Datalogging Results. Anyone know exactly what this means.

Hey,

 

So I went for cruise around town tonight to get some base data on my 05 Legacy GT. I made two datalogging charts at idle and one cruising around. I was wondering if anyone could tell me whats the problem of the slight stutter at idle. I noticed the MAF values were fluctuating. If you notice the RPM's they drop and recover 100 from time to time. Thanks

Data Log, Idle, Wednesday, June 30th 2010 (1).csv

Data Log, Idle, Wednesday, June 30th 2010 (2).csv

Data Log, Wednesday, June 30th 2010 (1).csv

You're logging a lot of parameters, which makes for fewer rows per second, which makes the logs less useful. Remove battery voltage, the AVCS parameters, and MAF voltage.

 

If the problem you're interested in is only happening at idle, you can remove wastegate duty as well.

 

The one thing that leapt out at me is that your long term fuel trim is almost maxed out. 15% is the limit and it's at 14.84%.

 

Logged data for the MAF and RPM parameters both tend to be a bit noisy. Due to the low data rate you're getting (due to the large number of parameters), they're going to look even more noisy.

 

In each log, what time did the idle stutter happen? And what was the AFR at the time?

Ill make some new maps tonight and what could my high fuel trim be caused by.

Your fuel trims may be off due to:

A post-MAF leak

An improperly scaled MAF sensor

An aftermarket intake that has not been accounted for, which is really just the same as above (improperly scaled MAF sensor.)

A malfunctioning o2 sensor

That's a good list. Does the car still have the stock intake?

Yes the car still has the stock intake so you can knock that one out. I uploaded a new datalog. This one has been things to try and capture more info.

 

NSFW i was reading some of your earlier post and i appreciate what your doing for your fellow lgt'rs. I was debating if maybe a new intake would solve the problem. Like a Cobb SF?

Data Log, Friday, July 2nd 2010 (1).csv

You should fix this problem before swapping intakes.

Where in that log (what time) does the problem happen?

Throwing parts at a problem that is not understood is a recipe for frustration and potential dissaster.

 

Do you have any logs of cruising or any way to pull a learning view from the ECU?

 

Did you purchase the car new? If no, do you know who owned the car prior and if it was ever modified?

 

Do you have AccessTUNER? If yes, would you provide a screenshot of your MAF sensor scaling?

I do not have AccessTUNER. I do have some earlier maps of crusing. If you check the 3rd datalog in the first post its cruising. I cleaned the MAF twice. I have a stock intake. I did not but the car new but i bought it with 40,000kms on the dial and all was stock never modified. Dealer agrees. Let me know what I should do and I will provide the proper maps. Ill try to download AccessTUNER and give you a screenshot of the MAF scaling.

 

Question: Where can I get AccessTUNER?

http://accessecu.com/register/cobb.php

 

If you are certain the vehicle has never been modified, then no reason to post the MAF table. It will be stock. This is likely a leak after the MAF sensor.

Maybe the coregated tubing following the MAF sensor. This is why I was debating a new intake to solve this problem.

Could be... I would pressure test to see if there are leaks.

Hey,

 

Im looking for someone's Stage 1 Logs of a completely stock 05-07 LGT with a OTS Cobb Stage 1 Map. Thanks.

Can I ask what are you looking for? You might not get meaningful data since no two cars run identically the same.

Sorry for the slow response. Im looking for what values a car should be putting out. Say MAF reading and All that good stuff. Im trying to figure out what this rough idle is all about.

Got your pm...

Whats your mods? Is this problem apparent with the Cobb tune and untuned? Post logs, the following paramaters will do:

Engine Speed (rpm)

Calculated Load (load)

Dyn. Adv. Mult. (DAM)

Ignition Adv. (deg)

Knock Correction (deg)

Throttle Position (%)

Boost (PSI)

Wastegate Duty (%)

Mass Air Flow (g/s)

MAF Voltage (V)

Yes the problem is apparent with both the tuned and untuned. The car is completely stock the only thing is a stage 1 tune from Cobb. The hesitation or stutter while pulling is completely gone since ive gone stage 1 but the idle stutter remains. I would like to do a few mods but not until I figure out this problem

Here's the link of some datalogs. Ill try and get more for you this evening.

 

http://legacygt.com/forums/showthread.php/datalogging-results-anyone-know-exactly-means-140762.html

Threads merged, looks like a lean idle is the issue. Check your airbox to see if it is secure.

Ill check that as soon as possible. Do you think if I use the brake cleaner method to check for any cracks in the airbox and piping leading up to the engine? If there's a leak the revs will build up. Would replacing the airbox with a Cobb SF be a good idea or should i try to find the problem first?

 

Also I know your saying im running a bit lean but what value would be considered as perfect numerically. Also for other things such as:

 

Calculated Load (load)

Dyn. Adv. Mult. (DAM)

Ignition Adv. (deg)

Knock Correction (deg)

Boost (PSI)

Wastegate Duty (%)

Mass Air Flow (g/s)

MAF Voltage (V)

 

Thanks

Bump

Short and oversimplified answers inline...

 

Also I know your saying im running a bit lean but what value would be considered as perfect numerically. Also for other things such as:

 

Mass Air Flow (g/s) This is just how much air the engine is pulling in. Higher is better.

Calculated Load (load) This is Mass Air Flow divided by RPM.

Dyn. Adv. Mult. (DAM) 1.0 is ideal, less is bad.

Ignition Adv. (deg) There is no short answer.

Knock Correction (deg) Zero is good, nonzero is cause for concern.

Knock Learning (deg) You didn't list this, but you should log it. Zero is good, nonzero is cause for concern.

Boost (PSI) More is better. Unless you have too much.

Wastegate Duty (%) There is no short answer.

MAF Voltage (V) As long as it's under 5.0 volts, it's fine.

 

I'm half-joking when I say that more is better.

 

Load is an axis for the timing and fueling tables, it's primarily useful in logs because it tells you which cells you should change if you need to adjust fueling or timing.

 

Longer answers here:

 

http://www.romraider.com/forum/viewtopic.php?f=33&t=6156

 

And here:

 

http://www.romraider.com/RomRaider/Articles

Perfect, this is exactly what I was looking for. Now just to find out why im running lean. Will look at the air box this weekend. Any suggested test?

NSFW. Ive been reading your post on Romraider and it clears up many of my questions. Your write up is perfect.

 

http://www.romraider.com/forum/viewtopic.php?f=33&t=5384

http://www.romraider.com/forum/viewtopic.php?f=33&t=6156

 

Thanks

Glad to help!