[AxelP]

2018 Tiguan SEL-P there, with almost all bells and whistles here, except it is 2 rows, not 3, and some luxury missing on
the back such as heated sits and 3zone climate...
+ APR ST 1 RON 87.
Input
1. APR ST1 RON87 newly flashed
2. Long trip 3000mi with 3000lb behind in UHAULT trailer,
3. Warm fall time around 28-30 Celsious
The same incidents close conditions
4. Loong uphill overtaking with full throttle on, upshift from 3 5500rpm to 4 ~3500 rpm so more torque needed.
4.1 Next day, not the same day
Long standing idling (1h or so) with A/C on (probably heatsoaked Intercooler) overtaking traffic same story WOT + upshift from 3 to 4 again ~5-5500k rpm to ~3500krpm
got really hard loud as hell buzzing/ kind of knocking sounds from the motor, sounds like detonation but I'm not sure, and I do know how detonation sounds on N/A motors, and I'm still not sure even up to this date.
Eased up on the throttle instantly, and drove it all the way through never pushing it past 3/4 ish...or downshifting manually on the uphills etc. Rocky Mountain with heavy trailer were fun drive)
5. Later on(2 days later) got floating idle and check the engine with misfires in cyl 2. did not have spark plugs but had tools, took it apart, gaped it tighter by the eye, drove all the way to a new home without incidents but never pushed car hard.

Yes It was my stupid that I did not change spark plugs on the spot after the flash
it was at 50k km and the original spark plugs set.

6. Had not stable idle and at 55k km changed spark plugs for new original NGK, did not gapped them, left with original I believe 0.7mm gap, need to verify
Got stable idle but after 3-4k km got back to square 1 with fluctuating idle it jumps in between 760 to 815 rpm and I can hear and feel it!
Now, there is not a lot of load on the car currently, just drive around the town, never push it to the limits and not towing anymore for now.
7. It was not a GAS quality for sure as I used RON93, all the way, because of tune, and because I want to be extra sure, still did not help...

Questions
1. APR knows nothing, the response is "it is not us, it is you"
2. How to diagnose what it was and what to do with it?
I was not able to find misfire counters in VCDS, can someone point me to it?
How to measure ignition retardation with VCDS in our motors?
Budackh cycle is tricky with variable compression cycle... I saw it fluctuate all the way from -26 at idle to 0 trying to understand how to properly measure it.
3. Will colder spark plugs help? Can someone point me to the recommendations? ignition coils possibly?
currently, the car drives 3-5 km day max, occasionally 50-80km just around the town. Does it make sense to go colder spark plugs...
But in the summer planning to have a small camper towed into the mountain, do not want to repeat what happened above and blow up the motor...

And yes Tig is capable of towing non-braked 3000lb safely, yes you need to take it steady above 3500lb would be a question of sanity...might try braked up to 5000lb - but the engine (more of a gearbox actually) will struggle in a mountain with that.
The gearbox on the longest hill in Rocky got up to 119C at 110 km/h (65mi-ish) and the engine still had an extra to go faster, but I did not want to push it.
The trip was migration from Toronto to Vancouver if anything.

 

[RatBustard]

lot going on here.

• so you didn't replace spark plugs or coils before you tuned it? most ECM tunes recommend that and if not, it's good practice. you don't need fancy coils, so new OEM coils are fine. if you're at altitude you should be fine with factory spark plugs, but you may want to reach out to APR to see if they recommend a direction cooler or hotter.
• where does VW state the 3000 lb pound towing capacity? North American towing capacity is listed at 1500 lbs - maybe find a different tow vehicle or tow/haul less. certainly hope you're not going to try towing 5000 lbs.
• you're talking about mountains - are you at altitude? what are you're A/F ratios? your tune is for 87 octane but you're using 93 octane fuel? flash it to the base 93 octane tune from APR if you're going to use the 93 octane fuel. you're probably fine, but you have so much going on, you need to step through a few things to eliminate anything on the fault tree.
• 3-5km a day is not enough time for the engine to ever get up to operating temperature. I would recommend warming it up to operating temperature and going for a 15-20 minute drive at least once a week.

 

[AxelP]

lot going on here.

