B7 TFSi Cylinder 3 Misfire, P0171, Rough idle, Hesitates etc etc

[keirGERS]

Hello all,
basically, I bought my first German car last week after having Japanese after Japanese. Went to veiw it, no fault code, no engine management illuminated and it ran fine. The car in question is a 2006 Audi A4 TFSi Quattro S-Line Auto.

Over the last week little niggly things have started to annoy me, I'll make a list, probably easier that way.

Engine management bulb illuminated ( P0171 & Cylinder 3 Misfire (forgot to get the code before I cleared it))
Slowly started to idle a lot worse, I've read on here people saying they are a noisy engine, but it's very noisy, has a very bad diesel clatter sound, according to the girlfriend *like a tractor*. I thought along the lines of the cam chain tension, but I'd of thought that would of been more of a rattle.
When the car is first started when cold, it misfires badly at idle. Standing around the rear you can hear the 'dunf, dunf, dunf' as it try's to idle out the exhaust. Usually clears after 10-15 seconds, however now it has started to return when the car is warm.
Feeling a slight stutter occasionally (like it's running out of fuel) under partial throttle, however, fine at WOT.
Engine management occasionally flashes a repeatedly a few times then goes off under WOT.
Loosing coolant (don't know if it could be related).
Idles very poorly, rocks the whole car.

At first I thought the misfire could be coilpack related, so phoned my local audi dealership to find it hadn't had the coilpack recall. So that got done yesterday, however I still have all of the above issues.

Bought a OBD2 Bluetooth connector and downloaded the app. I've found I'm boosting at a steady 8-9PSI. I've read on another topic it should be around 10-10.5PSI. Don't know how good the OBD2 connector will be though so I'm not 100%.

Read that the carbon build up apparently gets better as the engine warms up (mine appears to get worse) so that eliminates that I suppose.

It also feels sluggish, considering it's 200bhp, but I don't know if that's just because my old car was a Type R and the one before that a 320bhp S14a. Obviously the Audi is a big heavy car, but there isn't much or a turbo kick, you can barely feel it, which makes me think it's under-boosting.

Any recommendations would be greatly appreciated, as at the moment I feel like I'm going to be shooting in the dark.

Thanks
Keir

 

[Charlie Farley]

Hi, not being an expert on audi's or a4's i would'nt really like to make a spot diag to be honest. I purchased a manual 2.0 tfsi avant quattro s-line special edition just over a week ago , i did a 370 mile run out yesterday down to devon and back in her and it was great, smooth and fast, the boost can de felt from low down and the car really pulls in all gears, mines is a 220bhp engine so maybe yours is too, sounds like somethings is amiss , probably just a small thing, maybe get it check out by a pro on these models.
small problems can sometimes seem like much bigger issues.
good luck with it.

 

[keirGERS]

That's it buddy, I'm fairly confident it is just 2 or 3 small seperate issue but it'd be nice if somebody could pin point it. It'd just potentially save throwing money at nothing, you know. I'm a vehicle technician by trade so I can't imagine parts will be that expensive, and I'll be doing the work myself.
Hoping to get the PCV valve off tomorrow and have a look about for obvious leaks, the thing that's throwing me is the fact it's still boosting fine, or seems to be. When my old S14a had a boost leak, you know it had one. Would boost at 0.6 bar instead of 1.4 bar.
And it's booked in for a remap next week, so hoping to find the fix ASAP!

 

[Giosabcsl]

Hi Keir

Welcome to the forums.

To be honest I have read your issues it does seem like its boost a little low but not seriously low. The kick on the 200 is not a lot especially as its a Auto.

You are shifting like 1.6 tons with quattro so its more of a cruiser till its mapped then you will fell the boost. But keep in mind its only a tiny ko3 turbo.

