"Speed Buffer Sensor's" Purpose?
Thread Starter
Burning Brakes
Joined: Sep 2013
Posts: 1,206
Likes: 365
From: The Motor City
"Speed Buffer Sensor's" Purpose?
Does anyone know, what does the "Speed Buffer Sensor" do on an `82? I have searched the Forum, and Google - no avail under the "Buffer Sensor" designation. I do know that the ECM takes a speed sensor signal from the speedo that controls torque converter lock-up/ shift points as well as idle, but is that the purpose of the "Speed Buffer Sensor" housed in a small plastic yellow box with a long wire that the previous (and original) owner left dangling by the fuse panel for some reason? If that is the speed sensor, sort of curious why GM would reference as a `buffer.'
Btw, what happens if the speedo is inoperative on an `82 such as can occur if the cruise control transducer fails? Seems the ECM would immediately throw a code and check engine light, and cause problems with idle/transmission shifting if my speedo transducer fails? I love all the creature comforts on the `82 and wouldn't trade `em, but want to be aware of the technology of the day.
Btw, what happens if the speedo is inoperative on an `82 such as can occur if the cruise control transducer fails? Seems the ECM would immediately throw a code and check engine light, and cause problems with idle/transmission shifting if my speedo transducer fails? I love all the creature comforts on the `82 and wouldn't trade `em, but want to be aware of the technology of the day.
Burning Brakes
Joined: Sep 2006
Posts: 1,071
Likes: 86
From: Rotonda FL
On TPI, the successor to your crossfire injection, the system includes an idle control that comes into action when you remove your foot from the accelerator while the car is in motion. This will keep the idle elevated until the car has stopped, and is necessary for smooth operation with an automatic trans.
I speculate that your speed buffer provides a similar feedback for your crossfire.
I speculate that your speed buffer provides a similar feedback for your crossfire.
Thread Starter
Burning Brakes
Joined: Sep 2013
Posts: 1,206
Likes: 365
From: The Motor City
Thankyou
On TPI, the successor to your crossfire injection, the system includes an idle control that comes into action when you remove your foot from the accelerator while the car is in motion. This will keep the idle elevated until the car has stopped, and is necessary for smooth operation with an automatic trans.
I speculate that your speed buffer provides a similar feedback for your crossfire.
I speculate that your speed buffer provides a similar feedback for your crossfire.
Dave
Melting Slicks
Joined: Jan 2000
Posts: 3,326
Likes: 523
From: home
Vehicle speed sensor??? Does the wire have a small photocell on the end? Earlier vss's mounted to the back of the speedometer. There was a vane on the speedo head that rotated with the speedo cable. The photocell would "see" a reflection or no reflection and send that signal to the ecm.
