240260280

Integrated Oil Pressure Switch and Sender?

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    @Captain Obvious & @zKars

     

    Just checking with you to confirm that the 87 Fiero has a combination oil pressure switch and sender?  I wish to continue to use my oil pressure gauge and have a cut off switch for an electric fuel pump.

     

    https://www.rockauto.com/en/catalog/pontiac,1987,fiero,2.5l+151cid+l4,1249141,electrical-switch+&+relay,oil+pressure+sender+/+switch,4588

    Thanks

    RA-OPS1026__ra_p.jpg

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    Yes, both sender analog, and an on-off for the fuel pump. I didn't look anything up in any manuals, but anecdotal data says the switch should close over 4 psi.

    Here's a page with some info about the sender units. Note that 87 and earlier is different than 88, but I think it's mechanical differences only. Electrical they are the same 84-88.
    http://web.archive.org/web/20151002182213/http://home.comcast.net/~fierocave/oilsender.htm

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    My pleasure.

    Did you verify that the plumbing connection taper threads are the same? Most, if not all, of the plumbing on the Z is BSP, while the Fiero should be NPT.

    If you're just looking to jamb it in there once and have it not leak, you'll probably be OK with some schmutz and/or Teflon tape, but if you're a purist, you might not like mixing the threads.

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    What about STANDARD MOTOR PRODUCTS PS173? Supposedly, it's designed for a 1978 280Z. If I don't miss my guess, the vertical connector on the T is the one for the negative pin for your fuel pump relay. I have one in my parts stash just in case I ever want to convert to an internally regulated alternator on my 260Z.

    Edited by SteveJ

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    LOL. I don't think there was any disrespect. Here's my translation:

    "You know that for the 78 280Z, Datsun went to a three prong oil pressure sender that has a switch built in. And those switches are still available aftermarket for cheap.

    So with that in mind, why are you messing around with adapting Fiero parts (which may or may not have the correct plumbing thread) when you could just buy the sender unit for a 78 that already has the switch AND has the correct threads?"

    I believe that's what SteveJ and ZedHead are alluding to.

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    I've got a '74 260z and I just realized that the electric fuel pump was not functioning, just the mechanical. I'm not getting power to the pump and have yet to test the pump by applying power directly to it.  The double relay system in the car from the factory that uses the engine speed to kill the fuel pump seems like a complicated setup. Would I be better off switching to a combination oil pressure/fuel cutoff switch? It seems more straight forward and would offer protection if I lost oil pressure. My son wants me to install a fuel pump switch on the dash, but I think he likes the idea of having to flip switches. 

    Jeff

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    I'm not sure why you think it's complicated. The electric fuel pump has 3 switches. The first is the ignition switch. The second is a normally open contact on a relay. That relay coil is energized when the alternator is turning fast enough. (Note the voltage for that coil comes from the yellow wire between the alternator and voltage regulator. If you swap to an internally regulated alternator, you will remove the coil voltage from this circuit, and the fuel pump will never get voltage.) The last switch is a normally closed contact on a relay that opens up when you are cranking the engine.

    Diagnostics go like this:

    1. Turn the key to the ON position.
    2. Use a voltmeter or test light to verify you have voltage (to ground) on the black/white wire on Relay 1. (It's the 4 pin connector.) If this test fails, find the break in the wire.
    3. Start the car.
    4. Use a voltmeter or test light to verify you have voltage (to ground) on the green/white wire on Relay 1. If this test fails, you need to replace Relay 1. (This will require substituting a modern relay.)
    5. Use a voltmeter or test light to verify you have voltage (to ground) on the green/white wire on Relay 2. (It's the 6 pin connector.) If this test fails, find the break in the wire.
    6. Use a voltmeter or test light to verify you have voltage (to ground) on the black/white wire on Relay 2.  If this test fails, you need to replace Relay 2. (This will require substituting a modern relay.)
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    My 78 280z  rock auto special is a boat anchor... only two prongs and it simply switches on high pressure and low pressure. It is not what Nissan made (sensor output and switch on low pressure)... beware... rock auto lies.

    Edited by 240260280

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    9 hours ago, 240260280 said:

    My 78 280z  rock auto special is a boat anchor... only two prongs and it simply switches on high pressure and low pressure. It is not what Nissan made (sensor output and switch on low pressure)... beware... rock auto lies.

    I don't think the people at Rockauto were trying to misrepresent the part. They just follow the compatibility charts provided by their suppliers. 

    I looked at the information provided on the SMP and Beck-Arnley parts listed on Rock Auto. They list a parts number cross-reference that has many part numbers that line up to Nissan part numbering. I tried looking up the part number on Carpartsmanual.com, but I couldn't find it easily. I then put in the Nissan style part numbers into CourtesyParts.com. Here are the results (all of the positive hits came up with an oil pressure sender):

    25070-80W00 300ZX
    25070-55S00 200SX
    25070-55S60 200SX
    25070-N7600 No results
    25070-P7100 300ZX
    25250-S6000 300ZX
    25250-S6001 720
    25070-P8000 300ZX
    25070-P8100 300ZX
    25070-P9700 300ZX
    25250-N7600 300ZX
    25240-89908 No results

     

    So did Nissan use the same part with different numbers, or did Beck-Arnley and SMP take too many liberties in their cross-referencing? I went to the SMP catalog and searched for 1978 280Z parts. It lists a "Switch - Oil Pressure Gauge" with the same part number listed in the Rockauto catalog. For applications of this part, here is the compatibility list:

    Nissan 200SX (83-80) 

    Nissan 280Z (78)

    Nissan 280ZX (83-79) 

    Nissan 300ZX (84)

    Nissan 620 (79) 

    Nissan 720 (85-80)

    Nissan 810 (81-78) 

    Nissan Maxima (84-82)

    Beck-Arnley has a similar applications list in its catalog.

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    So the two prongs on the 78 are supposed to be on-off, and variable resistance. You're saying the 78 style sensor you got from rockauto does not operate like that?

    There's always the Fiero.   :ph34r:

    • Haha 1

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    16 hours ago, 240260280 said:

    My 78 280z  rock auto special is a boat anchor... only two prongs and it simply switches on high pressure and low pressure. It is not what Nissan made (sensor output and switch on low pressure)... beware... rock auto lies.

    Two prongs is correct.  One prong is the pressure sensor and the other is the switch.  Maybe you picked the wrong prong?  Bottom of the T is the switch.

    image.png

    image.png

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    Thanks guys!  I'll hook it up and see what happens.  The documentation accompanying said that it was just a switch that activated on very low oil pressure or very high oil pressure. No mention of pressure-to-resistance feature for driving the oil gauge.

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    Don't forget that the switch is normally closed.  It opens with oil pressure.  That's the flaw in it, if you unplug the oil pressure switch the fuel pump runs with the key On.

    You'll need another relay to make it act as a safety switch.

    That diagram hurts my head...

     

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    On 7/25/2018 at 7:10 PM, 240260280 said:

    Thanks guys!  I'll hook it up and see what happens.  The documentation accompanying said that it was just a switch that activated on very low oil pressure or very high oil pressure. No mention of pressure-to-resistance feature for driving the oil gauge.

    Which Z car are you wanting to install this oil pressure switch?  240?  Assuming the sender that you are buying does have a pressure>resistance sensor in it you will want to compare the resistance values to your original.  If it works great.  I'd like to know.  I did something similar  years ago.  It was a bit convoluted, I got a T and then used the original sender on one port and another sensor designed for idiot lights on the other port for my fuel pump control.  It worked fine however it did look like something you'd see in an oil field.  If you can get one sender that has all the function in it that's great.

    Edited by hls3073z

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