C7.5 A6 Melted Spark plugs and blow engine

[Helmsy]

I’ve got a 2016 A6 3.0T CREC running a stage 1 E85 IE tune. After switching to E85 for the summer I immediately had spark blowout at high RPM. I’m used to turbo cars so I knew I needed to change plugs and potentially regap. When I pulled the plugs out I found Cylinder 6 to be partly melted at the tip. I assumed it was due to age since I had not changed them in 30k. Swapped in a set of BKR6EIX since I didn’t have any 8’s handy and hoped this would fix it. However after some VERY light driving(compared to normal) I melted another plug this time on Cylinder 2. I had a dead miss and the whole tip of the plug was missing. Luckily the ceramic stayed in place. Somehow the engine survived both of these failures until yesterday. After the 6’s melted I put in some BKR9EIX, 4 steps colder than stock, and 1 step colder than recommended by IE. This alleviated the issue almost completely. You could tell the car was missing some power but was still plenty peppy to daily until I sourced a good engine. But yesterday I melted one of the BKR9EIX’s this time on Cylinder 1.

This marks 3 different cylinders to do this. I knew my engine was hurting after the initial spark plug change as I did a comp check and everything was at ~120. However, in my Honda days even when I blew my tubo’s Bseries it ran and never melted plugs even when all 4 cylinders hit low 80’s in compression. So I wouldn’t expect to be blowing plugs out simply due to low comp. If it were one cylinder I’d say injector(s) but since it’s on both banks I’m not sure what to lean towards being the cause of this. I’m very happy with my IE tune but when emailed they basically told me it’s all my fault since I didn’t have the “right” plugs in. Which although partially true now that I’ve melted 9’s I’m getting suspicious of the root cause. E85 at the station I pull from rarely dips below E70 although admittedly I did not test before the most recent fill-up(yes stupid I’m aware) however the first two sets blew when E content was tested to be at E78-E80

I’m wondering if anyone else has had similar issues to what I’m having? Any non-CREC owners had issues like this? All I’ve been able to find is new gen 1.8T that are tuned destroying plugs in a similar fashion..

Also I would love to post picture but I’m new posting on forums (this is my first post!) and I’m not sure what site to use to upload them. If anyone can point me in the right direction to figure that out I will upload some pictures!

[A6sport]

In order to post pics you'll need a host, like Fotki.

I hope you figure it out. Did you pull codes? Good luck with this.

[Helmsy]

Here are some pictures… hopefully

BKR9EIX (most recent set):
https://i.imgur.com/1b4DPXY.jpg
https://i.imgur.com/RhdlSxn.jpg

BKR6EIX (second set):
https://i.imgur.com/rK0JU3X.jpg

First plug to “break” sorry for bad quality:
https://i.imgur.com/rCLpCBK.jpg

[Mark.in.tulsa]

Are you able to scan to see if you're running lean?

Have you sent logs to IE?
Wondering if you fuel pump isn't delivering correct pressure.

[Helmsy]

In order to post pics you'll need a host, like Fotki.

I hope you figure it out. Did you pull codes? Good luck with this.

The only code my OBD11 shows is “Misfire Cylinder 1”

Depending on what I do with the bad engine when it’s out I may tear it down and investigate more. I will be swapping my new engine in this weekend and will most likely make a thread since I haven’t seen much in ways of service write ups for the CREC. The car has been rock solid until these small hiccups but I’m stumped as to why it just started doing something this catastrophic!

[VinnysS4]

In my experience his looks to either be a detonation issue, or a surprisingly lean(Hot) condition.
If the knock sensors are dumbed way down, or turned off like some companies like to do with their tunes, the ecu won't know the engine is knocking and thus won't pull the reins back in when it starts having issues.
The spark plugs look a bit dirty. I don't know how clean E85 (or whatever combination you had in it) burns but there's a lot of crap on those plugs. If you're running a K&N style filter, I'd suspect its letting in too much contamination. (Or from somewhere else on the intake system) This could lead to hot spots on the plugs. Carbon can glow bright red inside the combustion chamber. Which will cause detonation, and thus melt the plugs.
How is the oil consumption?
Can you map switch back to 91 or 93 octane with no corn and see how it runs on that? I'd suggest putting a boroscope into the cylinders and check the condition of the valves and seats.
You need to establish if the engine is running lean or rich. Do you have a way to graph stuff with a scanner or vcds?

Sent from my SM-N960U1 using Tapatalk

[A6sport]

Sure looks like a lean condition, really nasty.

[Helmsy]

Are you able to scan to see if you're running lean?

Have you sent logs to IE?
Wondering if you fuel pump isn't delivering correct pressure.

Once the new engine is in I will be doing lots of logs to get reviewed by IE. I’m hoping this is more due to an old worn out engine rather than a preventable issue like fuel pump/filter.

[Helmsy]

Sure looks like a lean condition, really nasty.

I agree, it looks very lean on the plug. Live views on OBD11 and on the new Bluetooth POWERlink showed all good. Although I know that does not tell the whole story. If it’s simply just running lean I am concerned it can get so lean to melt a 9 heat range plug without throwing a CEL or going into limp mode, especially from a tuner as reputable as IE. But I’m having faith as so many people have run these tunes before with no issues, at least that are evident on the forums.

[Speedooooo]

Sucks this happened to you. Makes me scared about running E85. I've been running E85 for about 5k miles non-stop. My car went into limp mode one time when I got on it, but that's been the only issue I've had (knock on wood). I don't really get on it that often and I'm pretty low mileage. I do wonder about the long term effects.

How many miles do you have on your car? According to IE, what are the “right” plugs? I'm still on stock plugs.

