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 which is earthed to the body behind the front passenger head light. A quick clean and retighten sorted the problem. Basically I could have save £250 for 10mins work.

My fault codes were,
4 Faults Found:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16685 - Cylinder 1: Misfire Detected
P0301 - 35-00 - -
16687 - Cylinder 3: Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -

Readiness: 0000 0000

I hope this helps someone in the future on the forum, afterall, sharing things like this is what it's all about!

cheers
 
There does seem to be a definite sway from the FSI being the butt of all jokes to now being considered a very viable option.

Is this in part due to the motoring press stating that its the most likely to be the appreciating classic amongst the flock or moreso the anti diesel sway over recent years.

I think the P1031 thread has done a lot to unravel the mystery around the inlet manifold and certainly in my case has made me less daunted of taking on an FSI.

I currently have 3 A2's here that I have the potential to keep as my main car (the other 2 must then be sold)

My 165k re-mapped TDI 90 that goes like **** off a shovel
A black 1.4 petrol with 70k and high spec or
A dolphin grey FSI with 50k and high spec

I feel the 1.4 is a little underpowered for my commute (up and down the welsh valleys) so I think I can scratch that one off, but I may just keep this FSI, which even a year ago would be something I could never imagine me saying.

A2Steve- on the cusp of starting an FSI journey :)
I fully agree, the FSI will indeed be the one to watch.
 
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I fully agree, the FSI will indeed be the one to watch.
Hello all,
Today I took delivery of my FSI after the fitting of a new windscreen and several small repairs, Steve sent me the little 2-holes rubber around the windscreen wipers pins and other stuff we've fitted at last. I had a hell of a good fast drive from Faenza then Bologna to Firenze, the FSI confirming to be the best of both worlds being compact, manoeuvrable, with a proper Audi interior that is on par with my A4 Allroad's AND powerful enough to make you smile if you keep it between 3000 and 5000 rpm (added bonus a very nice exhaust/engine noise) Everything was OK but the idle, despite the new plugs, injectors cam sensor etc, is still quite irregular when the engine is warm; when it's cold, it takes some turns of the starter to, well, start. What other sensor might be involved? The usual scans didn't produce any obvious clue....
Brst
Stefano
 
I’m not a mechanic so I can’t really offer advice here although agree with PlasticMac. I think your profile states your car is on 60-80k miles and this is usually when you see some issues with carbon build up (inlet/flaps/valves) which itself seems to be the start to some of these problems.

I’ve read lots on this forum and don’t know if I’m confusing myself but feel like if the carbon is kept at bay, it prolongs the life of other FSI items (other more experienced members may be able to add) so my plan was to monitor and if it gets to a point that it looks bad get it walnut blasted. I’m still however awaiting my endoscope which was a cheap import from China and probably still on a boat somewhere?
 
I’m not a mechanic so I can’t really offer advice here although agree with PlasticMac. I think your profile states your car is on 60-80k miles and this is usually when you see some issues with carbon build up (inlet/flaps/valves) which itself seems to be the start to some of these problems.

I’ve read lots on this forum and don’t know if I’m confusing myself but feel like if the carbon is kept at bay, it prolongs the life of other FSI items (other more experienced members may be able to add) so my plan was to monitor and if it gets to a point that it looks bad get it walnut blasted. I’m still however awaiting my endoscope which was a cheap import from China and probably still on a boat somewhere?

@Jeetesh, I agree 100% with your "prevention better than cure" stratagy. I replaced the coil packs on my FSI, just after I bought it, at 49000 mls. No errors, but post fitting the new, (Bosch) packs, pick up at low revs was much improved.

Hope your (Chinese) boat eventually comes in!

Mac.
 
I haven't done nothing to my FSI since my last post but realized today "check engine"-light is not burning anymore?
I haven't cleared fault codes or disconnected battery or something and the lamp is not burned either, selfhealing engine?
Still feals like sometimes drops a hard beat in 2500-3000 rpm, flaps moving or something else.
How do know if engine is doing lean burn or is it programmed away in all cars?
 
@SLEI
Unless your car has been remapped, lean burn, and the other two modes are still operational. You should get a VCDS scan to find out what is, or is not, working. A genuine VCDS scan is required, not a generic OBD scan.
Mac.
 
