Electrical connection of new gauges

[HandyAndy]

Help please

I have bought an Oil Pressure gauge & Oil Temp gauge.......

bought the correct Sandwich plate thinghy & installed it correctly, installed the sender units etc into it.

Mounted my new gauges in the dash, they light up when side & dipped lights are turned on

However.....the instructions............3 connections to make

1) connect "S" direct to sender unit at oil filter end = done that
2) connect "-" to engine negative earth = done that
3) connect "+" to ignition live terminal = done that

The problem = the temp gauge isn,t reading a temp....
the pressure gauge goes off the scale

what am I missing? ( sorry if its obvious, me & electrickery just don,t mix )

cheers
andy

[RAYLEE29]

you havent got the sender wires crossed have you just a thought
Ray

[HandyAndy]

Originally Posted by RAYLEE29

you havent got the sender wires crossed have you just a thought
Ray

I don,t think so....but knowing me & electrics then maybe

I purposely wired each one up at a time so as not to mix the wires.

Have I made a mistake with this ...... I,ve kept the original pressure sender that goes to the Sierra dash binnicle as I,d like to ensure that the oil pressure light goes out when the engine fires up.....could that cause a problem?

cheers
andy

[RAYLEE29]

ooh yes thatd be problem one the original oil pressure switch is just a switch the sender will change resistance according to pressure what you need to do is use a tee so you can fit the switch and the sender and wire both up as for the temp disconnect the wire and earth it to the block this should make the gauge read highest temp if not you have somat else wrong
Ray

[HandyAndy]

ok, thanks Ray, I,ll give that a try tomorrow .

cheers for your help.

Andy

[twinturbo]

I think you misunderstand Andy Ray, He has the preasure switch and a T-pice to the senders for the preasure and temp.

Perhaps these are back to front Andy?

TT

[mark]

My oil pressure goes off the scale when the oil is cold and thick, once it warms up its about 25psi idle and 80psi on the move

I thought i had it wired wrong when it initially went off the scale but i let it warm up to see what happened, maybe you need to do the same before you change any connections

Also oil temp guages take ages to get a reading as oil takes quite a while to warm up to temp, a good few miles of driving after the coolant temp is up to normal. It will prob take quite a while to get the oil temp up just revving it stationary compared to being under load when driving along

[HandyAndy]

Originally Posted by twinturbo

He has the preasure switch and a T-pice to the senders for the preasure and temp.


TT

Erm....no, don,t have a T -piece to the senders, each gauge is directly wired to its own sender...

This is why I don,t understand what I,ve done wrong
as i,ve followed the instructions for each gauge independant of each other

cheers
andy

[HandyAndy]

Originally Posted by mark

My oil pressure goes off the scale when the oil is cold and thick, once it warms up its about 25psi idle and 80psi on the move

I thought i had it wired wrong when it initially went off the scale but i let it warm up to see what happened, maybe you need to do the same before you change any connections

Also oil temp guages take ages to get a reading as oil takes quite a while to warm up to temp, a good few miles of driving after the coolant temp is up to normal. It will prob take quite a while to get the oil temp up just revving it stationary compared to being under load when driving along

Ahh, now that makes me feel less thick

As it was pouring down, I kept the car in the garage when fitting the gauges, tho I did let it run up to temp ( coolant).

Hopefully if weather is kinder tomorrow I,ll have the car outside & will give it some welly .....stood still

cheers
andy

[David_17]

Sounds like a bad earth to me Andy. I've got a water temp gauge that was having the same problems, all down to the earth on the sender.