[JOutterbridge]

Ran into a couple issues with my car the last week, not sure why. Stock 2013 R spec with 120k miles.

I was driving home from work after filling up on 93 and as I went up an incline in 3rd the engine stuttered and I heard a metallic sound. Seemed to come from the left side (driver) of the car. I eased off and it went away. Happened again the next night getting on the highway going up an incline. This time it was faint at around 3500 rpm but I lost power but my boost was still at 14 ish psi. Sounded like I had a boost leak and I heard the metal sound again After thinking about it a bit I decided to change the plugs out (10k miles ngk 1 step colder) I put the stock ones back in and the car had the same miss but less noise, missing around 6000RPM but only in 3rd gear, not 2nd or 4th or 5th. Figured it was spark blowout so I changed the gap to .028 instead of .034. Noted that the old and new plugs looked perfect except for the black carbon around the metal thread surface. With the plugs re gapped I drive again and this time I finally get smoother acceleration under partial throttle but I got knock at around 4k RPM again. It doesnt throw any codes but my Torque app log showed .5 knock and 1.5. It immediately took timing down from 12 to 7 degrees but was smooth after that. A small hiccup compared to before.

Anyways studying my logs to find out why i'm suddenly knocking. AFRs are the same as always 10.3 at the richest and near 10.8 at redline. Intake temps 70 to 90 degrees on all my logs. Cylinder temps 1600 max after cruising, in throttle 1500 down to 1350 as boost increases. Timing 9 degrees to 11 or 12 at redline. So all normal so far. Except my boost pressure. Normally it maxes out at 18.7psi. On my log I see a spike to 20.7 and 21.3 at my shift points (tip in). Do I have bad 93 gas? Dont tuned cars see 20psi at more timing than my stock 11 or 12 degrees? Could my wastegate be going bad? Engine rattling does seem to be louder recently. I'm kinda confused as to why after 2 years i'm over boosting if I don't ease into throttle after shifting. I'm fine if i shift and start wot under 3500RPM. It's only at high RPS shifts it spikes and makes bad noises

Sorry for the long post, wanted to include all info.

 

[Red Raspberry]

Does your car have a factory WB for the primary O2?

 

[JOutterbridge]

Does your car have a factory WB for the primary O2?

Factory. All stock including exhaust. I wish I could upload my log somehow:/

 

[Red Raspberry]

If it has the WB maybe it is getting near the end of it's life at 120K

 

[JOutterbridge]

If it has the WB maybe it is getting near the end of it's life at 120K

Ok I'll check into that. AFR's are staying as close to commanded but I'll watch them. It's always more lean with higher exhaust temps on the highway cruising/in vacuum than on the street going under 50MPH.

 

[JOutterbridge]

Just as a follow up, I ran some testing with E30 (blended 4gal with 93)

The overboost 22psi spike seems to be gone and it drops back down to 19.1psi at 6000 RPM to redline. No knock as seen below. Timing is up 2 degrees from my previous post as intake temps are down 30 degrees. No more strange noises or missing. Everything very smooth so definitely something with the gas I got or perhaps the exhaust was too heat soaked from traffic and a long drive. Either way I tested when 85 degrees out on the E30 and everything is ok as well. Tank will be empty soon and I'll fill back up on 93 at my normal gas station instead of the one near my job.

 

[JOutterbridge]

Click on pic to expand, couldn't upload so I took a screenshot. Top row shows the categories starting with knock and AFR, exhaust, coolant etc.

 

[[email protected]]

Ran into a couple issues with my car the last week, not sure why. Stock 2013 R spec with 120k miles.

I was driving home from work after filling up on 93 and as I went up an incline in 3rd the engine stuttered and I heard a metallic sound. Seemed to come from the left side (driver) of the car. I eased off and it went away. Happened again the next night getting on the highway going up an incline. This time it was faint at around 3500 rpm but I lost power but my boost was still at 14 ish psi. Sounded like I had a boost leak and I heard the metal sound again After thinking about it a bit I decided to change the plugs out (10k miles ngk 1 step colder) I put the stock ones back in and the car had the same miss but less noise, missing around 6000RPM but only in 3rd gear, not 2nd or 4th or 5th. Figured it was spark blowout so I changed the gap to .028 instead of .034. Noted that the old and new plugs looked perfect except for the black carbon around the metal thread surface. With the plugs re gapped I drive again and this time I finally get smoother acceleration under partial throttle but I got knock at around 4k RPM again. It doesnt throw any codes but my Torque app log showed .5 knock and 1.5. It immediately took timing down from 12 to 7 degrees but was smooth after that. A small hiccup compared to before.