I haven't done nothing to my FSI since my last post but realized today "check engine"-light is not burning anymore?
I haven't cleared fault codes or disconnected battery or something and the lamp is not burned either, selfhealing engine?
Still feals like sometimes drops a hard beat in 2500-3000 rpm, flaps moving or something else.
How do know if engine is doing lean burn or is it programmed away in all cars?
I had an EML that "self-healed" last year. I can only think that for some faults after some set time period or a number cycles e.g. misfire count < N over subsequent time period T or error free 'Set Point Not Reached' = 0 after N sucessive tests THEN the ECU thinks the fault has been fixed and cancels the EML. A bit fanciful but I don't know what else to think.

The driver of an FSI has no way of knowing which air/fuel trim is current at any point in time when driving, just generalisations; low engine load and engine speed = stratified, high engine load and engine speed = homogeneous, between these two lean burn homogeneous. Homogeneous seems to kick in > about 3000rpm.

Andy
 
I had an EML that "self-healed" last year. I can only think that for some faults after some set time period or a number cycles e.g. misfire count < N over subsequent time period T or error free 'Set Point Not Reached' = 0 after N sucessive tests THEN the ECU thinks the fault has been fixed and cancels the EML. A bit fanciful but I don't know what else to think.

The driver of an FSI has no way of knowing which air/fuel trim is current at any point in time when driving, just generalisations; low engine load and engine speed = stratified, high engine load and engine speed = homogeneous, between these two lean burn homogeneous. Homogeneous seems to kick in > about 3000rpm.

Andy
You are partially correct, some MIL light warnings are programmed to clear the MIL light and just leave a 'pending code' logged in the ECU's memory, they clear the MIL after a set number of stop / start engine cycles, varies per fault code how many to clear the MIL
Other's are hard set and will not clear until done so via a code reader like VAGCOM example of this is the airbag error light, once triggered it will stay on even if you fix the fault, until the ECU is read and cleared of fault codes.

These ECU's are old school by modern day standards, but they had a lot of functunality built in

Cheers,
Paul
 
I have Ross-Tech CAN-USB and there hasn't been other faults than missfire in two cylinders and some random.
Maybe it's the lean to mean point which feels like engine misses a beat, it's usually closer to 3000 in quit steady cruising.
Last misfire blinking was about 500km ago when I filled tank and drove away, been thinking maybe there is some kind of dirt in tank but that don't explain very well why driving in highway works with different G-forces and mild acceleration makes missfires.
Dash error light hasn't cleared before even when there hasn't been any missfires for long time, sometimes it has been blinking but goes away but harder missfire leaves light on and it hasn't gone away until I read and clear codes.
 
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Happy to report, i just re-earthed my car.

I am now driving a complelely different car, for once an easy fix on the FSI.

The missfires were just getting so bad, and the car was so sluggish.

I am over the moon, my car is just a joy to drive from what it was before.

Thank you!
 
My FSI has been exhibiting misfire symptoms but not throwing error codes although I have been pretty sure it is something to do with the ignition system as the exhaust fumes were very petroly smelling. I had checked the car for vacuum leaks,changed the spark plugs and ignition coil packs all without an improvement. Had a look at this earth point under the headlamp... I think this may be the cause of the issue, the cable was totally snapped!

Not actually sure how the car was working at all, is there another ground that runs from the engine? Now to find some way of repairing this cable...
 

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Not actually sure how the car was working at all, is there another ground that runs from the engine? Now to find some way of repairing this cable...
Normally just one earth, but as yours is running it does suggest another earth is present, probably fitted by previous owner - a common practice. Just replace the earth, £40ish from Audi, TPS will be cheaper if available to you, or eBay for not much but you will have to match the spec,

Andy
 
Normally just one earth, but as yours is running it does suggest another earth is present, probably fitted by previous owner - a common practice. Just replace the earth, £40ish from Audi, TPS will be cheaper if available to you, or eBay for not much but you will have to match the spec,

Andy
50mm2 cable ordered from eBay, heres to hoping that this was the cause of the problem even though no it was not throwing misfire error codes!
 
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