Making sure things are ok-3rd gear log

[DSM_6SL2 Power]

So I decided to do a log just to make sure things are running smooth and im not causing any harm to my new engine. I did a pull in 3rd at 14psi creeping to 18psi and holding.


Time RPM TIMING TPS
1.20 3664.0 9.00 100.2
1.52 3812.0 8.00 100.2
1.81 3940.0 9.00 100.2
2.11 4060.0 9.00 100.2
2.41 4196.0 9.00 100.2
2.71 4348.0 9.00 100.2
3.01 4472.0 9.00 100.2
3.31 4608.0 9.00 100.2
3.61 4728.0 9.00 100.2
3.91 4872.0 10.0 100.2
4.21 4992.0 10.0 100.2
4.51 5140.0 11.0 100.2
4.81 5280.0 11.0 100.2
5.11 5420.0 13.0 100.2
5.41 5540.0 13.0 100.2
5.71 5696.0 14.0 100.2
6.00 5844.0 15.0 100.2
6.30 5988.0 15.0 100.2
6.61 6104.0 15.0 100.2
6.91 6220.0 16.0 100.2
7.21 6368.0 16.0 100.2
7.51 6464.0 16.0 100.2
7.81 6596.0 16.0 100.2

 

[Calan]

If you aren't seeing any knock (and since the log doesn't show any timing being pulled), you're probably fine.

That log doesn't really tell us anything though, other than your TPS is slightly out of adjustment and you're maintaining timing.

For the pull, you really need to log AFR if you want to see where improvements can be made. Also, if possible you should log boost, as you can tell how your turbo is spooling, if it's creeping, how efficiently it's operating, etc.

Have you logged your fuel trims at idle and cruise?

What did you use to log with?

 

[DSM_6SL2 Power]

Im logging with a obdII logger. Im kind of limited in what I can log I guess. I didnt bother logging the 02 since everyone says it is not accurate enough. Ive got a wideand, I just need to install.

So I dont think im knocking since timing is not being pulled. Can I assume im not hurting anything, or is there more to it then that?

Also im pretty sure I have boost leaks, causing me to run rich.

 

[2gGSX]

Im logging with a obdII logger. Im kind of limited in what I can log I guess. I didnt bother logging the 02 since everyone says it is not accurate enough. Ive got a wideand, I just need to install.

So I dont think im knocking since timing is not being pulled. Can I assume im not hurting anything, or is there more to it then that?

Also im pretty sure I have boost leaks, causing me to run rich.

The log looks great, given the data presented

 

[CTP]

Judging by the complete lack of even the slightest timing hold or pull, I'm guessing you're probably running at <11:1 and/or making no power. Do you have a wideband?

Also, make the pull to at least 7,000rpm next time. You have another 1,000rpm worth of powerband you didn't log.

 

[snowborder714]

Also im pretty sure I have boost leaks, causing me to run rich.

You should have all of your boost leaks fixed before asking if a log is ok.

 

[kenamond]

It looks good to me, but looks can be deceiving without more information. I'd say that your next log should include airflow and go from before boost hits to redline (that is, if you have a place to do this that won't get you ticketed or killed - if not, you can let off and post what you logged). And you can stop logging TPS on the next log; it'll just tell you 100.2 a hundred times, and you could use that sampling bandwidth for airflow.

Although O2v aren't going to tell you AFR, they will tell you if you're leaning out badly.

 

[DSM_6SL2 Power]

Ill do a log tommorow with the advice above.

Probaly log airflow, timing, and o2.

 

[kenamond]

Before you do your pull, take a look at your IATs and coolant temps just driving around and with the car fully warmed up. Just monitor them, remember what they are, then set up the rpm, timing, airflow, and O2v for the log. Post the results.

I forgot to mention that you should listen to what snowboard714 said and BLT. I'd still do the above experiment but you should BLT, fix all leaks, then do another pull and see if you're still okay. Boost leaks can richen up the AFR due to loss of metered air, and that could be saving your butt at the top end when you're demanding the most out of your fuel system.

EDIT: Oh, and when you're looking at your coolant and intake air temps, also take a look at your LTFT and see if it's far from 0. Post that as well.

