2.0 Tdi glow plug fault symptoms and removal??

**petrolhead63** · 31-03-2021,10:28 PM

My totally unusable A6 has now been scanned with VCDS as well as my generic one, the only engine related fault code is one faulty glow plug.
On a 2006 year car could this cause constant running problems? misfire/lots of over fuel smoke even when warm??
I am used to older cars....the glow plug helps it start and nothing else.
Do these plugs under the cam cover have a habit of seizing or do they usually remove ok?
Thanks

**dean warren** · 31-03-2021,10:50 PM

Sounds more like injectors, whats the mileage?

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**Crasher** · 01-04-2021,11:11 AM

Modern diesel engines use the glow plugs in all sorts of situations to improve emissions but won't cause the trouble you are having and they don't tend to snap as they are in oil all the time,

as Dean says it's more likely to be injectors BUT I would open up the fuel filter first to check for engine oil contamination and make sure the in tank lift pump is running as these are common issues that won't come up as fault codes. If it is injectors you are looking at double the cars value to do it correctly and be guaranteed success.

**petrolhead63** · 01-04-2021,11:56 AM

okay, thats my thoughts, well oiled in that head so likely to be removed ok. The MIL light stays on, the only fault registered ( on engine/running side anyway) is one glow plug and it sounds like a big misfire and lots of over fuel. Starts first time every time though.
Should the VCDS scan I paid for have been able to point us to injectors?
The car has done just 200K, but is a very tidy high spec avant and too good to give up on, but not worth paying others to throw money and parts at it!! I am able to do most things.
Are the glow plugs coded on a 2006? or replace/plug and play.
Cheers

**Crasher** · 01-04-2021,01:15 PM

Normally the MIL will stay off for a while if only a glow plug code is stored, only in very bad instances will an injector come up as a fault code, when we do a VCDS read we don't just look at the code, we dig deeper in the measuring blocks but many garages just "bark at codes" as I call it.

**petrolhead63** · 01-04-2021,01:51 PM

Originally Posted by Crasher

Normally the MIL will stay off for a while if only a glow plug code is stored, only in very bad instances will an injector come up as a fault code, when we do a VCDS read we don't just look at the code, we dig deeper in the measuring blocks but many garages just "bark at codes" as I call it.

thanks.
I tend to agree with you all...injectors is a good possibility, I was surprised it did not show anything on the VCDS scan. However my own live data on a generic scanner I did mention showed 2 injectors running a +ve value and 2 a -ve value but I had no idea what oit meant

Glow plugs and injectors on the 2006 (BRE from memory) do either need coding on to work?

**Crasher** · 01-04-2021,03:03 PM

No coding required BUT replacement injectors have to be accurately set up for their peak stroke. The injector correction values will move around +/- and VCDS says anything greater than +/-2.80 is a problem, in reality anything even approaching 1.0 either way is a problem, I like to see them floating around +/-0.25 approx

**petrolhead63** · 01-04-2021,05:39 PM

Thanks yet again, so given we have no fault codes on VCDS scans other than glow plug it could very likely be injector/s showing no code.
I can change out the glow plug or even all simply with no coding.
Injectors can be changed with no coding too..but need setting up. If another set of injectors was fitted for initial start up to prove if it fixed the misfire is no setting up required?
Is the setting manual based using the old fashioned rocker type affair or computer based?
Finally, is there a way I could narrow down which injector/s it may be and could it be a sudden failure of the loom in the head? I recall doing one on a 1.9tdi in the past. I have checked the big plug is clean.

**Crasher** · 01-04-2021,10:43 PM

Yes the injector setup is the old fashioned max lift, wind down back off 180 degree system, if you fitted another injector and didn’t check the lift but unknown to you required a 270 degree back off, you would be vacuuming up the bits.

**petrolhead63** · 08-04-2021,11:42 AM

I decided to look proper today and the news I think is not good

Glow plugs out first and number three has lost its end...so that is in the bore somewhere and I am guessing it has damaged it, caused low compression and hence it sounds like its on three and belches smoke. It is actually on three I think.
I do not have a compression tester for glow plug hole but thats what I need to confirm worst fear.....the end of the glow plug must be somewhere.