I'm in the middle of the SD conversion from maf, How can I handle this VSS issue? on my '165, the vss input was pin A10, Where can I properly pin this on my '727 ecm so it knows what speed I am traveling? I assume I will have to play in the bin some to get the ppm correct? I also read something about "requires PROM change. Mag. VSS at 0x18 b6 for $8D PROMS", Whatever this means.
Senior Member
Mike Davis has this well documented.
if 727 and 730 are the same then looks like VSS gets inputed from A10(165) into BC6(730.
look here
http://www.eecis.udel.edu/~davis/z28/ECMs/86to92.txt
if 727 and 730 are the same then looks like VSS gets inputed from A10(165) into BC6(730.
look here
http://www.eecis.udel.edu/~davis/z28/ECMs/86to92.txt
And C6 from the 730 ecm goes into the B16 Port on the '727 ecm. The thing I don't understand is the required prom change it mentions. Is this already done in the super aujp v3? If not, How do I accomplish this? I edit my own proms using Tunerpro.
Senior Member
Basically what I did was uncheck Switch 18 (VSS M/AT U-TCC I-MAT VSS CCPE) - Bit 6 - VSS. Look under flags and switches.
I have an 86 camaro and run Speed Density. And it works great.
I have an 86 camaro and run Speed Density. And it works great.
So with that unchecked, The ecm then Properly reads the signal coming from the speedometer itself?
Thanks, I saved my bin with it unchecked now, And next time I run out to my car, I will pop the new chip in.
Now if I could fix my ses issue
Now if I could fix my ses issue

It stays on once I turn on the ignition, And I can't pull any codes. With the A & B terminals grounded, The light still just stays lit.
Moderator
If you don't get the SES blink at key-on then the ECM is running in backup mode (limp), not from the PROM.
The SES blink is: at key-on, engine-off the SES will come on, blink off , and come on solid.
That verifes that the ECM is running from the PROM. Need to look into why that isn't happening before continuing. Could be a bent pin, improper burn, PROM in incorrectly,. . .
RBob.
The SES blink is: at key-on, engine-off the SES will come on, blink off , and come on solid.
That verifes that the ECM is running from the PROM. Need to look into why that isn't happening before continuing. Could be a bent pin, improper burn, PROM in incorrectly,. . .
RBob.
I pulled the moates adapter and tried just the stock prom and there was no such luck. Still a solid light. Pins are ok as well. When I do a change to the proms I write too, I can tell the difference is happening when I drive. So I don't know. I was thinking a wiring issue, But I've traced all the aldl related wires and they are pinned correctly as far as I can tell.
