Fuel Cut/Misfires WOT?

4.0 V8 40v biturbo TFSI - 553 bhp
4.0 V8 40v biturbo TFSI - 597 bhp (Performance)
becausephilchow
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Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 20, 2018 5:01 am

I've got:

Eventuri Intake
HMS Full Exhaust (Downpipe, 200CEL Cats, Catback)
Simon Motorsports Stage 2 ECU Flash

Car pulls like a freight train, immense power. However, noticed yesterday when I went WOT, it would...feel like it's fuel cutting/misfiring? Feels more like a misfire than a fuel cut.

Car has 45,000KM (27,000 Miles). Thinking of just changing out the plugs, and maybe the coil packs, and other thoughts?

Anybody else ever encountered this?

RS6chris!
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Re: Fuel Cut/Misfires WOT?

Post by RS6chris! » Tue Feb 20, 2018 7:32 am

Twice with my Litchfield mapped car....albeit under medium acceleration?

EML winking at same time.

Put itself right though within a minute or so?

Also revs used to hunt on cold start really bad.

I blamed map.

Think yours will be coil pack...did you see if EML light was on?
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dasquade
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Re: Fuel Cut/Misfires WOT?

Post by dasquade » Tue Feb 20, 2018 11:03 am

from my just discovered and hopefully fixed powercuts...
1. check exhaust for leaks (loose bolts for example, mine came loose between catless downpipe and milltek exhaust :().
2. do you encounter those powercuts always or fuel tank level related (yesterday with tank on reserve i had the powercuts, today with full tank....express train again!)
3. must of been 1. check for codes and check your misfires.
4. still on original plugs (no 'colder plugs' and still on first set?)
5. warming up the car and making sure oil temps are at operating temps is kinda a must on these engine, otherwise misfire happy :(.
6. might want to make sure you have the latest factory/oem ecy update

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 20, 2018 3:52 pm

RS6chris! wrote:
Tue Feb 20, 2018 7:32 am
Twice with my Litchfield mapped car....albeit under medium acceleration?

EML winking at same time.

Put itself right though within a minute or so?

Also revs used to hunt on cold start really bad.

I blamed map.

Think yours will be coil pack...did you see if EML light was on?
No CEL or anything yet. Drove it again today, and then same thing. I feel like it does it at 3/4 throttle too. Doesn't seem to do it around 1/2 throttle though.

Car is booked in for new plugs on Monday, will also swap the coils if needed anyways. Been a VAG driver for a long time, I know the coils eventually <beep> themselves. Just picked up the car, so, I always assume nothing's been done by the PO anyways.

Was dealer serviced, but they won't release the records to me without the previous owner writing a letter, and then it take a 14 business days. Load of crap. Might as well just replace it all myself.

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 20, 2018 3:55 pm

dasquade wrote:
Tue Feb 20, 2018 11:03 am
from my just discovered and hopefully fixed powercuts...
1. check exhaust for leaks (loose bolts for example, mine came loose between catless downpipe and milltek exhaust :().
2. do you encounter those powercuts always or fuel tank level related (yesterday with tank on reserve i had the powercuts, today with full tank....express train again!)
3. must of been 1. check for codes and check your misfires.
4. still on original plugs (no 'colder plugs' and still on first set?)
5. warming up the car and making sure oil temps are at operating temps is kinda a must on these engine, otherwise misfire happy :(.
6. might want to make sure you have the latest factory/oem ecy update
1) Will have the Shop take a look on Monday about the exhaust being tightened and stuff, thanks for the suggestion.

2) Over 1/2 tank always.

3) So far no CEL, but maybe a stored code. Booked in for Monday, so they'll be able to find something if there is an issue.

4) I reckon it is. Doubt th dealer recommended the previous owner to change. Do people recommend 1 step colder NGKs for Stage 2?

5) Yup. Car is always warm before fully beating on it, always a habit of mine.

6) I'm Stage 2 flashes, so don't think that update would apply to me?

