Tach output option: possible repost?

dr.occa · Post by **dr.occa** » Thu Jul 12, 2007 8:40 pm

i found this on another mj user's site that showed his tach output from the EDIS unit itself. See below:

this image was borrowed from Matt Dearden's Megajolt Installation Website. thanks goto him.

i'm assuming though that the hi-v kickback will still be necessary for us 4AG owners.

MartinM · Post by **MartinM** » Thu Jul 12, 2007 9:37 pm

Pin 11 of a 4-cyl EDIS is indeed known as the CTO (Clean Tach Out).

There may be a challenge in making an electrical connection to CTO – although the pin will be on the EDIS module, there may not be a socket and wire on the connector for it. Some EDIS connectors seem to have a CTO socket and a wire, but most do not.

It is possible to drill a hole in the CTO position on the connector and make a contact with the pin, but this will need to be made electrically sound and environment proof.

I don't know exactly what voltage is on CTO (I've never been able to measure it as I've never found a harness connector with pin 11 connected and I've never bothered to make one) but I expect it is 12v/0V.

themaninthesuitcase · Post by **themaninthesuitcase** » Fri Jul 13, 2007 9:52 pm

I know of two people who use this configuration with Smiths Tachos to great effect. One of them did have to drill the hole, but I can't recall how he made the connection.

Gilesy998 · Post by **Gilesy998** » Mon Jul 16, 2007 9:49 am

I salvaged two EDIS connectors (after realising the first one's retaining clip was snapped) and kept a stock of pins for that very purpose, though lord knows where I put them when I move house

Simply solder the wire to the pin, drill a hole in the retaining strip, push in the pin and Robert is a male sibling of your ol' girl.

What I've not done yet though, is try and employ this method. Originally the coil -ve lead would run from the points, loop twice through the pickup on the dizzy and then off to the coil. Does the EDIS output loop through the pickp and then connect to earth?

'Case - I've not forgotten your EDIS bits dude

MartinM · Post by **MartinM** » Mon Jul 16, 2007 12:06 pm

I'm guessing a bit here.....

If your original setup looped the coil -ve through the tacho, then I think it's likely that the tacho is relying on inductively picking up the flyback pulses on the coil -ve wire...several hundred volts per ignition event.

I'm pretty sure that the CTO, as it's name implies, is a clean 0/12v signal. Whether this being looped through a tacho would work remains to be seen - there's only one way to find out of course.....

....report back!

fikus01 · Post by **fikus01** » Mon Jul 16, 2007 6:44 pm

i wonder if the pin 11 output taken thru the older smiths inductive pickup tacho then to earth via a condensor would work! anyone got one to try it with?

themaninthesuitcase · Post by **themaninthesuitcase** » Mon Jul 16, 2007 8:00 pm

I think I need to ask my friends how theirs are wired and what Tacho they use as I am sure they use pin11 to feed them, but I think one of them uses a NIPON tach.

Tom · Post by **Tom** » Sun Jul 29, 2007 3:27 pm

I have just drilled out my EDIS plug wit a 3mm drill and fitted a spare pin from another connector. It works perfectly on my standard mk2 Escort tacho so shouldn't be a problem on most