Oil Pressure Gauge

[robmarrs]

On my '94 Chim, the oil pressure gauge reads just below 30psi when the ignition is turned on, then 60psi when started and cold, and then just over 30psi when idling and warm,

Why does the gauge read a significant pressure when the engine is not running?

The electrics on this car are really starting to give me a headache!

[SimonV8ster]

My gauge was always stuck at 30 and never dropped. It did move higher when started from cold but never dropped lower than 30. Thought it was broken so sent it off to be repaired.

Now I'm wondering whether it was broken at all !!

[Cider Andy]

robmarrs said:

Why does the gauge read a significant pressure when the engine is not running?

It shouldn't as there isn't any. Check the sender connectors first. If they're ok, replace the sender before checking the gauge as it's easier to do (and probably cheaper).

[thegman]

i think the bible says (on a warm and worn in engine) 16ish is normal on idle , 30ish when under load

[robmarrs]

Cider Andy said:

robmarrs said:

Why does the gauge read a significant pressure when the engine is not running?

It shouldn't as there isn't any. Check the sender connectors first. If they're ok, replace the sender before checking the gauge as it's easier to do (and probably cheaper).

Yes that's what I thought but my mate has 93 chim and his gauge reads 25-30 psi with ignition on and not running!

Can we have a reader poll on oil gauge readings, with reg year, pressure with ignition on and not running, maybe its just another TVR quirk!

[SimonV8ster]

Just had a call saying that mine is fixed. Forty five fking quid !!

If it goes a bit higher when you start the engine up then it must be working. Don't look at it at any other times.

[spend]

No, my 93 works fine.. All I have done is painted sensor to protect it from water .

There are 2 connectors on the sensor, you might have connected the wiring to to the wrong terminal

Dave
ETA: or even worse mixed up the switch & sender wiring...

Edited by spend on Tuesday 1st April 13:32

[K4TRV]

robmarrs said:

Cider Andy said:

robmarrs said:

Why does the gauge read a significant pressure when the engine is not running?

It shouldn't as there isn't any. Check the sender connectors first. If they're ok, replace the sender before checking the gauge as it's easier to do (and probably cheaper).

Yes that's what I thought but my mate has 93 chim and his gauge reads 25-30 psi with ignition on and not running!

Can we have a reader poll on oil gauge readings, with reg year, pressure with ignition on and not running, maybe its just another TVR quirk!

With ignition on the "electric" gauges should all read zero, except the fuel gauge (unless it is empty?) and the clock !!

If they don't, I wouldn't rely upon the reading.

Electric, rather than capillary driven gauges, are the most inaccurate method of reading fuel, water temp and oil pressure you would wish to use on a vehicle.

For what's worth, mine is '93 and all except the fuel read zero with ignition on and all, except fuel, appear to be reasonably accurate. For me this means, if something changes, I would hope to spot it !!. Fuel gauge registers 3/4 full when full and 1/4 full when empty, but the warning light appears to operate with 10 ltrs left.

A bit of TADTS, I expect.

Trev McM

[spend]

K4TRV said:

..Fuel gauge registers 3/4 full when full and 1/4 full when empty..

Only because you are too lazy (like most of us) to engage in a bit of arm wrestling...

Is there any wonder TVR has a bad reputation for reliability when owners are so quick to jump on the bandwagon when their cars have not been maintained properly? Blame the servicing not the brand IMHO.

Dave

[K4TRV]

spend said:

K4TRV said:

..Fuel gauge registers 3/4 full when full and 1/4 full when empty..

Only because you are too lazy (like most of us) to engage in a bit of arm wrestling...

Is there any wonder TVR has a bad reputation for reliability when owners are so quick to jump on the bandwagon when their cars have not been maintained properly? Blame the servicing not the brand IMHO.

Dave

Nearly too lazy.....I wouldn't blame TVR specifically, but I know what you mean. It's too much effort to tear the boot/tank seals apart.

It's every vehicle built since 60's that have cheap gauges. Not until you go "digital" for everything, including proper engine management, is the information accurate, IMHO.

My fuel gauge tells when it needs a refuel, but since it's usually to be seen on Sprints and hillclimbs I rarely have time to look at specific readings. Got oil pressure at the start and usually some at the finish and no funny noises - all's is OK !!

Trev

[robmarrs]

spend said:

No, my 93 works fine.. All I have done is painted sensor to protect it from water .

There are 2 connectors on the sensor, you might have connected the wiring to to the wrong terminal

Dave
ETA: or even worse mixed up the switch & sender wiring...

Edited by spend on Tuesday 1st April 13:32

No definitley wired correctly, the pressure switch, is a spade terminal, the other is a tiny ring terminal

[spend]

... and does your pressure sensor have 2 terminals (IIRC as standard they come with a male blade bolted on one of them).

The switch is separate and has only a blade connector.

Dave

[robmarrs]

spend said:

... and does your pressure sensor have 2 terminals (IIRC as standard they come with a male blade bolted on one of them).

The switch is separate and has only a blade connector.

Dave

Not sure have to check, but went for first spring run on thursday with some oither lads to Goodwood.



Now the speedo does not read over 100mph and i was overtaken @ 140 by one of the other lads in a Porsche

More expense !

[im]

K4TRV said:

Fuel gauge registers 3/4 full when full and 1/4 full when empty, but the warning light appears to operate with 10 ltrs left.

You've got a low-fuel warning light!

Damn...where's mine?

'97 Chim 4L

[spend]

im said:

K4TRV said:

Fuel gauge registers 3/4 full when full and 1/4 full when empty, but the warning light appears to operate with 10 ltrs left.

You've got a low-fuel warning light!

Damn...where's mine?

'97 Chim 4L

One of the luxuries of the v.early cars but no ice warning... Didn't some of the later models have a version incorporated into the Main Dials?

Dave

[Cider Andy]

spend said:

Didn't some of the later models have a version incorporated into the Main Dials?

Dave

Mine's the second to last incarnation ('99, odometer is mechanical) and has no low fuel warning light.

[Tahiti450]

robmarrs said:

Why does the gauge read a significant pressure when the engine is not running?

Assuming that the gauge reads zero when the ignition is turned off then the problem is with the pressure sender unit, these can be very quirky since they rely on a very heath-robinson mechanical/electrical system. Basically it sounds that the wiper contact is not reaching the end of the rheostat when there is no pressure or that the rheostat is dodgy.
I have many times stripped these units to correctly zero and calibrate them, with moderate success but its a PITA and you need a good knowledge of the principles involved. The rheostat windings can wear through with use and any of the internal components can wear or fail. Probably simplest to fit a new sender, or try a known good substitute first.

[robmarrs]

Tahiti450 said:

robmarrs said:

Why does the gauge read a significant pressure when the engine is not running?

Assuming that the gauge reads zero when the ignition is turned off then the problem is with the pressure sender unit, these can be very quirky since they rely on a very heath-robinson mechanical/electrical system. Basically it sounds that the wiper contact is not reaching the end of the rheostat when there is no pressure or that the rheostat is dodgy.
I have many times stripped these units to correctly zero and calibrate them, with moderate success but its a PITA and you need a good knowledge of the principles involved. The rheostat windings can wear through with use and any of the internal components can wear or fail. Probably simplest to fit a new sender, or try a known good substitute first.

I like a good justified explaination, Thanks for that, i will try a new sender in the near future