• so you didn't replace spark plugs or coils before you tuned it? most ECM tunes recommend that and if not, it's good practice. you don't need fancy coils, so new OEM coils are fine. if you're at altitude you should be fine with factory spark plugs, but you may want to reach out to APR to see if they recommend a direction cooler or hotter.
• where does VW state the 3000 lb pound towing capacity? North American towing capacity is listed at 1500 lbs - maybe find a different tow vehicle or tow/haul less. certainly hope you're not going to try towing 5000 lbs.
• you're talking about mountains - are you at altitude? what are you're A/F ratios? your tune is for 87 octane but you're using 93 octane fuel? flash it to the base 93 octane tune from APR if you're going to use the 93 octane fuel. you're probably fine, but you have so much going on, you need to step through a few things to eliminate anything on the fault tree.
• 3-5km a day is not enough time for the engine to ever get up to operating temperature. I would recommend warming it up to operating temperature and going for a 15-20 minute drive at least once a week.

I'm crazy but not with safety)
Tiguan is good as all rounder + some ocassional towing.

Not really a lot going on, once you know what you are doing. That is why I gave looong input here)

1. Yes spark plugs was my bad, but at 50k km I would expect them being resonable and not 100% destroyed. As it turned out even the gaps were still there. I could potentially blame it on the plugs when I got detonations/hard misfires, but it is hard to beleive.
Felt more like a car was heatsoacked to death or something in both cases very possible...
Unfortunately did not have any devices to check data at that moment.
Altitude does not matter that much as car is l4 turbo + direct injection, would not blame it on thinner air at around 2500m elevation.
More if it would be 4000m yes, possible... I live almost at sea level now) no blame on the altitude at all.

2. VW Tiguan L in ROW and Tiguan NAR are structurally 100% identical, in Europe they allowed up to 2500kg with 10% hitch weight at 80km/h which make 100% sense for me to interpolate it to the NA standarts. I have proper hitch setup which can hold up to 6000lb per manufacturer specs. 2700kg if anything. 2" receiver + 1 7/8 ball on it for compatibility I think.
I do not beleive in **** sheet standart limited by NAR outdated standarts, there is full discussion our there about it.
With my own experience 1400kg loaded UHAUL ****ty 5x8 trailer full to the brink was just perfectly fine, I went through the skales to weight it, out of curiousity.
Heavy yes, but no sway up to 130 km/h, solid as rock, even though trailer jumped around a bit because of collapsed suspension on the trailer... load on the hitch was around ~100 kg I was not able to pull up tong myself easy. No wind sway either, to my wonder though)
Suspension sag was about normal, guestimate 5-7 cm, but hard to tell, car was not squatting at all.
And I did not race it with full car and family max we go was 120km/h straight and 100-110 km/h in the mountains with downhills reduced to 80~60 sometimes, engine brake etc.

3. A/F does not matter, computer suppose to compensate for itself + turbo, all wonders of the modern engines? Same as 93 octane was just for the sake of sanity and not getting in to situation I've got myself with detonation/misfires... 93 is always better then 87, especially on turbo, I'm not going with 93 tune though, want to have that cheaper option for gas, becasue prices are already crazy enough, although the way it runs on 87 like a diesel...personally not a big fan.

4. I warm up car to full operating temperatures every time I drive it, 3-5 km enough to warm it up, if it is uphil, with 2-3 traffic lights + our engines have cooled exhaust manifolds, yes it is thrue...it helps a lot to get up to temperature quickly.
Not floring it cold, but driving it moderatly normal + 30s-1min idle on start to get oil running + 3 min to get out of underground warm parking etc...

APR guys just use common exuses not to give any advice. I totally get it, but still...
The problem is that it is clearly misfiring now at idle again with new plugs after 3k km, not a lot to trigger check engine, but enough to cause rpms to fluctuate at idle. on brand new fresh plugs all was smooth as butter.
So my question remains, did somebody went colder plugs and coils after the tune?
And questions above about diagnosing misfires too.
I know there is a misfire counter per min somwhere, if it reaches certaing values it triggers chek light, can somebody point me at where it is in VCDS or something like that
I know that it is possible to determine engine performance by ignition timing retardation in degrees, ideally it should be 0 or close to 0. I found the data, but it does fluctuates all the way down to -26 degrees so I wonder if it is normal for B-cycle engines, and how to test it properly.