too many questions about a data log!!

[vinnio]

First ill tell you that my profile is up to date. I did my first log yesterday. I’m worried. Here’s my question(s) (bear with me).

First thing is my o2 sensor. (Bank 1 number 1) I know it is supposed to move around at idle. But how much? Mine is going from .04v all the way to .86v. It seems excessive to me. It will even move around when I'm getting on the throttle. Thing is, it’s not lazy. It will change at every frame.

Next is my LT FTRM. It is currently set at 12.5% is this excessive? I think this means my car wants to run lean, so the ecu is compensating? What could cause this? And is it really an issue?

Another? Every place I look, I find that 2g's are supposed to cap off timing at 16*. When I look at mine, say at 3/4 throttle it can be anywhere from 24 to 29+. At idle it sits at 7-8. This just flat out confuses me. No lie. Something is pushing it that high, but what. And why? I’ve been researching and I’m puzzled.

Today I was driving, I got on it a bit to merge onto the freeway, looked down and saw my maf reading was saying 90+ g/sec!! This seems excessive too.

Finally, my IAT is sending me some weird numbers. One occasion, it went from 85* down to 75* in >5 seconds. IDK what this means. I was told that this will retard my timing if it’s above 83. I know my turbo is just like an air heater, so does this really even matter?

Sorry for including so much info. Just covering the bases. Any info will help. I know at least one of those questions was probably stupid so be easy. . Also, if you would like I can upload the log I did. Idk if it will help, but its here.


TIA

 

[vinnio]

Okay. I found out that as long as my o2 voltage is moving that it is a good sensor. I think I can safely rule this as being okay.

I also did some math and found that my 16g flows 550 cfm (e3 16g) so if true, then that converts to 4115 gallons per min. Divide by 60. 68.5 g/sec. So my maf must be wrong when it’s saying 90+g/sec?? Either that or I did the conversion wrong...

I guess the main thing I’m still concerned with is the timing. However the long term fuel trim is kind of bothering me too. Ill keep looking.

 

[winterftbl]

You are correct that timing is capped on a 2g at 16. But that is at wide open throttle, If you are not at 100% throttle your timing will consistenly change. I am also learning so if you want you can post a log and I will try and help.

 

[2gGSX]

First ill tell you that my profile is up to date. I did my first log yesterday. I’m worried. Here’s my question(s) (bear with me).

First thing is my o2 sensor. (Bank 1 number 1) I know it is supposed to move around at idle. But how much? Mine is going from .04v all the way to .86v. It seems excessive to me. It will even move around when I'm getting on the throttle. Thing is, it’s not lazy. It will change at every frame.

Next is my LT FTRM. It is currently set at 12.5% is this excessive? I think this means my car wants to run lean, so the ecu is compensating? What could cause this? And is it really an issue?

That is maxed out. Your are correct in your interpretation. It can be caused by either a metering error (due to a dying MAS, or due to the turbo drawing in unmetered air), or low fuel pressure. This is assuming that your mods list is up to date though, and that you don't have any fuel system upgrades.

Another? Every place I look, I find that 2g's are supposed to cap off timing at 16*. When I look at mine, say at 3/4 throttle it can be anywhere from 24 to 29+. At idle it sits at 7-8. This just flat out confuses me. No lie. Something is pushing it that high, but what. And why? I’ve been researching and I’m puzzled.

In closed loop operation (idle and cruise) your timing will be very high, and that's fine. It's actually helping you get the most out of your fuel and maximize your fuel economy. At 3/4 throttle and WOT however, you enter what's called open loop operation. In this, your ECU looks up a 3D table for your AFR and timing, with the axes being load (g/rev airflow), RPM, and timing or AFR. At 3/4 throttle you are probably flowing such a small amount of air that you are in a very low load map, and thus get a lot of timing.

The "peaking at 16 degrees of timing" will only occur when you are on the highest load map (2.1 g/rev) and above about 6000 RPM.

Today I was driving, I got on it a bit to merge onto the freeway, looked down and saw my maf reading was saying 90+ g/sec!! This seems excessive too.

90 g(rams)/sec is only 11.9 lb/min (you'll find that this is the preferred unit of measurement amongst this community), which is fine. If this was at high RPM and WOT, you may actually have a low airflow problem.

Finally, my IAT is sending me some weird numbers. One occasion, it went from 85* down to 75* in >5 seconds. IDK what this means. I was told that this will retard my timing if it’s above 83. I know my turbo is just like an air heater, so does this really even matter?

Do you have an IAT sensor hooked up, or are you reading the "Intake Temp" output? The "Intake Temp" output is actually the reading from your MAS. Dropping that much temperature could just mean that your engine bay cooled down from you driving around. My intake temps at the MAS drop during a pull.

A perpetual high "Intake Temp" reading signifies that you are getting poor airflow into your engine bay, or that there is too much heat radiating from within your engine bay. This can be caused by not running the stock heat shield.

Sorry for including so much info. Just covering the bases. Any info will help. I know at least one of those questions was probably stupid so be easy. . Also, if you would like I can upload the log I did. Idk if it will help, but its here.


TIA

Okay. I found out that as long as my o2 voltage is moving that it is a good sensor. I think I can safely rule this as being okay.

I also did some math and found that my 16g flows 550 cfm (e3 16g) so if true, then that converts to 4115 gallons per min. Divide by 60. 68.5 g/sec. So my maf must be wrong when it’s saying 90+g/sec?? Either that or I did the conversion wrong...

IIRC, the big 16g is the one that was rated at 550 cfm, while the Evo 3 is rated for quite a bit higher. I'm not sure how you did your conversion since there was no mention of air density to change from volume-flow to mass-flow, but I don't think that worked.

I guess the main thing I’m still concerned with is the timing. However the long term fuel trim is kind of bothering me too. Ill keep looking.

I've responded to your question in bold within your quotes above.