I'm quite happy using VCDS to code modules, etc., but using it to diagnose engine problems is new territory for me.

Is there a way I can use VCDS to see if there is a misfire or other issue with my 2.0 Tdi PD Octavia?

No fault codes have been evident at all which would lead to this suspicion if a misfire, but someone pointed the noise out to me which I had drawn a conclusion of it being DMF failure imminent.

How can I check the glow plugs or injectors or other parts using VCDS?

I've had a look in VCDS measuring blocks, etc. but can see anything that gives (to me) any useable information in this issue.

I'm no mechanic, so it's no good suggesting taking the engine apart and swapping bits over without clear instructions, or better still, pictures. Plus I'd like to use VCDS first if I can.

Thanks in advance.

No one got any ideas or tips for me?

You can see the adjustment on each individual injector somewhere in measuring blocks - have a search for when people were having issues with injector replacements on PD170s and you will see the details.

Thanks andyvee.

I'll take another look at the measuring blocks tomorrow, but didn't see anything of much use when I last looked.

I'll take some screen shots of where I'm looking and see if that prompts anyone else.

I think I've found what you refer to; the logs are on my laptop at the moment.

What am I looking for or what should I see?

IIRC, injector 1 was quite different to the rest; 4 was a bit off but 2 & 3 were both identical.

They should all be within about 10% ish of each other, if they aren't you have a problem on the cylinder that is different - possibly injector, but could be anything that affects the combustion chamber - valves, rings etc.

Not sure if this is what I should be looking at:

Address 01 Engine

Group 013: Idle stabilisation

Injection Quantity Deviation:

Cylinder 1: -0.38mg/str

Cylinder 2: 0.16mg/str

Cylinder 3: 0.09mg/str

Cylinder 4: 0.07mg/str

The above was at idle, at c.1600 rpm I got this:

Cylinder 1: -0.40mg/str

Cylinder 1: 0.07mg/str

Cylinder 1: 0.07mg/str

Cylinder 1: 0.21mg/str

I've done a couple of scans of the same measuring block and got different results. Always cylinder 1 quite a way below zero and cylinder 4 slightly above 3 & 4.

Am I looking at the right thing or should I seek something else?

You are looking at the right thing, Cylinder one is weakening off, could be a dodgy injector or injector seal.

Sent from my phone so please excuse brevity and spelling

Brilliant. Thank you.

 

At least I know I'm looking in the right place.

 

I can also look into it a bit more and possibly get it to a garage with a little more info for them to look at.

Doing some reading on this (on this forum) and it could also be the tandem pump which, I have suspected for quite a while was on the way out (but had been told by a garage that the noises I heard were a failing DMF...)

 

Is cylinder 1 at the same side of the engine as the tandem pump (i.e. over the driver's side?)

 

As the injector seal set is only £10 per injector from Darkside Developments (are they a site sponsor?) would it be worth me getting one set for injector one, fitting it and seeing if that makes any difference?

 

How easy are they to fit?

 

I'm competent and methodical, but no mechanic.

Get a mechanic with the correct tool to do the injector seals.

Sent from my phone so please excuse brevity and spelling

I had a look yesterday and while I can get the tools to do the job, I think it is beyond my capabilities so will be getting to a garage as soon as I can.

Tandem pump is a good shout though as well.

That's where I've had noises coming from for quite a while, but the garage I took it to couldn't replicate the noises while I was there and said that it was DMF on its way out.

With so many possibilities, it's going to have to be an expensive trip to a garage...

Possibly a combination of:

Injectors (clean/replace/seals);

DMF & Clutch;

Tandem pump;

Timing belt (throw that in as its due a change now anyway).

Think I'll be lucky to see it get under £2000!

What mileage are you on now - my DMF and clutch lasted 110K and would have gone further.

 

Try running some Millers diesel additive through it first - a couple of tankfuls at double dose might make a difference

I'm on 136,000 miles roughly, but no consistent and reliable pointers to it being DMF. There is no difference at idle when clutch is depressed (usually). No judder on pulling away (occasionally on start up and shut down or if clutch dropped in too quickly). No juddering at high revs or heavy acceleration.

I've run Redex through it on several occasions, but doesn't appear to have much effect. I know it's not the best, but it's readily available and quite cheap.

Have been considering Archoil AR6400-D but more for cleaning the turbo than the injectors.

I've seen Millers and read about various additives. Maybe now is a good time to try something.

Give Millers a try, only about £12. Is the fuel filter fairly new?

Fuel filter changed every 8-9,000 miles by me. Last done in late April.

I'll give some Millers a try, but will be looking for a garage to get it too.

Got a big bottle of Miller's which was a pretty bargain as it had ten tanks worth for about £12 IIRC.

 

I've almost run two tanks through so far and there appears to be far less noise on startup from cold suggesting that it might have been an injector issue and not a DMF issue.

 

I'll run a VCDS scan on the injectors as before and see if the hint of a misfire is still there or has diminished or even gone.

 

Fingers crossed and thanks to 'andyvee' for suggesting Miller's.

Are you using it at double strength?

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Not quite.

50ml per 50 litre tank.

Does seem to be having some effect as I have not noticed the 'chattering' much on cold start recently (and I have been listening).

Actually just doublechecked and found out that 1ml/l is actually the recommended ratio!

I'll double up on the next tankful.

Worth doing double dose for the first couple of tanks.

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Been double dosing it for a while now. Car seems more economical and slightly improved smoothness and response. But this could all be psychosomatic!

Noise still there on cold start but haven't been able to check to see if the slight misfire is still registering with VCDS.

I used the Millers in my old VRS.

Mainly because I used to buy most my diesel at supermarkets. Yes, I know I'm cheap.

Saying that I did notice that the engine felt smoother after using it.

Hope it cures your problems.