TSI Misfire

[adamg1987]

Got a ongoing issue with a misfire, Seems to be uneffected by the temperature of the engine.

 

Seems to be worse when going uphill under load.

 

So far i have replaced the Coils and Plugs.

Had R-tech do a Inlet and Injector clean.

 

Issue still seems to be there but no Engine lights?

[rayx]

What engine code, size? Guess 1.8 or 2.0 TSI, engine code CDAA or CCZA?

[adamg1987]

2 hours ago, rayx said:

What engine code, size? Guess 1.8 or 2.0 TSI, engine code CDAA or CCZA?

 

Yes its the 2.0 TSI CCZA

[VRsdgm]

Maybe try replacing the PCV valve with the up to date iteration, I tried it after replacing plugs and coils to fix an intermittent problem with the car running on three cylinders without success.  Despite the existing PCV valve showing no visible signs of damage or incorrect operation, replacing it with the latest version solved the issue and it has done 6000 miles since without issue. 

 

Part number I used was 06H103495AJ.

[rayx]

Yes, could be the PCV/oil separator unit. You can test it for the tear in the main control diaphragm, then engine gets too much unmetered air and also can consume more oil then is normal because of higher vacuum under pistons, at the sump and head cover.

Technical Service Bulletin 2025501_2 PCV.pdf

 

 

When it does not help, it might be still the mess on the inlet valves because of the VVT though you paid for the inlet clean ...

 

Edited 21 August, 2018 by rayx

[adamg1987]

1 hour ago, rayx said:

Yes, could be the PCV/oil separator unit. You can test it for the tear in the main control diaphragm, then engine gets too much unmetered air and also can consume more oil then is normal because of higher vacuum under pistons, at the sump and head cover.

Technical Service Bulletin 2025501_2 PCV.pdf

 

 

When it does not help, it might be still the mess on the inlet valves because of the VVT though you paid for the inlet clean ...

1

 

Possibly then. I did, however, pull the dipstick out and the idle didn't change which is one of the checks in the bulletin. I will make some further checks to ensure it is not the PCV. 

[rayx]

1 minute ago, adamg1987 said:

 

I did, however, pull the dipstick out and the idle didn't change.

This is 100% the PCV/oil separator unit, trust me When you pull out the dipstick, you open access for the air under the pistons and crankcase. When the diaphragm is intact, engine will react on this with rough idle. When you see no reaction (yes, someone can see improved idle) its this. Bulletin does not say everything ...

[VRsdgm]

I did the dipstick test as well, made no difference in idle to mine either and yet it appears the PCV was the fault.

[adamg1987]

Thanks guys will have a look into this.

[rayx]

2 minutes ago, VRsdgm said:

I did the dipstick test as well, made no difference in idle to mine either and yet it appears the PCV was the fault.

 

When you do test now with OK PCV, you will see the difference

 

[adamg1987]

Ok guys so tested the PCV again, Dipstick makes a slight change in idle when you pull it out initially. Removing the Oil cap has a little bit of suction then the ideal begins to hunt. Also tried blowing down the pipe leading to the PCV to test for Leaks but all seems good. Also no suction on the little hole on the side of PCV which could also indicate an issue? 

 

As far as i can tell from my tests it would appear the PCV is actually ok.

[VRsdgm]

I wasn’t sure either but thought for about the £80 it cost, it was worth a go.  Turned out it worked, the PCV valve has undergone several revisions, can’t hurt to put the latest one in. That’s the way I think anyway. 

[adamg1987]

Had the PCV off tonight to check the orange valve underneath - seems good. Done a compression test on all 4 cylinders 10bar each so I think I can rule out piston/rings 

 

spark plugs look a little white too me? Would anyone care to chip in? 

[rayx]

13 hours ago, adamg1987 said:

Ok guys so tested the PCV again, Dipstick makes a slight change in idle when you pull it out initially.

 

Also no suction on the little hole on the side of PCV which could also indicate an issue?

 

My experience say engine must react significantly at pulled out dip stick, otherwise it show engine ECU has adapted itself on too much unmetered air, which can get into it through any leakage. Normal vacuum inside the crankcase is 25mbar, when more or less you have a problem.

 

Yes, if the main control diaphragm at fine oil separator / PCV unit shoul be teared, you would have suction on the little hole on side of the cover lid of main control diaphragm.

 

The orange valve underneath this unit is the PCV valve itself It is combined, two way. Under nomal condition its lip allow air entrance under head cover from the intake hose ahead of the turbocharger, therefore crankase ventilation, under load conditions when too much pressure of blow-by fumes exist it overcome the spring tension and release the presured fumes into intake hose ahead of the turbocharger to protect engine seals.

 

Difficult to advise anything else, still could be the inlet valves and carbon on its seats ...

 

[Ayush]

Hey adam, did you solve the problem ? My car is also doing the same and sparkplugs came out white. What was your fix ?

[adamg1987]

14 hours ago, Ayush said:

Hey adam, did you solve the problem ? My car is also doing the same and sparkplugs came out white. What was your fix ?

 

Hi, I havent actually found a fix. I still have a small misfire under load i.e going up hills etc.

So far I've done

 

• Compression Test
• New Plugs
• New Coil packs
• Tested PCV System
• Had injectors cleaned and tested
• Had inlet valves cleaned 
• New Fuel Filter

 

[Ayush]

How about high pressure fuel pump ? May be that is at fault causing the car to run lean ?

[Ayush]

20 minutes ago, adamg1987 said:

 

Hi, I havent actually found a fix. I still have a small misfire under load i.e going up hills etc.

So far I've done

 

• Compression Test
• New Plugs
• New Coil packs
• Tested PCV System
• Had injectors cleaned and tested
• Had inlet valves cleaned 
• New Fuel Filter

how about high pressure fuel pump ? May be that is at fault and causing the car to misfire ?

[adamg1987]

2 minutes ago, Ayush said:

how about high pressure fuel pump ? May be that is at fault and causing the car to misfire ?

 

I'm not 100% sure TBH. The misfire is very slight and is fine when driving hard I'm not sure it would be the HPFP but truth be told im not a mechanic so dont really know.

[Ayush]

On 18/02/2020 at 15:31, adamg1987 said:

 

I'm not 100% sure TBH. The misfire is very slight and is fine when driving hard I'm not sure it would be the HPFP but truth be told im not a mechanic so dont really know.

Hey adam this solved my issue, have a look at this link may be this can help you also.