 

[DSM_6SL2 Power]

Crap, I went out and did a log before you posted that, but I have been monitoring my coolant and intake temps. The coolant is usually seemed to be around 190-200. Intake temps were steady at 84. This was after a couple logs I did earlier today. I did not do the ltft, but I will tomorrow. What will that tell me? If its negative or positive what will that show?

Heres the log, again at 14psi creeping to 18 and holding. (just a side note that is irrelevant, this turbo is really strong going from 14-18. Its very noticeable difference.)



Time RPM TIMING AIR FLOW O2
0.420 2732.0 33.0 4.100 0.76
0.820 2852.0 16.0 8.010 0.98
1.210 2940.0 16.0 9.280 1.00
1.630 3088.0 13.0 10.77 1.02
2.030 3224.0 9.00 12.88 1.02
2.440 3396.0 8.00 15.33 1.00
2.840 3560.0 8.00 16.32 1.00
3.250 3728.0 8.00 16.97 1.00
3.650 3916.0 8.00 18.04 1.00
4.060 4088.0 9.00 19.14 1.00
4.460 4252.0 9.00 20.06 0.98
4.860 4428.0 9.00 21.17 0.98
5.270 4584.0 9.00 22.16 0.98
5.670 4768.0 9.00 23.79 1.0
6.070 4932.0 10.0 24.68 1.0
6.470 5104.0 10.0 26.14 1.0
6.870 5296.0 11.0 27.42 1.0
7.270 5476.0 13.0 29.23 1.0
7.670 5660.0 14.0 29.96 1.0
8.070 5844.0 14.0 31.23 1.0
8.480 6008.0 15.0 32.52 1.02
8.880 6180.0 16.0 33.63 1.02
9.270 6336.0 16.0 34.19 1.02
9.680 6496.0 16.0 35.05 1.02
10.08 6640.0 16.0 35.62 1.02
10.49 6796.0 16.0 35.73 1.02
10.88 6892.0 16.0 36.41 1.02


I havent even did a boost leak test, but im positive I have leaks. I cant fix those til spring break. Dont have the supplies here at college.

 

[kenamond]

Let me get on my other computer and check a couple of logged values. FYI, if you have the stock timing map (it's available on this forum...I'd have to search for the link though), then you can take one line from your log - (rpm,timing,airflow) - convert the (rpm,airflow) to load (load=airflow*454/rpm) and look at that (load,rpm) pair on the map and compare your logged timing advance to the ECU timing map's timing advance. If they're close, you're not knocking. If they're not close, you're knocking. I'm working with the server folks to try to get some tools like these installed on the site so that you can drop the log above into a window and click a few buttons and have it spit out what you put it PLUS knock sum. As an aside, airflow is usually logged as pounds of air per minute (lb/min) while load is grams of air per intake stroke of a cylinder (g/rev). The equation I gave you converts airflow in lb/min and rpm in rotations per minute to load in grams of air entering each cylinder during the intake stroke in g/rev.

As for the LTFT, the ECU has two modes for computing fuel delivery: open loop mode and closed loop mode. When you're at partial throttle, the ECU is in closed-loop mode. It relies on the O2v signal. The O2 sensor should return 0.5v if your AFR is 14.7 (stoichiometric). So the ECU tries to get the O2v signal to be right at 0.5v. What happens is that your O2v oscillate around 0.5v. If it's above 0.5v, it's richer than stoich, if it's below 0.5v, it's leaner than stoich. So the ECU will add or subtract fuel from the stock fuel map in order to get your O2v to oscillate around 0.5v. It's called closed-loop, because it the fuel control mechanism has a cause-and-effect "loop": if the O2 says I'm a bit lean, add fuel. If it's a bit rich, subtract fuel. It is a loop of checking the O2, adjusting the fuel added, and checking how that affects the O2 sensor voltage. Now the fuel trims are like short and long term memory of what the O2 says vs what the stock fuel map says. If the car constantly has to have more fuel than the map says, it stores this in the long term fuel trim (LTFT). So if you're running consistently rich, your LTFT will be negative. If you're running consistently lean, the LTFT is positive. The value stored in the LTFT tells the ECU to add or subtract fuel from the stock fuel map and then look at the O2v. It's constantly adjusting the LTFT.

