looking for table causing lean idle
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 50
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From: canada brandon
looking for table causing lean idle I have tuned my o2 camaro to run in speed density with hptuners os and also have tried with maf. With both methods the car will run lean at idle after it sits idling for several minutes. normal driving is fine. my commanded afr is 13.7 at idle and my actual will go as high as 17:1. Is there an idle table effecting the calculated air flow and intake air temperatue?
Why is your commanded AFR 13.7?, you should get it set correctly at 14.7 ish and set your PE, WOT 12.7 ish, make sure your IFR tables are stock (if stock injectors) DON'T TUNE THESE!, you need to TUNE the AIRFLOW tables, ie. the VE and MAF...for the idle it's the idle airflow tables that you need to tune, log the LTIT and STIT (I only use the STIT and keep LTIT turned off) and adjust the Idle airflow tables accordingly, my cam is not big but not small and I can make mine idle at like 500 rpm, not good but at like 700 it purrs.
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 50
Likes: 0
From: canada brandon
The reason the idle is at 13.7:1 and at really low kpa is because it gets red of almost all the come bucking, rough running at light load. The car drives way better like this with the cam I have (tsp 233/239). If you read the post you will see that my afr's are always what they are commanded to be (13.7 light throttle, 14.7 other areas, 12.7 full throttle).They only vary when the car sits and idles 5 minutes. The ve tables and maf tables are dead on for everything else.
Check your commanded fuel while in OL table; it's B3605 in EFI Live. Don't know what it is in HP tuners. The table sets OL fueling based on MAP & ECT. Also, can look into the after start enrichment tables to make sure that they are not part of the issue. Probably not, but, worth a look.
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 50
Likes: 0
From: canada brandon
Thanks for the reply. I have gone through those tables and they should be ok. The problem is more when the engine sits hot and then you start it or it idles for a long time. The commanded afr is always 13.7 when it does it. The maf readings (or map) are in the same spot when it runs 13.7 and when it runs 17:1 after the hot start/long idle. Is it do to the size of cam? I can get +8 to -8 afr error at the same map or afr points depending on idle time.
Go to my site and download the RussK-Idle-Airflow.cfg file. Right click the file, save to your hard drive in the config folder for HP Tuners.
Open the scanner, open this cfg.
Do a cold start and begin logging, idle only, do not touch throttle.
Allow to idle until up to full temp.
Copy and paste the numbers in Histogram table 1 into the p/n section of the base running airflow table.
If it is an automatic, do a cold start again, do all of the above except when you start it, immediately put it in gear and run up to temp, copy and paste table 2 into the same base running air flow file.
Open the scanner, open this cfg.
Do a cold start and begin logging, idle only, do not touch throttle.
Allow to idle until up to full temp.
Copy and paste the numbers in Histogram table 1 into the p/n section of the base running airflow table.
If it is an automatic, do a cold start again, do all of the above except when you start it, immediately put it in gear and run up to temp, copy and paste table 2 into the same base running air flow file.
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Staging Lane
Joined: Jul 2008
Posts: 50
Likes: 0
From: canada brandon
69lt1bird is this a histogram setup table to log stit and ltit? I will try it tomorrow. I am logging afr with an lm-1 wideband. I think it is pretty accurate as back when I was in closed loop (not now) it would read 14.6 in closed loop. I always thought the maf would control fuel at idle (in a Maf tune) but I will try that file and see what happens. Thanks for the help.
So, are you saying that in open loop, the wideband is showing it go lean after sitting idling? And when this happens, the commanded stays 13.7? If that is the case, I would say it is exhaust leaks showing up as a lean condition and it isn't really lean at all. Header leaks always effect O2 readings worse at idle when air gets pulled into the leaks...