[Mark.in.tulsa]

Sucks this happened to you. Makes me scared about running E85. I've been running E85 for about 5k miles non-stop. My car went into limp mode one time when I got on it, but that's been the only issue I've had (knock on wood). I don't really get on it that often and I'm pretty low mileage. I do wonder about the long term effects.

How many miles do you have on your car? According to IE, what are the “right” plugs? I'm still on stock plugs.

I've been running it for 1.5 years now. No issue as all, other than slight hesitation when starting when the temps are low. And obviously lower mpg.
But then again when I fill up it's only around 35 bucks.

e85 tends to help clean off carbon deposits, from what I have read. Shouldn't really be doing any damages. IE and other have said the C7 have all the correct plumbing for the fuel where nothing will get corroded.

[Audibellybutton]

The problem here is your car was running lean for extended periods of time. That’s very damaging to the engine. If you do choose to run E then you should data log to see how your fueling looks. E85 is not the cause of the failure although a tune that is not properly setup for E could definitely cause that situation. You have to flow about 30% more fuel with e85 so if your fuel system is not keeping up or not flowing an adequate amount then you will run lean. I think your tuner should have informed you of this or at least on how to datalog. If you are melting spark plugs something is wrong and you should have reached out to them before allowing it to keep happening. Unfortunately it’s too late now but just for future reference

It puzzles me how you were not getting lean codes though

[Helmsy]

Sucks this happened to you. Makes me scared about running E85. I've been running E85 for about 5k miles non-stop. My car went into limp mode one time when I got on it, but that's been the only issue I've had (knock on wood). I don't really get on it that often and I'm pretty low mileage. I do wonder about the long term effects.

How many miles do you have on your car? According to IE, what are the “right” plugs? I'm still on stock plugs.

I beat on the car pretty dang hard compared to most drivers I’d say. I’ve been running the IE 91 file since about 110k and just switched to E85 at 135k ish. This happened at about 145k.
Initially I had stock plugs(the one in the red rag is a stock plug melted slightly) I reached out to IE and was told the recommended plugs are NGK BKR8EIX. I went a search the website but could not find this information anywhere. I would change yours to the recommended as it’s super easy and would be good insurance. I would also data log and send to IE to ensure everything is OK with your car. I’m hoping my issue is one off rather than to be expected. The tune is 11/10 other than my current situation.

[Helmsy]

The problem here is your car was running lean for extended periods of time. That’s very damaging to the engine. If you do choose to run E then you should data log to see how your fueling looks. E85 is not the cause of the failure although a tune that is not properly setup for E could definitely cause that situation. You have to flow about 30% more fuel with e85 so if your fuel system is not keeping up or not flowing an adequate amount then you will run lean. I think your tuner should have informed you of this or at least on how to datalog. If you are melting spark plugs something is wrong and you should have reached out to them before allowing it to keep happening. Unfortunately it’s too late now but just for future reference

It puzzles me how you were not getting lean codes though

I agree this was very lean combustion. However this tune is designed for E85 and is an off the shelf tune by IE run by many people and “can compensate for e content down to E60.” I should have been sitting at about E75 during all of this. So this shouldn’t be a fueling issue. Each time the misfire started at 6k+ RPM. But no codes or anything appeared except “misfire cylinder 1” and an EPC light which deactivated the cylinder.

I actually did reach out to IE the first time I had a plug melt. They ask what plug I was running and basically said it was because I didn’t have their recommended in. They did not request data logs or anything. Again I could not find the plug recommendation on their tune page. I’m very happy with the performance and will be sending data logs to them when the new engine is in.

My main concern as well is the lack of codes. At the point a BKR9EIX is melting cylinder temps are WELL out of spec and AFRs are going to be as well yet no code.

Hopefully the root cause can be found to prevent others from having this issue especially considering the price of a used CREC engine.

[Helmsy]

I've been running it for 1.5 years now. No issue as all, other than slight hesitation when starting when the temps are low. And obviously lower mpg.
But then again when I fill up it's only around 35 bucks.

e85 tends to help clean off carbon deposits, from what I have read. Shouldn't really be doing any damages. IE and other have said the C7 have all the correct plumbing for the fuel where nothing will get corroded.

Glad to hear you are having no issue. How many miles are on your engine and when did you tune/switch to E? Did you change plugs when switching to E?

[Audibellybutton]

I agree this was very lean combustion. However this tune is designed for E85 and is an off the shelf tune by IE run by many people and “can compensate for e content down to E60.” I should have been sitting at about E75 during all of this. So this shouldn’t be a fueling issue. Each time the misfire started at 6k+ RPM. But no codes or anything appeared except “misfire cylinder 1” and an EPC light which deactivated the cylinder.

I actually did reach out to IE the first time I had a plug melt. They ask what plug I was running and basically said it was because I didn’t have their recommended in. They did not request data logs or anything. Again I could not find the plug recommendation on their tune page. I’m very happy with the performance and will be sending data logs to them when the new engine is in.

My main concern as well is the lack of codes. At the point a BKR9EIX is melting cylinder temps are WELL out of spec and AFRs are going to be as well yet no code.

Hopefully the root cause can be found to prevent others from having this issue especially considering the price of a used CREC engine.

I understand, the IE tune is an ots map used by a lot of people some have issues some don’t but my point is without data logging you wouldn’t know if your fuel trims are out of whack or if your fuel pressures are lagging behind target. The cause could be a fuel pump tiring out or some other hardware failure or it could be the tune, but datalogging would stop you from chasing your tail trying to figure out the cause.
Hopefully ie helps you out since you are on their recommended plug now. But all the signs point to the car running lean. Just need to figure out why