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I'm simply saying its unlikely to be the OP's problem on his tune being SD-only, since that in and of itself, is less likely to start. If I'm wrong and his tuner did that, then so be it, at least his problem gets solved.
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I might agree with you, not sure. I think he has a mechanical/physical problem with what the MAF sees due to location in the tube or an air leak. I don't blame the tune, MAF, or ECM, I bet they're all fine.
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Originally Posted by Super73
Take this in to consideration. GM's fall back SD mode puts you in a low timing table with most ECU's. Commanded timing in this "low" timing table has anywhere from 10-15* of advance pulled.
In addition every one I have forced in to SD by either unplugging the MAF or failing it through the tune has required VE table clean up. They are no where near stoich at idle/light throttle and are heavily relying on the factory narrow band O2 sensors to compensate which are not tied in to WOT fueling which should absolutely be addressed.
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I've never seen this. What ECMs do you believe cause this, as it would be important to avoid, but there's no info here. So far as I can tell the LS3 doesn't do that.
You'd want to fix the fallback timing table and clean up the VE if that's true, though I haven't actually encountered either, I'm by no means familiar with every GM ECM.
You guys are sorta funny - I've been daily driving the car you guys are afraid won't even run this whole thread! What doom and gloom! Of course I can only claim this for the LS3 but it works great.
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I did try another maf sensor that I had laying around and as soon as I pluged it up the engine stublemed and just cut off again . so that tells me something
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Doesn't tell you what you think it does. Your tune is likely fine and both MAFs are fine, you either have a air leak like an unrestricted PCV or the MAF is sampling from a bad spot in your tube. It's one or the other. You'll need to fix it or run without the MAF.
Stop cleaning and replacing your MAF, there's nothing wrong with it!