FSI erratic/uneven running
- Thread starter Lasse H
- Start date
A brief update about my car. It visited today a local Bosch Service (/ car electronics repair shop). That was nearly complete waste of time and money. 
According to diagnosis crankshaft and camshaft sensors are OK, and ignition coils were getting OK signal. That was pretty much the most useful information I got.
In contrast to what I had asked, injectors had not been checked at all. Instead, I was told it is not possible to diagnose fuel injectors in any way. (This was not only opposite to what was told me on Friday when I was making the appointment, but also not really true, AFAIK.) Instead, the guy was suggesting they could swap(!) injectors of a misfiring and the non-misfiring cylinder. For some reason he had started working with some Corolla instead, leaving A2 half-open (air intake disconnected, etc) until I came to get it back. I guess this was actually a good thing.
Another suggestion I got was to get the ECU checked. It would take 2-3 weeks. If a problem was found, cost to fix it would typically be around 300-400€. Is anybody aware of such issues (misfire, poor idle) issues with FSI ECUs? If this is not a typical failure I'd assume it would be cheaper and easier to just get a new used ECU.
I was also informed that high-pressure fuel pump and camshaft failures are "typical" in "these engines" and could cause this kind of symptoms. Is this true? I don't remember reading about either of these issues.
I ended up paying 188€ for the visit. The mechanic was suggesting this was already a highly discounted price (because of their internal communication failures leading to a lacking work order, and that I was earlier "lied" about them being able to check injectors). I'm now thinking about making a complaint, although I'm not expecting to recover any money from this. I understand diagnosis work can be expensive, but it should be also carried out professionally and with somehow decent customer service.
According to diagnosis crankshaft and camshaft sensors are OK, and ignition coils were getting OK signal. That was pretty much the most useful information I got.
In contrast to what I had asked, injectors had not been checked at all. Instead, I was told it is not possible to diagnose fuel injectors in any way. (This was not only opposite to what was told me on Friday when I was making the appointment, but also not really true, AFAIK.) Instead, the guy was suggesting they could swap(!) injectors of a misfiring and the non-misfiring cylinder. For some reason he had started working with some Corolla instead, leaving A2 half-open (air intake disconnected, etc) until I came to get it back. I guess this was actually a good thing.
Another suggestion I got was to get the ECU checked. It would take 2-3 weeks. If a problem was found, cost to fix it would typically be around 300-400€. Is anybody aware of such issues (misfire, poor idle) issues with FSI ECUs? If this is not a typical failure I'd assume it would be cheaper and easier to just get a new used ECU.
I was also informed that high-pressure fuel pump and camshaft failures are "typical" in "these engines" and could cause this kind of symptoms. Is this true? I don't remember reading about either of these issues.
I ended up paying 188€ for the visit. The mechanic was suggesting this was already a highly discounted price (because of their internal communication failures leading to a lacking work order, and that I was earlier "lied" about them being able to check injectors). I'm now thinking about making a complaint, although I'm not expecting to recover any money from this. I understand diagnosis work can be expensive, but it should be also carried out professionally and with somehow decent customer service.
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Sorry to hear of your difficulties with the workshop today. I've had similar disappointing experiences with a UK Bosch Worskhop - I'm not sure what they have to do to get accredited and use the Bosch name but have found them expensive and not necessarily good at diagnosis.
You're correct to say that injectors can be checked, although this would need to be through exhaust emissions testing -e.g. for Hydrocarbons which if very high might suggest an injector that is over-fuelling e.g. due to sticking internals or very lean running due to an injector that is fouled or with a blocked filter basket.
Althougth injectors would need to be tested on a bench (there are specific Bosch rigs for this) an Oscilloscope (Picoscope) could be used to analyse the waveform and compare one injector with another e.g. cylinder with misfire v's cylinder running normally which might confirm suspicions about an injector before the expensive process of stripping down and removal.
I've had a complete set of injectors, MAF, Camshaft sensor, both Cats, Lambda sensor, intake manifold and as far as I can tell have no intake leaks but still hesitancy at low revs, so am about to re-test everything adn looking for a leaking injector seal / weeping injector will be my first call after rechecking all the vaccuum pipes- I'm suspicious about the Vacuum hose to the brake servo which connects to the intake manifold at the back - many VW models have similar hoses which perish and split at the connectors allowing an air leak.