Will keep everybody updated on the fix! Hopefully some new NGK Colder Plugs and then maybe some new packs fix the issue!

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 20, 2018 3:58 pm

Anybody have a PN for the 1 step colder NGK Plugs?

And what they should be gapped to?

dasquade
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Re: Fuel Cut/Misfires WOT?

Post by dasquade » Tue Feb 20, 2018 10:48 pm

NGK R7437-9, APR recommands gapping them on 0.6mm - 0.024" (but mines came out of the box correctly gapped) like that).

Personally i recommand (everybody) to buy obdeleven (sadely android compatible only). It costs +-40-60€ and it is a phone app with obd bluetooth dongle.
It allowed you to scan your car, access modules, data log and even programming (some stuff are even 1 click pre programmed apps :) ).
Super handy and have it in the car always (scanning the car monthly). It almost should be a must imho.
*once had a broken turbo sensor, it didn't threw a display code or limp mode. Only felt the car weaker....a quick scan showed me it was the sensor. Simply stuff like that but otherwise you might of ignore for a good week or untill you finally figuer something is really odd and decide to go to the stealer.
Anyway, just saying, simply scanning the car can already tell you alot without putting a step in the dealers garage....

OEM plugs are normally good for 60.000km but since you tuned and stage 2, i would recommand reducing that too 30.000km and indeed maybe go for the NGK race plugs.

Well it depends, most tuners altough they say they 'custom tune' the car, most of the times they start with your current software and tune it based on that version. Big tuners like APR still kinda tune the cars on older software (if not mistaken), at least there is the famous cylinder 5 issue that is currrently beeing ironed out....from what i read and heard, the latest OEM software kinda adressed the misfiring issues.
No RS owner here and don't know about your tuner, if you are UK person i would recommand MRC :).

Anyway, good luck :).

PS: how is that eventuri intake doing? :)

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Wed Feb 21, 2018 3:05 am

dasquade wrote:
Tue Feb 20, 2018 10:48 pm
NGK R7437-9, APR recommands gapping them on 0.6mm - 0.024" (but mines came out of the box correctly gapped) like that).

Personally i recommand (everybody) to buy obdeleven (sadely android compatible only). It costs +-40-60€ and it is a phone app with obd bluetooth dongle.
It allowed you to scan your car, access modules, data log and even programming (some stuff are even 1 click pre programmed apps :) ).
Super handy and have it in the car always (scanning the car monthly). It almost should be a must imho.
*once had a broken turbo sensor, it didn't threw a display code or limp mode. Only felt the car weaker....a quick scan showed me it was the sensor. Simply stuff like that but otherwise you might of ignore for a good week or untill you finally figuer something is really odd and decide to go to the stealer.
Anyway, just saying, simply scanning the car can already tell you alot without putting a step in the dealers garage....

OEM plugs are normally good for 60.000km but since you tuned and stage 2, i would recommand reducing that too 30.000km and indeed maybe go for the NGK race plugs.

Well it depends, most tuners altough they say they 'custom tune' the car, most of the times they start with your current software and tune it based on that version. Big tuners like APR still kinda tune the cars on older software (if not mistaken), at least there is the famous cylinder 5 issue that is currrently beeing ironed out....from what i read and heard, the latest OEM software kinda adressed the misfiring issues.
No RS owner here and don't know about your tuner, if you are UK person i would recommand MRC :).

Anyway, good luck :).

PS: how is that eventuri intake doing? :)
Thanks for the NGK P/N. I picked up the car completely stock, but, in HK, we have a lot of stop and go and everything, so maybe that takes a toll on the Spark Plugs a bit more. Either way, they're not too expensive, and I'll get them done anyways. Hopefully if fixes the issue.

I actually have a little OBD Bluetooth Dongle, have to see if I can still find it. Know if I can use another Bluetooth Dongle with the OBDEleven? Not sure if mine was for iPhone or Android though, so maybe i'll just order a new one. Agreed, I've had this on my other cars, and it's been pretty good for me, so, probably worth it to pick one up that works with the RS6. Luckily, my Shop doesn't charge me anything to scan and stuff, but, it is a hassle to have to swing by and get it all done.

