AUDI A2 1.6 FSI 2002 Throttle Body part no 036133062D seems to be discontinued

[PhilipS]

What with everything else that has been replaced and the repeated mentions of the "old" injectors, I am actually a little surprised that the injectors haven't been taken off, sent away to somewhere like Injectortune and given an ultrasonic refurb plus calibration check / jet pattern analysis. Did this with our AUA and it contributed to it running better than it ever had before, and a lot cheaper than buying new injectors of unknown Aliexpress/Amazon provenance. I actually managed to remove and refit the injector / fuel rail combo myself without setting myself or the car on fire!

Being a Molecular Biologist isn't incompatible with basic car mechanics (after nearly 30 years tinkering with DNA I should know!)...

Yes that is what we are going to do know get a refurbished set of injectors in there. Should have probably done this on day one because I purchased the car broken with an injector fault and I just purchased a single injector and got that fitted with a much cheaper mechanic thinking I will sell this car but then my wife fell in love with the A2. It's a beautiful car. Then I got all this trouble.
DNA for 30 years do we know each other? I've worked for people like Agilent

 

[A2Steve]

I can recommend Mr Injector UK for the injector refurb.

 

[PlasticMac]

For me, the only, logical way to diagnose the cause of the misfire is by logging a selection of measuring blocks, to see what is going on. It seems like the problem is quick to trigger the misfire count, so the logs will not be of a very long duration.
The misfire count block should be the first group in every log, to provide a consistent reference to the other blocks
As long as a Windows laptop is available, then for less than £100, you're good to go, and a few hours of light work, should provide an insight into what the engine is actually troubled by.
The alternative is to continue changing parts.
If the idea appeals, I'll post a list of relevant measuring blocks and their groups.
I've attached the listing and description of those that are available.
One thing the FSI is blessed with is lots of engine sensors.
Mac.

 

[PlasticMac]

I'm not keen on guesses, but thinking about your misfire counts, not cylinder specific, and the car seems to run OK, makes me sceptical of it being injectors, as it seems unlikely that all injectors would be dodgy, and any cylinder with a dodgy injector, would, surely flag the misfire as that cylinder? So, the ECU can't pin the misfire down to a specific cylinder, it's just seeing output from the crankshaft sensor that look like a misfire.
You don't feel any signs of a misfire, and the misfire count tots up very rapidly, which doesn't, to me at least, make sense.
I think misfire detection is via the crankshaft sensor, so maybe the cause is related to that sensor?
That would explain why none of the changes so far have helped. Maybe suggest this to your mechanic. Replacement is not too difficult, as long as the car's on a lift.
Picture below, courtesy of @Andrew
Mac.

 

[PhilipS]

@PlasticMac Thanks for pointing out the crankshaft sensor is the sensor logging misfires the mechanic said something about that but only when he described what was happening with misfire counting. But the misfires are cylinder specific its 1 and 2 with the codes P300, P3001, P3002 arn't they. P3001 for 1 and P3002 for 2 and P300 for there being a misfire

@PlasticMac I am also very interested in your posts about the measuring blocks in the software. I did write out the details of the software version and type in this string that my mechanic has. You seem to be saying there is a way of going further with this software or perhaps there is a software that is be better version of the software.

@A2Steve Thanks yes I was already recommended there to Mr Injector yes I have an appointment

 

[Crgwal]

Just butting in here, from what I have read it sounds to me like you have a mechanic that is actually pretty clued up. Yes he got the throttle body wrong but the fsi is hard work sometimes.

I had many issues like you. New fuel injectors is how I would go. Only if you are actually sure there are no vacuum leaks.

Have an extra good look around the oil separator.

Does your car smell of fuel? This is also a massive clue towards needing new fuel injectors if so.

 

[PlasticMac]

@PlasticMac Thanks for pointing out the crankshaft sensor is the sensor logging misfires the mechanic said something about that but only when he described what was happening with misfire counting. But the misfires are cylinder specific its 1 and 2 with the codes P300, P3001, P3002 arn't they. P3001 for 1 and P3002 for 2 and P300 for there being a misfire

@PlasticMac I am also very interested in your posts about the measuring blocks in the software. I did write out the details of the software version and type in this string that my mechanic has. You seem to be saying there is a way of going further with this software or perhaps there is a software that is be better version of the software.