So looking at the LTFT will tell you if your car is running consistently rich or lean...if rich, I'd say a boost leak. If lean, I'd suspect a fuel supply problem (clogged injectors, old fuel filter, etc.). I forget the guidance, but it's something like +/-4% is within spec on LTFT. If it's 15%, you have a problem that you need to track down and fix.

EDIT: Okay...on the other computer with the 2g timing map file on it. I checked your timing at a few spots (between 4500rpm and 7000rpm), and it matches the stock map to within 1° (only one sample I tested was different than the stock map). So I don't think you're knocking. But if you have boost leaks, you could potentially have more power by fixing them...but you may also push the stock fuel system to the limit in the process. So boost leak test, fix all leaks so that you can hold 20psi and leak down no faster than 1psi every few seconds...then do another pull and post it.

 

[DSM_6SL2 Power]

Great info, I love learning stuff like this. Keydiver chips kick some serious ass, its nice not to really have to worry about your tune.

I will check out the LTFT tomorrow, I have a pretty free day tomorrow to mess around. I suspect im running rich. I can't really do much about my suspected boost leaks, so I dont know whether to tune it out with the safc (which I would hate to do as a cover up for my boost leaks) or just run it as is and get bad gas mileage. I don't really plan on beating on my car, I rarely go into boost even.

I'll probably turn the boost up to 18 after I fix the boost leaks, and see how that does. Then when I get my fmic, run around 20-22. I can't wait to get some logs for that.

Couple more questions first. How should I look at my LTFT. Just at idle? Different rpm points? Cruising?

What about the STFT, I was always under the impression you used it to tune your low throttle rpm points? Ive also heard you use both the LTFT and STFT and get them as close to 0% together. Like LTFT is at -3 and STFT is at +3, then you would be good.

 

[DSM_6SL2 Power]

I just re-read that, and understood a little better. I get how you would tune for low throttle with the STFT since it is short term, it will give you an current update at where you are at.

Looking at the LTFT will show me if I have been running rich this whole time. Correct?

 

[Calan]

I just re-read that, and understood a little better. I get how you would tune for low throttle with the STFT since it is short term, it will give you an current update at where you are at.

Looking at the LTFT will show me if I have been running rich this whole time. Correct?

Close... but not exactly

To expand a bit on what Mack said... you actually always have two fuel trims in effect; the STFT (short term), and either a Lo LTFT or High LTFT. (1Gs also have a Mid LTFT).

The STFT represents immediate changes that the ECU is making to the A/F mixture, based on readings from the O2 sensor. The LTFT's are adjusted over time based on the "trends" in the STFT that the ECU sees. In other words...the LTFTs are used sort of as a prediction for what the ECU is going to have to do, based on STFT trends over time. So the ECU is going to try to adjust AFR by an amount equal to the current STFT reading + whichever LTFT is in effect. (Which LTFT is in effect is a function of airflow).

The reason that LTFTs aren't necessarily accurate by themselves is that they can take some time to update, and will only be updated under very strict conditions (certain load, coolant temps, intake temps, etc). So you must always look at the sum of the STFT and whichever LTFT is in effect for any given amount of airflow.

Lets look at an example...

You have to think of LTFTs in terms of how much air your engine is flowing. So lets say you've driven your car around for 3 months under pretty consistent conditions and no new mods or anything. Over this time, your ECU has been updating both the low and high LTFTs depending on what it sees going on with the STFT at two different operating states. While you've been idling at stoplights, (if all conditions are met), then the ECU is updating the low LTFT in an attempt to get the STFT at 0. While cruising, it's been updating the high LTFT.

So lets say that after these 3 months, your low LTFT has been adjusted to -4.6% (meaning the ECU is fighting a rich condition at idle), and your high LTFT is sitting at 3.2% (you're tune is a bit lean at cruise). Your STFT will probably be oscillating around 0 as long as nothing has changed much since the last time the LTFTs were updated. Now you go add a mod (new injectors, intake, whatever). Your STFT is immediately going to be out of whack, but the LTFTs haven't had time or the right stable conditions to update yet. So to get a true idea of whats going on, you have to add the STFT with each of the two LTFTs, depending on which condition you are trying to dial in (idle or cruise).

Using the idle (low LTFT) example...if your new mod is now causing the STFT to show -5% at idle... you now have some tuning issues to deal with, because you are now actually -9.6% rich at idle (50hz airflow, STFT + low LTFT). If after the mod your STFT is reading +4 or so at idle, your low LTFT would eventually adjust itself out and you'd be close to 0 on both STFT and low LTFT. Same idea applies to the cruise LTFT.

