The 'E' Type Forum

Hello everyone. Unfortunately my rev counter stopped working the other day. I have not had a look yet but guess I will need to remove the dash top and check to see if any wires have become detached etc. If not I guess something else is wrong with the counter itself. Does anybody know of a specialist instrument repairer
in case I need to go down that route please.
Regards,
John

Speedograph Richfield in Nottingham amongst others.

The year/model of your E-type will help determine the most likely causes of the tach not functioning. S1 cars have a dead simple two wire system run by the tach generator on the backend of the inlet camshaft. Tach failures with these tend to be mechanical in that the fiber drive element that fits in the end of the camshaft can fail, or the drive dog in the tach generator slides back and disengages. Later cars have a more conventional tach wiring arrangement that requires both a 12v power feed and a signal from the coil, so problems there are more likely to be wiring related. Failure of the tach itself is relatively rare.

Some searching on this forum will give more guidance on chasing down the issue, whichever type you have.

Were in the S2 section

Many thanks for the information. Will check coil wiring first before delving under the dash.
Cheers

Might be worth checking to see if anything else like the radiators fans have also stopped working as they are fed from the same fuse (6 I think). I had mine stop working a couple of years ago and it was a poor fuse connection which I spotted when the fans failed to kick in one time.

A surprising amount of "mission critical" stuff runs through the No.6 fuse: brake lights, horn, cooling fans, and rev counter.

Easy enough to check for - see if your horn's working, and if not just bear in mind that your brake lights won't be working either. Change the fuse though and immediately you're back in business.

Many thanks to Geoff and Darren for pointing all this out to me and helping me sort out the problem when I was scratching my head in the Silverstone car park last year!

Also interesting to note that the glass fuse that was giving the problem looked perfectly unblemished and intact when I pulled it out - nothing to give it away at all.

Unless you have large hands, there is no need to remove the dash top to extract the tacho. Though I have now shrunk to about 5' 6" tall, I can get my hand in behind the dash/steering column to undo the clamp screws.

Good morning everyone,
Took my 1969 series 2 (20130) out last night and found a pool of coolant on the floor when parked up, this had come from the expansion tank on the bulkhead. Will check fuse 6 as suggested to make sure all working and radiator not blocked or anything obvious. What next? Otter switch? Thermostat? Any simple checks to narrow my search?
Also rev counter on the blink again!
Any replies appreciated
Cheers John

Had you recently topped up the coolant? They will happily burp out any excess via the overflow pipe that comes out of the neck of the expansion tank if so. Perfectly normal.

Simon

John, you took your car out but hadn’t checked fuse 6? So you hadn’t checked if your brake lights were working?

Geoff

No Geoff I did not see if horn or brake lights were working but everything was a few days prior, anyway it dumped a lot of coolant so obviously something amiss. Will check.
Thanks for responding and DWW for the wiring diagram
Cheers John

Danny's wiring diagram is not for your car, John, but is for a S1 4.2

Ok thanks Chris

All working now, simple fuse replacement on number 6, bit of a fiddle to extract but there goes.
Is there any way to put the fans on a separate fuse so as not to overload the fuse board. Quite a large current to draw on a 35 amp fuse that supplies the tachometer. Brake lights, horn and cooling system
Thanks
John
Series 2 fhc 1969
Chassis 20130 R

You can use a 50A fuse instead or even better connect it to the feed side from the ameter gauge with an external own inline fuse.

I recently had a situation with an after market fuse (6) that was intermittent, I thought it was a connection issue but it finally gave up and went open circuit but not blown.

John, well now your brake lights work as well as the fans, etc. The circuit diagrams are all in the maintenance manuals and owners operating manual. Also in the knowledge base including coloured versions.
I made up a simple curved hook with several layers of heat shrink on the end to insulate it and then you have a ready to use fuse extraction tool. Every E Type should have one.
Also, have you checked how clean the fuse holder terminals are? That could be the reason for poor operation.
Putting the fans onto a different circuit/fuse will need you to start re-wiring. Where could you put the fuse as there’s little space under the dash with the other fuses? Unless you place it out of easy reach. Some owners fit a simple override switch for the fans. A search on here for words like fans, override, etc. will show you how others have neatly done that.

Geoff

DWW wrote: ↑

Thu Jun 22, 2023 4:14 pm

You can use a 50A fuse instead or even better connect it to the feed side from the ameter gauge with an external own fuse.

50 amp fuse? You could go one better and just use a six inch nail as a fuse
No ammeter, it’s an S2

"50 amp fuse? You could go one better and just use a six inch nail as a fuse "

So could take the feed from the volt meter live wire.