Azure Blue - A2 FSI Faults and Fixes

A

AndyBa

Member
I thought I'd start a Project thread to document progress maintaining and repairing my Azure blue FSI.

So when I bought the car in 2023 it
didn't start on first attempt and needed a bit of throttle, it had a minor misfire, badly resprayed rear arches and signs that the passenger doors had been partially resprayed. Oh and 4 ditch-finder tyres. This doesn't sound promising but in reality the overall condition was very good for its age. Complete with the book pack showing patchy service history...I think it started on long-life service intervals which haven't turned-out to be cost effective based upon various forum posts!

I've tried to resolve the poor starting and misfire on cylinder 2, but neither a new coil pack, nor swapping a known good spark plug or adding another earth strap has resolved this issue. Thanks to lots of help/advice from @PlasticMac and other members. I wonder if there is a breakdown in the wiring is the issue (I had this on my Beetle TDI). I did have the A2 booked in at WOM Automotive, however I had to cancel since my colleague was on paternity for a month, so I need to reschedule.

Today I was investigating why the red genie oil light has recently been coming on. I ordered a pressure gauge kit since I couldn't find mine....I've now uncovered 3 sets! This is an issue I had on the ex BG 1.6 Caddy and I was hoping the outcome wasn't the same.
So fully warmed-up at idle the oil pressure is 1 bar, upping the revs to 4000 shows up to 4 bar (the gauge is marked-up 0.6-0.8) so I'm not sure why it was alerting.
I had a spare oil pressure switch so have swapped it out and will monitor.

I also started to change the rear arches for a pair I bought off @Ami . Have swapped the OS one, but the NS one had a stuck screw. I've got it turning but I suspect the captive nut has sheared. I'd have drilled it out but my son has borrowed my electric drill :(

I also decided to check the rear brakes since the pads are binding and "clonk-off" when starting off. The discs and pads have been renewed but when I took the caliper off the pads were locked in the carrier. I needed to use quite a lot of force to persuade them out with a strong screwdriver (that's not right). I cleaned the sliding surfaces and re-installed with the rattle shims but they were far too tight, so I removed the lower shim and the pads are snug and release when taking the handbrake off. I need to get some new quality pads (not sure what brand are currently installed.

I also removed the bonnet rubber drains, the left one was full of debris. I also sprayed 3-in-1 on the gearbox selector pivots.

I will get some service bits and change the oil, oil filter, air filter and cabin filter. I already have the spark plugs. The dipstick readings are questionable since I'm sure any oil in the tube distorts the readings. I'm going to try a netting rail (plastic covered spring thingy).

'til next "playtime" :{) .
 
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Belated Update:
I've got other distractions going on in my life!

So I've replaced the two rear arches so the car looks loads better, thanks @Ami . I'm going to remove the Ali rings on the wheel caps and that should improve the looks further.

I've done an oil change. The oil filter was a PITA to get off. I had to improvise with my tools to fit the "top nut". Why don't they all have a standard shape?!

edit....I also replaced the oil pressure guage with the one I had from the Caddy. No more red genie lamp since. I wasn't expecting that since I thought the sensor would either work or not.

I've replaced the spark plugs but there is still an issue with starting and cylinder 2 misfire recording on the VCDS logs but not the initial error code listing. I need to take some fresh VCDS logs.
 
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Last week I overdosed the A2 on some Redex and took it for an Italian tune-up to work and back, it's a 32 mile route mainly on dual carriage way / Motorway.

Today was MOT test time which it passed with only an advisory for the number plate suffering minor delamination.... YAY!
When I started it this AM it started first time ! however when I repeated it would only start on second attempt.
Tonight I connected up VCDS. Firstly I looked for fault codes:

Intake Air System: Leak Detected
P1504 - 35 - 10 --- Intermittant
edit: just read @Yellow_Peril post:
"Now - going back to a previous fault code;
  • P1504 Intake air Fault - Intermittent
I noted the oil filler neck on the rocker cover was rather loose fitting, you need to remove it to be able to remove CYL.1 Coil pack. I think this could be the cause of the fault as its allowing air to pass through the seal.

