Mechanical causes for timing corrections? Need some help figuring out the cause

Empire087

Lurker
Jun 13, 2022
15
2
0
Kinda give the quick run down:
Single turbo kit pulsar gtx3582r gen 2
Custom built manifold w/3.5" turbo back to vrsf street exhaust
New index 12 injectors last fall
Walbro 535 pump
One step colder plugs and Delphi coils replaced 3 weeks ago.


Was on 93, but opted to go 91 and had the tune switched over due to lack of 93 availability. Problem existed with 93 aswell. I get this 3 degrees of timing corrections on next to no timing and plenty of fuel. Also was told to try Lucas octane booster to help rule out octane as an issue. Does identical timing corrections 14-20# which should be well within what this turbo can handle. im down to a mechanical issue. Tuner hasn't seen this issue before and I'm reaching out. If you need a log of anything just ask I'll grab one in the evening when my logging spot is clear.

Thanks!
 

Empire087

Lurker
Jun 13, 2022
15
2
0
Hey, Curious what you plugs are gapped too?
I have tried everything from .018 to .024 with no change.

Where did you place the o2 Sensor?
Rear 02 is at the bottom backside of the elbow at a 45 to the block. Front bank is coming off at a 90 pointing to the rear of the car. Here's a pic, disregard first placement of rear. Did not work out how I hoped.
 

Attachments

  • 20220503_223237.jpg
    20220503_223237.jpg
    312.1 KB · Views: 38

Slowagon54

Corporal
Aug 21, 2020
165
62
0
Hm... check your AFR and STFT. While Bank 2 on both parameters is quite smooth, Bank 1 is bouncing. But i am not sure if thats causing your issues as there is nothing really out of spec. Timing corrections start on increased boost, so really no idea.

Is your tuner a known company or is it a guy from facebook ?
 

Empire087

Lurker
Jun 13, 2022
15
2
0
Hm... check your AFR and STFT. While Bank 2 on both parameters is quite smooth, Bank 1 is bouncing. But i am not sure if thats causing your issues as there is nothing really out of spec. Timing corrections start on increased boost, so really no idea.

Is your tuner a known company or is it a guy from facebook ?
Cd919, has a good reputation to my knowledge. It's strange how it's through both banks, and throughout the whole log. Almost like fuel is just crap, from two different stations at that. However I'm trying a third station, and things seem good so far. With the equivalent of 93 e10 fuel. Gonna try their 91 next fill up and see how the logs look. Way better though. Suspect I'm gapped a touch big now

Try desensitizing knock tables in mhd and get another log.
How risky is doing this? I thought about it, but never asked my tuner.
 

E90TommyB

Private
Apr 9, 2018
34
8
0
Indiana
Ride
2007 E90 335i
Cd919, has a good reputation to my knowledge. It's strange how it's through both banks, and throughout the whole log. Almost like fuel is just crap, from two different stations at that. However I'm trying a third station, and things seem good so far. With the equivalent of 93 e10 fuel. Gonna try their 91 next fill up and see how the logs look. Way better though. Suspect I'm gapped a touch big now


How risky is doing this? I thought about it, but never asked my tuner.
Don't do it long term, just desensitize the knock tables and take it out and get a log real quick.
 

rac

Sergeant
Nov 14, 2016
322
177
0
Australia
Ride
135i ST
I don't get it, a splash of 2.5 gallons of e makes it go away, but 91 should not be getting knock that low on boost.

everything is pointing to real knock. cr8p fuel is cr8p fuel. this platform is getting old (so engines are either old or rebuilt to all sorts of different specs, quality and tolerances) and so it's reasonable to expect a widening gap between how engines perform. i am not surprised at all that some engines will knock at those boost levels with 91 and / or 93 if the fuel contains no ethanol at all. are you in the states? i am pretty sure you can have up to 10% ethanol undisclosed correct? its fact that 93 that contains ethanol is not going to behave the same as 93 that does not for a DI boosted engine because the CFR machine that establishes the octane rating of the fuel is not representative of DI engine. so depending what part of the country you are in you may be getting e10 or not, without knowing.

- i would trial a richer mixture on spool up and mid range at boost to keep the cylinders as cool as possible on cr8p fuel.
- oil contamination reduces knock resistance, where is your blow-by being routed - back to intake? if so look at your VTA and/or filtering options. check your intake ports for oily residue and carbon build up.
 
  • Like
Reactions: jzx_andy and Jern54

Empire087

Lurker
Jun 13, 2022
15
2
0
everything is pointing to real knock. cr8p fuel is cr8p fuel. this platform is getting old (so engines are either old or rebuilt to all sorts of different specs, quality and tolerances) and so it's reasonable to expect a widening gap between how engines perform. i am not surprised at all that some engines will knock at those boost levels with 91 and / or 93 if the fuel contains no ethanol at all. are you in the states? i am pretty sure you can have up to 10% ethanol undisclosed correct? its fact that 93 that contains ethanol is not going to behave the same as 93 that does not for a DI boosted engine because the CFR machine that establishes the octane rating of the fuel is not representative of DI engine. so depending what part of the country you are in you may be getting e10 or not, without knowing.

- i would trial a richer mixture on spool up and mid range at boost to keep the cylinders as cool as possible on cr8p fuel.
- oil contamination reduces knock resistance, where is your blow-by being routed - back to intake? if so look at your VTA and/or filtering options. check your intake ports for oily residue and carbon build up.
So I'm definitely suspecting just overall crap fuel. Worst way is there is no real good way to test it. The fuel I'm on now says it's 91 non ethanol, I'm pretty sure by law they have to specify if it potentially has it. I'm in the US.

So as far as my pcv situation goes, I simply left the factory setup in place dumping into the rear intake pipe to atmosphere. I'm gonna take my intake off today to see how things look on the valves. I'd run a catch can setup, but I just couldn't find the one that everyone says works. I'm open to recommendations though.
 

Empire087

Lurker
Jun 13, 2022
15
2
0
Well pulled the intake, might be time to go with a full on new setup for pcv, and delete the intake ports on the head. These are pretty dang dirty, a lot dirtier than 20k ago.
 

Attachments

  • 20220618_171135.jpg
    20220618_171135.jpg
    203 KB · Views: 13
  • 20220618_170950.jpg
    20220618_170950.jpg
    213.9 KB · Views: 13

Empire087

Lurker
Jun 13, 2022
15
2
0
also gonna add, went and plugged the head ports, replaced valve cover, and now hoping that my rb external pcv arrives before the weekend.
 

rac

Sergeant
Nov 14, 2016
322
177
0
Australia
Ride
135i ST
sorry there was no improvement. ultimately the ambition for this fuel is too high. big turbo's help with lower IATs and lower exhaust temps keeping overall temperatures lower, increasing the threshold to knock. but there is a limit to that, wont perform miracles. WMI is the easiest solution if your not running E and dont want to run lower boost. you can still throw more fuel at it in the lower rpms which might help delay the onset of timing corrections but again having excess of standard fuel not as effective at cylinder cooling as WMI.
 

Slowagon54

Corporal
Aug 21, 2020
165
62
0
You have maxed out your fuel delivery at 4k, check the STFT´s. And thats where the corrections start. Also strange enough you are at only 3° of crk timing... If octane booster did not help at all, i am not sure where to look next for the issue.