Oil Pressure Sending Unit ?

[Mike Mileski]

Is anyone aware of another oil pressure sending unit from another vehicle that is smaller than the stock Datsun unit but still gives an equal signal that will work with the stock oil pressure gauge? I am putting in an LS motor and need to tap into the LS oil system for a sending unit and I sure would like to use something a little smaller than the large stock one, even if it's a different thread size. I do not want to convert to different gauges at this point. Any help would be appreciated.

 

Mike Mileski

Tucson, AZ

[Pac_Man]

Hi Mike,

 

To my knowledge, there seem to be two styles of oil pressure senders on the S30s. My '76 280z has a fairly small one, and I imagine it would interchange with the larger unit without issue.

 

 

It's kind of difficult to see in this image but if you lean toward your screen you'll get a better idea of how large the profile is in comparison to the rest of the engine:

 

 

ACDELCO Part # E1802 

STANDARD MOTOR PRODUCTS Part # PS171

AIRTEX / WELLS Part # 1S6539

ULTRAPOWER Part # 1S6539 

[Mike Mileski]

Pac_Man, I did some cross checking and it looks like that unit will work on a 240Z. Thanks a bunch.

 

Mike Mileski

Tucson, AZ

[Sjoost]

Hi guys,

 

I am working on this same topic. For my 280z 1976 model i have now bought like 4 different sender units by now. One same as like the picture in the top of this thread (The Rockauto one). But it does not work for me. My oil gauge stays on 0, and the gauge does work, because when i ground it, the meter climbs all the way. I put in another one (i think a switch again) and that one climbs all the way up on my gauge at ignition, and drops all the way down when engine starts running (looks like a reverse switch).

 

Somewhere, i found that these are actually switches, and what the gauge needs is a continues pressure sender, giving different resistance over the pressure range like in this Post: https://forums.hybridz.org/topic/114259-oil-pressure-sender-and-gauge-specifications/

So i have been looking around, and found that there are many sender units, 0-145 psi but the resistance seems to be other way round (so LOW resistance a LOW psi, and HIGH resistance at HIGH) compared the linked article.

I am puzzled, anyone know the clue to this all?

 

Besides, the engine block tread, anyone know what that is. Is it  1/8 "BSPT , or 1/8 "NPT? or something else?

 

Hope someone knows the details?

 

cheers,

 

Joost

 

[NewZed]

You should put the part numbers or links in to your post.  Nobody knows what you actually worked with.

 

The hole is BSPT.

 

After 1977 the sender was combined with a switch.  Those parts has two terminals.  One terminal is the pressure sender and one is the switch.  You can use that on your 76 and just leave the switch terminal unused, if you already have one.

 

Beck Arnley has been supplying Z parts for years.  Their sender probably works.  If I was starting from zero I'd go with that one.  It has the best odds.

 

p.s.  make sure that you use a thin wrench on the flats to tighten it.  Don't try to turn the body it will break loose, spin, and damage the guts.

 

https://www.rockauto.com/en/catalog/nissan,1976,280z,2.8l+l6,1209226,electrical-switch+&+relay,oil+pressure+sender+/+switch,4588

Edited June 16, 2020 by NewZed

[Sjoost]

You are right NewZed, bit confusing without part details.

 

Well in the rockauto link for example, I have the part ACDLCO E1802. However when installed, it did noting to my pressure gauge. I think it's just a low oil pressure switch with a fixed low pressure alarm (correct me if i'm wrong). Indeed, i did notice the later models have the continues pressure measurement, and a low pressure alarm and figured that will also function on older 280z, without the alarm connected.

From the sent link, only the BECK/ARNLEY 2010239  &  WVE 1S6561 will work for the gauge, right?

I was actually looking for a alternative part easily bought in europe (or china). Therefore i was looking at alternatives but needed the correct tread details (most common is 1/8inch NPT). Thx for that. The point of the Low pressure low resistance, vs high pressure, higher resistance i still do not fully understand. Or do cars really have gauges with other way round meters (resistance wise)?

 

Thx NewZed.

 

Regards,

Joost

 

[NewZed]

I don't know why Rockauto even has that AC Delco switch on that page.  They are slipping.  The description is all wrong for the car, even the brand.

 

The Beck Arnley should work.  It's a sensor.

 

 

[SteveB]

I have a 1977 and it has the 2 terminal oil pressure sender.  Gauge was not working at all but plenty of actual pressure. I tested it manually.  So I bought a new sender from Z Parts.   It’s the larger 2 terminal one.   Now the gauge goes all the way up as soon as you turn on the key, or start the engine, then slowly goes back down to zero.  
 

I’m pretty sure that means the gauge is fine, so is the sender faulty or ??   I hate seeing no oil pressure on the gauge even thou I know I have pressure.   Any suggestions?

 

Thanx 

 

Steve

[NewZed]

Not so sure that means your gauge is fine.  Why would it slowly drop to zero?  Kind of sounds like the bimetal strip heats up and causes the slowly drops to zero part.  If I read the description right you should be able to connect an ohm-meter to the pressure sensor side and see resistance change when you start the engine.  Not sure where it starts though.

 

These old gauges have some odd operating features.  Internal voltage regulator, for example.  I think its purpose is to correct for voltage changes as the alternator kicks in and out.

