Oil Pressure Gague

[rabowman]

Since I have had my car (98 model) the pressure gauge goes to max as soon as the ignition is switched on.
I have fitted a new sender and still the same, plus I tried an additional earth from the sender body.

The car has had a very recent replacement c/f dash fitted, do you think the wires could be crossed on the gauge itself?

Rob

[Skyedriver]

Mine does that too.
It'll read correct for so long then flick for a couple of seconds over to max again then back.
First time it did that I had a heart stopping as I thought the pressure relief valve had stuck.
I bought a new sender, didn't make a ha'pth of difference

[rabowman]

Not quite !! mine reads max even when engine is turned off.
Starting makes no difference. Always on max until ignition is off

[dwhitaker]

I had all kinds of fun with mine. Numbers subject to faulty memory. Swapped sender with one from ebay, was the wrong type, some go from 270 ohms for zero pressure and zero ohms for 100PSI, others the other way round. So thats the first possibility, you have the wrong type of sender. My seller swapped for free.

Mine always read high (about 70PSI). In the end I got a replacement gauge from a scrappy, and all worked perfect except the glass was scratched on the replacement. So as I had nothing to loose I set about dismantling the old one to find out how, and to see if I could swap the glass over. Good news its possible.

Put the gauge in a vice. Then use a pointed implement like a bradawl, and tap carefully round and round the folded aluminum to stretch it out straight, then you can (after some struggling) twist off the aluminum surround. The instrument will then drop out. It is badly made. Resistors joined just with a bit of solder - not even twisted first. Two had separated on mine. An easy repair. So reassembled and put back in. My hacking attempts are not visible when installed.

The gauge can be tested on the bench. If you know the characteristics of the sender, have a few resistors, and a battery.

Say the sender is 30 to 270 ohms, 0-100psi, then apply power and earth to the gauge, then connect the sensing lead of the gauge to earth via a 30 ohm, (should read zero PSI) and then the same with a 270 ohm, should read 100PSI. If not the gauge is faulty.

[griffer500]

Send the sender and gauge to
http://www.speedycables.com/
they can calibrate the gauge.

[rabowman]

I was hoping that I would not have to take the dash top off,
but thanks for the advise

[Tyre Tread]

Just be aware that speedy cables are anything but speedy and can take six to eiht weeks to turn stuff around.

[rabowman]

Tell me about it !!! I sent them a MGB speedo in 2005 for recal on a v8 conversion....still waiting and I sold the car in 06

[rabowman]

Done !! Gauge was kaput, managed to get a replacement from breakers.
Rob

[zed4]

rabowman said:

Done !! Gauge was kaput, managed to get a replacement from breakers.
Rob

Glad you got it sorted. I've still not managed to change my sender yet. Might try to do it this evening actually.

[rabowman]

Zed4 I have got a new sender from Racetech if you want to borrow it.
Rob

[zed4]

rabowman said:

Zed4 I have got a new sender from Racetech if you want to borrow it.
Rob

Thanks. I'll let you know how I get on with my cheapy one first!

[zed4]

My cheapy ebay oil pressure sender works perfectly, just fitted it this evening. Much better than the original TVR one.

I bought this one: http://www.ebay.co.uk/itm/370678852601?_trksid=p20...

Although it was £12.95 not £912.95!!! Not sure what that's all about!

[Tyre Tread]

zed4 said:

My cheapy ebay oil pressure sender works perfectly, just fitted it this evening. Much better than the original TVR one.

I bought this one: http://www.ebay.co.uk/itm/370678852601?_trksid=p20...

Although it was £12.95 not £912.95!!! Not sure what that's all about!

Yep, I fitted one of those to my P5B a couple of years ago. works fine.

[lancepar]

zed4 said:

My cheapy ebay oil pressure sender works perfectly, just fitted it this evening. Much better than the original TVR one.

I bought this one: http://www.ebay.co.uk/itm/370678852601?_trksid=p20...

Although it was £12.95 not £912.95!!! Not sure what that's all about!

Info......... When prices are inflated - seller is out of stock and in the above case, will drop to £12.95 when they have stock. Something to do with keeping place in listing and putting off buyers until stock is replaced.

[zed4]

The only thing I will say about that pressure sender is the thumb screws don't screw up very tight, and the slightest movement in the wire will loosen them. I'll probably replace them with ni-loc nuts and maybe spring washers.