speedo problem

[gogsy400]

hi all
just had my chimaera out today after winter lay up ,only to find my speedo not working , the mileometer moves but very slowly (moved three tenths over about a 5 mile run)does anyone have any ideas ?

[Mossyboy1978]

Check sensor on diff - it may have gummed up through lack of use.

[gogsy400]

doin it tomorrow got access to a ramp ,is it easy to get to ? cheers

[Blues]

Yes. You'll see it on the off side of the diff fixed through a cast bracket and lined up with the serrated cog. There should be a slight gap(ten thou? - but it will be in the bible). Check this is clear, clean he end of the sensor, and reset the gap. Not a difficult job, unless the sensor has corroded into the bracket

[EGB]

Not a difficult job, unless the sensor has corroded into the bracket

[/quote]

Clean up the electrical contact plug first. Can be a big pain. Take it off with the bracket. 2 13mm bolts.

[Moses78]

The bible doesn't say what the gap should be, instead he suggests using an oscilloscope which I don't have access to. Any ideas? Secondly what should I clean it with, or perhaps more appropriately, is there anything I SHOULDN'T clean it with?

Seems to be the season for this fault!

[Blues]

Meths, white spirit or single malt but do this with the sensor off the car

google search said:

Set with a gap of 0.010" to 0.012" but take a close look at the diff output flange, excessive play in this could wreck your new sensor

[gogsy400]

thanks for the input guys,had a look today there is no room ,got to the sensor but it wont budge , gonna have do drop the exhaust,roll bar and lower diff to get at it properly , gonna tackle at the weekend when ive more time , the sensor was covered with gunge (thats the only word i can call it) so hope its just dirty.
cheers

[JonyTVR]

is yours picking up signal from a cog on the drive shaft or one from the propshaft?

[EGB]

gogsy400 said:

thanks for the input guys,had a look today there is no room ,got to the sensor but it wont budge , gonna have do drop the exhaust,roll bar and lower diff to get at it properly , gonna tackle at the weekend when ive more time , the sensor was covered with gunge (thats the only word i can call it) so hope its just dirty.
cheers

If on the driveshaft like mine, you do not need to drop the exhaust or the diff. Need a good light and the top 13mm bracket bolt needs a long shaft ratjet. You may have to drill and chisel split the (27mm I think)lock nut to remove sensor from the bracket. Clean up the electrical connection before pulling it carefully apart.
If sensor is on the prop I have heard from posts, that it can be accesed through the wheel arch sideways. May be an easier job?
I cleaned mine as best I could with a slip of fine emery paper pushed into the 11-12thou interface. No good, and bought a new sensor from Clever Trevor. £60

[JonyTVR]

Yep if its on the prop you can get to it with long arms from the drivers wheel well. I had problems with mine, replaced sensor which was quite expensive then had the guage refurbed for about 30quid and voila!

The only way to tell which it is, is by either using an oscilator? Thing or if someone nearby has bought Steve heaths New sensor which comes with a tester box.

[gogsy400]

lots of useful info , thanks guys,im gonna have have a go this weekend but sounds like i will have to change the sensor ,is it readily availlable?
cheers

[gogsy400]

hi guys
looking for more help ,got the sensor out and cleaned it ,but cannot see the electrical connector,where is it located ? anyone got any pictures?thanks

[EGB]

Mine is on the drive shaft. Connecter comes out the back of the sensor. Yours is on the prop so it is different. Try 'Clever Trevor' for new one. Check your sensor the wire has not broken off somewhere. Could save you £60 ! Hope !

[hiltonig]

I have just ditched mine in favour of a different type , therefore I have the old,sensor and bracket available if u need a s/h one

[gogsy400]

hi
if the sensor was taken off while still working , i would very much like to have this
cheers
gordon

[hiltonig]

Yep,it's working, might need a pic of yours just to make sure they r the same

[gogsy400]

nice one , its the same one thats on clever trevors website , the threaded cylinder type , was not aware there were different types. cheers
gordon

[gogsy400]

help !!
removing the speed pulse sensor, and cannot see the electrical connector,can anyone tell me where to locate this ,the wire appears to go through the floor ,(is it accessed from inside the car?)
cheers
gordon

[Blues]

Mine was visible from under the car, where it was cable tied to the chassis.