Will be great to hear if you make any progress and solve your problem- so many of us FSi owners love our cars when they run well and are just searching for that one little problem which results in poor running. Clearly VW / Audi realised that the engine mapping and sensor layout on the BAD engine is less than ideal - Golf FSis have additional sensors e.g. separate fuel temperature and fuel pressure sensors within the High Pressure pump, and TFSis have more sensors still which I think makes them easier to diagnose and troubleshoot, and less likely to run very very lean then overcompensate.
P
You're correct to say that injectors can be checked, although this would need to be through exhaust emissions testing -e.g. for Hydrocarbons which if very high might suggest an injector that is over-fuelling e.g. due to sticking internals or very lean running due to an injector that is fouled or with a blocked filter basket.
Althougth injectors would need to be tested on a bench (there are specific Bosch rigs for this) an Oscilloscope (Picoscope) could be used to analyse the waveform and compare one injector with another e.g. cylinder with misfire v's cylinder running normally which might confirm suspicions about an injector before the expensive process of stripping down and removal.
I've had a complete set of injectors, MAF, Camshaft sensor, both Cats, Lambda sensor, intake manifold and as far as I can tell have no intake leaks but still hesitancy at low revs, so am about to re-test everything adn looking for a leaking injector seal / weeping injector will be my first call after rechecking all the vaccuum pipes- I'm suspicious about the Vacuum hose to the brake servo which connects to the intake manifold at the back - many VW models have similar hoses which perish and split at the connectors allowing an air leak.
Will be great to hear if you make any progress and solve your problem- so many of us FSi owners love our cars when they run well and are just searching for that one little problem which results in poor running. Clearly VW / Audi realised that the engine mapping and sensor layout on the BAD engine is less than ideal - Golf FSis have additional sensors e.g. separate fuel temperature and fuel pressure sensors within the High Pressure pump, and TFSis have more sensors still which I think makes them easier to diagnose and troubleshoot, and less likely to run very very lean then overcompensate.
P
Thanks for your support and insights, muggles! I hope your issue will be sorted out too. That's sounds like a lot of effort and parts changed already.
I did some ECU logging (misfire counters, injector timing, etc.) during the weekend. Unfortunately, I was unable to draw any conclusions from the data. Reported misfires seem to happen pretty much in all load conditions, with warm and cold engine, and are not clearly affected by the injection time. Usually cylinder 1 counter leads, and cyl 2 and cyl 3 increase same time but not so much.
I was hopeful about seeing a connection between low injection time and misfires, but that was not obvious. However, logging sample rate might well be too slow to show it.
Today I had to take the car back to the aforementioned repair shop, as I noticed the mechanic had forgotten to reinstall engine bay bottom shield. They did not want to install it back while waiting. Not even a single word of apology... I had to leave car there for the day and continue to work by a bus.
I did some ECU logging (misfire counters, injector timing, etc.) during the weekend. Unfortunately, I was unable to draw any conclusions from the data. Reported misfires seem to happen pretty much in all load conditions, with warm and cold engine, and are not clearly affected by the injection time. Usually cylinder 1 counter leads, and cyl 2 and cyl 3 increase same time but not so much.
I was hopeful about seeing a connection between low injection time and misfires, but that was not obvious. However, logging sample rate might well be too slow to show it.
Today I had to take the car back to the aforementioned repair shop, as I noticed the mechanic had forgotten to reinstall engine bay bottom shield.
They did not want to install it back while waiting. Not even a single word of apology... I had to leave car there for the day and continue to work by a bus. 
Topsie
Member
That's not ideal, a really poor show from that workshop, may i suggest you name and shame, you can leave negative reviews on google so you have some chance of warning people.
The BAD engine is causing lot's of people headaches, I really want to find out what is causing the poor running on mine also but it is proving difficult. I was hoping new injectors may cure my problem but from muggles post i'm no so sure... When i checked the timing on my engine I was ever so tempted to remove the head and have a good look at the piston crowns and valve heads and see just how much carbon build up there had been... Kind of wish I had now!
