1.6 FSI - day one fault codes

s2ulk

Member
Hi all, picked up an FSI last night (2003, full service history, 77k miles) and so chuffed about that.

It was fine on the test drive and the VCDS scan threw up a few codes which didn’t appear too serious but on getting the drive home underway, once it got warm, it started to stutter quite a lot and when idling, the rev counter was bouncing and shaking the car a bit. When accelerating, it seems to get a bit of a surge in acceleration when it hits around 3000rpm. Also, when driving at 65mph, I could feel it stuttering which would stop if I then put the accelerator down.

On getting it home I ran the diagnostic check again and have 8 codes now including throttle actuator (mechanical failure), cat system below threshold and knock control regulation limit exceeded on cylinders 1, 2,3 and 4. So the process of DIY elimination begins before I book it into B&F in Hounslow:

- will start with a full tank of shell v power once I’ve emptied what’s currently in the tank.
- will also check the Earth behind the headlight.
- will then change the ignition coils and spark plugs.

I have the Bosch part code for the ignition coils but can anybody recommend a specific spark plug? And assume it’s also 4 spark plugs?

If anybody has anything else I should add to the above list based on the fault codes, that would be much appreciated.

Thanks
 

Ami

A2OC Donor
Yes, a Proboost ECU, if all above fails, but do the headlight earth point first before buying coil packs & plugs.
with the earth point issue the scan shows misfire on all cylinders.
 

s2ulk

Member
Yes, a Proboost ECU, if all above fails, but do the headlight earth point first before buying coil packs & plugs.
with the earth point issue the scan shows misfire on all cylinders.
Thanks Ami. My dad lives in Germany and I’m seeing him next week so may see if I can get a second ECU to give to him then and he could then get that back to me once it’s been re-mapped. Will put a message out to A2 Steve on this.
 

Evripidis

Member
The surge can be anything but I will give you a list of what I have done. I have done the following through the years in this order of appearance and now the surge has disappeared:

1. Fixed the flap actuator arm.
2. De-carbonised the EGR, throttle body and everything intake/fuel related.
3. Replaced the MAF.
4. Replaced the gearbox oil.
5. Replaced the exhaust flexi joint (welded up an aftermarket replacement in its place).
6. Removed the injectors and renewed all the o-rings + retainers.
7. Gave the injectors a good ultrasonic bath.
8. Manually cleaned the intake valves (lots of carbon).
9. Replaced the clutch.

All of the above were done over a long period of time not all at once. But I have noticed a considerable improvement in the surge department after having done the intake valves. At some point I began using 98 octane fuel relegiously on all the cars that I drive. I also use 5w30 fully synthetic.
 

Andrew

A2OC Donor
Hi all, picked up an FSI last night (2003, full service history, 77k miles) and so chuffed about that.

It was fine on the test drive and the VCDS scan threw up a few codes which didn’t appear too serious but on getting the drive home underway, once it got warm, it started to stutter quite a lot and when idling, the rev counter was bouncing and shaking the car a bit. When accelerating, it seems to get a bit of a surge in acceleration when it hits around 3000rpm. Also, when driving at 65mph, I could feel it stuttering which would stop if I then put the accelerator down.

On getting it home I ran the diagnostic check again and have 8 codes now including throttle actuator (mechanical failure), cat system below threshold and knock control regulation limit exceeded on cylinders 1, 2,3 and 4. So the process of DIY elimination begins before I book it into B&F in Hounslow:

- will start with a full tank of shell v power once I’ve emptied what’s currently in the tank.
- will also check the Earth behind the headlight.
- will then change the ignition coils and spark plugs.

I have the Bosch part code for the ignition coils but can anybody recommend a specific spark plug? And assume it’s also 4 spark plugs?

If anybody has anything else I should add to the above list based on the fault codes, that would be much appreciated.

Thanks
I bought some spark plugs from Crew Audi as part of a service pack and they turned out to be Bosch. NGK seem to be respected as well but whatever you should end up with the 4 electrode variety.

My FSI used to have a surge at 3000rpm but no longer after the flaps were fixed so maybe connected but unless you have 17439/P1031 in your fault codes not to worry.

One piece of standard advice is to clear the codes then go for a 20 minute drive and see what comes back. Post the scan output here.

Andy
 
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GTSpec

Member
Carbon build up around the intake valves will be the likely cause of your misfires in idle/stratified injection mode once you rule out spark, fuel and compression. This is a well known issue with direct injection engines.

Watch this video:

I recommend all FSi owners use some GDi valve cleaner as routine preventative maintenance.
 

s2ulk

Member
Thanks all, very helpful. The hesitation / lurching actually seems worse as the engine warms up. It starts from cold no problem but if you drive it for 15 minutes and then turn off and restart, it dies unless it’s getting a lot of revs. For the carbon build up, are any of the additives like wynns injector cleaner worth a try?
 

GTSpec

Member
Injector cleaner doesn’t clean the valves as the fuel is injected directly into the combustion cylinder. I recommend CRC GDi valve cylinder. You spray it in after the MAF sensor as not to damage it.
 

Evripidis

Member
Having amassed an entire tea cup full of carbon debris that was on the back of the valves, I highly doubt that any form of cleaner will shift them loose as they had solidified and well stuck on the valves and runner. I used a wire-brush and a pick to chisel it out!

Cleaners might be good for preventive maintenance otherwise I would not waste money or even bother if this has never been done before. Mechanical removal must be the only way.
 