I'm in Hong Kong, so unfortunately can't swing by MRC! Interesting. I assume the dealership will be the one to flash the OEM Software? Or, is that something that can be downloaded and flashed yourself? I used to have a E90 M3, and we could flash "OEM-Software" and stuff ourselves.

Oh, and on the Eventuri. I don't really have anything else to compare it to, since I installed the Eventuri and the HMS and Tune at the same time. However, my Shop has done the same Simon Motorsports Stage 2 Tune and HMS Full Exhaust on another local C7 RS6 before, and, without a doubt, he says mine definitely faster. As for how much faster, I really can't comment on that. However, Eventuri does have a very good track record of actually making power gains on the Dyno, both by their own, and by independent Dynos on other vehicles, so, I'm inclined to believe their numbers. I believe they quote around a 20-30HP increase, which, I definitely could see.

Is it worth the money for it? Not too sure for others, but, it looks great, and I'm very happy with it, so, worth it to me!

I'll see if I can find that other RS6 that has the HMS/SMS Stage 2, and run him, to see.

For anybody else interested, I also had Simon Motorsports tune my TCU (Transmission), and, I can tell, 100%, that it made a better difference. It no longer upshifts on redline if I'm in Dynamic, and, the shifts are firmer and shift faster, and, I used to notice at low speed, it wasn't the smoothest thing, maybe had some speeds where it was slightly jerky, but this definitely improved all of that. Well worth it IMO!

dasquade
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Re: Fuel Cut/Misfires WOT?

Post by dasquade » Wed Feb 21, 2018 9:57 am

Yup cant go wrong with new spark plugs especially tge one step colder.

Obd eleven is android only.

Most bigger tuners can actually perform oem software upgrades aswell, but the key thingy is they back retune the car based on the upgraded software (lots of parameters).

Good luck :)
*please report back as it might help others ;)

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Wed Feb 21, 2018 1:59 pm

dasquade wrote:
Wed Feb 21, 2018 9:57 am
Yup cant go wrong with new spark plugs especially tge one step colder.

Obd eleven is android only.

Most bigger tuners can actually perform oem software upgrades aswell, but the key thingy is they back retune the car based on the upgraded software (lots of parameters).

Good luck :)
*please report back as it might help others ;)
Yup! Booked in for Monday, will pick up and swap in the new NGK Plugs. If anything, will also swap in new coils, I'll keep everybody posted! :bigwave:

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 27, 2018 9:50 am

Nope, not the plugs. Didn't solve the issue.

No codes, no nothing. Shop seems to think it's maybe the Fuel Pump. Anybody run into fueling issues with their Stage 2 tune before? They said they had a CLS63 AMG with similar issue before, changed the fuel pump, and it was fine.

I know AutoTech has an upgrade for the HPFP, anybody haev any experience with it?

dasquade
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Re: Fuel Cut/Misfires WOT?

Post by dasquade » Tue Feb 27, 2018 10:48 am

All pipes (exhaust-downpipes) still bolted tight? Leaking exhaust can throw of the lambda sensor...
Did they try to live log the fuel pressure rails?
Tune based on latest oem ECU software?

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Tue Feb 27, 2018 2:32 pm

Yes to all.

Seems the car is pulling timing, but only around 5000RPM+ on WOT essentially.

Sent logs to tuner, will report back shortly!

dasquade
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Re: Fuel Cut/Misfires WOT?

Post by dasquade » Tue Feb 27, 2018 4:29 pm

Then i suppose it is tuning related, hope they sort it out :).
*could also be the eventuri airtake...get ride of it asap...i volentair ;)

becausephilchow
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Re: Fuel Cut/Misfires WOT?

Post by becausephilchow » Wed Feb 28, 2018 4:09 am

Yup, car back at the Shop again today for some extra logs. Tuner asked for them.

Not too worried about it, should be solved pretty easily!

Heh, love the Eventuri Intake, it's so beautiful!

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