The metal retainer was bent - after confirmation from Audi that this filler neck is now obsolete, I carefully straightened the retainer with some pliers to create a tighter seal."

I'll take another look at the retainer prongs

I also took some readings whilst taking it for a fast drive on a local dual carriageway. There are still some low-level misfire (single figures) so a lot lower than before.

Not sure how I upload full files, but here is a summary of the log
 

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On the face of it, the crankshaft sensor, G28, is dropping out intermittently. I think that would feel like a misfire, but not trigger a DTC, as the ECU doesn't know the engine is running.
So far, Group 141 is a mystery, even Ross-Tech can't help, so I'd ignore that.
Fuel pressure looks good.
Mac.
 
Changing the G28 looks to be a breeze....not 😞

Engine speed sensor/Crank position sensor FSI

For a change this is a fix rather than a problem and I hope it helps a few people with some erratic running problems. I was getting a intermitent warning on the sensor in the last few weeks and the car refused to start twice but now that is has been fixed it has cured a myriad of problems...
www.a2oc.net www.a2oc.net
 
Looking back at the service info indicates that the fuel filter hasn't been swapped recently so I bought a new one from ECP. It's a PITA to get the connectors off but I managed it. There's a missing cover so it was a little dirty but it can't be too old because the fuel ran out clear.
I've tightened the oil filler on top of the engine and was looking to break into the fuel line to check flow. I the spotted what looks like a manky in-line fuel filter in the engine bay. Looks OEM, but what is the part number? That can't be helping fuel flow

20240507_165338.jpg
 
Sussed it. Twisted it round and it's a charcoal filter.

Does anyone know what this is please?

Hi All, Does anyone happen to know what part number 8z0201801 is please? It looks like some sort of filter and sits in the left hand side of the engine bay as you face the car. It appears to be sitting in the fuel line, but we dont think its the fuel filter as we know where that is and its...
www.a2oc.net www.a2oc.net
 
Today I started the car from being standing 5 days and it started first time!
Not sure if it is the correct procedure but I tend to turn the ignition on, floor the pedal and release, then start the engine without touching the pedal.
When warmed-up it started fine on 3 of the 4 occasions whilst I was out.
I can't think the new fuel filter did anything but we'll see what happens next time.
 
AndyBa said:
Today I started the car from being standing 5 days and it started first time!
Not sure if it is the correct procedure but I tend to turn the ignition on, floor the pedal and release, then start the engine without touching the pedal.
When warmed-up it started fine on 3 of the 4 occasions whilst I was out.
I can't think the new fuel filter did anything but we'll see what happens next time.
Click to expand...
I press the clutch down, to lessen the starter load from the gear box, (something I've always done).
Dont touch anything else.
Mac.
 
A little bit of fettling...
The passenger door check strap was broken so I ordered some brass rollers from James Abbott. I've repaired it and swapped over the driver's check strap to the passeger door and vice versa.
Those door "tweeters" are a PITA to fit back in, otherwise a straightforward task.

I also removed the corroded alloy centrecap trim which has improved the look.

I also had the aircon recharged so that runs nice and cool now.

The car isn't used much, starting can still be problematic and I will get it booked into WOM but unfortunately Stoke isn't that convenient for me.
 
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AndyBa said:
A little bit of fettling...
The passenger door check strap was broken so I ordered some brass rollers from James Abbott. I've repaired it and swapped over the driver's check strap to the passeger door and vice versa.
Those door "tweeters" are a PITA to fit back in, otherwise a straightforward task.

I also removed the corroded alloy centrecap trim which has improved the look.

I also had the aircon recharged so that runs nice and cool now.

The car isn't used much, starting can still be problematic and I will get it booked into WOM but unfortunately Stoke isn't that convenient for me.
Click to expand...
Check out the fuel pressure from the electric pump, ignition on engine not running. VCDS Group (Editted)140. Should be 3.8 Bar.
Mac.
 
