Bouncy Speedo
#1
09-09-2006, 09:29 AM
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Bouncy Speedo
97 F150 V8 4.6L
About a month ago, i had to replace two speed sensor gears, because my speedo wasnt working at all...one of them on the speed sensor on the tailshaft of the transfer case, and one on the internal driveshaft inside the tailshaft
My speedo was fixed after that and now it bounces back and forth...say im goin 45mph, my speedo needle bounces back and forth between 40-45...but after about 5 mins of driving or until the engine gets warm (i dont know which one) it seems to kick in and work correctly
sometimes when i start it for the first time and drive it, it works...but then sometimes it doesn't...just wondering what is making it bounce for a short time, then kick in properly...thanx
About a month ago, i had to replace two speed sensor gears, because my speedo wasnt working at all...one of them on the speed sensor on the tailshaft of the transfer case, and one on the internal driveshaft inside the tailshaft
My speedo was fixed after that and now it bounces back and forth...say im goin 45mph, my speedo needle bounces back and forth between 40-45...but after about 5 mins of driving or until the engine gets warm (i dont know which one) it seems to kick in and work correctly
sometimes when i start it for the first time and drive it, it works...but then sometimes it doesn't...just wondering what is making it bounce for a short time, then kick in properly...thanx
Last edited by Chris 97 F150; 09-09-2006 at 09:48 AM.
#3
09-09-2006, 06:48 PM
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It is not always just the gears. You might need to buy the VSS sensor itself. That's the piece that you put the new gear on that bolts to the tailshaft and sends the signal to the PCM and speedo. An incorrect speedo reading affects everything the PCM does like shifting and fuel mixture and timing etc. New VSS is only $40+/-. You can test for a dead VSS by removing the gear and chucking the square shaft into a small drill. Pull the trigger (very slow speed only) and the speedo should register something with just the ign on. If yours is working but bouncing I would buy a new one.
#4
09-09-2006, 11:08 PM
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Well i might be incorrect but my Grandma had the same problem on her 95 Mercury Sable it would go up and down even though you would be driving at a steady speed it was under warranty and they just took it in and they took off the cover where there speedometer is and put some elbow grease on it or something and i dont think it did it again at all im not sayin it would work for you but you never know worth a try?
#5
09-10-2006, 02:28 AM
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Originally Posted by alberta46
Not sure what is happening but I replaced mine on the tailshaft still out how hard is it to replace the one inside?
