118TSI Misfire Count

[The_Hawk]

I’m posting this in here in the hopes that someone can answer the question (it also means I keep it out of the public forum for the moment too (just in case).

Driving home the other day I had a momentary splutter on hard acceleration (with a cold engine) leave a car park. There is a 50/50 chance it was TCS kicking in rather than anything else, but it got me looking into these things a little closer.

While playing with my Polar FIS I noticed the misfire detection and misfire count so have been watching them closely.

From what I gather one of the counter is misfires in the last xx/minute/second or what ever it is. (Or maybe it’s a 0/1 = No/Yes for misfires detected in the last time period).

In either case watching the report for cylinders 1 - 4 I see a zero become a 1 every now and again on my drive to work. (About 10km so on a stone cold engine for most of the way). I get one, maybe two misfires detected.

Then there is the culmlative count (not sure if you can reset the count (or when it was last done if you can), but I’m up to about 1500 on each of the cylinders and the car is about to about 16,000km.


I’m running a stage 1 APR tune and yes I always run 98, although with 10 km a day each way for the vast majority of it’s life the fuel can sit in the tank for a month sometimes. (then there’s Wakfield Park or WSID on occasion too).


Are misfires expected/normal with this engine, especially running higher boost??
Is ~1500 in 16000km acceptable?

I understand this could potentially be a failing coil pack or even the first signs of a bigger issue… but then if it’s normal… maybe it’s nothing??
Anything else I should test/check?

Plan B is to ask the dealer and see what they say?

[tigger73]

The ecu registers misfires but you have to exceed a certain threshold before you get a cel and stored fault code.

I believe the autopolar only displays the count over a period so that is why it shows 1 and then back to 0.

I'd be hooking up VCDS and checking if there's any misfires being logged. If so you may have some recourse going back to the dealer (like getting some new coil packs). But you'd probably want to be "stock" when you go back to a dealer if you don't want ot have your car flagged with VW.

Would be interested to find out if you have the same fault without the tune. Is your APR tune switchable?

[The_Hawk]

I haven't had a chance to pull out VCDS yet, but it's on the list of things to do. I have no CEL and I don't even notice anything when FIS notes a miss so I don't expect any errors, but plan on checking anyway.

Yes the tune is switchable so I'll flick it back to stock and see what happens. These one off's are happening what seems like a couple of times a trip so I should see very quickly if that stops them or not.

Given I'm seeing 1 or 2 misses in the 10km trip that means it's currently hitting say 20 per 100km meaning either the rate is accelerating or they are a new issue possible indicative of a failing part.

I'm interested in if anyone knows what that threshold is and if it's a culmative count or if it's a particular amount in a particular time frame that would set of a CEL... maybe questions for the dealer.

[tigger73]

I doubt you'd even feel one miss - particualrly if it happened at cruising/light loads.

Do you know if it happens on the same cylinder or does it jump around?

Sorry can't help on the misfire# to create a CEL - that info was just off autopolar forum and seems to be bandied about the web in other places too so likely that's how it works. I'd imagine that one misfire isn't going to throw a CEL.

The only thing I can suggest is to drive it harder to see if you can get a CEL and then take it to the dealer

Though in reality I don't think it's a major thing if there's the odd misfire, but yours does sound to be a bit on the high side I would have thought. Best to ask someone that knows - I could be totally wrong

[The_Hawk]

Well I had a fun afternoon...

Scanned it all up with no errors and I have also confirmed that the Autopolar is just displaying existing measuring blocks. I can read the same values with VCDS. There are about 1,400 to 1,500 misses on each cylinder in total. The other figure is misses per 1000 revs which is why it goes to 1 (I saw 2 this afternoon too) then back to zero (presumably when I have done more than another 1,000 revs since the last miss.

But the fun part.

I tried to turn on the APR tune and it wouldn't let me, thinking it might be the AutoPolar I decided to remove it and somehow managed to completely kill my car. I checked all the fuses and no dice. Roof down, windows down I couldn't start it, I couldn't put the roof up or the windows *eeek* Plugging in VCDS saw no comms at all so here I am thinking I had destroyed the canbus or something.


Called VW Assist and had someone sent out, but while I was waiting I rang and spoke to Mr White who pointed out it was likely just a fuse. So I went over them all again and must have somehow missed the busted one. Dropping a spare in and BAM everything was running again although I had errors across virtually all the modules?? In any case they were cleared and all is well again. ... about 10 minutes before the VW assist guy showed up. On the upside he gave me the needed 5 amp fuse (the smallest I had was 10).

I've now also worked out that the APR must have somehow fallen into lock mode... possibly from accidentally pressing buttons or what I don't know. So now I have to re-install the Autopolar box, switch back to stock and see what happens.

I have also booked the car in for the dealership to look at it... although their next appointment is the 24th of Feb. I don't think they are going to find anything at all and all I really need is someone to tell me what's normal... but then maybe the VW machine auto flags the number and tells the trained monkey... I mean technician what to test and/or replace.



