Amk s3 fault codes help

[dusty]

Hi, I have a 2001 amk s3, with fault codes, 16684 - random/multiple cylinder misfire detected p0300 - 35-00- and 16687 - cylinder 3 p0303 - 35-00- misfire detected, I have replaced the plugs, fitted tfsi coilpacks, replaced coilpack wiring loom, fitted 008 DV, fitted catch can, visually checked the rest of the hoses for splits, I wondered if anyone has any ideas of what else I can check thanks

 

[ex911driver]

Can you post the complete log/scan?

 

[dusty]

I haven't logged any measuring blocks but the two codes are what I got when I did a full scan

 

[<tuffty/>]

Have you cleared the codes and they have come back?

<tuffty/>

 

[dusty]

Yes mate I've cleared the codes and they've come back, the car seems to be making boost ok, it does feel like a coilpack failure as I've had the coilpacks fail before, the tfsi coilpacks have been sat in my garage for 3 months before I fitted them, I wonder if one of them is faulty

 

[<tuffty/>]

Nope... don't assume its the coil packs the minute you get a misfire...

These multiple misfire codes are usually fuelling related... typically happen during cold start period when fuelling is richer and you let off the throttle as its coming on boost... also indicative of a vac leak or similar... if you have a full copy of VCDS you can view fuel trims in block 032 (not directly after a fault code reset though as fuel trims will reset also) to see if they are far out of whack...

Are these the only codes?

<tuffty/>

 

[dusty]

I've just been out for a run in the car and the problem seems to have developed a little, i now have a horrible tapping noise coming from the engine I think from the top end, when I took the oil cap off with the engine running it looked like steam coming out of the cam cover, the noise speeds up as I increase the rpms

 

[<tuffty/>]

Humm... difficult one to diagnose like this dude...

Worst case it could be a head gasket (quite rare tbh), cracked head, burnt valve, bent rod... sorry to put a dampener on things but a miss fire with a knocking noise is normally valve train or bent rod...

Does it misfire on idle?

<tuffty/>

 

[dusty]

Doesn't seem to be misfiring on idle but the noise is very worrying, I suppose the best thing to do would be to take the head off and look for damage the timing belt is almost due anyway, I can't really afford garage labour rates at the moment, are there any special tools I will need besides the head bolt socket when removing the head

 

[superkarl]

amk's are cursed im telling you!
Mine misfired, lost a cylinder, turned out to be a melted piston. No idea how or why.

Get your car checked thoroughly. How do the plugs look?

 

[<tuffty/>]

Bore scope would be less intrusive as would a compression test and leak down test really

Taking the head off is quite a drastic move especially if you don't know whats wrong as yet... you can test for a bent rod easily by removing the plugs and putting a rod/stick of some description down into the bore... check cyl 1 and 4 at TDC comparing the measurement of the protruding piece to see if they are noticeably different, repeat on cyl's 2 and 3...

You could also drop the sump to look into the bottom end to check for bent rod and signs of a piston hitting a squirter (could be what the noise is...)

Also worth removing the cam cover and just giving the valve train a once over before taking the head off

<tuffty/>

 

[dusty]

Thanks for your help tufty and Karl I will have to do some further investigations at the weekend, I had the plugs out earlier today and they were a light brown colour all 4 were similar in colour I will whip the plugs out after work tomorrow and use tuftys method to check for a bent rod, now I think it's time for a beer

 

[superkarl]

If you do or dont find anything it might be worth getting the injectors cleaned, either in an ultrasonic bath, or professionally like from mrinjectoruk, whom ive used, good service

 

[dusty]

I cleaned the injectors and fpr about 3 months ago in an ultrasonic bath, also replaced the o-rings and the plastic seats in the inlet and fitted a phenolic Spacer, tbh the noise sounds serious, definitely won't be driving the car again till I find out what has gone wrong