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Looking for someone to review my logs, recorded via torque pro. I do not know what value ranges should be for what, especially with the VQ. I have been noticing for some time that my car has basically zero acceleration. On the highway, I’m hardly exaggerating, I think a civic si would walk me. I'm in Phoenix AZ now, elevation 1100+/-, 91 octane. Really trying to see if there are any points of concern. This was on my way to class, so I was only able to do a 2nd gear pull, but hit red line or just shy. I may have gone a little overboard with the parameters (lol) but I wanted to make sure that I was covering as many bases as possible.
From looking at the logs, I see my A/F is all over the place. I also see timing advance is also all over the board.
You are in Arizona where habbos happen. When was last time you changed your sir filters and cleaned maf?
Those damned habbos lol. But it’s been a while since I changed the air filters. But I was having this issue when my cai m, before I sold it and went back to the stock boxes and filters. I can take them out and check after class.
Originally Posted by SonicVQ
I'll take a look :
Does the car have any mods?
Any spreadsheet can open a CSV file, just double click on the logfile
Sorry! I should have listed mods. All I have at the moment is fast intention TP, and gt haus axel back. Factory intakes and manifold.
It is normal for the timing and air/fuel ratios to move around a lot, it all depends on engine load.
Here is one item I noticed:
At 34% engine load, your short term fuel trips dips to -20% for a moment.
This may be due to the test pipe. Some of the newer ECUs use the post cat O2 sensor to check for a lean/rich bias on the front air/fuel ratio sensor.
Without the cat, the ECU may see the lean signal and over compensate.
Also without the cat, your rear O2 sensors almost aways show rich, unless the throttle has just been closed. This may impact the overall fueling.
Follow up questions:
• What year is your G37?
• Stock ECU/Tune? (want to double check)
• Do you have a CEL (P0420 / P0430) due to the test pipes?
• Do you have O2 extenders / defoulers on the post cat O2s?
I will continue to dig into this...
(Yes... I *LOVE* this stuff)
It is normal for the timing and air/fuel ratios to move around a lot, it all depends on engine load.
Here is one item I noticed:
At 34% engine load, your short term fuel trips dips to -20% for a moment.
This may be due to the test pipe. Some of the newer ECUs use the post cat O2 sensor to check for a lean/rich bias on the front air/fuel ratio sensor.
Without the cat, the ECU may see the lean signal and over compensate.
Also without the cat, your rear O2 sensors almost aways show rich, unless the throttle has just been closed. This may impact the overall fueling.
Follow up questions:
• What year is your G37? 2011 coupe, six speed.
• Stock ECU/Tune? (want to double check) it is the stock ecu with the stock file at the moment. I have been running the stock file for about 2 months now.
• Do you have a CEL (P0420 / P0430) due to the test pipes? No CEL should be present. My test pipes have never provided a CEL due to the defoulers
• Do you have O2 extenders / defoulers on the post cat O2s? Yes fast intentions builds their test pipes with defoulers, or at least mine have them.
I will continue to dig into this...
(Yes... I *LOVE* this stuff)
Originally Posted by SonicVQ
One more question, what OBD scanner did you use for the log?
Torque pro, if you’d like I have ecutek and the software to do some better logs. I also can do a highway pull for better readings.
Thanks Hanks for taking the time to read my logs! I really appreciate that! I just cannot figure out why my car has been such an issue for the past year. When the light turns green, I basically have to floor the car to get it to come off the line within a reasonable time, or I can ride the clutch out more. I have drove a six speed for the last 11 years now, so I know it’s not me learning the car or something.
Anyway, thanks again! And let me know if you’d like me to do a 3rd year pull and record with ecutek
No, this is something from amazon I bought years ago. I bought it to scan and clear codes. But since it an Android is smaller than a laptop, I used this to grab some quick logs.
Honestly, if it’s easier, I can just grab logs via laptop, ecutek’ hardwired obdII reader and use ecutek’s software. I’m sure it will be much better anyway.
I'm just looking for the make and model of your scanner, it's PID read speed is fairly quick.