@A2Steve Thanks yes I was already recommended there to Mr Injector yes I have an appointment

I agree, the misfires are cylinder specific I think I'm confusing your car with another, so sorry for that.
The software I'm meaning is still using VCDS, but as well as scanning for errors, you can run a log, (which takes a reading of a several sensors, several times a second, and stores it), so that you can see what is happening in real time. You can log three groups at one logging session.
For example you can log misfires by cylinder.
You start a log with the lap top connected, then tuck the laptop under the seat, or get an assistant to hold it, then go for a drive.
You can view the results as a spreadsheet, so you have the output of several sensors, all in sync with the misfires.
I wondered if, maybe you could do this yourself, with our help, and maybe, see something that coincides with the misfire.
Mac

 

[PhilipS]

Thanks for this guys I will have a good look round the A2 and see if I can smell petrol. This is a good idea because that is something I can do. The mechanics right hand man who is also very good did a smoke test looking for leaks. Is that the correct test for the possible leaks around the oil separator please and would that have been where a mechanic who knew stuff would look or is that something learned by trial and error i.e. you just know that on this car cracks and holes or whatever ingresses happen there please @Crgwal ?

Anyway more generally these are great suggestions so was the battery one @Robin_Cox . Fact is that this injector reconditioning and replacement is parts darts and its going to cost me loads of money because the whole engine needs to be taken apart. Plus as I say I've just got the same feeling as you guys that on a car this complicated it won't be the injectors at all it will just be a hairline crack in something and I will have replaced all these parts for nothing.

 

[Crgwal]

I can just imagine if the fuel system is dirty those fuel injectors must be having a right hard time.

My car passed a smoke test at first, it was then taken to a different garage (friend of the garage it was in) supposedly he had a higher pressure smoke test system. It was only then they found two additional leaks in the system. I wish I knew more details about this.

It was then found the oil separator was leaking along with another leak.

My car would behave the same it could be fine for 1 hour of driving then just go crazy.

Does your engine light flash ever?

I absolutely understand that it's worth getting the car scanned. I also understand you can go and check so many things on the car with the errors that are being thrown.

With the A2 FSI, you can get so many false positives. I would really stick to basics.

The audi a2 fsi is known for.

Having air leaks (old plastic)(oil separator/oil dip stick filler tube)
Having bad injectors.
Having the flaps on the manifold jam.
Issues with the low pressure fuel pump.
(Personally I don't think the high pressure fuel pump is a common issue. )

Anything else is likely not going to make the engine behave how you are describing in my honest opinion.

I say this because I have done it all before with my car. When really it was best I just stopped messing around with various sensors and diagnostics.

When all is done above, redo the timming belt if its due.

I genuinely believe this will have your car running like it should be.

I am just an FSI driver with only some basic mechanical knowledge though. My FSI runs amazing now though. With 140k miles on the clock. With no engine errors for the last 1.5 years.

Good luck!

 

[Robin_Cox]

another FSi misfire thread, here reported as being solved-in-part by cleaning up / repairing the behind-headlamp starter earth point, although there was another linked thread where someone found that it may be related to either the ECU connection itself (where the injector earthing is routed?) or the ECU itself having a bad soldered joint cured by gently heating the ECU overnight before putting it back into the vehicle. Not sure if I've misunderstood those references.

If you have a 1.6 FSi with random misfire, READ THIS.

I thought I would share this with anyone who is interested. The wifes 1.6 FSI has been driving like a pig for weeks. After replacing all coil packs, spark plugs, camshaft and crank sensors at a cost of 250 quid, I got the circuit diagrams out and the fault was traced to a poor coil pack earth...

www.a2oc.net

 

[Crgwal]

another FSi misfire thread, here reported as being solved-in-part by cleaning up / repairing the behind-headlamp starter earth point, although there was another linked thread where someone found that it may be related to either the ECU connection itself (where the injector earthing is routed?) or the ECU itself having a bad soldered joint cured by gently heating the ECU overnight before putting it back into the vehicle. Not sure if I've misunderstood those references.

If you have a 1.6 FSi with random misfire, READ THIS.

