Help, I'm extremely confused

Printable View

08-27-2009
0-60n3

Help, I'm extremely confused

I'm chasing my tail on a couple of issues. All sparking from me doing research and confusing me further.

Basically I have been chasing the perfect wot a/f. It seems to flucuate. I was going to different dynos and getting different results. So I decided to buy a wideband.

With the same PE setting in the tune, the wot a/f seems to flucuate. I believe it's related to the LTFTs. On the wideband during the log attached during wot the a/f was 13.7-13.0. With the same tune I had an a/f of 13.0-12.4ish just a few nights before. The 8/22/09 log was with the same tune as the 8/26/09 logs.

1) My logs show that when I go wot my fuel trim cell is 15. How/where do I find that cell to modify it?
2) When i go wot the logs show that my LTFT is negative. Is that subtracting from my PE Enrichment table?
3) My commanded a/f ratio seems to stay at 14.7, even at wot. Why is that?
4) In the attached tune what should my commanded a/f be at wot?
5) How can I tell if PE Mode is enabled in the log?
6) At the beginning of the 8/22/09 log the 02 sensor voltages vary but ALOT. Cause for concern?
08-27-2009
Bill@HPTuners

1. You can view the different cells in the OL & CL section of the help file www.hptuners.com/help
2. No, negative numbers do not carry over into wot fueling.
3. Because thats whats being commanded in your fueling tables.
4. It would be best to get on a dyno to find best power then dial it back slightly, most LS2's are between 12.5-13.0:1 wot similar to most ls1's.
5. It is but I believe theres a status bit you can log as well.
6. normal.

You have alot of tuning to do from the looks of it.
08-27-2009
0-60n3

Quote:

Originally Posted by Bill@HPTuners

1. You can view the different cells in the OL & CL section of the help file www.hptuners.com/help
2. No, negative numbers do not carry over into wot fueling.
3. Because thats whats being commanded in your fueling tables.
4. It would be best to get on a dyno to find best power then dial it back slightly, most LS2's are between 12.5-13.0:1 wot similar to most ls1's.
5. It is but I believe theres a status bit you can log as well.
6. normal.

You have alot of tuning to do from the looks of it.

If the negative numbers don't cary over why does the LTFT show -6 at WOT?
How do I log the status bit?
I realize it's normal for the 02 sensor voltages to vary, what I meant was that bank 1 and bank 2 vary by alot.
If 14.7 is what's being commanded...what table is causing that?

Funny thing is that my car has been tuned by one of the most well known LS tuners in the country. Interesting.

Can someone please tell me how to setup a histogram and step by step how to dial in the fuel trims...I think that would be a good start.
08-27-2009
Tony

Your PE EQ ratio is .996, which is commanding 14.75 AFR (stoich/.996=14.75).

If you want 12.8 AFR, EQ needs to be 1.148
08-27-2009
0-60n3

Quote:

Originally Posted by Tony

Your PE EQ ratio is .996, which is commanding 14.75 AFR (stoich/.996=14.75).

If you want 12.8 AFR, EQ needs to be 1.148

With a 1.13 I was getting 11.4.:banghead:
08-27-2009
Bill@HPTuners

Quote:

Originally Posted by 0-60n3

With a 1.13 I was getting 11.4.:banghead:

That just means your injector &/or maf tables need to be tuned.
08-27-2009
Tony

Is this the same tune that you went 10.90's@125?
08-27-2009
0-60n3

Quote:

Originally Posted by Tony

Is this the same tune that you went 10.90's@125?

Close. Supposively the shop dialed in my LTFTs after I complained. I still don't think they are where they need to be. But pretty much the same tune. Same timing and such.
08-27-2009
0-60n3

Any way you can coach me through tuning the MAF, etc so that my fuel trims are spot on? I'm pretty technical...just need to push start on this histogram business.
08-27-2009
0-60n3

Of topic but if I see 0.2-0.8 KR from 5200-6000 is it something I should be concerned with? I see that a lot in that range. I tried taking out 1 degree of timing but it didn't stop it.
08-27-2009
0-60n3

Would the the size of the injectors make a difference on what I would put in the PE field?

For example, would a 32lb injector require a higher number than a 46lb injector?
08-28-2009
RWTD

Quote:

Originally Posted by 0-60n3

Would the the size of the injectors make a difference on what I would put in the PE field?

For example, would a 32lb injector require a higher number than a 46lb injector?

Oh man!

NO! PE is a Commanded table. You set it to what you want, and then you dial in the MAF and/or VE table until your Commanded becomes Actual.

And, FYI, whatever injector you have you put the proper calibration data for such in the Injector parameters. Also, you can not just rape the IFR table. You need ALL the proper injector calibration data.

What injectors do you have anyway? Brand and part #, please.
08-28-2009
0-60n3

FAST 46lb injectors. Is the calibration correct for those?

I currently have the LTFT disabled and I'm trying to dial in my PE. Right now I have 1.04 in the colum and I'm seeing mid 12s in second gear and 12.0s in 3rd gear. So should I only worry about what the a/f is in 3rd gear at wot since I have an A4?

Am I going about this the correct way or do I need to dial in MAF/Injector calibration first?

Wanting to go to the track tomorrow and I want to make sure I will be ok if I just dial in the PE for now. With the LTFTs disabled my STFTs tell a big story. Seems very rich in some areas and lean in other areas. I'd really like to know exactly how to tune the fuel trims. Because reading is confusing me. I've always wondered if the shop made the injectors too small in the tune.