Recalibrate speedometer?

[natedlee]

The previous owner of my '98 BB TC2000 upgraded to highway gears, so the speedo is about 15mph off. How do I fix it?


Sent from my iPhone using Tapatalk

[CaptSquid]

I would imagine that your local dealer could do it. It's not a DIY project.

[turf]

i don't know if thats mechanical or not, but the mechanical transmissions have a speedometer gear by rear end.

i have seen a list of different part numbers on a '92 BB partlist for the speedogear.

here is picture of a page from an online catalog.



if you have an electronic motor, i have no clue.

hope that helps

[cadillackid]

easy way to tell is crawn underneath and at the rear of the transmission tailshaft (on a 545 its usually on the driver side).. see if there is a pair of wires coming off or a cable coming off (not the shifter)..

if its a cable then you have a gear.. if all you need to change is the DRIVEN gear and not the drive gear then its super easy... that cable pops out and you swap a new gear in..

if you have an electronic speedometer then there is any number of ways that it might need set..

for example my 1991 bus is a fully mechanical engine but I have an electric speedometer.. in that case there are dip switches on the speedometer cluster that you set.. (I did it when I changed tire size).. im not sure on a bluebird how its done. just throwing out ideas..

-Christopher

[natedlee]

Originally Posted by cadillackid

easy way to tell is crawn underneath and at the rear of the transmission tailshaft (on a 545 its usually on the driver side).. see if there is a pair of wires coming off or a cable coming off (not the shifter)..

if its a cable then you have a gear.. if all you need to change is the DRIVEN gear and not the drive gear then its super easy... that cable pops out and you swap a new gear in..

if you have an electronic speedometer then there is any number of ways that it might need set..

for example my 1991 bus is a fully mechanical engine but I have an electric speedometer.. in that case there are dip switches on the speedometer cluster that you set.. (I did it when I changed tire size).. im not sure on a bluebird how its done. just throwing out ideas..

-Christopher

Thanks! I'm familiar with the dip switches as my van has that. Couldn't find one on the bus so that's what prompted the question. I'll take a peak under the bus when we stop for wires and such.


Sent from my iPhone using Tapatalk

[natedlee]

Originally Posted by turf

i don't know if thats mechanical or not, but the mechanical transmissions have a speedometer gear by rear end.



i have seen a list of different part numbers on a '92 BB partlist for the speedogear.



here is picture of a page from an online catalog.







if you have an electronic motor, i have no clue.



hope that helps

Thanks!!


Sent from my iPhone using Tapatalk

[natedlee]

Originally Posted by cadillackid

easy way to tell is crawn underneath and at the rear of the transmission tailshaft (on a 545 its usually on the driver side).. see if there is a pair of wires coming off or a cable coming off (not the shifter)..

if its a cable then you have a gear.. if all you need to change is the DRIVEN gear and not the drive gear then its super easy... that cable pops out and you swap a new gear in..

if you have an electronic speedometer then there is any number of ways that it might need set..

for example my 1991 bus is a fully mechanical engine but I have an electric speedometer.. in that case there are dip switches on the speedometer cluster that you set.. (I did it when I changed tire size).. im not sure on a bluebird how its done. just throwing out ideas..

-Christopher

Ok - so a couple details that might be helpful. The rear axle ratio is 4.78, which I am told by the previous owner is the newer gears he put in.

I finally got around to crawling under there. So this must be the speedometer sensor and there's a wire coming out of the top. So does that mean I need to find some dip switches somewhere?








Sent from my iPhone using Tapatalk

[turf]

i'm curious about the speed sensor too.

my at545 has 2 wires that come off in the same spot as the picture above.

my at1545 has 2 wires that come off next to the gear selector.

in either case, those 2 wires have to carry a neutral start switch, a reverse light indicator and a speed signal.

the only other electrical connection is the ground strap on the transmission.

someone start splainin'

curious that the old owner would put in a 4.78. that would take you from probably 58mph to 65mph.

mines a 4.78 and i'd go for a 4.3 or 4.1

[natedlee]

Originally Posted by turf

i'm curious about the speed sensor too.

my at545 has 2 wires that come off in the same spot as the picture above.

my at1545 has 2 wires that come off next to the gear selector.

in either case, those 2 wires have to carry a neutral start switch, a reverse light indicator and a speed signal.

the only other electrical connection is the ground strap on the transmission.

someone start splainin'

curious that the old owner would put in a 4.78. that would take you from probably 58mph to 65mph.

mines a 4.78 and i'd go for a 4.3 or 4.1

I suspect my RPMs are lower. Iowa to Ohio I stayed around 60mph and my RPMs were 2k. Tracking via GPS I got just over 12mpg. Bus weighed ~18,500 on that trip. On a flat run I can get just over 70mph tops.

So, how does all of that compare to someone with stock gears? ¯\_(ツ)_/¯


Sent from my iPhone using Tapatalk

[turf]

thats real good!

i have the same set up

5.9, at545, 4.78 rear. i'm 19k lbs

top speed of about 72

i get 7.5mpg

[natedlee]

Originally Posted by turf

thats real good!



i have the same set up



5.9, at545, 4.78 rear. i'm 19k lbs



top speed of about 72



i get 7.5mpg

So - was your 4.78 an add-on and your speedo is off too?&


Sent from my iPhone using Tapatalk

[turf]

Originally Posted by natedlee

So - was your 4.78 an add-on and your speedo is off too?&


Sent from my iPhone using Tapatalk

all factory

i keep my foot on the floor and push it all day long.

[natedlee]

I'm wondering if these circle doohikies on the back of the dash cluster are dip switches.

Also the dang dash bulbs are touchy. :/





Sent from my iPhone using Tapatalk

[family wagon]

To me those look like sockets for replaceable lamps.

[natedlee]

Originally Posted by family wagon

To me those look like sockets for replaceable lamps.

That's what another person said on FB. But there are separate lamp spots like this... And they're stupid sensitive. Can't figure out why some aren't working.




Sent from my iPhone using Tapatalk

[natedlee]

Originally Posted by family wagon

To me those look like sockets for replaceable lamps.

Ah - you're right. They are the bulbs for the fuel/temp/charge/oil menu that I can toggle through. Some of them must be out bc I can't see them well at night.


Sent from my iPhone using Tapatalk

[natedlee]

It was pointed out in another forum that technically I'm not 15mph off. I'm a % off. So he run the math and I'm 133% off across all speeds.


Sent from my iPhone using Tapatalk

[cadillackid]

since its a Bluebird, it doesnt hurt to call a bluebirds dealer and just ask what it takes to recal the speedometer.. if its a hard coded thing and you need a new gauge, or if its a reprogrammable thing in the field or dealer.. I just noticed your gauge [anel itself was marked bluebird.. so its made by them and not a chassis builder.

-Christopher

[natedlee]

Originally Posted by cadillackid

since its a Bluebird, it doesnt hurt to call a bluebirds dealer and just ask what it takes to recal the speedometer.. if its a hard coded thing and you need a new gauge, or if its a reprogrammable thing in the field or dealer.. I just noticed your gauge [anel itself was marked bluebird.. so its made by them and not a chassis builder.

-Christopher

[emoji106] I'll probably do that this week. Thanks for the discussion!



Sent from my iPhone using Tapatalk