 

[2gGSX]

2g's actually only have LTFT Lo and LTFT Mid.

The actual requirements for LTFT's to be updated are...
1g
Coolant temp > 190F
Intake air temp < 123F
Baro > 22.9 inHg
Baro < 31.6 inHg

2g
Coolant temp > 180F
Intake air temp < 133F
Baro > 22.9 inHg
Baro < 31.6 inHg

 

[Calan]

2g's actually only have LTFT Lo and LTFT Mid.

Semantics... It's still a high and a low

Thanks for the clarification though Tom

BTW - Isn't there a certain amount of time at a stable load/RPM also?

 

[2gGSX]

AFAIK you'll stay in learn mode as long as you're within those parameters and the car stays in closed loop operation.

 

[DSM_6SL2 Power]

Well heres a log just showing a few things at full operating temp, I was just in 3rd gear. I hovered around 2k rpm before slowly climbing up to 3500. Im running alot richer then I would have liked. It seems that 2k and below it's at -11, and above that it's at -8.

My coolant temp rose to about 195 after I got done logging. At idle it seemed to be around 200-203. Of course the intake temps went high sky at idle. By the time I turned my car off, it was still rising past 75.

Im leaning towards the reason for sure being boost leaks. Can someone explain why at a lower rpm it would be richer?(if there is a reason)



TIME COOLANT LTFT RPM AIR INTAKE TEMP
0.400 190.0 -10.0 2000.0 48.0
0.790 190.0 -10.0 1996.0 48.0
1.190 187.0 -10.0 1960.0 48.0
1.589 190.0 -8.00 1960.0 48.0
1.980 190.0 -8.00 2000.0 48.0
2.370 190.0 -8.00 2016.0 48.0
2.770 190.0 -8.00 2052.0 48.0
3.170 190.0 -8.00 2072.0 48.0
3.560 190.0 -8.00 2092.0 48.0
3.960 190.0 -8.00 2104.0 48.0
4.360 192.0 -8.00 2104.0 48.0
4.750 192.0 -8.00 2120.0 48.0
5.160 192.0 -8.00 2136.0 48.0
5.560 192.0 -8.00 2168.0 48.0
5.960 190.0 -8.00 2192.0 48.0
6.350 190.0 -8.00 2228.0 48.0
6.750 190.0 -8.00 2276.0 48.0
7.150 190.0 -8.00 2304.0 48.0
7.550 190.0 -8.00 2332.0 48.0
7.950 190.0 -8.00 2388.0 48.0
8.350 190.0 -8.00 2428.0 48.0
8.740 190.0 -8.00 2444.0 48.0
9.150 190.0 -8.00 2452.0 48.0
9.550 190.0 -8.00 2468.0 48.0
9.960 190.0 -8.00 2480.0 48.0
10.36 190.0 -8.00 2492.0 48.0
10.75 190.0 -8.00 2512.0 48.0
11.15 190.0 -8.00 2536.0 46.0
11.55 190.0 -8.00 2572.0 46.0
11.95 190.0 -8.00 2596.0 46.0
12.35 190.0 -8.00 2624.0 46.0
12.75 190.0 -8.00 2648.0 46.0
13.15 190.0 -8.00 2676.0 46.0
13.55 190.0 -8.00 2696.0 46.0
13.95 190.0 -8.00 2704.0 46.0
14.35 190.0 -8.00 2716.0 46.0
14.75 190.0 -8.00 2728.0 46.0
15.16 190.0 -8.00 2736.0 46.0
15.56 190.0 -8.00 2748.0 46.0
15.96 190.0 -8.00 2764.0 46.0
16.35 190.0 -8.00 2784.0 46.0
16.75 190.0 -8.00 2800.0 46.0
17.15 190.0 -8.00 2812.0 46.0
17.54 190.0 -8.00 2832.0 46.0
17.95 190.0 -8.00 2844.0 46.0
18.34 190.0 -8.00 2860.0 46.0
18.74 190.0 -8.00 2876.0 46.0
19.15 190.0 -8.00 2892.0 46.0
19.54 190.0 -8.00 2888.0 46.0
19.96 190.0 -8.00 2920.0 46.0
20.36 190.0 -8.00 2932.0 46.0
20.75 190.0 -8.00 2944.0 46.0
21.15 190.0 -8.00 2952.0 46.0
21.55 190.0 -8.00 2956.0 46.0
21.95 190.0 -8.00 2972.0 46.0
22.34 190.0 -8.00 2988.0 46.0
22.74 190.0 -8.00 2996.0 46.0
23.15 190.0 -8.00 3020.0 46.0
23.55 190.0 -8.00 3052.0 46.0
23.95 190.0 -8.00 3084.0 46.0
24.35 190.0 -8.00 3124.0 46.0
24.76 190.0 -8.00 3148.0 45.0
25.16 190.0 -8.00 3176.0 45.0
25.56 190.0 -8.00 3184.0 45.0
25.96 190.0 -8.00 3208.0 45.0
26.35 190.0 -8.00 3236.0 45.0
26.75 190.0 -8.00 3256.0 45.0
27.15 190.0 -8.00 3284.0 45.0
27.55 190.0 -8.00 3316.0 45.0
27.95 190.0 -8.00 3344.0 45.0
28.35 190.0 -8.00 3372.0 45.0
28.74 190.0 -8.00 3396.0 45.0
29.15 190.0 -8.00 3404.0 45.0
29.55 190.0 -8.00 3412.0 45.0
29.96 190.0 -8.00 3424.0 45.0