The BAD engine is causing lot's of people headaches, I really want to find out what is causing the poor running on mine also but it is proving difficult. I was hoping new injectors may cure my problem but from muggles post i'm no so sure... When i checked the timing on my engine I was ever so tempted to remove the head and have a good look at the piston crowns and valve heads and see just how much carbon build up there had been... Kind of wish I had now!
I had already decided take the car to a workshop, remove all injectors, get those checked and serviced, replace possibly faulty ones, then assemble it back.
However, I realized because of disconnecting battery the car possibly had lost throttle body adaptation setting. So diagnostics codes were cleared and adaptation was done. Next evening errors codes were checked. There was none. All OBD checks had passed OK too! Even weirder, the misfire count is now increasing in cylinder 4 counter (which didn't have those earlier). On idle misfire was usually audible exactly when the counter was increasing. Some rare random misfires appeared in cylinder 3 counter too. None to 1 or 2 (1 was the worst before)!! I think this was not good news for my theory about faulty injectors.
I can't understand this. No much ideas how to proceed now. Perhaps I'll just take it to another diagnostics workshop.
However, I realized because of disconnecting battery the car possibly had lost throttle body adaptation setting. So diagnostics codes were cleared and adaptation was done. Next evening errors codes were checked. There was none. All OBD checks had passed OK too! Even weirder, the misfire count is now increasing in cylinder 4 counter (which didn't have those earlier).
On idle misfire was usually audible exactly when the counter was increasing. Some rare random misfires appeared in cylinder 3 counter too. None to 1 or 2 (1 was the worst before)!! I think this was not good news for my theory about faulty injectors.I can't understand this. No much ideas how to proceed now. Perhaps I'll just take it to another diagnostics workshop.
bretti_kivi
Member
Hi Lasse,
The high pressure pump does *sometimes* cause issues. Apparently there can be hairline fractures so it looks OK, but can't deal with the pressures involved.
this thread might help, including the error messages: https://a2-freun.de/forum/forums/topic/27555-hochdruckpumpekraftstoffdruckregelventil-tauschen/. There's also a part number for the high pressure pump... but it's not cheap.
I would possibly have expected that level of service with the motor protector from Laakkonen... or maybe not, but then I'd be paying €100 an hour for the privilege.
- Bret
The high pressure pump does *sometimes* cause issues. Apparently there can be hairline fractures so it looks OK, but can't deal with the pressures involved.
this thread might help, including the error messages: https://a2-freun.de/forum/forums/topic/27555-hochdruckpumpekraftstoffdruckregelventil-tauschen/. There's also a part number for the high pressure pump... but it's not cheap.
I would possibly have expected that level of service with the motor protector from Laakkonen... or maybe not, but then I'd be paying €100 an hour for the privilege.
- Bret
steaman
A2OC Donor
You need to identify if the engine is running lean or not. if not you can rule out Vacuum leaks at the intake manifold, vacuum hose connections or throttle body.
If you have access to VCDS you can identify if the engine is running mean lean by studying Long Term Fuel Trim (LTFT) and Short Term Fuel Trim (STFT) in Block 032 and 033.
If STFT is greater than approx. 10 to 12, the engine is running LEAN.
Have a beer and study these videos!
This is a good generic tutorial: https://www.youtube.com/watch?v=pIJdCZgEiys
This video demonstrate how to do measure on a VAG engine: https://www.youtube.com/watch?v=yM3iarhSP68
If you have access to VCDS you can identify if the engine is running mean lean by studying Long Term Fuel Trim (LTFT) and Short Term Fuel Trim (STFT) in Block 032 and 033.
If STFT is greater than approx. 10 to 12, the engine is running LEAN.
Have a beer and study these videos!
This is a good generic tutorial: https://www.youtube.com/watch?v=pIJdCZgEiys
This video demonstrate how to do measure on a VAG engine: https://www.youtube.com/watch?v=yM3iarhSP68
Just a quick update on my fuel leak
I removed the intake manifold, long job but not as difficult as I thought. I started by using an engine brace across my car so i could lower it but soon realised it was in the way of removing the manifold so I just went with a wooden block and jack under the sump, much easier and would do it his way again if I had too.
