Jump to content

oil sender


Glen

Recommended Posts

Hi, my oil gauge when i turn on the iginition goes to maximum and then to minimum, After a little reading it seems i need a new sender as the gauge is working. Does anyone know where can i get a brandnew one from in melbourne?

 

cheers

glen

Link to comment
Share on other sites

ok so installed the new sender it still the same symptoms. I put the ignition on, the oil goes to full pressure, start the car and it returns to zero and remains there. If i leave the ignition on without starting it stays on full pressure. Is there something else i should be checking? Does this sound familar to anyone.

cheers

glen

Link to comment
Share on other sites

it almost sounds like oil pressure switch than oil pressure sender.

 

if you have a multimeter disconnect the gauge and connect the multimeter in ohms range. check the values when engine off and when u start it and recheck when warm etc....

 

if you have realy high or almost a short when its off and reverses when you turn the engine on it wil indicate that its a oil pressure switch and not a sender. sender will give you a value which would be consitant to the oil pressure. in service manual it probably has the values when checking oil pressure senders. if u have an air compressor you could dial the relevant pressures and check the resistance again verifiying against service manual values.

 

if all that fails check some of the wiring from sender to gauge makes sure they are not shorted to something else.

 

after that check the gauge itself. again this could be done with a multimeter and a variable resistor (suitable value) and a 12V power supply. you could do it in the car but you have to disconnect the sender from the circuit. u install the variable resistor accross the terminals where the pressure sender would have been. vary the pot and you should see the needle move. again setting the right resitance and checking it against service manual values should give you indication what is malfunctioning.

 

though ill first check if the oil sender is a sender and not a switch.

Link to comment
Share on other sites

I seem to remember a lot of people have problems with the generic senders basically they don't work on the L-series motors, don't know why!  My advice is steer clear or repco etc and spend the $ to get

the genuine artice.

 

At least then you know u getting the right reading, I got one a couple of years ago from Z Shop for bout $80, on line site is not operating at the moment but give them a call they usally have heaps of that stuff in stock.

 

NB- on cold start up pressure should rise at least halfway @ 2-2500rpm, at idle it usuall falls to basically zero, at least thats what happens on all my cars.

 

Dale

Link to comment
Share on other sites

that makes sense dalee as the one i took out looked pretty new. I will try the one out of my friends car in mine to see what happens but im thinking thats the problem. If not i will try and diagnose the problem as rbz 260 suggested

Link to comment
Share on other sites

Hi

 

I would bet you are connecting to an oil pressure switch. The original oil pressure sender on the 240 has a single round post that the wire from the loom connects to. The 240 does not have an oil pressure light. Some replacement senders for the later model cars ie 280ZX, have 2 spade terminals on them. One is for the oil pressure gauge and one if for the oil pressure light. You can still use them on a 240 but you need to connect to the correct terminal and modify the connector. If you are connected to the oil pressure light terminal at switch on the connection is almost a short circuit to earth to light the lamp in the dash, once oil pressure rises the resistance increases and the light goes out. If you connect the gauge to this terminal the gauge will go to max oil pressure at switch on and 0 after oil pressure builds up.

 

So you either have the wrong sender unit fitted to the block or you are connected to the wrong terminal on the sender.

 

Warren

Link to comment
Share on other sites

i prob buy the genuine from nissan one. im sure they not that expensive. i bought one recently for a 2000 pathfinder only cost me $57 trade price. dont think the L series one be much more. ill check with them as im going to pick few parts in a day or two.

 

but i suspect its definetly a oil pressure switch and not a sender.

Link to comment
Share on other sites

but i suspect its definetly a oil pressure switch and not a sender.

 

So what am i replacing then, when i connect the old one it has a red wire with a like a round sliding connection. Isnt that the sender?

Link to comment
Share on other sites

they look identical you cant tell the difference unless u test it or theres a part number stamped on it.

 

if its combination sender switch you should have 2 terminals on the end of it. i dont think 240z had a low oil pressure lamp so dont think they had the 2 terminal oil sender. so the oil pressure switch and old version of the oil pressure switch would be identical in appearance.

 

if it only has one terminal you can either use the two terminal unit and plug in the correct pin to get your guage reading.

 

 

just measure the resistance. switch is either on or off. while the sender will have set resistance depending on the pressure applied.

 

i couldnt find the values in the 240/260z manual but i had a look at the other service manuals i have. being nissan they keep most of their methodolgy the same through the years.

 

but from r34 manual

 

oil pressure sensor. it has 2 terminals like someone mentioned before. one pin is the oil pressure switch for your lamp.

 

When engine off should read short circuit or close to 0 ohms.

when engine started it will read high or over the range or open circuit.

 

they do this if there is a fault on the switch or guage to automaticaly go to low and get your attention that is no pressure and to check the system

 

Pin 2

 

it should read approximately

 

42-50 ohms when pressure is at 1bar

37-45 ohms @ 2bar

25-35 ohms @ 4bar

 

now these values are from r34 skyline rb25det engine so values may vary slightly but it is good indicator what a oil pressure sender/ switch should do.the r34 is same for r32 and r33 and z32. other models only have oil pressure switch liek s13,S14 etc.........

 

i know fuel senders between the s30 zeds and r32 are same value 0-90ohms but the curve obviously matches the tank.  the guages are calibrated to read this. i asume they have done the same thing for oil speedo and rpm. im using a s14 spedo sensor to drive N15 pulsar speedo. though i havent checked the calibration yet. but it does read speed.

 

thats y i love nissans and love working on them. most stuff is interchangable or using same methodology.

 

 

 

Link to comment
Share on other sites

  • Moderators

One quick way to tell the difference is oil pressure switches are small and stubby, almost the same diameter as a $1 coin and only 20-25mm long and pressure senders are about 10 times the size... if it looks like a short stubby bolt with a single terminal out the end you have a switch and not a sender!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...