Cold start afr?
Apr 2, 2012 | 01:46 PM
#11
What should I be aiming for the cold start afr? Right now my truck idles at like 10-11 until it goes into closed loop and it stinks pretty bad. It has a pretty crappy maf tune. I bought hptuners so I'm gonna start playing with it and convert it to sd. Just wondering what you guys are commanding on cold starts?
specs are 5.3L mp76 with a 225/225 .581 113lsa cam if it matters.
specs are 5.3L mp76 with a 225/225 .581 113lsa cam if it matters.
Apr 2, 2012 | 02:15 PM
#12
Stoich at 0 degrees is way too lean. You need to be mid to high 11's if the motor is that cold. You will know when it's too lean because if you drive up the street, it will pop out of the exhaust real bad.
Anything 140* and up in the open loop EQ table should be set to 1. That is the main fueling table referenced on warm up.
I don't think there is a better purchase than your own tuning software.
Anything 140* and up in the open loop EQ table should be set to 1. That is the main fueling table referenced on warm up.
I don't think there is a better purchase than your own tuning software.
Do this as you probably are going to be very surprised.
Apr 3, 2012 | 01:24 PM
#13
So getting some mixed input here. Does it need to be the same afr as stock or should it be richer with turbo and aftermarket cam?
Apr 3, 2012 | 01:47 PM
#14
I have found that leaning it out a little bit with a cam helps. Bigger cams will most often have lower DCR and therefore less heat during compression, so cold idle can suffer. It can't burn all of the fuel, so it makes less power at idle and can result in a PCM trying to compensate and surging. Also makes it smell real bad, like you mentioned.
Apr 3, 2012 | 04:59 PM
#15
I have found that leaning it out a little bit with a cam helps. Bigger cams will most often have lower DCR and therefore less heat during compression, so cold idle can suffer. It can't burn all of the fuel, so it makes less power at idle and can result in a PCM trying to compensate and surging. Also makes it smell real bad, like you mentioned.
Apr 6, 2012 | 10:21 PM
#17
Here is the tune. I will try get a log tomorrow.
I compared to a stock tune file and it looks to be the same except my stft are disabled while the stock tune is enabled. Should I enable them?
I compared to a stock tune file and it looks to be the same except my stft are disabled while the stock tune is enabled. Should I enable them?
Apr 6, 2012 | 10:24 PM
#18