 

[2gGSX]

Well heres a log just showing a few things at full operating temp, I was just in 3rd gear. I hovered around 2k rpm before slowly climbing up to 3500. Im running alot richer then I would have liked. It seems that 2k and below it's at -11, and above that it's at -8.

My coolant temp rose to about 195 after I got done logging. At idle it seemed to be around 200-203. Of course the intake temps went high sky at idle. By the time I turned my car off, it was still rising past 75.

Im leaning towards the reason for sure being boost leaks. Can someone explain why at a lower rpm it would be richer?(if there is a reason)

That's not a huge difference nor may it be a continuous trend.

The boost leaks would definitely make you run more rich--get that test done!

 

[DSM_6SL2 Power]

That's not a huge difference nor may it be a continuous trend.

The boost leaks would definitely make you run more rich--get that test done!

What exactly do you mean by its not a huge difference nor may it be a continuous trend.
Im not exactly sure what your referring to.

 

[Calan]

What exactly do you mean by its not a huge difference nor may it be a continuous trend.
Im not exactly sure what your referring to.

There is not a lot of difference between -10 and -8. And, that may be just a temporary change to -8 that will revert back. What is STFT showing? Are you logging a specific LTFT, or "Selected LTFT"?

or...

Remember that the ECU switches LTFTs depending on airflow. So you may be looking at low LTFT one minute, and then high (mid) LTFT the next if you cross the airflow switchover point. What you see in a log depends on what you are logging with and what it allows you to monitor.

In your log above, if you crossed 250hz (150 for 2g?) at around 1960rpm and are monitoring which ever LTFT the ECU is using...then you would see the change because your looking at two different LTFTs. You need to log airflow to know for sure.

Regardless, your rich and need to fix the boost leaks and tune it

 

[DSM_6SL2 Power]

Well, im running rich, and thats what ill go about fixing now. Thanks for all the help guys.

 

[2gGSX]

First of all, pardon my sorry excuse for English in regards to that last post. Luckily Craig was able to explain what I meant.

For a pocketlogger, the LTFT displayed is "SelectedLTFT" which is whatever one is in use. LTFT Mid is updated between 150-400 Hz, so it's absolutely possible that the displayed LTFT simply shifted from LTFT Lo to LTFT Mid.

 

[DSM_6SL2 Power]

Alright, that makes sense.

To tune low throttle, you just try and get the STFT as close to 0 as possible, right?

Is it a bad idea to tune out boost leaks? I dont have the means to check/fix them until I go home for spring break.

 

[2gGSX]

As a rule of thumb, never start tuning around issues (especially ones that are easy to fix). It's a vicious circle, and you end up doing some really weird stuff which inevitably messes up.

To tune closed loop (low throttle), get your LTFT as close to 0 as you can. Your STFT will eventually hover around 0 unless you max out LTFT at + 12%.