Regarding your code

16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean

Possible Causes
Mass Air Flow Sensor (G70) defective
Intake System Leak(s)

Possible Solutions
Check Mass Air Flow Sensor (G70)
Check Fuel Pressure Regulation
Check Fuel Pump
Check Injectors
Check Intake System for Leaks
Check Exhaust System for Leaks
Check Secondary Air System for Leaks
Check Vacuum Pipes for Leaks
Special Notes

With you loosing coolant, well is your car getting up to temp? Does it sit dead on 90 regardless of outside temps?
If yes to all the above at the rear of the motor there is a coolant pipe/flange that is prone to cracking and a bit of a pain to get to and are very common place to show signs of were it leaks. To test this you can try park the vehicle on a flat surface and lay a towel horizontal between the 2 front wheels and see if you getting any drips hopefully will help locate the leak if there is one.

Unless you got a issue in the head and you are getting white or mayo in the oil cap.

Another thing is did you use a proper vag come or a generic scanner?

To be quite frankly I know you may know your scene when it comes to jap and Sr20det motors.

But these engines are a different ball game. So I would tread lightly with mapping your vehicle before ironing out the issues.

 

[keirGERS]

The car is getting up to temp fine buddy, except when giving it death, drops below the 90 a little, but I can only presume that is due to more air being forced through the intake/intercooler. By death I mean 100mph+ on A class roads, closed at the time obviously...
And it really seems to struggle beyond 120.

Coming from Jap things to the A4 I'm struggling a little, purely because with the jap things, there's only a few sensors so 99% of the time it's purely mechanical.

To be perfectly honest, to me. I may be completely wrong.
The coolant leak, seems un related.
And the misfire seems un related to the p0171.

I had a fuel pump fail on a Type R I had, and it does feel like that, except when it was the fuel pump it was at it's worst at WOT, whereas the only time this issue really stands out, and you notice it, is at partial throttle, say accelerating out of a 30 into a 60. If the gears are going via the throttle mode, at 2k to 4k rpm it will stutter a little in every gear. Whereas into the 'manual' mode, pop it down a gear and it goes fine.

The misfire is mostly at idle, it smoothens itself out up the rpm however the ECU does still recognise it's there. At idle, you can hear it missing, rev it with a dab of the throttle to 3k ish rpm and it's fine. Hold it at 2k to 3k rpm and you notice the odd miss.

Again I may be completely wrong, but to me, when previous cars have had a boost leak, it's been blatantly obvious, you know.

And it was just a generic OBD2 scanner, an ELM327 if you know the device bud. It was basically only bought so I could recognise the fault code/codes and take it from there. So I'd imagine the boost/vacuum pressure won't be too accurate.

 

[Giosabcsl]

Ye then you got a sensor issue or a thermostat issue on your car regardless of were you throw it or how you throw it. It should never move. Has nothing to do with the air or were its going. Thermostats are very prone on our engines.

Ye im almost from a jap background and still own my little Honda.

Well what you can do is start the car and unplug the MAF sensor by the air filter. And see if you notice a change in idle. I know exactly what you referring to when it idles and shakes.

But the shaking is usually caused bad engine mounts "generally speaking" especially on the autos. But there is a few occurances were the cars shake in P but dont shake in N or D. Just try that next time and see. Otherwise I would be looking at your timing is out.

And by the sounds of it you getting the real diesel noise and the clackety noises. Next time when you start the car cold have the bonnet open and try listen out of for like grinding noise on start up. It should disapear almost instantly if it keeps making a grinding noise what has happend is your timing chain has stretched and the tensioner has shot. Which will in turn cause the misfire.

If yours sounds anything like this then sadly its your chain and tensioner.

And you should try get a proper scan with a VAG COM. Either try find someone in your area under the VAG com section, buy one from the sales members on here, or take it to a garage and let them scan it with the correct scanner. Generic ones dont usually scan well with the VAG vehicles.

