Ls1 problems
11-03-2008, 10:33 PM
#21
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you get **** gas mileage because you just completely disabled all the learn and adaptive strategies of the factory PCM. you're stuck in open loop - the car is running off preset tables based off rpm and throttle position.
this is not a tune. this is a ghetto make it work, or suitable for a racecar. if you take a car that's tuned in such a manner say to an elevation or a dramatic change in temperature, anything that would affect the air charge, the car is going to run even shittier because it's working off preset tables with no adaptive strategies.
that's not tuned, that's a car stuck in limp mode.
this is not a tune. this is a ghetto make it work, or suitable for a racecar. if you take a car that's tuned in such a manner say to an elevation or a dramatic change in temperature, anything that would affect the air charge, the car is going to run even shittier because it's working off preset tables with no adaptive strategies.
that's not tuned, that's a car stuck in limp mode.
limp mode is when the ecu senses a problem or a significant sensor failure (MAF for example). it runs the engine on the absolute bare minimums. 2500rpm rev limit, NO power, SUPER rich, etc. its designed to limp your car home or to a shop.
open loop is when the computer does not use data from your o2 sensors to make slight adjustments to your fuel trim/ignition timing. lsx's are pretty amazing engines. since they use MAF AND MAP systems they have a pretty damn good idea how to adjust fuel trims/ignition based on whats going into the engine.
my car was tuned at about 1500 feet above sea level, and i was in salt lake city (6500 feet) racing over the summer. i had 0 drivability issues or changes other than less power because of the alt change.
and my car IS a racecar. my entire argument in this thread is that THEY ARE NOT A NECESSITY TO MAKE THE ENGINE RUN. YES i know they are needed for any form of economy, but it will NOT hurt your performance (see below)
fast400, i dont need to "relook" my info. when you go wide open throttle (generally anything over 50%~ throttle), your engine runs in open loop and your o2 sensors have 0 input in your fuel trims and timing. you may need to brush up on your EFI system knowledge.
11-15-2008, 09:55 PM
#22
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I still didn't install my 02 sensors... and my car seems waaaay under powered... I mean it dosn't even spin in first gear... (240sx ls1 swap 4l60e tranny) could all that power loss be from my 02 sensors? I personally doubt it, but I've never encountered a situation where I've actually unplugged the 02's and compaired... anyhow, my car dosn't even downshift if I go WOT on 3rd gear... (didn't clear o2's by reprogramming my PCM, I'm buying 2 on monday...
