Lumpy T6 - Triggers Broom! Misfire & Vibration under 1500rpm.

[Blind_Spark]

I think 7 digits is for older injectors,

When taking the old ones out they had a 20 digit code that matched the numbers on vcds.

 

[mmi]

Another a relatively easy check before teardown would be to make yet another log by using the following measurement values:

IDE00021 Engine RPM​

IDE00351 Main injection: start of activation​

IDE00352 Main injection: duration of activation​

IDE00589 Fuel pressure​

IDE09327 Cylinder 1 bank 1 internal moment​

IDE09328 Cylinder 2 bank 1 internal moment​

IDE09329 Cylinder 3 bank 1 internal moment​

IDE09330 Cylinder 4 bank 1 internal moment​

IDE12085 Fuel injection time deviation: cylinder 1​

IDE12086 Fuel injection time deviation: cylinder 2​

IDE12087 Fuel injection time deviation: cylinder 3​

IDE12088 Fuel injection time deviation: cylinder 4​

​

Tick Group UDS requests - by 7 (IMPORTANT!!!)​

​

Preferably start logging before cranking.​

Just a view from different angle to see if/where the imbalance is. Neither cylinder internal moments should not deviate much.

---

Here was another mystery - though resolved - by replacing camshaft module.

Won’t start. No fault codes

Nice, if i disconnect camshaft sensor, engine will start so i quess camshaft module needs to be replaced. I couldn do it correctly. I have hex+can cable andwhile trying to "Tick "Group UDS requests" - by 7" it says i need new interface. So i got only 1 time logging whivh didnt show anything...

www.t6forum.com

 

[Blind_Spark]

There you go.

 

[Blind_Spark]

just realised the 2nd log is further down the page.

 

[Blind_Spark]

another fresh one

 

[Nam600]

Looks like they are 20 digit nowadays. .

Another a relatively easy check before teardown would be to make yet another log by using the following measurement values:

IDE00021 Engine RPM​

IDE00351 Main injection: start of activation​

IDE00352 Main injection: duration of activation​

IDE00589 Fuel pressure​

IDE09327 Cylinder 1 bank 1 internal moment​

IDE09328 Cylinder 2 bank 1 internal moment​

IDE09329 Cylinder 3 bank 1 internal moment​

IDE09330 Cylinder 4 bank 1 internal moment​

IDE12085 Fuel injection time deviation: cylinder 1​

IDE12086 Fuel injection time deviation: cylinder 2​

IDE12087 Fuel injection time deviation: cylinder 3​

IDE12088 Fuel injection time deviation: cylinder 4​

​

Tick Group UDS requests - by 7 (IMPORTANT!!!)​

​

Preferably start logging before cranking.​

Just a view from different angle to see if/where the imbalance is. Neither cylinder internal moments should not deviate much.

---

Here was another mystery - though resolved - by replacing camshaft module.

Won’t start. No fault codes

Nice, if i disconnect camshaft sensor, engine will start so i quess camshaft module needs to be replaced. I couldn do it correctly. I have hex+can cable andwhile trying to "Tick "Group UDS requests" - by 7" it says i need new interface. So i got only 1 time logging whivh didnt show anything...

www.t6forum.com

Is it worth taking a set of fuel injection quantity values as well? mg/s

 

[mmi]

Getting better... but still not as smooth as the reference in post #9​

Cylinder internal moment - no outliers?​

 

[Blind_Spark]

Thanks for taking the time to produce the graph!

Certainly helps me understand it, where would you advise I go from here?

Do you think it's an injectior issue, or is there an underlying mechanical issue?

I guess HPFP is ok as readings are ok.
Knackered rings/valves that seal up when warm?
A bent rod wouldnt disappear when warm?

Or do I just drive it until it throws a rod or really shows me what the problem is

 

[Nam600]

Thanks for taking the time to produce the graph!

Certainly helps me understand it, where would you advise I go from here?

Do you think it's an injectior issue, or is there an underlying mechanical issue?

I guess HPFP is ok as readings are ok.
Knackered rings/valves that seal up when warm?
A bent rod wouldnt disappear when warm?

Or do I just drive it until it throws a rod or really shows me what the problem is

It's hard to say from a distance but it seems the original failure was caused by a split EGR cooler. I would take that back off and check that the EGR to inlet manifold are clear. I had a Qashqai in where the garage said DMF had failed. I found the EGR was wrecked and the gearbox/engine mount knackered so the EGR caused a mis-fire/rough low rpm running and was exaggerated by the knackered mounts. All solved for £300 instead of the £1400 Nissan wanted.

I would trace back the steps:
- Check EGR pipes and inlet manifold clear and not jammed/blocked with soot.
- Swap #4 and #1 injectors around. See if readings move with the injector.
- Check timing of timing belt and camshaft position sensor.
- Check compression. (I know garage said it's alright but I have heard garages wrongly say that about a lot of things)
- Check fuel - Mis-fuel perhaps? Water in fuel?

 

[mmi]

I guess HPFP is ok as readings are ok.

I would agree - the pressure builds up quickly and obviously the pressure regulation works as the pressure is stable.

Do you think it's an injectior issue, or is there an underlying mechanical issue?