Anyways studying my logs to find out why i'm suddenly knocking. AFRs are the same as always 10.3 at the richest and near 10.8 at redline. Intake temps 70 to 90 degrees on all my logs. Cylinder temps 1600 max after cruising, in throttle 1500 down to 1350 as boost increases. Timing 9 degrees to 11 or 12 at redline. So all normal so far. Except my boost pressure. Normally it maxes out at 18.7psi. On my log I see a spike to 20.7 and 21.3 at my shift points (tip in). Do I have bad 93 gas? Dont tuned cars see 20psi at more timing than my stock 11 or 12 degrees? Could my wastegate be going bad? Engine rattling does seem to be louder recently. I'm kinda confused as to why after 2 years i'm over boosting if I don't ease into throttle after shifting. I'm fine if i shift and start wot under 3500RPM. It's only at high RPS shifts it spikes and makes bad noises

Sorry for the long post, wanted to include all info.

Recheck the gap on the plugs..Set them OEM SETTING. I HAD THAT ISSUE WITH MY 13 3.8V6. My issue was the same. After changing plugs and, gaping them to OEM SETTING..Drove like a new coupe again.

 

[JOutterbridge]

They were initially the 1 step colder .032 for about 15k miles. I did replace them with stock plugs which are twin tip .040. They were missing above 15psi too. That's when I started to gap down, finally stopped missing after I got below .030 (.28/.28)

No issues the last few weeks aside from the strange low RPM noise at idle and under 2k while accelerating. I think its wastegate rattle because it's noisiest at startup and low load. I can hear it on bridges and through tunnels Sounds clackety.

 

[Gaijinn]

Gap all colder better than oem plugs at .028
2.0T's and 3.8's
HKS,NGK racing, all .028 gap. Its a sure thing.

Hotter temps with a little spike in boost will visit you with "knock". Octane increase is the best surest way for this not to happen.

 

[JOutterbridge]

Currently gapped at .028 on Denso twin tips for the last 2 weeks. Plug color on all 4 look perfect. No issues, or missing since.

I've never ran under 93 octane. Boost levels have restabilized somehow at 19.3lbs. E30 no longer needed thankfully. Still hear the wastegate rattle at startup and under 2krpm though

 

[Gaijinn]

E30??? Woah. Yuk. Commit either way. What I mean by that is:

1. Fuel mix a no ethanol 91 with aromatic solvents to make at good 96 or 98 octane. If you need the recipe I can give it o you.
2. Go full E85,....tune, lines, bigger injectors if your a 2.0T,(not needed for 3.8).

 

[JOutterbridge]

E30??? Woah. Yuk. Commit either way. What I mean by that is:

1. Fuel mix a no ethanol 91 with aromatic solvents to make at good 96 or 98 octane. If you need the recipe I can give it o you.
2. Go full E85,....tune, lines, bigger injectors if your a 2.0T,(not needed for 3.8).

Good advice but for my car E30 is alright. I'm stock power level, I don't need upgraded anything. 93 octane is enough for me as far as I know. I've run up to E50 by mixing 93 and E80 before. Totally unnecessary but premium gas is $3.10 vs $2.02 for E85. I like to add a little ethanol in the summer only for safety. Definitely not needed though, used it recently for diagnostic only. I have other cars that run flex fuel so I know what i'm doing with it

 

[JOutterbridge]

Updated after 15000 miles again. Denso IKH20TT(stock) first picture vs the 1 step colder Denso IKH22 2nd picture. Mostly everyday driving and highway cruising 93 octane pump gas. Cylinder 1 to 4 is left to right. I felt like on the stock heat range cylinder 4 can detonate easily? I put colder plugs back in. As you can see they carbon foul quite a bit. Definitely rich but nearly the perfect temp for cylinder 4 which is my main concern. I'm thinking this is the safer route long term. Gapped to .024 this time because after 15k miles at .028 I started getting slight missing at high RPM. Gap after removal showed .033 after pulling them out.

 

[Red Raspberry]

Have you thought of mixing the two plugs, coldest on 4?

 

[AKGC]

cylinder 4 being rich?
cylinder 4 is usually lean, due to the fuel rail and intake manifold design.

 

[JOutterbridge]

Have you thought of mixing the two plugs, coldest on 4?

I didn't think of it but I'm not sure if that could affect the ignition system or timing somehow? Unless every spark plug sparks the same and gives uniform combustion regardless. Idk but something I'll have to consider

 

[JOutterbridge]

cylinder 4 being rich?
cylinder 4 is usually lean, due to the fuel rail and intake manifold design.

Yes, cylinder 4 lean but the rest of the cylinders very rich when running 1 step colder. And also 4 looks extremely lean on the stock plugs while the rest look perfect. Sorry I rambled and wasn't clear:/

 

[AKGC]

Do a compression test