I have tried quite a few different things and I can't seem to figure out exactly what to do to get the o2 sensors working like factory. I have it running good in open loop, but I would like to put it in closed loop like factory has. What would someone suggest that has done it before to get it to work right, without surging or being sluggish? thanks
Post your tune and a description of mods. Just bigger injectors? Still need a part number to check the file.
I don't have my tune on this computer. I have decaped stock injectors, flow like 75 pounds. It is a lq4, 230 duration cam, 3 bar, s480. I have it running good it open loop and have for a couple years, I am just curious of how to get it to also run good while in closed loop. Have you done that before? If so, what tables do you mess with or what do you leave stock
Did you send the injectors out to be flowed?
De-capped injectors can be a huge pain to get sorted out.
yea i did. And they are all real close. I haven't found decaped injectors to be tough at all to tune. I have done a couple of them and I think they are better than siemens deka injectors. Everything on the truck is real dialed, it is just the closed loop fueling that wants to surge.
Most likely proportional fueling. The factory computer swings the fueling up and down a bit across stoich during normal closed loop operation. With bigger injectors these swings can get out of hand and cause surging. The bigger the injector, the more this can be a problem if it is not tuned properly. With big cams it is common to cut off this feature at idle to smooth out cam lope.
Respectfully, You realize this contradicts itself.Originally Posted by ryan_axberg
You can try slowing down the proportional tables and add time to the integral if your OS has it.
Injector changes do not typically require changes to get the O2's to work right. Long tube headers and sometimes camshafts will. This problem is likely because there is no good injector data available for decapped injectors. If it needs to make a small fueling change and the injector data isn't correct..the small change it made to the injector PW will not be right. Does that make sense?
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I was meaning the air fuel is really close to my commanded all the time when in open loop and the issue of surging only arises if I put it into closed loop. For the injector data I kept that stock except for the flow rate, with my thinking that the body of the injector is the same all that I am doing is removing the cap so it seems like it should act the same as the stock injector but flow more. Thanks I will try messing with it some more and see what I can do with it. I really don't need it to be in closed loop, I just don't like not knowing how to do something that I am trying to do.
yea, for me it isn't a problem at idle it is more so like light throttle that I am struggling with. thanks
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