I thought I would share this with anyone who is interested. The wifes 1.6 FSI has been driving like a pig for weeks. After replacing all coil packs, spark plugs, camshaft and crank sensors at a cost of 250 quid, I got the circuit diagrams out and the fault was traced to a poor coil pack earth...

www.a2oc.net

This is worth doing which I forgot about!

 

[PhilipS]

PLEASE NOTE THIS POST IS ABOUT A SCAN ON AN AUDI A2 1.6 FSI DONE BY AUDI ON 23RD JUNE 2021

Hi Yes I already saw that thing about the earth point. Thanks for that though. A mechanic checked that earth point behind the light for me right in front of me when I first got the car in 2021 because when I first got the car it had a misfire on cylinder 4. That mechanic who was from Lithuania (wish that guy was still here he charged me a very small amount of money to take the whole engine apart and do the injector) then took the whole engine apart in front of me himself and replaced injector 4 with an injector I had purchased on e-bay for £20 and that fixed the car. It is Luton do I then went to the next garage alone on the road and got an MOT! Which at that point in time with the car only having just over 53700 I was a very happy. So my first cousin who I purchased the car from had a scan done in Essex by an Audi dealer ship and he got

17428- Fuel Pressure Regulation P1020 - 35 - 10 Control Range Exceeded - Intermittent

16684- Random / Multiple Misfire Detected P0300 -35 -00

16688- Cylinder 4 P0304 35- 00 - Misfire Detected

then some time later the HPFP and low pressure fuel pump sender water pump and belt were replaced and aside from a leaky cooling system its been trouble free motoring to 65000 miles and the present time. With sun roof replacement bit of cosmetic work. This brings me to my point that this fault now is giving P300 P301 and P302 and a big logic jump here which I don't think I'm qualified to make but it goes back to the conversation with @PlasticMac here in this thread please back me up. If there was a leak why wouldn't all cylinders be misfiring and not just 1 and 2 @Crgwal was your car misfiring on all cylinders please or is there a way a leak like this could just make cylinders 1 and 2 constantly misfire hundreds of times a minute please? @Crgwal thanks for this this really is the most likely suggestion for me of this whole string everyone knows on every car forum on earth that rubber plastic and the dreaded Jubilee clip and other plastic rubber tube grips are a nightmare but that would just give random misfires wouldn't it please? Saying that if you think about near microscopic cracks that take big pressures to open could there be cracks like this all over the car and the ones we have here are in fuel line feeds to specific injectors. We are talking about a twenty year old car here that has been very badly taken car of in its passed

 

[PlasticMac]

Do you feel the misfires, or is the log, (other than the EML), the only evidence of them?
Mac.

 

[PhilipS]

According to the mechanic you cannot feel the misfires in the car actually driving the car i.e. no vibrations noises nothing and this was the same in 2021 with the misfire on cylinder 4 you could not feel it. Saying that I have not seen the car since I broke down in it in December. So yes the scan is the only evidence of the misfires on cylinders 1 and 2. So yes correct the misfires on 1 and 2 are only evidenced by the scan and by the fact that engine lights come on after 45 seconds due to the misfire count. According to the mechanic in the later FSI engines you can switch off the misfire counter then you would get no warning lights or counting but in these early FSI engines you cannot switch off the misfire counter

 

[PhilipS]

I've discovered that the same logic does not apply to the coil pack earth thing because the guy who posted this had a scan which showed misfires in cylinders 1 2 and 3 but not 4 maybe we are getting somewhere if someone can tell me if the wiring diagram for these cars shows that not all coil packs are earthed on the same place on the car or if there is a considerable length of wire coming of each coil pack. The mechanic did notice a phenomena here which was when he switch coil he did get a slight improvement in Cylinder 2 rate of misfire

 

[PlasticMac]

OK, I'm back with my earlier suggestion.
My understanding, (not necessarily fact), is that a misfire is a "fire" (ignition), as detected by the crankshaft sensor, that occurs after Top Dead Centre, (TDC). Any fire before TDC is a knock.
So what the ECU is seeing is a signal, from the crankshaft sensor, that looks like a fire after TDC. If that is the case, then injectors wouldn't be my first suspect.
Also, an injector problem would, likely, be felt as a misfire.
So, I'm back to the crankshaft sensor again.
The fact that the misfire is cylinder(s) specific is a negative against the crankshaft sensor though. However, the crankshaft sensor is triggered by a toothed ferrous iron trigger ring. There will be tolerances in the maching of the trigger ring, so the gap between ring and the Hall Effect semiconductor will vary, ever so slightly, as it rotates. So it's plausible, imo, that a marginal sensor will fail at the same point each revolution.
Mac.

