Midas Cars Forum - www.midascarsforum.com

Hans Efde wrote:I rechecked the reading on the small blue resistor. I can't get a better reading than 75 ohms, measured with different settings on my ohmmeter, via the plug and via the wires. But I don't know what the effect is of the fuel gauge itself. Maybe you can measure this on your own car by taking a reading from the 2 outer pins of the plug (with the ignition in off). If that's an open circuit the resistor must be 75 ohms. If you do get a reading it should be possible to use this to calculate the correct resistance.

I'm fairly certain that the two wires which the blue resistor is connected across will be the two terminals going to either the fuel tank sensor or the water temperature sender (although I could be wrong!), which would mean that you wouldn't be able to measure the resistor's value directly with a meter. However, this also means that the value you measured (75 ohms) will vary depending on the coolant temperature (if it's the water temp sender) or the level of fuel in the tank (if it's the fuel tank sender)!
One thing which would help, is if you could give me your interpretation of what colours the bands are on the two resistors. Despite the clarity of your photos, there's always the chance that the colours might show up differently in "real life". I thought the blue resistor looks like "red, violet, black, black, red" (the gap between the black and adjacent red is wider than the other gaps, which I believe means that wider gap separates the resistor values (first 4 of 5 bands, or first 3 of 4 bands) from the tolerance percentage (the final band).
By the same token, the buff resistor I interpreted as "brown, grey, black, gold".
Would you agree that those are the colours you see?
Many thanks (and a special award if you've managed to make sense of this post!).

Yes you're right about the fuel tank sender. I hadn't thought about that. Depending on the amount of fuel it's resistance will change. I can see if I can get to a plug and disconnect the fuel sender.
The coding of the buff resistor is spot on, that image is close to reality. The blue one I have to check. It's in the car and access isn't very good. Also artificial lighting doesn't help. It's also very small, about half the size of the tan one. I'll check on Friday (have to work tomorrow) and get back to it.

There's no rush, I haven't had much time to play with the Midas recently. I tried to start it at the weekend and the battery was completely flat; I hope I don't have to replace it, I'd rather spend the money on other things!

I've got one of those 2.7 watt trickle solar panels to keep the car batteries topped up.

They work a treat....even in cloudy weather.

about £13 at maplin.

That's all very well in Blackpool, but where I am, I might need a bigger solar panel! I've seen those, and thought, "seems like a good idea if it works". I can feel a trip to Maplins coming up.

Blackpool sunny?

Not sure about that. These panels dont need direct sunlight though....even cloudy sky works. Just plug in the cigarette lighter port.

manifold wrote:Blackpool sunny?

Not sure about that. These panels dont need direct sunlight though....even cloudy sky works. Just plug in the cigarette lighter port.

Something else I need to fit to my car!
I'd planned to fit a cigarette lighter socket anyway, it's just somewhere on the list of things to do.

Has anybody had any luck with the resistors on the instrument binnacle as I'm fed up with running out of petrol and pushing my car uphill to petrol stations on my own

Sorry Barry, still have to determine the resistance of the 2nd resistor (see my previous post with pics). But I can only do that when the fuel tank is disconnected and at the moment don't have time for that. First is to finish the front because I should get the engine back within 2 weeks now.

If I bought a rover 213 petrol tank and filled it with water connected a battery to it and measured the voltage from the sender unit and then filled the Midas and checked the voltage on my tank would that then give us the difference we need to work out how to solve this problem