I have my car running very well. Now that's it running well, I just HAVE to make it run better, right? One of the 'small' problems I have is what me and my buddy call, 'the hurky jerky'. It's a hesitation that occurs under very slight load between 25 and 35 mph,'cruising speed' and 1200 to 1500 rpm's. Sometimes it's very slight, sometimes it's quite annoying, like the engine just quits running for a revolution then snaps back on. When it's bad it bangs the rear end, when it's slight you almost can't notice it.
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We've tried logging every table while driving and inducing this. It's not any spark, VE, MAF, yada, yada. The other day it was occuring and when it did I punched my clutch in and the engine went from 1300 rpm's to 1600, then quickly settled to 850. I thought it must be the Throttle Cracker. I pulled some air out of the table and went and found it was much less, but it happened in other places, like at 35 instead of 30 and 1400 rpm's instead of 1300. Also, while it was happening in another area when I punched the clutch in the rpm's would drop, or rise...
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It definitely seems that throttle cracker is contributing to this, but just multiplying the whole table, or changing values by row or column isn't giving me the granularity I need and the table provides, so... maybe a custom PID?
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I'm now guessing what PIDS contribute to the final airflow sum, or if that is the one I need to base it off of. I'm wondering if the PID should be based on IAC_SUM_DMA, or MAF. I'm thinking I could make a sort of 'BEN factor' map by using the measured airflow and the final calculated airflow, and subtract the contributing PIDS to come up with a 'BEN factor' to apply to the throttle cracker table. I am doing one now with IAC_SUM_DMA + (IAC_TF_DMA - IACDES_B). Not sure, only guessing at this point. I can't see the tables in the .prn file to know how the DMA's are being combined to form the calc'd pids. The only ones I have in sae_generic.txt are the few hp, kw, VE, and AFR customs.
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I'll definitely report what I find, but I know there are some experts with this stuff here that may be intrigued by this and be willing to give me an educated guess as to where to start first or stop wasing my time and thought process. Also, if this technique works, there are a number of other tables that would benefit from this also, Throttle Follower being another possibly.
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I just read the the link above The sticky above. and it looks like GM.CYLAIR_DMA * 8 is what the map should be based on. Going on from here...
Ok, after more research here is what I came up with...., just thinking out loud...Code:({GM.CYLAIR_DMA.cylair}*8)-(({GM.DYNAIR.gps}*8)-{GM.IAC_TF_DMA.gps})