Late wedge V8 speedo...
Discussion
Ant. said:
You sure its the speedo itself and not one of the cables? (mechanical, not electrical) There are 2 on a wedge, one from box to underbonnet unit thingy and then from that unit to the speedo. Either one can break, although the most common one is the one from the box.
Andy, he's talking about a Griff, I think it uses the electronic sender (in the gearbox rather than inline) that the later SD1 used.
There seem to have been three ways to get speed info from the LT77 to the driver:
1. Cable direct from gearbox to speedo
2. Cable to speedo, with inline pulse generator to help the idle stabilisation (as 400SE)
3. Cable deleted and gearbox drive replaced by a pulse generator that feeds an electronic speedo. This was introduced on the SD1 and the pulse train drove the cruise control as well as the speedo.
4. Cable from gearbox to the inline pulse generator, blanking cap fitted to 'output' side of generator, pulse train drives an electronic speedo. Some Rangeys did it this way, as far as I know, but not used on TVRs UNLESS that's how the Griff did it, in which case it could be the drive cable. I thought they just used the in-box generator (as 3) though.
I had to look into this when I was working out how to fit cruise control to the 390SE; I needed a cable for the speedo but electronic pulses for the cruise ECU, and a standard 'split' Rangey cable won't fit the VDO speedo, so I had to have a 'special' made.
'Course I could be wrong and the Griff might have a cable driven speedo with the Rangey/400SE inline sender...
To the OP: have you checked the fuses? If the speedo gets no power then neither does the pulse generator.
There seem to have been three ways to get speed info from the LT77 to the driver:
1. Cable direct from gearbox to speedo
2. Cable to speedo, with inline pulse generator to help the idle stabilisation (as 400SE)
3. Cable deleted and gearbox drive replaced by a pulse generator that feeds an electronic speedo. This was introduced on the SD1 and the pulse train drove the cruise control as well as the speedo.
4. Cable from gearbox to the inline pulse generator, blanking cap fitted to 'output' side of generator, pulse train drives an electronic speedo. Some Rangeys did it this way, as far as I know, but not used on TVRs UNLESS that's how the Griff did it, in which case it could be the drive cable. I thought they just used the in-box generator (as 3) though.
I had to look into this when I was working out how to fit cruise control to the 390SE; I needed a cable for the speedo but electronic pulses for the cruise ECU, and a standard 'split' Rangey cable won't fit the VDO speedo, so I had to have a 'special' made.
'Course I could be wrong and the Griff might have a cable driven speedo with the Rangey/400SE inline sender...
To the OP: have you checked the fuses? If the speedo gets no power then neither does the pulse generator.
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