No rev counter.....

[sspogman]

Hi All,

Having gotten to around 85% complete on my build, I'm now up against a problem that is really confusing me - I can't get the rev counter to work!

All seemed to work fine in the donor, but it won't move at all now. I've checked the wiring as per this link www.justanswer.com/car/1gy2n-1993-mazda-mx5-when-ignition-turned-rev-counter.html and this one www.rivercityroad.com/garage/cas_testing.htm but to no avail.

I've even tried changing the cam angle sensor just in case that was faulty and failing to send a tacho signal. Again, no change.

Anyone got any ideas on what to try next please? I don't really want to go changing the dash cluster if I can help it.....

Cheers,


Steve.

[Deleted]

i had a similar issue with mine, id removed tome of the unneeded wiring that was for the aircon, interior lights and stereo, i think i must have cut a shared ground, as i back tracked and rewired it all back in, i managed to get it all working.
That said, it wasnt just the rev counter that went dead on mine, it was all of the dials.

[Kevin Patrick]

I am currently experiencing the same issue. Aside from the airbag and parking brake light, none of my gauge cluster works (tach, fuel gauge, oil pressure, water temp). I assume this is due to a missed ground connection. I went over the wiring again over the weekend and did not find a solution. I even lengthened the main ground wire for the gauge cluster and moved it to another location. I have to be missing something.

I'll go through the wiring diagram again and recheck everything. I'll post if I find a solution. Any other suggestions are welcome...

[sspogman]

Thanks Guys, it's good to know that I'm not the only one with this sort of a problem.

I've not been on the open road yet to test the speedo (although I could jack up the rear end to check it I guess) so I can't be certain that it is working, however, the other gauges & lights all seem to be working fine. Also, as electrics aren't my strongest point, I decided not to chop up the wiring loom at all, so it is all still intact...

Oh well, I'll just have to work on some other bits for now and come back to it again later on, unless anyone else comes up with an idea to try

[fasteddie]

I`ve had similar issues, no gauges working, found 10 amp fuse blown, replaced, all ok for a while,then nothing, fuse ok, changed cluster for another, every thing fine for a week then saturday rolled her out of the garage and gauges dead again, hav`nt had chance to check fuse yet but I have tested the ground with meter no resistance and a good 11.98 volts at the supply point on old cluster, will keep you all posted when I have sorted it AND I WILL SORT IT.

[kitcrazy]

Eddie

I'm interested to find out what the cause of your problems are as i I'm suffering from electrical woes too. My 1.8 will start and run for 2 seconds and then cut out, i've checked the CAS which seems to be ok and made sure all the groundings are good but i just can't seem to get her to start. its worth noting that the rev counter isn't working or the fuel gauge either.

This was a no runner when i got her (big mistake!) and i'm beginning to wonder if all the relays are present.

Any ideas???

Cheers

KC

[sspogman]

Hi KC,

Reading your post rang a few bells from some research I was doing before and I found the following posts that may be of help:

forum.miata.net/vb/archive/index.php/t-367862.html

www.mx5oc.co.uk/forum/forums/t/1531.aspx

Couple of things that seem to be quite common themes are:

• MAF Sensor
  
• Coil Pack
  

The second link is quite a lengthy post and it turns out that it was the ignition module.

Hopefully that'll give you a few new ideas - good luck!

[blobnnob]

Hi Steve n everyone who is having probs with this, we have simular thing everything works fine starts, runs dials all work until we put side lights on, rev counter dies also temp gage, indicator lights come and main beam light? We have disconected all lights in case its something weve done but it still happens, re checked all earth points.
Spent all day Sunday n can't sort it, MOT booked for next week, any ideas.
Regards Jeff

[sspogman]

Hi Jeff,

Certainly sounds like an earth problem to me.

From what I've read, there are 2 earths that I would focus on first:

• Not sure about 1.6s, but on the 1.8 there is an earth going from the back of the engine, just to the off-side and below the CAS - apparently this is the one that the rev counter specifically uses, don't know if it is used by other components;
  
• The pivot bolt on the alternator is a major earth for lots of components and, if not tightened fully, can cause all manner of problems - defo worth checking that this is fully tightened.
  

Hope that gives you some help

Cheers, Steve.

[fasteddie]

Right guy`s although I`m not sure why the 10 amp fuse blew in the first place, replacing it with a15 amp,( which is fitted to later models ) caused a break in the printed circuit on the rear of the instrument pod, the one that supplies the gauges from the black and yellow supply. I`ve repaired it and await to see what happens, obviously have gone back to 10 amp fuse. gauges working at the moment. Ted

[blobnnob]

Hi Steve, thanks for the info, cant remember seeing an earth on alternator but will check again.

Cheers Jeff

[sspogman]

Hi Jeff,

There isn't an earth lead on the alternator, the earth is the actual pivot bolt itself. You need to ensure that it is ultra-tight otherwise it can give all manner of issues.

Cheers,


Steve.

[sspogman]

Update:

So, I jacked up the rear end today and took her up to 85 mph on my driveway - clearly the speedo is working

After that, I left her running for a good 10 minutes and found the temperature gauge and fan to both be working fine. Next up I swapped out the whole cluster with one that a friend lent me - sadly there was no change in the rev counter

I've heard some reports that a faulty ignitor can cause this - does anyone know whether I am right in thinking that the ignitor on a 1996 1.8 is combined with the coilpack? I'm starting to think that it could be the coilpack at fault as she also seems to be 'missing' quite a lot nowadays, another thing that never used to happen. Figured that a faulty coilpack could be responsible for both issues - anyone else got a view? I'd like to be sure before I go down the route of changing the coilpack as a new one seems to be best part of £250!!!!

Cheers,


Steve.

[blobnnob]

Hi Steve checked it, just the same, got an auto trician calling tonight, 85 on jacks!!!! scary, weve had ours round the block seems lively but brakes crap more bleeding I guess.

Jeff

[Stiggy]

We need to remember that nothing changes with the wring when you transfer it to the Exocet, therefore if it worked in the MX5 it will work in the Exocet if all the plugs are connected to the right sockets and all the earths are connected. There are 3 multiple earths. One near the tank, and one to the left and one to the right of the front bulkhead. There is also a large earth on the alloy beam near the battery and one above the exhaust to connect to the chassis. The only other thing you can get wrong is connecting the lights up. Stop, tail, left, right, reverse, fog and plate lights at the rear and sides, left, right, repeaters, dip and main at the front. These all need good earth points. You also need to solder an earth wire to each of the rear stop tail lights.
It is always best to do this systematically ensuring each wire is correct before carrying on. There is nothing more to it.
Items such as rev counter may well find an earth path via a light bulb filament if it is connected incorrectly.
If in doubt then pull ALL lights wires off and start again.
A word of warning though.
It is possible to put the plugs in the wrong sockets on the column.
Labelling sockets on the donor before you strip is absolutely imperative.
If you cut any plugs off that are not required you may find you have caused a problem if that plug shared an earth with something else. Some earths are spliced into others half way down a loom tube or under some tape.
Any modifications should only be carried out after you have proven all circuits work properly.