2.0 FSI Poor idle when cold

[MEL744]

Glad to hear you are making some progress. As for the frequency of this event occurring on my car, it will do it basically every morning (the car has been off for 8+ hrs). I have never seen it happen if the car is off for under about 3 or 4 hours. Given how much I use the car I've only noticed it on the first start of the day. Will keep a closer track on times for the next few days.

[saabman]

Yep that sounds Like the same symptom at least.

I was a bit hasty in my thought of making progress my daughter reports it is still playing but noted the battery voltage is still reading around 13.8V when running. So more to look into at least.

I’m trying to understand how WinOLS works to attempt to decifier the start up parameters I have at least some hard data on timing to look into.

[saabman]

Ive spent a LOT od time trying to look at the MAPs from an ecu dump off a BLX motor but due to absolutley NO information about the MED9.5.1 ECU all I managed to achieve was a headache... Biut I have learnt alot about how the diesel maps work and the importance of the EGR valve - dont block it off it is an important part of making the engine run efficiently. yes it can cause problems but.....

Any way last night I sat down with the logs I had made every time i started the car for nearly a month in the hope something would jump out at me. And i have found a small anomally with one of the measuring blocks. Block 145 in particular. unfortunately due to the lack of info regarding the BLX motor and the MED9.5.1 ECU there is no label file and Im using the label file from the BLR engine which is close but not quite right. Needless to say My best guess at this stage is that block 145 is an exhaust gas temp sensor and it is giving erroneous readings when cold.

When the engine plays up block 145 starts at 762 and then after a short period drops to around ambient temp. When the engine starts fine block 145 starts at ambient and goes up as expected. Ill post some graphs and logs tomorrow..

[MEL744]

Very interesting, would love to see the graphs. Cheers

[saabman]

still working on that one. Due to the range involved from 24 - 768 there isnt much to see

[MEL744]

Have you considered using a logarithmic scale on the temp axis? Also have just ordered VCDS to replace my OBDeleven, are you using that to read the measuring blocks?

[saabman]

Yes VCDS for logging etc. unfortunately there is no label file for the BLX engine so a lot of the returned values are without specific explanation there Ive set it to use the BLY label file (I’ll check that tonight) which makes sense of a lot of the data but it has a few things missing. Hence the lack of info on MB 145. I’ve got to have a look through some other label files and see what they have for 145. The tricky bit at the moment is my daughter has taken her car back so I only have the logs I collected while I had it.

Yes I was going to see about converting to a log scale either that or just let the big figure go off scale as soon as the engine starts it drops down.

[saabman]

Here we go log of MB 145

this is when idle is bad Im not sure what the first temp value actually is. As there is no Lable file for the BLX engine I am taking stabs in the dark the best I can come up with so far is from the ALX engine label file which describes the two figures as
145,1,Exhaust Gas,Temperature (calc.)
145,2,Exhaust Gas,Temp. Bank 1

its the 145,1 that is causing me concern as its 762 there abouts when the issue occurs and around 24 when it starts fine.

[aprr32]

The FSI engines with an air pump all idle fast for upto around 50 sec when cold so the cats can light off with the extra oxygen and fuel thats dumped in the engine and exhaust.

[MEL744]

Interesting viewing of the graph - will plot one when my VCDS arrives (should be soon). Would be interested to compare the value to a car that doesn't have this issue. One of my friends has a mk5 with the same engine, might see if I can make some logs on his car.

The FSI engines with an air pump all idle fast for upto around 50 sec when cold so the cats can light off with the extra oxygen and fuel thats dumped in the engine and exhaust.

I understand that the idle might be fast for the reason you described, but misfires and rough idle does not seem normal?