Stuff you have made today

[Cobbler]

If you replace the MX5 switch with an oil pressure sender off a Eunos, the gauge will work. The gauges are the same, just the switches are different. It is on the mk1’s

 

[Munkul]

I love that statement "it doesn't measure anything - it just goes to a reassuring position when the engine is running"

I'm sure that most modern coolant temperature gauges do something like this... the needle never moves but you can see the temp fluctuating quite a bit with diagnostics.

 

[Misterg]

If you replace the MX5 switch with an oil pressure sender off a Eunos, the gauge will work. The gauges are the same, just the switches are different. It is on the mk1’s

No, the gauges are different too - the swap needs both the gauge and the sender from a pre'94(?) MK1. I did look at modifying the later gauge to work with a pressure sender, but it gets quite messy - the gauge is full of very heavy damping oil and takes several seconds to move. I quite fancy the option of being able to display other things there too. ([cough] Boost [/cough] )

That just seems to be a claim waiting to happen, to me. "Well, of course I was monitoring the oil pressure gauge, but my engine still exploded". I'm even more surprised a Japanese manufacturer would be doing something like that.

The MK3s are even worse:

"The oil pressure gauge display is based on an algorithm in the PCU and is based on engine revs and coolant temperature. It does not represent the actual oil pressure in the engine unless there is no pressure at all but by then it’s probably too late anyway."

I'm sure that most modern coolant temperature gauges do something like this... the needle never moves but you can see the temp fluctuating quite a bit with diagnostics

The temperature gauge on the MX5 certainly does that - it's got a 'dead spot' in the middle, so that the needle rises up quickly, and then doesn't move much until it's about to boil. (There's a fairly simple mod to change this though). The gauge on my Relay van does the same thing, but I think that's under ECU control.

 

[dobbslc]

My Surf is like this, the dash gauge will quickly go to just under the middle and just sit there, meanwhile my digital temp gauge is reading much lower for the first few minutes when warming up then rises to about 84° untill you hit a long uphill section and it'll go up to about 99° , the dash gauge never moves.

 

[droopsnoot]

^ Same on my TT - 90 degrees on the display equates to anywhere between about 82 and 98 when shown on the diagnostic. So if it does start to go up, the gauges does nothing until it alarmingly races for the top.

But when my seventies Vauxhall goes to the centre and stays there, I think there's something wrong with it and don't trust it.

 

[bricol]

MY old shape Renault 5 avoided all this guage trouble by not having one . . . when the fan belt fell off in central London back when I working there in 1991 ish, I couldn't work out what all the funning noises coming from the front were, or the sudden random shaking of the car in traffic . . .

I hadn't noticed the little red light come on in the dash . . . the coolant was boiling merrily. Parked it, walked into the shopping areas for a time, wandered back, drove it back to digs in Peckham. Strong engine!