Once I had access to the injectors I removed the injector adaptors that sit on top of the injectors and checked the seals. Thank goodness one of them (in the same position as the leak) was damaged as shown below.
Simply replaced all the seals and reassembled and the leak is all sorted
For the rough running I finally got around to using a quality fuel additive ( Wynns Gold injector cleaner) and a full tank of Shell V-Power.
I was dubious about this as I have tried it on other cars with no noticeable difference.
WOW, almost an immediate difference. The tickover has always been very low to almost stalling and after only a few miles the tickover is slightly higher and no signs of judder. The only issue left was between tickover (750 revs) and 1000 revs, it would bounce around, but once past 1000 it was perfect.
After a good run on the motorway the entire range of the throttle is now very smooth whilst previously the car would lurch forward or hold back at certain points, and the problem between 750 revs and 1000 revs is now gone
I am one HAPPY CHAPPY.
Apologies for the length of time between posts but we are ALL busy at work and home.
P.S. I also got sidetracked fixing broken indicator relay http://www.a2oc.net/forum/showthread.php?32726-Indicator-Relay-Repaired
I removed the intake manifold, long job but not as difficult as I thought. I started by using an engine brace across my car so i could lower it but soon realised it was in the way of removing the manifold so I just went with a wooden block and jack under the sump, much easier and would do it his way again if I had too.
Once I had access to the injectors I removed the injector adaptors that sit on top of the injectors and checked the seals. Thank goodness one of them (in the same position as the leak) was damaged as shown below.
Simply replaced all the seals and reassembled and the leak is all sorted
For the rough running I finally got around to using a quality fuel additive ( Wynns Gold injector cleaner) and a full tank of Shell V-Power.
I was dubious about this as I have tried it on other cars with no noticeable difference.
WOW, almost an immediate difference. The tickover has always been very low to almost stalling and after only a few miles the tickover is slightly higher and no signs of judder. The only issue left was between tickover (750 revs) and 1000 revs, it would bounce around, but once past 1000 it was perfect.
After a good run on the motorway the entire range of the throttle is now very smooth whilst previously the car would lurch forward or hold back at certain points, and the problem between 750 revs and 1000 revs is now gone
I am one HAPPY CHAPPY.
Apologies for the length of time between posts but we are ALL busy at work and home.
P.S. I also got sidetracked fixing broken indicator relay http://www.a2oc.net/forum/showthread.php?32726-Indicator-Relay-Repaired
Congratulations for those who got their FSIs running well! And thanks for debugging ideas.
I ended up buying a BMW and then driving A2 to a local car diagnostics specialist. After some weeks I just got a call: A very difficult engine to debug because of few sensors available. Best guess at the moment: Adjustment of camshaft timing is not responding. They told seeing similar symptoms with some Volvo engines, but had no idea if these VAG FSIs behave same way.
New parts would cost around 800€ and would take 4 hours to install or so. No guarantee it will work, but that is the only next step they could recommend.
This would explain why car felt sometimes (most of the time!) so powerless, but occasionally not. I already though I had just been imagining it.
On the other hand, I do not remember about reading issues with those adjustment units. Part price is also a bit painful.
I ended up buying a BMW and then driving A2 to a local car diagnostics specialist. After some weeks I just got a call: A very difficult engine to debug because of few sensors available. Best guess at the moment: Adjustment of camshaft timing is not responding. They told seeing similar symptoms with some Volvo engines, but had no idea if these VAG FSIs behave same way.
New parts would cost around 800€ and would take 4 hours to install or so. No guarantee it will work, but that is the only next step they could recommend.
This would explain why car felt sometimes (most of the time!) so powerless, but occasionally not. I already though I had just been imagining it.
On the other hand, I do not remember about reading issues with those adjustment units. Part price is also a bit painful.
Thanks! I haven't used WhatsApp but maybe that should be considered.
Do you refer to issues with cam timing adjustment, or in more general FSI issues?I'm just wondering, shouldn't ECU give an error code about cam timing not following the setting...?
