Timing out or injector problem?

[zoli888777]

Hello everybody, its me again with an other question. I was playing with vcds and checked measuring values and came to this one:

 

 

1., This one is with cold engine on idle (the engine is shaking for few minutes)

 

Address 01: Engine  (03L 906 022 RE)

18:18:50 Group 013: Idle Stabilization (Injection Quantity Deviation)
-0.42 mg/str  Injection Quantity Deviation Cyl. 1
 0.40 mg/str  Injection Quantity Deviation Cyl. 2
 0.28 mg/str  Injection Quantity Deviation Cyl. 3
-0.31 mg/str  Injection Quantity Deviation Cyl. 4

 

 

2., This one at 1500RPM

 

Address 01: Engine  (03L 906 022 RE)

18:19:47 Group 013: Idle Stabilization (Injection Quantity Deviation)
-0.38 mg/str  Injection Quantity Deviation Cyl. 1
 0.19 mg/str  Injection Quantity Deviation Cyl. 2
 0.38 mg/str  Injection Quantity Deviation Cyl. 3
-0.24 mg/str  Injection Quantity Deviation Cyl. 4

 

 

3., This one after 10-15 minutes on idling

 

Address 01: Engine  (03L 906 022 RE)

18:27:04 Group 013: Idle Stabilization (Injection Quantity Deviation)
-0.21 mg/str  Injection Quantity Deviation Cyl. 1
 0.40 mg/str  Injection Quantity Deviation Cyl. 2
 0.00 mg/str  Injection Quantity Deviation Cyl. 3
-0.24 mg/str  Injection Quantity Deviation Cyl. 4

 

The car is allways shaking for a few minutes when its cold (not in use for a day). There is no power loss or any other problems with it. Does it look like an injector failure? Or can it be caused by the timing belt? (its would be time to change it)

Edited 26 August, 2014 by zoli888777

[KBPhoto]

I've got a similar issue with my 2.0 Tdi PD140 Octavia. I'll dig out the scans and post them here.

Mine is due a cambelt & water pump change, but I suspect it might be injector related or tandem pump related. I'm not sure.

[nick74]

The cam timing being fractionally out can cause this. Mine has always had a very slight shudder on idle but never enough for me to worry about it.

It can be checked by looking at the torsion value with VCDS, which should be as near to zero as possible. Below zero is reckoned to make the idle lumpy but give better economy, above zero supposedly gives worse mpg but a smoother idle. Mine was -2 last time I checked.

[zoli888777]

I read that the above values should be almost the same or within 10%. I have no misfire, or smoke from exhaust or power issues. Just that shudder on idle when the engine is cold. If I drive it for 0.5 miles the shudder goes. There is a knocking noise coming under the driver side of the car what I think its a failing DMF. Can this cause this, too? Or is it a noise caused by something else? The car has 62 on the clock.

[nick74]

Your injector values look OK to me, no injectors obviously way out of spec.

From what you say about the knocking noise I do wonder if it's the dmf? That noise would be from the passenger side though (assuming a right hand drive car).

[zoli888777]

yes, its a UK car. So the values are ok? Because as I wrote it in the post above I read that they should be almost the same or within 10%. So what can cause this? Timing belt? It would be changed now. But than why the car is not shuddering on idle after a short drive?

Edited 26 August, 2014 by zoli888777

[silver1011]

Has your vRS had the injectors replaced under the recall?

 

A lot of members on here (me included) suffered from very poor cold starting during the winter months and a rough idle for a few minutes after each cold start. 

 

My dealer tried everything to fix it, even sending live diagnostics over to the engineers at Skoda in the Czech Republic whist adjusting the timing and lots of other stuff.

 

It was never fixed. Some bed time reading for you...

 

http://www.briskoda.net/forums/topic/189502-cold-start-problems-with-a-pd-tdi-170/page-1?hl=+injector

 

http://www.briskoda.net/forums/topic/197422-vag-170-ps-diesel-injector-failures-vosa-action/page-1?hl=injector

Edited 26 August, 2014 by silver1011

[zoli888777]

I dont know about a recall. Do I qualify? I have a vRS CR Tdi with DSG transmission on 10 plate. I dont have starting problems. Its starting on a first turn of the key. Just the shuddering.

 

Can that knocking noise caused by timing belt?

[silver1011]

Ignore me, the injector recall was on the PD170, not the CR170.

[nick74]

I think anything between +2. 0 and - 2.0 for the injectors is considered to be acceptable, yours are well under +/- 1.0 so I don't think it's an injector problem.

A failing dmf could well cause the shuddering .

Edit: I didn't realise your engine is a CR!

Ignore my point about cam torsion then, that doesn't apply to CR engines at all, sorry!

[silver1011]

The best way to test the strength of the DMF is to load it with hard acceleration in a high gear at low speed / RPM.

 

If the DMF is worn you'll get shuddering which feels like clutch slip.

[zoli888777]

I think anything between +2. 0 and - 2.0 for the injectors is considered to be acceptable, yours are well under +/- 1.0 so I don't think it an injector problem.

A failing dmf could well cause this.

These are good news. But why that big difference between 1,4 and 2,3? Sorry, Iam not very mechanical minded. The gearbox oil was changed before 5000 miles and the gearbox was inspected as well, but they didnt say nothing about any problems with it.

[zoli888777]

The best way to test the strength of the DMF is to load it with hard acceleration in a high gear at low speed / RPM.

 

If the DMF is worn you'll get shuddering which feels like clutch slip.

Sometimes the gearbox changes up to 6 and the rpm is around 1200, but no problems at all.

Edited 26 August, 2014 by zoli888777

[zoli888777]

Sometimes the gearbox changes up to 6 and the rpm is around 1200, but no problems at all.

Oh I understand what you are saying. But no, no problems. If I drive in manual mode in 5 or 6 gear and try to accelerate hard from low speed its going without shudder.

[nick74]

These are good news. But why that big difference between 1,4 and 2,3? Sorry, Iam not very mechanical minded. The gearbox oil was changed before 5000 miles and the gearbox was inspected as well, but they didnt say nothing about any problems with it.

That's just the engine ECU tweaking the fuelling settings for each injector to try and keep the engine as smooth as possible. Even on a brand new engine it would be very unlikely for them all to be exactly at 0.00.

Those differences your seeing between injectors aren't actually very large.

[KBPhoto]

These are my figures, but they seem to be within a similar range to yours (not sure how you work out 10% deviation of a reading of zero though...)

 

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

 

[zoli888777]

Oh ok. I just saw KBPhotos topic here: http://www.briskoda.net/forums/topic/313181-diagnosing-misfire-with-vcds/#entry3913920 and there was an advice that if it is out of the other values its a faulty injector. I dont know what else to check regarding this knocking noise and shuddering. I think these two things are related each other because when the engine is warm there is no shudder and no noise.

Edited 26 August, 2014 by zoli888777

[nick74]

I would be wary of comparing the results from a PD with those from a CR - they're very different systems.

[nick74]

It would probably be worth doing an injector leak off test, which can show up a faulty injector on common rail engines when electronic diagnostics has failed.

Basically you remove the leak off pipes from the injectors and instead connect a piece of tubing to each injector, with the other ends into plastic bottles. Run the engine for a few minutes and see if the leak off from any particular injector is significantly worse than the others. If you Google injector leak off test there are a lot of sites showing how it's done.