Running rich, no codes.
08-05-2011, 06:53 PM
#1
Running rich, no codes. Here is a datalog, can anyone help me figure this out - why I'm getting 14 mpg on the HWY?
http://www.mediafire.com/?3e4tp5gt7tk0hml
http://www.mediafire.com/?3e4tp5gt7tk0hml
08-05-2011, 08:36 PM
#2
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I don't know for certain that you're going to necessarily drop codes if you're rich. I was running rich after my header install and it turned out being faulty O2s that I apparently jacked up when I reinstalled them.
08-05-2011, 09:06 PM
#3
Vacuum looks not so great for the combo in your sig and the speed/load you were running. Timing is low for the cruising speed and load at around 32 deg should be more like 37-40 if not a bit more depending on the combo. Try and keep it under 1800 rpm... go faster and get into 6th, less vacuum, less engine speed, more ground speed.
Lots of cold starts will absolutely destroy your econ.
I don't really see anything crazy just the small things I mentioned.
Airflow isn't high enough to make it jump out at least to me, then again 10% is only 2.5g/sec.
Also you have what seems like some very large injectors. It takes time to open and close them, the big injectors make the control crappy. If you can only trim in 0.1ms increments, and you only have 2.0ms to fire the injector and 1ms of that is opening and closing what are you left with for fuel control? That might account for a little bit of your issue.
Lots of cold starts will absolutely destroy your econ.
I don't really see anything crazy just the small things I mentioned.
Airflow isn't high enough to make it jump out at least to me, then again 10% is only 2.5g/sec.
Also you have what seems like some very large injectors. It takes time to open and close them, the big injectors make the control crappy. If you can only trim in 0.1ms increments, and you only have 2.0ms to fire the injector and 1ms of that is opening and closing what are you left with for fuel control? That might account for a little bit of your issue.
08-06-2011, 08:18 AM
#4
Vacuum looks not so great for the combo in your sig and the speed/load you were running. Timing is low for the cruising speed and load at around 32 deg should be more like 37-40 if not a bit more depending on the combo. Try and keep it under 1800 rpm... go faster and get into 6th, less vacuum, less engine speed, more ground speed.
Lots of cold starts will absolutely destroy your econ.
I don't really see anything crazy just the small things I mentioned.
Airflow isn't high enough to make it jump out at least to me, then again 10% is only 2.5g/sec.
Also you have what seems like some very large injectors. It takes time to open and close them, the big injectors make the control crappy. If you can only trim in 0.1ms increments, and you only have 2.0ms to fire the injector and 1ms of that is opening and closing what are you left with for fuel control? That might account for a little bit of your issue.
Lots of cold starts will absolutely destroy your econ.
I don't really see anything crazy just the small things I mentioned.
Airflow isn't high enough to make it jump out at least to me, then again 10% is only 2.5g/sec.
Also you have what seems like some very large injectors. It takes time to open and close them, the big injectors make the control crappy. If you can only trim in 0.1ms increments, and you only have 2.0ms to fire the injector and 1ms of that is opening and closing what are you left with for fuel control? That might account for a little bit of your issue.
08-06-2011, 09:34 AM
#5
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Am I the only one that sees the "data ok" box flash red every so often? Also, does anyone else see a 5 second gap between rec# 242-243? Just wondering if it's just my computer or the actual datalog because all my logs do that and with the sound up it dings and gets very aggrevating.
But to the OP, I only have experience with datalogging my car, so I'm no expert....but my O2 mvs jump around like that too. I'm pretty sure that's normal.
Do you have a wideband O2? How do you know it's running rich? What kind of O2's and how old are they?
But to the OP, I only have experience with datalogging my car, so I'm no expert....but my O2 mvs jump around like that too. I'm pretty sure that's normal.
Do you have a wideband O2? How do you know it's running rich? What kind of O2's and how old are they?
08-06-2011, 11:32 AM
#6
The o2 mv are SUPPOSED to do that. There is no mystery as to why, and I will explain. The narrow band can't tell you anything besides which side of stoich it is on (no matter what the stoich is for your pump fuel this week). So what your pcm does is based on a set point in mv for o2 switching it adds and pulls fuel to try and cross that switch point. Its really a simple and somewhat dumb algorithm. If its on the rich side the short term trims pull fuel and if its on the lean side they add fuel until they cross the threshold. What you get is an average a/f ratio of stoich for your fuel. The only calibration work on the oem side is to set the gains for the short term and long term trims achieve some stability. Pretty easy task on a dyno with a dev ecm.
If you look at the response of a narrow band to air fuel ratio it should be obvious why it works this way. Its also dirt cheap and effective.
The data box thing is probably because of her data cable being loose a usb/rs232 adapter or some other wiring issue.
If you look at the response of a narrow band to air fuel ratio it should be obvious why it works this way. Its also dirt cheap and effective.
The data box thing is probably because of her data cable being loose a usb/rs232 adapter or some other wiring issue.
