08, stage 1 log

[Kicnit]

I know these aren't full RPM range pulls. I've been hearing/feeling an odd noise during light throttle, and only around 2-3500 RPM. Doesnt sound like rod knock, but almost like a heatshield. However I cant find any that are loose. How does this look?

https://docs.google.com/spreadsheet/...k00dUJEZXQtRnc



08 WRX
Cobb CB
Cobb SF intake
Accessport stage 1 +intake 93

cheers,
kyle

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[Cobb Tuning]

Originally Posted by Kicnit

I know these aren't full RPM range pulls. I've been hearing/feeling an odd noise during light throttle, and only around 2-3500 RPM. Doesnt sound like rod knock, but almost like a heatshield. However I cant find any that are loose. How does this look?

https://docs.google.com/spreadsheet/...k00dUJEZXQtRnc



08 WRX
Cobb CB
Cobb SF intake
Accessport stage 1 +intake 93

cheers,
kyle

Your long-term fuel trims (A/F Learning 1) have some borderline extreme values. May be an intake tract leak or other fueling issue. It would be a good idea to get a pressure or smoke test of the intake tract done.

Wide open throttle (WOT) portion of the log is a little short. If you can do so safely, try to get a WOT log in 3rd gear from 2500 RPM on up. But, I would address the fuel trim issue above first before doing any more WOT pulls. You can view the individual fuel trims that make up A/F Learning 1 via the A/F Learning 1 A,B,C,D parameters.

Bill

[Kicnit]

OK, thank you for looking. Is this something that is caused by gas too? Im running the 93 map, but have been thinking about trying to run 93 in the 91 map. Sorry for the NOOB-ish questions.

cheers,
kyle

[Cobb Tuning]

Originally Posted by Kicnit

OK, thank you for looking. Is this something that is caused by gas too? Im running the 93 map, but have been thinking about trying to run 93 in the 91 map. Sorry for the NOOB-ish questions.

cheers,
kyle

No, you can run 93 octane on the 91 map - this will not cause fuel trim issues. Fuel trim issues are because the front oxygen sensor is reporting fueling to be consistently off in certain airflow ranges (dictated by the A,B,C,D ranges). This can be because the car is metering air and then losing or gaining air after the fact (i.e. an intake tract leak), a bad sensor (such as MAF or front o2 sensor itself), or other fueling issue. The intake tract leak is the #1 most common problem on these Subarus when it comes to fuel trim issues. Bad or contaminated MAF, on older cars, is not uncommon, but you tend to see all positive fuel trims when that is the case. Bad front o2 is also not uncommon, especially with older cars or cars with higher mileage.

Bill

[Kicnit]

Thank you for the explanation. I'm going to take a look around the intake as well. Just to make sure nothing has fallen off, or anything. Is it ok to drive for now?

cheers,
kyle

[Cobb Tuning]

Originally Posted by Kicnit

Thank you for the explanation. I'm going to take a look around the intake as well. Just to make sure nothing has fallen off, or anything. Is it ok to drive for now?

cheers,
kyle

Yes, you are fine, although I would avoid WOT pulls for now and just keep an eye on A/F Learning 1 A,B,C,D to see if they get worse. Generally each of these individual values should be within around +/- 5%. You are as bad as 7% and -6.25%, which is borderline.

Bill

[Kicnit]

OK, thank you for all your help! Ill try to play around with it.

cheers,
kyle

[Kicnit]

After a quick look, it looks like the hose clamps on the intake for a few turns loose. Im going to tighten them up, and check everything else. Do you think something that minor would cause that?

cheers,
kyle

[Cobb Tuning]

Originally Posted by Kicnit

After a quick look, it looks like the hose clamps on the intake for a few turns loose. Im going to tighten them up, and check everything else. Do you think something that minor would cause that?

cheers,
kyle

Clamps on various intake tract hoses shouldn't be too tight - you shouldn't be cranking down on it - generally should be tightened until you start feeling some resistance (so fairly low torque). A visual inspection is not enough to check for intake tract leaks. The only sure way is via a pressure or smoke test. I would keep an eye on the trims to see what they do over time (get worse or not).

Bill

[Kicnit]

Bill,
I needed to change my air filter, so I cleaned the MAF as well. I had reset the ECU when I did the MAF. This is a log after about 100 miles. Now it seems like there is some knock. Maybe that's because the ecu is still learning?
https://docs.google.com/spreadsheet/...U4tWlE2QUkyR0E

cheers,
kyle

[Cobb Tuning]

Originally Posted by Kicnit

Bill,
I needed to change my air filter, so I cleaned the MAF as well. I had reset the ECU when I did the MAF. This is a log after about 100 miles. Now it seems like there is some knock. Maybe that's because the ecu is still learning?
https://docs.google.com/spreadsheet/...U4tWlE2QUkyR0E

cheers,
kyle

You have two counts of knock at time 8.36. This is at very low load before the WOT run takes place and is not a concern (likely just noise). The corrections you see during the WOT run are just the ECU holding the prior correction and ramping it slowly back to zero (so no knock during the WOT run).

Bill

[Kicnit]

Thank you once again. I will run some more gas through it, and take a look at those a/f numbers this weekend. They do look lower, but i've only ran about 100 miles through it since ECU reset.

cheers,
kyle