And if it sounds anything like this, then you got another issue on your hands because this is what controls your fueling and if this goes well then ye you got problems

Listen carefully as they both very distinct noises. Best have the engine started and take the end of a long screwdriver and touch it on areas and put ur ear on the screwdriver and listen. And see if it relates to either of the above. If its the first one its quite a costly one. The second one not so bad. Unless its failed already.

And just out of interest what makes you think your pcv is failed? or failing? that you need to check it?

 

[keirGERS]

What kind of honda you got bud? I'm toying with with idea of buying another EG6, purely as a weekend toy though, don't think I could get rid of the audi now.

I'll try unplugging things tomorrow to come to the bottom of it, and I'll try sitting it in 'N'.

Sounds exactly like that bud, but it's strange. Sounds bad when you first start it, miss after miss. Then 10-15 seconds in it clears the misfire. Still rocks the car at idle though. And then again, after say a 10 mile journey it will start to miss constantly again.

But it's gradually getting worse, like a stretched timing chain, I know with the Type R's, it stretches a little, then generally speaking it doesn't get much worse, or better. But this issue seems to gradually be getting worse, you know.

When I go out tomorrow, I'll get a video of it when I first start it when cold, you'll hear it calm itself down after a few seconds, and then I'll take it a run and get a video when it's warm.

 

[Giosabcsl]

I have a P reg ek4 vti saloon adolesant pearl blue which only came in 97 with under 80k on the clock. 100% stock. Full honda service history My little show car. Does around 100 miles a year otherwise in dry storage. I dont mind the EG6 but im more of a saloon guy.

The rocking is either engine mounts for sure or its I think the torque converter that goes inside the auto boxes. As i say check if it shakes in N or D as well as P.

The stretched chains on our vehicles can be very bad news as they controlled by the exhaust camshaft were the front cambelt runs off. unlike the Ep3/fn2/f20c etc they can stretch but still last for thousand of miles. Not our engines sadly. The chain goes you might as well push ur car off a cliff, if the tensioner goes well dont even bother with the cliff just torch it lol.


I would take it easy mate especially if your engine is miss firing to be honest as well as hold off on the remap.

 

[keirGERS]

I have a P reg ek4 vti saloon adolesant pearl blue which only came in 97 with under 80k on the clock. 100% stock. Full honda service history My little show car. Does around 100 miles a year otherwise in dry storage. I dont mind the EG6 but im more of a saloon guy.

The rocking is either engine mounts for sure or its I think the torque converter that goes inside the auto boxes. As i say check if it shakes in N or D as well as P.

The stretched chains on our vehicles can be very bad news as they controlled by the exhaust camshaft were the front cambelt runs off. unlike the Ep3/fn2/f20c etc they can stretch but still last for thousand of miles. Not our engines sadly. The chain goes you might as well push ur car off a cliff, if the tensioner goes well dont even bother with the cliff just torch it lol.


I would take it easy mate especially if your engine is miss firing to be honest as well as hold off on the remap.

Ahhh, see I've never really been into the coops, turbo'd and got a really aggressive stance going on my old jordan. But stance plus 300 odd bhp in a small hatch just doesn't work Lol I'll try add a pic of it.

I'll try these things tomorrow buddy, and add a video of each. You seem to know your stuff when it comes to audis and to be fair, that's exactly what I need. I'd imagine you'll recognise exactly what it is when you hear it.
But I only payed, the equivalent of £1k odd for the car, so if I need to replace the engine, I'll do it in my driveway, you know.

 

[rizzini7]

Not sure if yours has one? (Assume it does) but when mine started playing up last year, shaking like hell and recording misfires it turned out to be a seized cam adjustment valve. Only after changing the clutch and flywheel did I find this out

 

[hades-]

coil pack

 

[keirGERS]

The coil packs were replaced on Friday under the outstanding recall.
I'm trying to upload some videos at the moment, do I just do it via youtube?
It's started clicking now aswel, but only intermittently. It does sound a bit like chain rattle.

 

[Giosabcsl]

You could always upload the videos to youtube and pop the link in chat.