How important is accurate vehicle speed (VSS) for EFI?

[CoryOBrien]

Bought my Bronco with an EFI swap already done. The VSS was connected to the computer, but the PO didn't get the EFI speedometer cable, so the speedo was never connected. Got the new cable installed this weekend, and it looks like the speed is off by about 20%. (Speedometer reads 50 when GPS says 60.) I'm going to get a new speedometer gear to correct the speed, but that got me thinking: Are there any EFI issues with the computer thinking the vehicle speed is different than what it's actually going? It runs well as-is, so I haven't had any major issues, just wondering if it'll run better once the computer has more accurate info.

 

[Viperwolf1]

No issues with the EFI. You most likely don't even need the VSS.

 

[chuzie]

It is sometimes an issue with manual transmissions as it signals the iac to engage to help prevents stall from sudden throttle drop after mashing clutch for stop.

Otherwise, like viper said, u can live without it.

 

[70_Steve]

It is sometimes an issue with manual transmissions as it signals the iac to engage to help prevents stall from sudden throttle drop after mashing clutch for stop.

Otherwise, like viper said, u can live without it.

Like chuzie says, if your EEC is from an auto, there is a dashpot setting that sets idle at about 1000 RPM (just a guess) as you're coasting to a stop, until you come to a complete stop. Kind of a pain when running a manual transmission like I am, but you get used to it.

 

[Steve83]

AFAIK, the only EEC-IV strategy that needs VSS (other than E4OD/4R70W management) is return-to-idle. But I ran a stickshift EEC w/o VSS for several years with no problems.

 

[Rox Crusher]

AFAIK, the only EEC-IV strategy that needs VSS (other than E4OD/4R70W management) is return-to-idle. But I ran a stickshift EEC w/o VSS for several years with no problems.

Steve, what's your opinion on whether it is needed for 4R70W when Bauman controller is being used ?

 

[Steve83]

I know nothing about the Baumann controller. Ask them.

 

[chuzie]

4r has its own vss.

 

[Steve83]

The OSS in the 4R70W does not replace the ABS (VSS); it's an additional input to the EEC.