On a side note, I'm going to go out on a limb and say the spark plugs haven't been changed ever... so two years in I suppose that's as good (and cheap) a place as any to start swapping things out to see if things improve.

[AdamD]

Hey Aaron,

A few things:

As you're seeing misses in all four cylinders, I'd say that's almost a good sign. Repeated misses in a single cylinder might be a sign of a single failed (or failing) coil pack or plug, and likewise rough running and a single cylinder might be indicative of a loss of compression and engine damage. All four seems to suggest something else. Knowing what we know about the behaviour of the 118 and its propensity to run lean as **** when cold, I wonder if it's just a characteristic of the engine.

Have a look through the Mk6 section for threads on spark plugs for the 118; a member in the UK with a 118-powered 'Roc had quite a few problems with misses, and ended up tracing it to plugs with poor tolerances; he's posted a lot of info about getting better plugs, and possibly also altering their spacing slightly to get better firing. Let me know if you can't find anything and I'll have a hunt around.

When you take the car for a longer drive, over, say, 60+ minutes, do the misfires stop altogether, or decrease in frequency?

A thought: Do you have lambda on any of your FIS screens? If so, have a look, and see what sort of numbers it displays when the engine is cold, versus once the cat is hot and it's properly up to temperature. I've been watching lambda like a hawk on my GTI at the moment to get an idea of what it tends to sit on (my car is running stock at the moment - I switch it to stock over the summer months here in Adelaide), and although the figure is always moving around, it's mostly in the 0.97-1.01 range, occasionally dropping to 1.03 for a moment (and 1.99 when off throttle - which presumably indicates no fuel). Does the 118 show similar numbers normally? As an aside: I've even seen it dip to ~0.75 under WOT - and here I thought running that rich was solely a Japanese thing...

Ref the tune, IIRC the ECU will automatically default to the stock program (well, program 1) and enable the ECU lock if power to the ECU is interrupted for an extended period of time? Your fuse moment may well have enabled that default behaviour ("I'm being serviced by a dealer; best to play it safe"). Also, don't forget that the VW systems can now detect a tuned ECU even if you're locked and in stock mode. Now that I know this, I don't even bother switching back to stock when taking my car to the dealer anymore, although I'm out of factory warranty. If you want to play it safe (and you know your car hasn't yet been flagged as TD1), maybe head over to your APR dealer and get them to flash it back to stock completely before heading in to VW. If you're concerned about engine longevity and anticipate follow-ups/replacement parts may be in order, it's probably worthwhile - it certainly will reduce the likelihood of the dealer being difficult.

[The_Hawk]

The way mine is tuned program #1 is Stage 1 and #2 is stock (#3 is valet)... so disconnecting the battery only ends up back to stage 1.

ATM I'm back to stock tune and have the PolarFIS out. I'm looking to see if I can monitor those parameters from an Android tablet via a bluetooth OBD port dongle (so I don't have to keep plugging in and out the FIS). Torque Pro doesn't seem to show that parameter so I'm toying with some other apps to see what I can see.



Interestingly RossTech now have a WiFi adaptor so you can use an iPhone or laptop or android device.
There is the $499 "unlimited VIN" version or a 10 VIN job at $399.
Ross-Tech Store: HEX-NET WiFi Interface - unlimited VINs

Still bloody expensive compared to the USB model and I assume the 10 VIN one locks you out on the 11th VIN.
Great for private use, painful if you share it around.

[tigger73]

Just a quick one re autopolar. If you want to use an OBD port tool at the same time you can - just make sure you're off the FIS screens on your MFD and you'll be fine. The autopolar will only request data when you're on the screens. All other times it isn't requesting data so won't stuff up your VCDS.

The other option is to leave the FIS+ in but turn it off. You can do this through the menus. To turn it back on move onto your phone screen and press the ok button for 30 seconds and the unit will switch back on.


Sent from my iPhone using Tapatalk

[The_Hawk]

Yeah, I've done VCDS with it in place before and as you say you just have to have it on another screen and it's all good.

I had all sorts of problems getting the tune to switch with the autopolar unit in place but I'm starting to think that was user error on my part pressing the wrong combo mixed with a lock I didn't know about... put it back in tonight and it allowed me to switch tunes and has been reporting nicely. I've only done a few KM's (around the block and back) to make sure it's all working, but no misses showing on the stock tune so far. Will keep driving like this for a bit and see what happens.

On a side note, wow does the stock tune suck balls.

[Transporter]

Yes, something similar happened to me when I've fitted AP to our Tiguan. I forgot to exit the AP screen and when I went to clear the codes with VCDS I got some undesirable affects (no start). After that, I've decided not to use the AP, just in the case that the device would fail while driving, since you could end up stranded. Haven't said that, I was quite pleased with the amount of information you can get from AP, especially when fitted to TDI with the DPF, very, very useful.
But as I said, should the AP fail while my wife drives the Tiguan (99.9% of the time), I'm not sure if she would be able to remove the glovebox and the AP with the wiring to get the car going again.