GTSpec

Member
Having amassed an entire tea cup full of carbon debris that was on the back of the valves, I highly doubt that any form of cleaner will shift them loose as they had solidified and well stuck on the valves and runner. I used a wire-brush and a pick to chisel it out!

Cleaners might be good for preventive maintenance otherwise I would not waste money or even bother if this has never been done before. Mechanical removal must be the only way.
I agree. Preventative maintenance after the deep physical clean has taken place. Did your FSi run smoother after the clean?
 

Evripidis

Member
Hard to tell mate. It had been on a 6-month fit of critical things breaking all the time and acted as a lawn ornament for most of the time. I cannot remember how it ran before if I am honest. It has been back on the road for 4 weeks or so and has been all right. Fuel economy is great and it can be described as smooth bar the road noise. It is a lot more responsive and does not surge at all now but most of the overall improvement is owed to the new clutch as it was in pieces when I took it out.
 

PlasticMac

Member
Yes, a Proboost ECU, if all above fails, but do the headlight earth point first before buying coil packs & plugs.
with the earth point issue the scan shows misfire on all cylinders.
If you go the ProBoost route, you must remove the "S" on the rear hatch. No Flaps = No Stratified. No "S"
Mac.
 

PlasticMac

Member
Hi all, picked up an FSI last night (2003, full service history, 77k miles) and so chuffed about that.

It was fine on the test drive and the VCDS scan threw up a few codes which didn’t appear too serious but on getting the drive home underway, once it got warm, it started to stutter quite a lot and when idling, the rev counter was bouncing and shaking the car a bit. When accelerating, it seems to get a bit of a surge in acceleration when it hits around 3000rpm. Also, when driving at 65mph, I could feel it stuttering which would stop if I then put the accelerator down.

On getting it home I ran the diagnostic check again and have 8 codes now including throttle actuator (mechanical failure), cat system below threshold and knock control regulation limit exceeded on cylinders 1, 2,3 and 4. So the process of DIY elimination begins before I book it into B&F in Hounslow:

- will start with a full tank of shell v power once I’ve emptied what’s currently in the tank.
- will also check the Earth behind the headlight.
- will then change the ignition coils and spark plugs.

I have the Bosch part code for the ignition coils but can anybody recommend a specific spark plug? And assume it’s also 4 spark plugs?

If anybody has anything else I should add to the above list based on the fault codes, that would be much appreciated.

Thanks
I'd fill up with V Power straightaway. With luck, one or two faults will be primary, the rest secondary, a consequence of the primary.
🤞
Mac.
 

s2ulk

Member
Hi all, I’m working through my remediation check list on the FSI. Full tank of v-power and some wynns fuel injection cleaner made the idle shake less violent! I checked and cleaned the Earth behind the headlight but it had clearly been done recently as was looking very clean (with evidence of a sand paper rub down).

I swapped out all four spark plugs and 2 coil packs last night. When cold it definitely now runs better - much smoother acceleration but once it warms up it picks up its bad habits again of lumpy acceleration and slightly erratic revs when going at a constant speed. Before I swapped out the sparks and coils it was showing that knock levels were too high on 3 of the 4 cylinders and so I was thinking faulty knock sensor potentially. But I ran the VCDS again after changing the sparks and the coils and all the knock related fault codes are now gone apart from an intake air leak fault code which has been there from day 1.

So not sure exactly where to go with this now but I’m hoping that B&F in Hounslow has some means of testing for leaks when it goes to them next Saturday as I suspect it’s a heat/expansion related problem. When I had a Rover Mini 20 years ago, it would drive great when cold but lose all power once warmed up - that was due to a split in the manifold which expanded when warm and so I’m wondering whether there is something similar going on here… Any words of wisdom appreciated as ever.
 

PlasticMac

Member
Hi all, I’m working through my remediation check list on the FSI. Full tank of v-power and some wynns fuel injection cleaner made the idle shake less violent! I checked and cleaned the Earth behind the headlight but it had clearly been done recently as was looking very clean (with evidence of a sand paper rub down).

I swapped out all four spark plugs and 2 coil packs last night. When cold it definitely now runs better - much smoother acceleration but once it warms up it picks up its bad habits again of lumpy acceleration and slightly erratic revs when going at a constant speed. Before I swapped out the sparks and coils it was showing that knock levels were too high on 3 of the 4 cylinders and so I was thinking faulty knock sensor potentially. But I ran the VCDS again after changing the sparks and the coils and all the knock related fault codes are now gone apart from an intake air leak fault code which has been there from day 1.

So not sure exactly where to go with this now but I’m hoping that B&F in Hounslow has some means of testing for leaks when it goes to them next Saturday as I suspect it’s a heat/expansion related problem. When I had a Rover Mini 20 years ago, it would drive great when cold but lose all power once warmed up - that was due to a split in the manifold which expanded when warm and so I’m wondering whether there is something similar going on here… Any words of wisdom appreciated as ever.
 

PlasticMac

Member
Does sound like a perished hose somewhere on the inlet side. Maybe ask B&F if they can do a smoke test, or similar to check all hoses. They're probably all getting on in years.
Excellent result with the coil pack/plug swap👍
Mac
 

Evripidis

Member
Check the flap vacuum hoses (small diameter) in the vicinity of the flap actuator. Probably 3-4 hoses in total, on the left hand side of the intake manifold as you are looking at the engine bay. Try and rub them slightly and see if any black deposits remain on your finger. If so they have perished and need replacing, cheap but you may have to make a blood sacrifice if performed in situ.

Mine looked all right until a closer on inspection took place and as soon as I tried to take them out they'd disintegrated.
 
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