Tachometer and Oil pressure gauge

[pcashman]

Hi Folks,

My oil pressure gauge and tachometer have not been working since I picked up the car, which is far too long and just a bit embarrassing to admit. Anyway, I finally got around to checking that they are both getting good earth, 12V (nearer 14V to be honest) from the live, and also voltage from the input wire as follows:
- tachometer gets its feed now from the Omex ECU via a tacho driver OMEM 6020 (that I picked up a few months ago) which is also getting 12V and earth, with the driver putting out just under 12V
- oil pressure input is around 6V

Both are nicely lit up when it is dark, which is a totally beside the point, but there isn't even the slightest movement out of the needle. When I plugged in the Tacho driver, I attached the computer to the ECU and fiddled with the tacho driver feed from the ECU (you can increase/decrease the output so that the RPM on the computer monitor matches the tachometer), but nothing registered on the tachometer so I left it back the way it was.

I would be grateful if someone could help me by letting me know what the next step/steps would be? Otherwise the car is going really well and I'm hoping to get up to Snetterton next month.

Any and all ideas are much appreciated

Paul

[steve j]

I assume that you are getting the correct voltages to the gauges, if so it must be mechanical (prepares to be shot down) I too had tacho problems and was sick and tired of the misting up. My solution, which cured both the misting and non operation was, drill a 3/32 inch, 1.6 mm hole in the back of the tacho casing, just big enough to take a WD40 aerosol straw, I gave it a short burst of WD40 and hey presto the misting stopped and the tacho was functioning again. I made sure that the hole was low so as to drain excess fluid. I now have only one gauge that doesn`t mist up. what prompted me to do it was the cost of the repair or a new gauge, good luck and I hope you get it sorted.

[glenrobbo]

Hi Paul,
Good to hear your Cossie is running well.
I've no idea about your tachometer problem, but could the oil pressure issue be a problem with the sender?

I'm not sure of the location or size of tapping on the Cosworth block, but I bought a replacement for my S1 from Hose Fittings UK for just under £15 inc p/p,
and it works perfectly. Worth a try at that price.
For further info, search on here for S1 oil pressure sender, it should bring up the old topic threads

Good luck,
Glen

ETA: an alternative would be to install an old-fashioned mechanical oil pressure gauge fed by a capilliary tube from the tapping on the block.

Edited by glenrobbo on Sunday 12th January 10:54

[phillpot]

pcashman said:

- oil pressure input is around 6V

Have no idea what's going on with your tacho, but guess it's some kind of "issue" between the original tacho (if it is the original) and the Cozzie/ECU electrics? Basic car electrics I half understand but electronics are not my forte!

Oil pressure gauge is a bit more straight forward, should be 12v at one side of gauge then other side goes to earth through the "sender". If you earth the wire that is connected to the sender the gauge should go to max?


The joys of having a TVR and a Hybrid !

Edited by phillpot on Sunday 12th January 13:35

[pcashman]

I'll pop them out and bench test them. Cheers Folks