Here is my analysis summary:
Working as expected:
• throttle body fully open at WOT
• good AFR: 14.7 at idle and <12 at WOT
• engine coolant sensor good
• absolute engine load maxed out at 98% (this is engine load based on air flow)
• Rear o2 sensors switching as expected (<0.1 to > 0.8 volts)
Concerns:
• Fuel trims spike VERY negative
• Total fuel trim (short term + long term) has LARGE changes:
• Bank 1 total fuel trims range from -21% to +15%, with an average of -4.5%
• Bank 2 total fuel trims range from -19.5% to 14%, with an average of -1.07%
Other observations:
• The datalog elevation was about 1220 feet and the LOWEST air intake temp was 109F (highest was 132!)
• This elevation and air temp calculates to an equivalent density altitude of 4,962 feet!
• This results in the engine making about 7% less power (~21 HP) due to the thinner air density.
• The "absolute engine load" is based on cylinder filling and at wide open throttle it correlates to volumetric efficiency.
• With your temperature and elevation, it maxed out at 98%.
• At my elevation of 258m / 846' on a 30C / 86F day my maximum absolute engine load will be 105-106%. (2011 G37S)
I think the elevation and air temperature are the main reasons for the lack of power. At 93% relative horsepower, your car is down about 21 HP (assuming 300 HP (J13489) at the wheels) There just isn't the air density for the engine to make the more power.
Your fuel trims, they have large swings, but that shouldn't come into play as as wide open throttle the fuel trims are not used as the engine is in "open loop" (and that is why they drop to 0"
On my G37 Sport sedan (just Stillen cat back) the total fuel trims min/max are: -14 to 10 and bank 1 averages to -0.48 and bank 2: +1.01
I wonder if the test pipes (with defoulers) interfere with the fuelling calculations, since the ECU is programmed to expect a catalytic converter.
That's all I got...
I'm just looking for the make and model of your scanner, it's PID read speed is fairly quick.
Here is my analysis summary:
Working as expected:
• throttle body fully open at WOT
• good AFR: 14.7 at idle and <12 at WOT
• engine coolant sensor good
• absolute engine load maxed out at 98% (this is engine load based on air flow)
• Rear o2 sensors switching as expected (<0.1 to > 0.8 volts)
Concerns:
• Fuel trims spike VERY negative
• Total fuel trim (short term + long term) has LARGE changes:
• Bank 1 total fuel trims range from -21% to +15%, with an average of -4.5%
• Bank 2 total fuel trims range from -19.5% to 14%, with an average of -1.07%
Other observations:
• The datalog elevation was about 1220 feet and the LOWEST air intake temp was 109F (highest was 132!)
• This elevation and air temp calculates to an equivalent density altitude of 4,962 feet!
• This results in the engine making about 7% less power (~21 HP) due to the thinner air density.
• The "absolute engine load" is based on cylinder filling and at wide open throttle it correlates to volumetric efficiency.
• With your temperature and elevation, it maxed out at 98%.
• At my elevation of 258m / 846' on a 30C / 86F day my maximum absolute engine load will be 105-106%. (2011 G37S)
I think the elevation and air temperature are the main reasons for the lack of power. At 93% relative horsepower, your car is down about 21 HP (assuming 300 HP (J13489) at the wheels) There just isn't the air density for the engine to make the more power.
Your fuel trims, they have large swings, but that shouldn't come into play as as wide open throttle the fuel trims are not used as the engine is in "open loop" (and that is why they drop to 0"
On my G37 Sport sedan (just Stillen cat back) the total fuel trims min/max are: -14 to 10 and bank 1 averages to -0.48 and bank 2: +1.01
I wonder if the test pipes (with defoulers) interfere with the fuelling calculations, since the ECU is programmed to expect a catalytic converter.
That's all I got...
Thanks for taking the time to go through everything. I will get a 3rd gear pull in tonight with the cooler air. Maybe that will help shed some light? Either way very good deep dive and this makes me feel a bit better!
@SonicVQ , do you have a document with parameter ranges for our cars? I'd love to read my logs, but have had a hell of a time trying to get any info on what the proper numbers are.... Maybe a DIY guide if you've got the time?
