I just finished my adaptor for the 870 to 730 ecm conversion and hooked everything up and it starts and drives fine but when i get above 40 or so and let off the gas i get the check engine light. Code 24 which is a vss problem. Sometimes the car will stall and sometimes it will idle down around 300-400 rpms and then go back up to 650 or so. I made the adaptor as outlined on Mike Davis' website so i can switch back to the 870 setup easily. I switch back and it does not throw that code or stall when slowing down. I have pin A10 on the 870 side going to pin BC6 on the 730 side and have continuity on that wire from pin to pin.

Don't know if these are relevant, but i think the speedo cable is wearing out b/c the speedo bounces a little and i can hear the cable squeaking. also, with the 870 ecm hooked up, the transmission does not shift right. It will shift into O/D at 30 mph if i let it and it doesn't downshift right...like you'll have to floor it to get it to downshift and it'll drop down from O/D to 2nd at 60 or something like that. Also, when i'm accelerating and it's in 3rd, it'll almost act like it's shifting gears and then it will shift into O/D. If i only put it in drive instead of O/D and speed up to 55 it'll shift into 3rd and then act like it's shifting again and then when i put it into O/D it will actually shift into O/D. What the tranny does with the 870 setup is kindof hard to describe, but with the 730 ecm in, it drives just like it should with the exception of the code 24 and stalling. none of the weird tranny shifting krap happens with the 730 ecm. Anybody at all have any ideas?

 

I got the problem fixed. Nothing was wrong with the VSS. It was something with the vss settings for the prom that was set wrong when Leirch programmed it. It works fine with no problems now.