Also, why these guys want immediately change the whole timing adjustment unit, not just the solenoid? Well, I'll give them a call in a moment...
I got some answers. The intake camshaft timing solenoid was making a sound, so it was likely working. However, detaching its connector made no difference to engine running on idle or higher revs, so they assumed the non-repairable adjustment unit was somehow stuck. They were telling "normally this makes an engine stall".
They had not been able to read setting or current camshaft timing value. Unfortunately this is not a VAG specialist shop. Should these values be available with VCDS?
They had not been able to read setting or current camshaft timing value. Unfortunately this is not a VAG specialist shop. Should these values be available with VCDS?
Topsie
Member
unfortunately not the case, disconnecting the solenoid just puts it in a 'safe' position and registers a fault code, if it were failing you would get errors with the intake camshaft position sensor. The values are present on VCDS (though i can't remember where off the top of my head)
Nick
Nick
Many thanks for the information. This could save me from an unnecessary expensive repair. But then, back to the starting point...
Topsie
Member
I'm happy to make a quick video of me pulling the plug on mine while it's running if they insist.
If you can get hold of VCDS you can carry out a basic settings test of the solenoid or an output test, one of the two so you can hear it clicking away. I removed my solenoid and powered it with a 12v battery just to get it moving, you can tell pretty quickly if it's not working.
Mine has behaved itself since I cleaned the electronics for the throttle body, although I still get the occasional misfire and almost always a misfire code in-waiting, just not severe enough to bring up the EML. I also get occasional "inlet camshaft excessively retarded (over advanced)" but i can't nail that one down and is again intermittent. I know she's stopped dropping into stratified mode thanks to a naughty exhaust gas temp sensor that i'm still to look at.
So keep going, hopefully you'll fine your cure!
If you can get hold of VCDS you can carry out a basic settings test of the solenoid or an output test, one of the two so you can hear it clicking away. I removed my solenoid and powered it with a 12v battery just to get it moving, you can tell pretty quickly if it's not working.
Mine has behaved itself since I cleaned the electronics for the throttle body, although I still get the occasional misfire and almost always a misfire code in-waiting, just not severe enough to bring up the EML. I also get occasional "inlet camshaft excessively retarded (over advanced)" but i can't nail that one down and is again intermittent. I know she's stopped dropping into stratified mode thanks to a naughty exhaust gas temp sensor that i'm still to look at.
So keep going, hopefully you'll fine your cure!
Thanks for your help and support again!
I'll ask from the diagnostics shop if they would be interested in the video. I already wrote them there definitely should be an error code about cam timing, if that was the case. I was suggesting perhaps issue is in injectors. AFAIK removing, checking and reinstalling injectors would be cheaper than the probably useless cam timing fix they are suggesting... From the German forum I found some very similar looking misfire-case (just my language skill isn't too good to understand all): https://a2-freun.de/forum/forums/topic/26646-fsi-zündaussetzer/
I've understood those cam timing solenoids can get blocked and partially fail, even in they work electrically. Maybe proper cleaning or replacing it could help, if your timing issue keeps appearing?
I'll ask from the diagnostics shop if they would be interested in the video. I already wrote them there definitely should be an error code about cam timing, if that was the case. I was suggesting perhaps issue is in injectors. AFAIK removing, checking and reinstalling injectors would be cheaper than the probably useless cam timing fix they are suggesting... From the German forum I found some very similar looking misfire-case (just my language skill isn't too good to understand all): https://a2-freun.de/forum/forums/topic/26646-fsi-zündaussetzer/
I've understood those cam timing solenoids can get blocked and partially fail, even in they work electrically. Maybe proper cleaning or replacing it could help, if your timing issue keeps appearing?
Topsie
Member
Yeah I removed and cleaned mine by forcing solvent through while operating the solenoid, though it wasn't dirty to start with! I've also renewed the Cambelt, tensioners and guides and water pump. Other than the throttle body the biggest difference was seen by using a injector cleaning additive and repairing the flap in the inlet manifold which also made noticeable differences and maybe worth trying (wynns gold I think) before removing injectors, which can be a real pain to remove. Let me know if the video will help and I'll pop one on YouTube once home.
Nick
Nick