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Hmmm. Getting 60bar. This is after the engine has been running. Turn off then restart. Also idling at 60bar.
Whenn I connected VCDS for the first time in months I saw no error codes.
I've been using the car more regularly...daily and for some reasonable length journeys. It seems hesitant picking-up from low revs. Starting off uphill/at traffic lights.
 
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AndyBa said:
Hmmm. Getting 60bar. This is after the engine has been running. Turn off then restart. Also idling at 60bar.
Whenn I connected VCDS for the first time in months I saw no error codes.
I've been using the car more regularly...daily and for some reasonable length journeys. It seems hesitant picking-up from low revs. Starting off uphill/at traffic lights.
Click to expand...
The important thing is to compare Blocks 2 & 3 in Group 140. Fuel Pressure Setpoint, (what the ECU wants), and Actual, what the pump actually produces.
See my suggestions in the Green Goddess post, to properly check fuel pressure in a dynamic situation, by logging .
Mac.
 
Hesitation on acceleration, or pulling away, may be due to the fuel system, (electric pump filter HPFP, etc), not responding to the the instantaneous demand for higher pressure and flow that the ECU will call for..
The only way to check if fuelling is the problem, is to log rail pressure and do your best to induce the hesitation symptom by loading the engine. Accelerate enthusiastically, between 3,000, & 4,000 rpm a few times.
Fuelling is not the only suspect, but using a VCDS log, maks it the easiest to diagnose.
Mac.
 
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I took a trace of 140 and for most of the time the pressure columns were in sync. However there was a chunk of the trace where the readings were well over 5psi difference. I'd share the trace but a house move means no broadband and tethering was problematic!

I took a closer look at the paintwork on the two door that have evidence of new paint which lacks the deep shine of the original. It appears new paint is only above the swage line. I'll try some 2 & 3000 grit to see if it improves the finish.
 
AndyBa said:
I took a trace of 140 and for most of the time the pressure columns were in sync. However there was a chunk of the trace where the readings were well over 5psi difference. I'd share the trace but a house move means no broadband and tethering was problematic!

I took a closer look at the paintwork on the two door that have evidence of new paint which lacks the deep shine of the original. It appears new paint is only above the swage line. I'll try some 2 & 3000 grit to see if it improves the finish.
Click to expand...
Run a log of Groups 001, 007, & 140. You'll be able to see when the pressure difference occurs, rpm, engine load, & operating state, Stratified Homogeneous etc.
Mac.
 
I will hopefully run a trace tomorrow to see what that shows.
Noted the there id a Pro Boost ECU up for grabs so I'm tempted to get one. Overall the car runs fine over 2500, but starting first time is still hit/miss and the lack of torque under 2500 makes driving around town quite challenging.
 
Find out what's wrong, then fix it, not the other way around.

ProBoost is not a fix.
Depending on what the problem is, ProBoost can be an economical alternative to a fix, depending on the type of fault.
You have already seen a hint that that rail pressure may be a problem. A remap is not going to help.
Create a log, (Groups 001, 007, & 140), and on a varied drive, including an enthusiastic acceleration in third, from about 2,000 rpm to 3,500 rpm, to maximise engine load, and fuel demand.
That log will give a very good idea of fuel system pressure over varied conditions.
Post the log here. (Change the file type from csv to txt).
Mac.
 
....and time went by.... the problems with "shared ownership" of a laptop!

2 traces from today. The car failed to start first time. Noted this "exhaust gas" error before taking the first trace, have cleared.

No dash error lights at all during the scans

A search for that error finds this post on the A2 forum:
EGT Post

There is another post on the TT forum that indicates a broken connector/possible dry solder join on the EGT circuit board.

A quick search for a replacement shows that Autodoc has some decent brand replacements for less than £50. never used Autodoc but I've heard good reviews aside from the delivery taking a while.

However I don't have this EGT error all the time !
 

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