My speedeometer cable has been broke for awhile and I haven't worried about fixing it since I barely drive the car and when I do it's on back roads to log data.

Question - Is my ECM pulling data off of the speedo?

Will it hurt my performance if it's not connected?

I need to get off my lazy a$$ and fix it soon.

How about the tach?
I did the 305 to 350 swapin a 5-speed IROC.

My stock tach seems to be off.
Comparing the Moates scanning software tach read to my stock guage tach blew me away.

My stock tach is 1.5k- 2k higher than what the software is reporting.

I'm assuming that the scanning software is correct considering that the rpms I'm seeing are being reported to the ECM.

Anyone got an explanation for that one?

I've got a whole buncha questions to ask the programming gurus here but I figured I'd start small.

Help me out guys!

 

Search here on VSS (vehicle speed sensor) and you'll find out what the problems are, then ask a more specific question.

I don't know about your model, but every Delco equipped car's wiring diagram I've seen (all 5 of them!) gets some sort of signal back from the speedo to the ECM. You need to fix it.

Your tacho is irrelevant as well as possibly inaccurate

John

 

Not if he has a speedo "cable"..

-- Joe

 

I do.
The cable is busted.
I have a new one.

Maybe I'll have time this afternoon . . .

 

Someone hacked your car then.. 89?? suposed to be electronics.

-- Joe