2.0 FSI Poor idle when cold

[MEL744]

Today I ran all basic settings related to the cat and lambda sensors, all showed as working properly. Heading on holiday today for 4 weeks so won't be able to reply, but just keep posting your findings and I will catch up when I get back.

[saabman]

When you get back would you be able to post the figures in particular the aging values for the cat(s)
I’ll be getting my hands on Nats car in a couple of weeks so will give it a go with hers.

Enjoy your holiday

[MEL744]

Hi,

Apologies for not getting back to you sooner, had some issues with VCDS after an update. Went to get these aging values today. In the basic settings tab I ran the cat aging test and got the B1S1 'dynamic factor' as 1.05 - is this the value you meant? Does not have a value for any other banks/sensors.

[saabman]

Good Question

Ive been distracted by other things (kids/work/kitchen renovations/repairs to my SAAB, needed to drop the sump and clean the oil pickup after it getting blocked)

Ill have to go back and reread the FR again But I think that is what Im after. I havent seen my daughters car since I took it back to her in Feb. so I havent ot any further figures. Ill check it out tomorrow again and see what sense we can make of it.

My current though is the high idle is due to the cat ageing so is normal but the misfiring is possibly as a result of build up on the intake, but I dont understand why...

[saabman]

I started gettiong back into the docs again today to try and refresh my mind - I didnt fond what I wanted but found a bit in the FR that talks about the time required to reset the high idle which is 10,000 seconds which is around 3 hours which fits with our observations of the high idle reoccuring after sitting for about 4 hours.

I did come across a snippet on a nother forum that indicated that the aging value should be around 0.5 and 1 indicated that the cat was pretty well exhausted - but Im not sure if that value is the same as what you have reported - Ill keep at it.....

I did see on the thingiverse site ( 3d printer repository) a file for an adaptor to screw on the head which allows a vacuum to be attached to suck out the walnut shells while blasting the build up on the valves - BUT on ours we still have to remove the injectors and stuff to get to the lower part of the manifold off

Volkswagen 2.0T - Valve Blasting Adapter by bikermahn - Thingiverse

[MEL744]

Been having a look around the docs and online, it seems that the aging test I did reports in two different ways, as a period (in seconds) and as a dynamic factor. And apparently the test in block 034 is actually an O2 sensor test - in order to test the cat you need to run 034 then 046. The value of the 034 test should apparently be above 0.8s and will decrease over time so 1.05s is within range as indicated by B1S1 OK. I think the period reported might be the period of oscillation of the signal reported by the O2 sensor, apparently rapid fluctuations in readings (and therefore a shorter period) represent a bad sensor or cat. Here is some info I found about the tests its for a mk4 but I'll see if it applies to a mk5 tomorrow... VWVortex.com - VAG-COM procedures for testing the MAF, O2 sensors and catalytic converter

The 10,000s finding is interesting, did you find it in the BBKH section (about page 2390)? I agree the valves are definitely due for a clean based on everything that is out there about build up on direct injected engines (my car has about 140k on it). If you don't have a 3D printer but wanted the valve blasting adapter I'd be happy to print it out and send it your way.

[saabman]

Yes APP BBKH 3.20.2 application Notes

Cooling characteristic
Tabst [s] | 100 sec | 500 sec | 1000 sec | 2500 sec | 5000 sec | 10000 sec
---------------- + ---------- + ------------- + ------------- + ------------- + ------------- + -------------
ABKKATTAB | 1.0 | 0.75 | 0.2 | 0.16 | 0.12 | 0.0

ABKKATTAB is The "Cooling curve as a function of the shutdown time"


YEs MB46 I just had a look through my Block Map logs and they all show something like
46 800 /min RPM 330.0°C Temperature 0 (no units) Test OFF

The only thing that changes is the RPM and Temp the 3rd value seems to be the important one.

[MEL744]

Tried running the test today, ran 034 first as it says to do, that came back as B1S1 okay. Ran the one on 046 and this is what happened:

Foot on the brake and accelerator; rpm rises to 2000 4th value shows Test OFF

After about 10 seconds the 4th value changes to Test ON

After about 30 seconds the 4th value changes to System OK

The whole time the 3rd value shows 0.00 and is labelled as Catalytic Conversion Bank 1, the temperature labelled Catalytic Converter Bank 1 stayed around 250C during the test.

[saabman]

That’s interesting - a pity it doesn’t give an efficiency reading though. That would give an idea as to how much life is in the cat and would indicate how long the high idle would be.

There maybe a way to still check it. I was just looking at this video from “Scanner Danner” YouTube

I’m thinking I might order in some walnut shells and have a go at blasting the crud off the valves the next time Nat comes to visit. Probably not till Christmas now.
I was thinking of making a media blaster using the coke bottle method and putting a long nozzle on it so I can get around the flaps rather than removing them. It s not ideal but better seems better than pulling the injectors.

[saabman]

Just an update on this - I took the car back to my daughter and left it at that. the rough idle didnt seem to have any further effect and i couldnt be arsed doing any more to it

Now nearly 12 months later I have the car back with some other issues (wireing in the passenger door harness) a couple of water leaks - Coolant distributor and upper heater hose. Disintegrated crank vent pipe (pipe between crank and head)id already blocked the PCV inlet on the manifold.

But aside from all that I noticed is the idle is high at cold start for the same length of time but quiet smooth. This golf is just worn out the elctrical faults and disntgrating plastic components in the engine bay is just insane. Im gald my Ex wife took my Mk5 when she left

[saabman]

Just come across this interesting video about the Cold start misfire issue and how to fix it - clean the inlet valves ..

BUT more importantly it has a nice section in the video about WHY it causes the problem, basically disturbed airflow causing lean mixture at spark plugs resulting in misfiring

Tsi cold misfires explained - YouTube

[MEL744]

Excellent video, explains why if you turn it off and on again the problem goes away, because the engine must switch from stratified to homogeneous mode. I was having a look at BVY in the wreckers, seems like you do have to pull the injectors to remove the flaps to get to the valves. But I noticed with the method he uses you don't need to remove them.

[JustCruisn]

Would the hydrogen clean by one of these services work ?
Carbon Cleaning - Carbon Cleaning Australia

[MEL744]

From what I understand, no it won't, there is just too much to remove and the deposits are too stubborn. The only options are chemical soak + scrub or media blasting which both require the manifold off.

[saabman]

Excellent video, explains why if you turn it off and on again the problem goes away, because the engine must switch from stratified to homogeneous mode. I was having a look at BVY in the wreckers, seems like you do have to pull the injectors to remove the flaps to get to the valves. But I noticed with the method he uses you don't need to remove them.

THere is not much room past the flaps - I had a go at scraping the crud off and also soaking in carby cleaner and soaking and scraping, neither were successful. just not enough room. Trying with a small media blaster might work. I was thinking of using walnut shell Green Abrasives - IBIX Australia

It looks like Ive got the car for a while so might have a go. Im taking a fair bit of time of work in a couple of weeks so might get some projects out of the way before I go back