda dealer quoted £170+ VAT on the phone for one injector alone. Can't believe that?

Whoops forgot to say so it looks like getting the diagnostics route seems favourite!!

Don't think  you'll need all 3 doing. Only ford diesels need matching sets AFAIK .

 

As usual Pappafox is going well ahead of himself, please SLOW DOWN, try the cheap things first, go and get some injector cleaner and give it a try. This car doesnt seem to get any use. First thing i do when something is running a bit rough is to give it some welly to blow the cobwebs out...

Modern fuels at supermarkets have only a minimal amount of cleaner, Tesco fuel seems particularly prone to contamination problems that hit the news from time to time. (due to them sourcing fuel from the open market on occasion). I would say that these injector cleaners will work, but bear in mind they are attempting to clean from inside out, they rely on flow alone, don't have any assistance i.e. someone physically scraping or brushing the injector, and they have to be compatible with all the fuel system and the fuel itself, so their action tends to be somewhat gentle and slow.

I wouldn't describe supermarket fuels as "quality" fuels

It's about £60 to get three injectors serviced , easy to remove and refit , just post them off

Yeah you are right Xman...I'm too hasty.

 

So would the next steps be;

 

1. Additive for injector cleaning 

2. Send injectors for servicing ....with whom and where?   

3. Ignore service and go to Skoda dealer for diagnostics.

 

The car is hardly used and I would be loathed to see it go!! 

My list would be

1) Dealer or helpful forum member to scan with VCDS

2) if injectors send off for service

3) then fill up with premium fuel like vpower , add a system cleaner and take the car for a good long drive

I think you will find that VAG don't recommend additives, if I had a faulty injector it would be replaced with a new one.

It's ok, all manufacturers say this. But tech's use it in customer cars to treat fuel systems all the time for specific reasons/purposes. It's another tool. It works well for both petrol and diesel engines. 

Injector cleaner won't sort out a blocked /poorly atomising injector .

 

Yes, it often will. The stuff you buy in the shops is normally sufficient for most cars. But techs have access to more 'wicked' stuff that does an even better job.

 

On a more general point. You can replace just one injector without a problem. New is not costly. It has to be calibrated and will match the other two no problem. It's silly replacing all three injectors if you don't have to. Pappafox, you should be able to get an injector supplied, calibrated and fitted for less than £170. But by all means try the injector cleaner first if you can, but if I suspected an injector of behaving like that I'd replace it.  

Edited 17 October, 201411 yr by Estate Man

With regard to types of fuel cleaner, use one that contains polyetheramines (PEA) like Archoil 6400. These are the latest generation of fuel additive cleaner that do seem to be more effective than earlier ones.

Getting all three out and cleaning them, servicing and tuning would be the best option really, I'd agree with richf here. I would however not agree that those specific fuel additives are a waste of time. If the condition of the injectors was beyond the fuel additives cleanres then the engine would be in much more trouble than it is at the moment I'd hazard a guess

 

http://www.injectortune.co.uk/

 

Check them out, nice vid to look at and prices look good as well.

I'm getting the impression that pappafox hasnt really taken this car for a run anywhere even now. Lack of use is possibly the reason behind this problem and not using it now is not doing anything to help.

I'm thinking now that maybe there has been or is water accumulated in the fuel, has pappafox checked the air filter is in reasonable condition, etc? Has he checked all the pipework around the engine is connected?

Fuel/injector cleaner is a cheap and easy first step, but pappafox needs to understand he needs to approach this properly, bang in the cleaner with fresh fuel to ensure it mixes properly, and then spend **lots** of time driving around to let it do the job. He shouldnt expect it to fix it on a first drive, it will take time to work, if it works at all.

If he hasnt got time, press gang his wife into doing some, even leaving it idling for half an hour at a time is better than doing nothing.

Edited 17 October, 201411 yr by xman

No idling, glazed bores ...

Well, basics first, full services with all the filters changed and oil changed as well are a must, how can you even start working on a car without this being done??

Then indeed take her for at least two hour drive with varying engine speeds to get the running gear through all working speeds and make sure engine gets and stays at working temp for a while.

Best would be to take the car for a track day really, not being funny here.

You can't take it for a run until the injector is sorted it will keep fouling the plug and going into limp home mode and you may well end up damaging the bore with bore wash as well as the cat