 

Maybe this will give you a clue.

 

Here's a thought, that might tell you if it's the gauge.  Disconnect the pressure sensor, open circuit.  Turn the key on.  If  the needle does the rise and drop thing it almost certainly has to be the gauge, or the wires.  Check your wires for short circuits to ground.

 

Edited December 20, 2020 by NewZed

[SteveB]

Thanks for the reply and the suggestions.   

I’ll give those a try.  

When you say to disconnect the pressure sensor do you mean the oil sender???   

Plus what are each of the wires that connect the sender for?  Most senders, including many other year 280z, have a one wire sender.  

I read somewhere that you could check gauge by using just one of the 2 wires.  But don’t know which one.  

 

Thanks again

 

SteveB

[NewZed]

Looks like the one with the yellow wire with black stripe.  The other prong is a switch for the fuel pump relay.

 

[SteveB]

Thank you!!!

[NewZed]

Notice though, that the diagram says switch.  I think that's a typo since the diagram is for the oil pressure gauge.  The switch is described in the Engine Fuel section under fuel pump operation.

 

[Sjoost]

 

I have been trying many alternative senders on my 1976 280z. In the end I only got the Beck Arnley to work. Many of those compact senders, are switches.  The 2 I had of those, did not give a signal with which the gauge would work. Beside that I did try many replacements that look like the Beck Arnley, some with a switch wire and a continuous wire (for gauge), but the issue was that they had a reverse resistance path. When putting the power on, gauge would run to 100. After starting the engine, the gauge would drop to 0.

I gave up, and got the Beck Arnley. If anyone knows of a different one, I also would like to know.

 

[SteveB]

Thanks for the update.  That is just the info I needed.  I’ve checked everything again today and all seems in order but gauge still doesn’t work right. 
 

I have the 2 terminal oil sender set up.   I just got a new one, 2 terminal one, from ZCarDepot, but it’s not a Beck Arnley part.   It’s an Intermotor part, SKU # 800-036 from ZCarDepot, and part #PS173
 

My gauge with the part above does exactly what yours did.   Goes all the way over with key in on position, then as soon as car is started it slowly drops down to zero and stays there.    I’ll see if Z Car Depot will send me a replacement that is a Beck Arnley, or just take it back if they don’t have the right one.   It was pretty expensive, $46 bucks, so I’m disappointed it didn’t work.  Glad you replied to my post.  Thanks!
 

Also!  Where did you get yours?   Do you have a part #?  
 

Thanks and Merry Christmas.   

[heyitsrama]

I used a Ultra-Power PS153 that i got from rockauto.com, it was $3.33 no complaints, the gauge works great for the past 4 years.

 

https://www.classiczcars.com/forums/topic/59905-71-240z-oil-pressure-sending-unit-not-working/?tab=comments#comment-547841

 

I don't see them on sale on RockAuto anymore, i see the BnN one for $15 bucks.

[SteveB]

The one you suggest is the single terminal oil sender.   I need the 2 terminal one.   Wish I had the one wire/terminal set up.    Much cheaper and seems like they are not an issue like the 2 wire ones.   Thanx 

[Sjoost]

SteveB,

 

Sorry for the confusion. I have an early 280z, which has the one wire setup. But the operation to the gauge is still the same, I expect. Resistance should be

1/8" below 0 psi - infinite ohms (open circuit).
0psi - 90ohms
60psi - 25 ohms
90psi - 12 ohms

 

 

For the two wire version, I am not sure, but if you know the switch setting needed, and the sender gives the correct ohm's, it should work.

[SteveB]

Thanks to everyone who replied and helped me out.   I found the Beck Arnley 2 terminal sending unit on Amazon and ordered it.  Part # 201-1170.   Hopefully that one will work.  ( Still waiting to see if ZCarDepot will let me return the Intermotor part for credit) 

I am curious about the sender/switch description for the 2 terminal part.   I know the sender portion sends different level of ohms to the gauge based on the oil pressure.   What does the switch control?   I thought it might switch on an idiot/low pressure light when pressure drops too low.   But I don’t think I have a low pressure light on my car.   Then I read on some wire diagrams that there is a fuel pump relay involved in the same circuit.  Any thoughts on that?

My car is 1977 280Z, but has this 2 terminal sender/switch,, wiring diagrams for 1977 show a one wire sender,   I believe 2 wire units didn’t arrive on these cars until later years and /or the 280ZX.  So should I be looking at wire diagrams for later years and ZX’s?   
 

Thanks again and Happy Holidays!

 

SteveB
 

 

[NewZed]

9 hours ago, SteveB said:

My car is 1977 280Z, but has this 2 terminal sender/switch,, wiring diagrams for 1977 show a one wire sender,   I believe 2 wire units didn’t arrive on these cars until later years and /or the 280ZX.  So should I be looking at wire diagrams for later years and ZX’s?  

 

 

You could have a 78 car or system, or a 78 engine and the sender wasn't swapped.  But the two prong sender/switches were used from 78 on in to the ZX's.  Might be that you got a late 77 with a 78 system.

 

What is the build date of your car?  It should be on the plate on the door jamb.

 

Here is the 1978 system.