rev counter

[terryreed1664]

Hello All, I am the proud owner of my first Berli a MK 3 Cortina 1600 GT donor with point dizzy and am very pleased with it. The small problem is when switching on the ignition the rev count go's up to about 3 thousand and when starting and running its in the red all the time. The clocks are all MK 3 Cortina. Has anyone come across this before.
Thanks in advance
Terry

[macdonald.dm]

Re: rev counter

Hmm, other than suggesting you stop driving with your foot hard on the floor...

Does the needle return to zero smoothly when turned off (no physical stickiness)?

I understand the Mk3 Cortina rev counter (like mine) has three terminals - a +ve, a -ve and the 'sensor' wire which goes to the contact breaker side of the coil.

I guess the first thing to check is that they are all secure - the electrical contact is made between the 'PCB' and the actual rev counter using nuts - I can see only two in my photos. Check these are secure.

The connector plug to the rev counter has only 4 terminals as far as I can see, and 2 of them supply the illumination lamps. I can only guess that the rev counter gets either its +ve or 'ground' from one of them, leaving the other two to provide the 'signal' and the remaining power supply.

Check that the ignition coil has the rev counter lead coming from the CB side.

Or, it's a faulty unit! Cortina binnacles are cheap - I picked up a complete unit for around £5 on ebay.

Are your clocks in the single Cortina binnacle or are they separate?

[macdonald.dm]

Re: rev counter

Ok, looked at and old 'un I have in the garage:

The -ve supply is shared by the lamps. There are three nuts which you could check for tightness.

Of course, the fault may lie inside the unit...

[terryreed1664]

Re: rev counter

Hi Donnie, and thanks for your help. Yes the the speedo and rev counter are all one as cortina. And yes the needle dose go to zero when switched off. I'll have a good look at the nuts ( they may loose ). Maybe I should by a spare anyway.
Thanks
Terry

[h_m_cumming]

Re: rev counter

do the revs then appear to run as normal after 3k Terry or go straight into the red as soon as the engine starts?

[terryreed1664]

Re: rev counter

Hi Hugh,it goes straight to the red after starting. I cant find any loose connections as Donnie thought. It maybe the PCB is at fault buy I'm no sure.
Terry

[h_m_cumming]

Re: rev counter

Have you checked that the wires to it definately go to the places their supposed to and not got crossed up? It sounds like you could be putting power directly to it and not through something like the coil windings, or am I barking up the wrong tree.

[terryreed1664]

Re: rev counter

Hi again Hugh, I haven't checked the wiring yet ( next on the list ) its the original Cortina loom and all looks well.
Terry

[macdonald.dm]

Re: rev counter

Hi Terry.

Checking the wiring should - I think - be pretty straight-forward.

If you look at my photo above, I reckon the 4-way plug can be tested as follows (this is my best guess, but shouldn't cause problems even if you get it wrong!):

The 'topmost' terminal (in my pic above - but this is upside-down compared to how it's in the car!!) is, I believe, the -ve or 'ground'. If you look, it also supplies the illuminating lamps - I know it's the -ve because I had to test it as I was fitting replacement LED bulbs in there so had to get the polarity right! (The bottom terminal is the +ve to the lamps - nothing to do with the rev counter itself).

This leaves two terminals in between... One should be permanently +ve as soon as the ignition is turned on, and the other will 'pulse' +ve as you crank the engine and the points close.

I reckon if you get these results, the fault will lie inside the tachy itself - could be a simple broken/dry joint (there are a few leccy components in there), or else a completely failed component which could be hard to tell.

As I said before, replacements are cheap. While you're at it, there's this article I read about re-doing your dash...

[terryreed1664]

Re: rev counter

Hi Donnie, I followed the re-doing your dash with interest as I fancy doing something like that myself. I'll check the plug over the weekend and let you know how I got on.
Terry

[terryreed1664]

Re: rev counter

Hi Guys, OK all checks have been made to the wiring etc, as far as my limited knowledge will allow.So I connected the rev counter directly to the coil and battery started the engine and it went straight in to the red, I'm assuming from this the rev counter is US. Dose anyone out there have one they would like to sell. The one I need is the one that lives in a pod of three in angled tunnels, rev counter speedo and a clock.

Regards to all

Terry

[macdonald.dm]

Re: rev counter

http://cgi.ebay.co.uk/1970s-Ford-Cortina-MK111-Dashboard-Clock-Cluster_W0QQitemZ250445597501QQcmdZViewItemQQptZUK _CarsParts_Vehicles_CarParts_SM?hash=item3a4fb88b3 d&_trksid=p3286.c0.m14&_trkparms=65%3A12|6 6%3A2|39%3A1|72%3A1683|240%3A1318|301%3A0|293%3A1| 294%3A50


http://cgi.ebay.co.uk/1970s-Ford-Cortina-Clock-Cluster-Dashboard_W0QQitemZ250445598024QQcmdZViewItemQQptZ UK_CarsParts_Vehicles_CarParts_SM?hash=item3a4fb88 d48&_trksid=p3286.c0.m14&_trkparms=65%3A12 |66%3A2|39%3A1|72%3A1683|240%3A1318|301%3A0|293%3A 1|294%3A50

Either of these?