Hard to say - I would be think the issue is something more traditional - possibly even a moved cam lobe? Wondering if an audio clip could be captured of rough idling?
Something similar as here

[T6_measured] Injector failure

Keyword “loud knocking metallic noise from engine”. VW has published in September a service note which can be found with vehicle's VIN. The sound clips from my engine (150PS, EU6) with comments on 21 Oct 2017 in thread Tick over noise EDIT: audio files from the thread copied here as...

www.t6forum.com

- Check timing of timing belt and camshaft position sensor.

Based purely on the gathered data (blockmap data, below) I would say these are not the prime suspects.

IDE00182

Camshaft adaptation intake bank 1: phase position

0.3​

°

Is it worth taking a set of fuel injection quantity values as well? mg/s

I'm not sure if that would be any different - I guess it would correlate strongly with injection duration. At the moment I'm lacking reference data on that.

Had Map removed - No different.

So it was running factory map on all the above measurements?

 

[DXX]

Have you re-torqued the injector clamps since changing the injectors? I’ve seen injectors loosen on a Transit after the installer mistakenly applied grease on the injector joints. Normally audible blowing but a minor leak could be covered by other engine noise. As compression ignition it would prevent or hamper fuel ignition, however when engine is at full operating temp’ the situation would improve. There may well be fuel splashed about, easy to spot on a clean engine.

Another possibility is that one of the connecting rods is very slightly bent as a result of the leaking charge air cooler dumping water into a cylinder causing hydraulic lock.
It maybe so slight that the engine runs but with a slight deviation in compression ratio, again causing issues with fuel ignition.
As you know that all injectors are easily removable it would be a simple procedure to compare measurements to the piston crowns at TDC with a depth gauge.

 

[Blind_Spark]

Just coming back to this...

Another 1000 miles under its belt, still no fault codes, still lumpy and missing when cold, but ok when warm!

Have been advised by a T6 specialist far far away, that more than likely it has bent a rod when the EGR failed, He has seen a few where this has happened and said its possible just to replace the rod if there is no further damage, they can be purchased individually from TPS, but he will do a full inspection when he gets the van but hes 90% sure thats what it is.

I will keep you all posted! I will name the specialist once all sorted!

Adam

 

[DXX]

First issue was it started to use coolant, I swapped a known good charge cooler to eliminate that, Max to min in around 100 miles, So took it to VW specialist in MK about 10 miles away, on route it started misfiring at low rpm, EGR/Cooler changed for £1.4k….

So was it the charge air cooler or the EGR cooler that was replaced, or both? (from your first post)

 

[Nam600]

So was it the charge air cooler or the EGR cooler that was replaced, or both? (from your first post)

It might be worth making a temporary blanking of the EGR and seeing how it runs then. The 3 EGR problems I dealt with all shared the common problem that they leaked exhaust gas all the time and allowed it in the inlet manifold. EGR is not necessary at idle or low loads as its there to introduce inert gasses into the inlet to dampen the firing temperature below 1200degC. This effect reduces the amount of NOx formed. This only happens under engine load thus is not needed at low load or idle. If it does happen at idle or low loads , then it causes misfire or rough/lumpy engine behaviour.

Could be you got a dud EGR again. (Longshot but not impossible). Blanking it would rule it out but it will put an EML light on the dash. Also check they fitted the EGR feed and return correctly to ensure its not sucking unmetered air into the inlet. Doesn't look like it is but...

 

[Blind_Spark]

So was it the charge air cooler or the EGR cooler that was replaced, or both? (from your first post)

Both, Changed charge cooler and no change, Changed EGR and coolant loss stopped immediately.

 

[Blind_Spark]

Good shout, I can try that tomorrow I will report back,

I have open and closed EGR via VCDS and it appears to function but I will block it off and see how the van reacts.

Thank you all for your help - I will report back!

Adam

 

[iaindicky]

Good shout, I can try that tomorrow I will report back,

I have open and closed EGR via VCDS and it appears to function but I will block it off and see how the van reacts.

Thank you all for your help - I will report back!

Adam

Hey man, seen your post, had the same issues with my van so everything you did I did the opposite. I managed to find a VW master tech which diagnosed it to be the G247 fuel pressure Sensor valve on the side of the fuel rail once fitted with fuel additive next day, perfect. Hope this helps

 

[Blind_Spark]

Ooh that is something new to try, Let me see if I can get one ordered. Thanks!

NAM600 - Blocking the EGR made no difference to the lumpy idle, if anything it was worse. it's just so strange how it runs perfectly once up to temperature.

 

[iaindicky]

Ooh that is something new to try, Let me see if I can get one ordered. Thanks!

NAM600 - Blocking the EGR made no difference to the lumpy idle, if anything it was worse. it's just so strange how it runs perfectly once up to temperature.

Cool. I ordered mine from TPS which was in stock and they said it’s a common part they sell and the part has been updated due to its common fault ¯\_(ツ)_/¯

 

[DXX]

Ooh that is something new to try, Let me see if I can get one ordered. Thanks!

NAM600 - Blocking the EGR made no difference to the lumpy idle, if anything it was worse. it's just so strange how it runs perfectly once up to temperature.

Your vans fuel pressure is stable according to post #30, renewing the pressure regulator valve or pressure sensor doing seem like the obvious route for diagnostics.
Have you checked for a bent rod as I suggested in post #31 and as you said your mechanic suggested in post #32?

From post #30:
I would agree - the pressure builds up quickly and obviously the pressure regulation works as the pressure is stable.