having just re-fit the whole car the only thing that doesn't work is the rev counter does anyone have any pics of how it should be wired.
What is the wire on the back of it that has bullet connectors and is joined together?
having just re-fit the whole car the only thing that doesn't work is the rev counter does anyone have any pics of how it should be wired.
What is the wire on the back of it that has bullet connectors and is joined together?
I assume you ahve a 6 dial dash and the car has the correct loom to make it all work.
The wire with the bullet connectors forms an inductive loop. You should see a small threaded post on the back of the tacho.
There should also be a small u shaped piece of metal which with a small knurled nut holds the wire close to the post.
Then it should work.
Sorry don't have any pictures.
HTH
David
the loop has to go in sieres with the coil LT - Points, if you have electronic ingnition you ma have to make up some sort of a switched load ( 21w lamp willdo) or more turns on the loop to increase inductance.
Behind the dash there should be two bullet connectors joined togther (I thinkl the wire is black, but it might not be). Split them and use the white wire on the rev counter to connect them back together.
If you have fitted an electric dissy with a 12volt unballasted system you may have bypassed this wire, so that won't do it.
In that case the white wire on the rev counter has to be fitted in the feed to the coil somewhere.
cheers fellas, think i've got it now
now your sorted i can hijack the thread
does anyone have a pic/diagram of the back of the tacho... ive got to connect it to my Megajolt... i have one wire with the rpm feed but think i have to connect it to two wires, havent a clue which ones.. im guessing i try the white one, and if that dosnt work connect that and the threaded bar with an induction loop type thing
no problem mate, good luck with that!
PICTURES SPEAK A THOUSAND WORDS so lets have em
I'm not sure the Mk1 rev counter can be made to work with megajolt. It works differently to an electronic revcounter. I have heard of them being converted to electrical though.
thers an extra circuit i have to make so that it generates the right pulse for the tacho,
only problem is ive lost the wires that connected the coil to the tacho, so having to pull the dash off to find out wich one i should put this feed into... i may just sack it off and buy a new tacho instead.. might be easier
I might well be wrong Dan, but I think that may be how to make the tacho work in a Mk2.
The way I understand it is on a Mk2 the tacho is at the end of a piece of wire connected to the coil and measures what is going on at the coil.
On a Mk1 the tacho has a piece of wire near it (the white wire that isn't connected to the tacho at all) and measures what the electric is doing on its way to the coil.
On a Mk2 if you disconnect the tacho, just the tacho stops working.
On a Mk1 if you disconnect the wire the engine stops as that is the supply to the coil.
Summat like that anyway.
hmmm
problem is there is no dizzy or coil anymore. just a coilpack and megajolt... when i finally get the dash apart i'll find out whats what... cheers anyways
dave you are right the mk1 tacho works on pulse from the coil feed wire
which is black thats near the multi plug for the dash.
i have known of them being rebuilt to be electric tacho but as to who does it i am not sure.
I thought I had read somewhere that Speedy Cables could do it. Seemed a bit odd as I thought they were a cable company.
But they do.
http://www.speedycables.co.uk/
cheers guys.. guess i'll aim for the black cable, connect it up and see what happens
got this incase it helps anyone else out
well i finally got the dash off today, and it looks like its the wrong type of tacho to work with megajolt... as it has the inducton loop bit
have to buy a new tacho then
Ask speedy cables how much to change it Dan.
Got to be better with the original one in there.
just bought one one ebay for 20quid.. only just realised its 80mm and i think escort dashes have 100mm holes in them still its cheaper than the 55quid speedycables have on their site to recalibrate the old one.. i wanted to make a custoom dash anyways
hopefully it'll work i dont like driving around without a tacho and this new engine which keeps asking me to thrash it
good job i found this post as i need to no this
I know it's an old post but I changed the wiring diagram a bit:
Mk2 tach is connected to coil - side.
Mk1 tachos are never accurate anyway, best off buying a small aftermarket one and taking it apart to fit behind the mk1's dial, bet its cheaper than a conversion.
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