A/F Ratio and Fuel Trimming/Scaling Question.

[AnthonyR23]

Hey guys, so I just bought a Innovate LM1 wideband kit from ebay that should be here within the next few weeks. So, this is something I have always wanted to get. Just have one quick question. So I do plan on replacing my TB, TB Spacer with a 75mm unit, and am going to get a larger mass air meter, thinking velocity 96mm meter and probably a 4 inch andersand power pipe.

So I want to use what I have now just until I get the above intake units, is it a bad strategy to account for a maf meter that is supposed to be calibrated for 30 pound injectors, that could be a problem, by adjusting the fuel pressure to balance things out to closer to 14.7.1, especially before an emissions test??? Thanks! I heard it is also helpful to turn the timing back to 8 degrees aswell.

 

[strtrcr50]

Did you ever get your eec tuner working? Also, I'm assuming that you have 30 lb injectors to go with that mass air...

 

[AnthonyR23]

I actually ended up reselling the tuner, got it to work, but am really interested in the moates quarterhorse, so I am probably going to get that in the next few weeks. I would be happy with the above tb, spacer, tube and mass air meter with that innovate kit and the quarterhorse this year. Then Next year I will work on some rear end type improvements like gears, possibly shocks, control arms and some reinforcements, and some need asthetics.

Ya I do have 30 lbs injectors, .... it's a 347, tfs heads, intake, powermax 2030 crane cam. Etc.

I was just thinking that if my maf is kinda off, and it takes a slight adjustment in fuel pressure to get it closer to 14.7.1, that may help me with emissions. I don't want to throw of the fuel scalling trimming though, by changing the fuel pressure. But I think until I get that tuning software where I can tune on the fly I probably can still make some adjustments to get it emissions ready.

 

[strtrcr50]

What kind of emissions do you have to pass? Dyno, or just a sniffer? Do you still have your egr and smog pump? What is your wideband saying the a/f is at idle? To actually change the mixture, you're going to have raise/lower the fuel pressure enough to get past the percentage the eec will compensate for btw. Not something I'd do.

 

[90lxcoupe]

messing with the fuel pressure isnt going to do much for you but cause more headaches, set it around 38-40 psi and leave it, the computer uses the o2 sensors to determine the fuel curves.

what your doing is like trying to take a lug nut off with a hammer and chisel, its gonna do something, but the results arent gonna be what you want. get the right tool for the job, like a custom chip, tweecer, or a PMS

 

[Foxfan88]

get yourself that QH and then input the correct MAF curve for your meter as well as the injector slopes. since you have a WB, shouldnt need much more that maybe some slight tweaking on the maf curve to get things in check then.

 

[AnthonyR23]

I totally agree that I need a tuning device to do this properly, I have been playing with the unregistered versions of a bunch of programs, like bin editer and eec analyzer. So I already have a good idea of what I would like to change. I am curious to see what the wideband tells me as is.. with the fuel pressure set at 39. And I am curious to see if changing fuel pressure from 39 to say 42, only 3 degrees makes any difference. Probably won't since the computer will be compensating for the changes I make, but it will still be interesting to see. One quick question. I have a set of o2 sensor's that are bad. What I was wondering is if I take out the good o2 sensor's, and plug in the two bad o2 sensors just to plug the holes and keep the two bad sensor's unplugged. What will the car be running off of. Then with the wideband if I set the fuel pressure to the closest point to 14.7.1 ranging from say 36 psi to 42 psi. Then put the good o2 sensor's back in and plug it in. Wouldn't I be compensating (in the meantime) for a maf that could be slightly off. While making sure to not change the fuel pressure by more than 3 psi either way. Like I don't think this will have a terrible effect until I get a tuner. How does the engine run without o2 sensors?