Where's CAGS in $8D???

I drive a 1990 Corvette running $8D on a 1227727 ECM. I did most of the tuning for a new engine ~3-4 years ago, and I'm revisiting the subject to dial things in finally. The Corvette has CAGS (Computer-Automated Gear Selection) that forces you go shift from first to fourth sometimes. I promptly disabled this when I made my first BIN years ago. Now I'm trying to find this, and I can't find it anywhere.

I feel like I'm losing my mind. I've tried probably 4-5 XDFs, and none of them have parameters related to CAGS. I vividly remember seeing these parameters (I think relating to TPS, MAP, and vehicle speed) when I was first tuning; I think I set min speed for CAGS to the max or something to disable it.

While editing BINs based on hex addresses is Greek to me, I've even tried to find info on CAGS parameters' hex addresses to no avail. Please tell me I'm not insane.

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Originally Posted by 90Vette

I drive a 1990 Corvette running $8D on a 1227727 ECM. I did most of the tuning for a new engine ~3-4 years ago, and I'm revisiting the subject to dial things in finally. The Corvette has CAGS (Computer-Automated Gear Selection) that forces you go shift from first to fourth sometimes. I promptly disabled this when I made my first BIN years ago. Now I'm trying to find this, and I can't find it anywhere.

I feel like I'm losing my mind. I've tried probably 4-5 XDFs, and none of them have parameters related to CAGS. I vividly remember seeing these parameters (I think relating to TPS, MAP, and vehicle speed) when I was first tuning; I think I set min speed for CAGS to the max or something to disable it.

While editing BINs based on hex addresses is Greek to me, I've even tried to find info on CAGS parameters' hex addresses to no avail. Please tell me I'm not insane.

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FINALLY found it. "$8D" here is the only of ~8 XDFs I reviewed that had it ("C.A.G.S. Enable Coolant Temp" at 0x300).

I recall seeing a lot more parameters, and I see in the XDF that the next address is 314. Perhaps 301-313 are additional CAGS parameters? Anyone know how I'd figure that out?

Alright, found the hack for $8D, and it lists the missing parameters. L8301 (0x301 in TunerPro) is reset speed, L8302 (0x302) is enable speed, L8303 (0x303... you get the pattern) is disable speed, L8304 is RPM disable, L8305 is %TPS for disable, L8306 is kPa low baro disable, and L8307 is kPa low baro for re-enable.

I assume CAGS is enabled if vehicle speed reaches the value indicated by L8302, it's disabled if speed exceeds L8303, and it's re-enabled if speed falls back below L8301. L8304 and L8305 are also both pretty obvious; I'm assuming the former indicates the max RPM at which CAGS will trigger, and the latter the max %TPS.

I can't quite decipher L8306 and L8307, though. By the hac's comments, I would assume that 306 indicates the maximum allowable MAP for CAGS to trigger, and CAGS will be re-enabled once MAP falls below 307. Both of these are set to 00 in several bins I've looked at though, which would mean CAGS would always be disabled. I have a bin for a '90 Corvette with the 6-speed, which is what I have, and I know for a fact that CAGS was enabled for that combination. Plus, all of the other parameters are set with reasonable values in these bins. Does anyone know what's going on here? Were these parameters just unused?

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Originally Posted by 90Vette

I can't quite decipher L8306 and L8307, though. By the hac's comments, I would assume that 306 indicates the maximum allowable MAP for CAGS to trigger, and CAGS will be re-enabled once MAP falls below 307. Both of these are set to 00 in several bins I've looked at though, which would mean CAGS would always be disabled. I have a bin for a '90 Corvette with the 6-speed, which is what I have, and I know for a fact that CAGS was enabled for that combination. Plus, all of the other parameters are set with reasonable values in these bins. Does anyone know what's going on here? Were these parameters just unused?

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The CAGS logic was removed from the S_AUJP code as it was deemed to be unnecessary. The associated calibration values 0x301 through 0x308 are not used but were retained for future use and set =0. If you want to use CAGS, must use a BIN before S_AUJP.

Thanks. I'm still based on the stock bin (ARFP but with the 3.33 rear end), and I was just trying to get a better feel for what's in that. I suppose there's not gonna be much support around here for stock bins with everyone running S_AUJP.

In fact, I'm working on transitioning to S_AUJP v6 myself. I don't really need or want CAGS, but exploring what was going on there is just part of my self-education before I feel comfortable enough to start messing around with patched bins.

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Originally Posted by 90Vette

. . . I don't really need or want CAGS . . .

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Understand, and this is exactly why it was eliminated.