For those of you with the SOS oil sending unit.

[K1ng124]

SOOooooo, I recently swapped my oem sending unit for the SOS relocated one. The reason I changed it was because my oil pressure(per the oil pressure gauge) after start-up stayed constant no matter what. Never went up or down, no matter temp of engine/rpm. Just remained around 2.5. I rarely drive my cars hard, but the other week I also noticed it wasn't engaging vtec. Thought maybe this could be linked. Anyways now that I have the SOS oil sending unit installed, my oil pressure never leaves "0". I have not driven the car ever since the install. Any ideas?

 

[ATERPAK]

Which kit is it? Is it the complete oil pressure sensor upgrade or just the oil pressure adaptor block? Need to know this.

Al

 

[K1ng124]

http://www.scienceofspeed.com/produ...products/NSX/ScienceofSpeed/oil_press_sensor/
The complete kit.

 

[nsxnut]

I have one of these and it works just fine.

Later,
Don

 

[winreboot]

I have one too and notice it work the same as OEM. It would show lower then expected pressure so I installed stand alone aem unit to make sure my oil pressure is fine. The aem displayed correct much higher pressure then gauge cluster.

 

[K1ng124]

Gotcha, just not understanding how I was reading pressure before the kit was install, but now nothing??

- - - Updated - - -

Small update: Just got off the phone with SOS and was told the wire from the top of the sensor may have a shortage.

 

[leexong77]

I have a SOS sender too. Lately is been acting up, oil pressure not consistent. The need goes between 2 and 3 1/2. Never goes pass 4 or higher. I was just wondering when you said that it's a shortage worth the top wire, what did they ask you to do? Replace it or is there a DIY. Please share the infor. Thanks

 

[sparkin3]

Sorry to raise an oldish thread, but recently I've been having an oil pressure issue - and I have the SoS kit too. I fitted this because I was suffering the common problem of erratic readings with the OE sender unit. Although, like others, my readings with the SoS kit have been a little lower, at least the readings were consistent and steady. Now though, the reading is a little over 4 at idle after start-up, but then, with the engine warm, the reading will drop to 0 at idle (stopped at traffic lights for example) then move back up to 4 as I drive away. Oil level is normal and the oil pressure warning light has never come on other than at the 'systems check' at key-on. I've checked the installation for leaks and any indication of a bad connection or short - nothing. Anyone have any ideas? Thanks.

 

[CL65 Captain]

Sorry to raise an oldish thread, but recently I've been having an oil pressure issue - and I have the SoS kit too. I fitted this because I was suffering the common problem of erratic readings with the OE sender unit. Although, like others, my readings with the SoS kit have been a little lower, at least the readings were consistent and steady. Now though, the reading is a little over 4 at idle after start-up, but then, with the engine warm, the reading will drop to 0 at idle (stopped at traffic lights for example) then move back up to 4 as I drive away. Oil level is normal and the oil pressure warning light has never come on other than at the 'systems check' at key-on. I've checked the installation for leaks and any indication of a bad connection or short - nothing. Anyone have any ideas? Thanks.

Same exact issue. I replace the wire (which has a resistor inline) with just a plain wire. It reads high now, but I prefer it that way vs 0 at idle. Now it reads 2 at idle and 6 or so under load. Which is fine by me, as I couldn't stand pulling up to a stop light and looking down to see 0 on the gauge.

 

[sparkin3]

Same exact issue. I replace the wire (which has a resistor inline) with just a plain wire. It reads high now, but I prefer it that way vs 0 at idle. Now it reads 2 at idle and 6 or so under load. Which is fine by me, as I couldn't stand pulling up to a stop light and looking down to see 0 on the gauge.

Thanks for the quick response :smile: I find it strange though that it has worked 'fine' for several months, and only recently has it started to drop to zero at idle when warm

- - - Updated - - -

Oh, and where is the resistor? Thanks.

 

[ATERPAK]

It's not his kit as much as it's the sending unit itself. It's just slow in it's response and also it tends to read low. My original stock unit worked the same way but it's still on the head instead of being isolated from the vibration. For some reason when I first got the car back in 1993 the oil pressure at idle and warmed up would be "0" zero. After my first oil change to Mobil 1 synthetic 10/30, the pressure moved up to the first mark at idle. Seems the oil made a difference for some reason. Eventually I decided to go to an aftermarket Defi gauge setup and I isolated it's sending unit, like SOS's setup, and left my stock unit on the head so that the stock gauge also worked. I now have two oil pressure gauges working from that same port area and I get the more accurate and speedy response reading from the Defi setup.

Al

 

[Mac Attack]

Oil density and viscosity differences can have a measurable affect on oil pressure.

Dave

 

[ATERPAK]

True dat! :biggrin:

Al

 

[winreboot]

Same exact issue. I replace the wire (which has a resistor inline) with just a plain wire. It reads high now, but I prefer it that way vs 0 at idle. Now it reads 2 at idle and 6 or so under load. Which is fine by me, as I couldn't stand pulling up to a stop light and looking down to see 0 on the gauge.

That is great find. Where is the resistor wire and how did you replace it?

Thx

 

[CL65 Captain]

That is great find. Where is the resistor wire and how did you replace it?

Thx

See the blue wire in the pic? It's just soldiered in between the wire and the connection on the end. The black heat shrink area on the right end....