I've discovered that the same logic does not apply to the coil pack earth thing because the guy who posted this had a scan which showed misfires in cylinders 1 2 and 3 but not 4 maybe we are getting somewhere if someone can tell me if the wiring diagram for these cars shows that not all coil packs are earthed on the same place on the car or if there is a considerable length of wire coming of each coil pack. The mechanic did notice a phenomena here which was when he switch coil he did get a slight improvement in Cylinder 2 rate of misfire

Here's the circuit diagram, which seems to show a single earth point for the output/spark plug side of the coils, and a different single earth point for the input side of the coils too. Please check it carefully, to be sure. Earth point 12 is the infamous behind the headlight one, so you can see why it's infamous!
Mac.

 

[PhilipS]

@PlasticMac Thanks for this. I think you are definitely onto something here. With the 2021 Cylinder 4 misfire on my A2 I seem to remember the mechanic who put the replacement second had injector in there showing me that the engine was moving a bit as it run on idle and we looked under the bonnet of the car. So I'll get the mechanic to check the earth points and then the crankshaft sensor. Reason I say that is the earth point thing is easy to check and fix i.e. no taking apart engines. What about the crankshaft sensor does replacing this require just as much of the engine to be taken apart as replacing injectors please? Or is it located outside the engine block. If it is right in there then I will get the mechanic to do this and the injectors together as one you open the engine you might as well do everything you can.

 

[PlasticMac]

@PlasticMac Thanks for this. I think you are definitely onto something here. With the 2021 Cylinder 4 misfire on my A2 I seem to remember the mechanic who put the replacement second had injector in there showing me that the engine was moving a bit as it run on idle and we looked under the bonnet of the car. So I'll get the mechanic to check the earth points and then the crankshaft sensor. Reason I say that is the earth point thing is easy to check and fix i.e. no taking apart engines. What about the crankshaft sensor does replacing this require just as much of the engine to be taken apart as replacing injectors please? Or is it located outside the engine block. If it is right in there then I will get the mechanic to do this and the injectors together as one you open the engine you might as well do everything you can.

As long as the car's up on a lift the crankshaft sensor is, judging by posts on here, a bit fiddly, but doesn't require much in the way of parts removal, and the sensor is not expensive either.
There's a picture in my earlier, (and erroneous), post.
Mac.

 

[Indi]

My understanding, (not necessarily fact), is that a misfire is a "fire" (ignition), as detected by the crankshaft sensor, that occurs after Top Dead Centre, (TDC). Any fire before TDC is a knock.

My understanding is that a misfire is no ignition,
pre-ignition is ignition before the spark plugs fire (due to hotspots or spark plugs running too hot) ,
and knock is spontaneous ignition ahead of the flame front, so when the the cylinder fires, the flame front should move down the cylinder starting at the spark plug, but if the cylinder pressure is too high then the initial ignition can cause an increase in pressure to the point that the air fuel mixture ignites unpredictably ahead of the flame front

 

[PlasticMac]

My understanding is that a misfire is no ignition,
pre-ignition is ignition before the spark plugs fire (due to hotspots or spark plugs running too hot) ,
and knock is spontaneous ignition ahead of the flame front, so when the the cylinder fires, the flame front should move down the cylinder starting at the spark plug, but if the cylinder pressure is too high then the initial ignition can cause an increase in pressure to the point that the air fuel mixture ignites unpredictably ahead of the flame front

I am meaning the ECU's definition, not the engineering one.
The ECU expects to see an "impulse" from the crankshaft, just past TDC, as the combustion gives the piston a sharp push, momentarily changing the mark space ratio of the crankshaft sensor signal. Any other similar "impulse" after TDC, but not at the expected crank angle is, I think, seen by the ECU as a misfire.. The knock sensor is separate, and is monitoring for the shock of combustion while the piston is still rising towards TDC.
This view is formed from general reading about how various engine fault conditions are detected by the ECU. I'm not claiming them as the proverbial tablets of stone. When I see what seems to be a "phantom" fault reported, I try to work out how it might have happened.
Mac.