Speed input to ECM. Is it needed?

[Fordman114]

I have just finished my MKIV build and have been doing some test drives. I have a Gen 3 Coyote from a 2018 mustang with a 6 speed manual transmission and a Power Pack ECM from Ford Performance. I have been running on the base tune from Ford. I don't seem to have any drivability issues so far other than a little idle hangup on shifting. There are no flat spots on acceleration and it has more power than I need for a cruiser. I have an HP Tuner and I looked at the tune and logged it while driving. The only issue I have is that with the vintage gauges from FFR and the GPS speedometer, I am not using the VSS signal from the transmission. I am wondering if I should still have a vehicle speed sensor input to the ECM. I noticed that while logging the run on the HP tuner software that the ECM does not show a speed input. Should this be a concern if I have no drivability issues?

[edwardb]

By Power Pack ECM from Ford Performance do you mean the aftermarket control pack from Ford Performance? If so, then no, that calibration doesn't have a speed value in the data and doesn't require it. Interesting that your Gen 3 is running OK on the base tune. Mine sure didn't and others didn't either. Maybe Ford Performance adjusted the tune. Just watch because the base tune used to run really rich.

[Fordman114]

By Power Pack ECM from Ford Performance do you mean the aftermarket control pack from Ford Performance? If so, then no, that calibration doesn't have a speed value in the data and doesn't require it. Interesting that your Gen 3 is running OK on the base tune. Mine sure didn't and others didn't either. Maybe Ford Performance adjusted the tune. Just watch because the base tune used to run really rich.

Doesn't seem to run rich. On my initial startup it did, until it did a little learning. It had a really stinky exhaust. Now after I have about 80 miles on it, it runs really good. I know some have had problems with stalling at stop signs, but mine never has. The idle is good, awesome power, and no smell from the exhaust. The only issue I thought I had is not coming back down to idle between shifts. It seems like it hangs up longer than I like when shifting. But I have found that it pretty much goes away when the engine is fully warmed up.