I just replaced that wire with another plain wire (no resistor). I believe that the resistor that SOS uses goes bad over time due to the heat. You can also ask Chris at SOS to send you a new wire (with the resistor) and it will probably be back to normal --- for a period of time before it goes bad again.

 

[ATERPAK]

Why would SOS add a resistor into the circuit from the sender to the gauge? Isn't it just an extension of the original wire which doesn't add a resistor into the circuit? Or is his new sending unit different enough that the resistor is used to adjust the output to a correct voltage for a given pressure? Not sure just asking.

Al

 

[sparkin3]

See the blue wire in the pic? It's just soldiered in between the wire and the connection on the end. The black heat shrink area on the right end....

I just replaced that wire with another plain wire (no resistor). I believe that the resistor that SOS uses goes bad over time due to the heat. You can also ask Chris at SOS to send you a new wire (with the resistor) and it will probably be back to normal --- for a period of time before it goes bad again.

That's brilliant! Thank you :smile:

 

[CL65 Captain]

Why would SOS add a resistor into the circuit from the sender to the gauge? Isn't it just an extension of the original wire which doesn't add a resistor into the circuit? Or is his new sending unit different enough that the resistor is used to adjust the output to a correct voltage for a given pressure? Not sure just asking.

Al

No, there is a resistor where the black shrink rap is. I think the problem we are all having is that eventually that resistor is going bad causing low readings (almost 0 at idle when warm).

On Oct 18, 2010, at 1:15 PM, ScienceofSpeed Info wrote:

hi Jim --

Thanks for your e-mail.

The gauge readings have been the same as factory sensors on cars we have installed our sensor because our sensor is within +/- 2.5% of the factory output (see graph below):

<image003.png>

The sensor would output would be higher if the harness we include with the sensor was not installed or is not working. The harness has a 10 ohm resistor inline. If this resistor is not in the circuit, the readings will be 10 ohm higher, and thus at the same oil pressure, output a higher pressure reading than should be. The harness is a simple inline affair, so it would be hard to not work properly. They did use this when installing your sensor, correct?

You can easily test this by starting the car and letting it idle until fully warm (about 5 minutes). If you take a ohm reading on both contacts of the sensor, you should see approximately 45 ohms.

Is there a reason you've gone through several stock sensors? I seemed to remember your car is somewhat newer?

take care,
-- Chris

Chris Willson
General Manager
ScienceofSpeed, LLC
___________________________________
The ScienceofSpeed Team - NSX & S2000 Performance Specialists

Phone: 480-894-6277
Fax: 480-452-0964

Join the new ScienceofSpeed Product News, Updates, & Specials Newsletter!
http://www.ScienceofSpeed.com/newsletter



-----Original Message-----
From: James Ackerman [mailto:[email protected]]
Sent: Saturday, October 16, 2010 3:49 PM
To: ScienceofSpeed Info
Subject: oil pressure sender Q

Chris,

Justin finished the oil pressure sender. Thanks for getting that part to me, that's appreciated.

Before the car idled at the 2 mark on the gauge and was slightly above the 4 mark at cruise. The last two oil pressure senders (OEM) read more or less the same with slight variations. With the new SOS remote unit it idles at just under the 4 mark (1/2 way on the gauge) and shows 6+ mark under power. This is after the car is thoroughly warmed. Have you seen these sorts of results with other NSXs?

Jim
</image003.png>
​

<image003.png>
</image003.png>

 

[ATERPAK]

Well then if you know it's going to read higher without the resistor, you can then mentally recalibrate it as that as you are driving and roughly know the corresponding pressure. At least on the bottom end it will now show some pressure at idle which is better than not showing any even though there is some. Without the resistor, I would start worrying that I show "0" pressure at idle when I know it should be reading higher and showing at least 1 bar, especially if I have a known good sending unit. That's also another reason I went with a second oil pressure gauge and sending unit since I also track the car once in awhile. That way if one goes to "0" and the other is reading okay, I can feel more comfortable while driving hard. If they both go out, then "SHUT IT DOWN...NOW!" :distress: JMO

Al

 

[NSX2398]

Mine idled close to zero before the SOS upgrade .. and since. But I do run Mobil1 so maybe the viscosity has something to do with it. And since I drive mine in the winter, I'm usually running 5w30 for at least 4-5 months of the year which probably makes it even worse. But don't forget that we also have somewhat of a security blanket in the sense that there is also the low oil pressure switch that drives the idiot light so if the gauge is near zero but the idiot light isn't on, I think we're ok. I had the reverse condition once where the low pressure switch malfunctioned and the idiot light started to come on .. but the gauge was still showing decent pressure which gave me some comfort. I gather that the other test is whether or not the gauge moves up as revs increase .. also I was told by a mechanic who races/rebuilds other Honda products, that if there's a loss of oil pressure, the valve noise gets very noticeable.

Getting back to the thread, and with my EE background, I can't say that I've heard of that many pcb resistors failing. Capacitors yes .. resistors rarely. And the only reason I can think of for SOS adding a resistor would be to more closely calibrate it to stock although he seems to already be claiming that the sensor is within +/- 2.5% of factory. Either way, I think we're kidding ourselves to make something artificially better by removing a component .. although if you were selling the car, it would be a definite improvement. I would think most buyers would be intimidated by a zero oil pressure reading.

 

[Rope]

when warm 5w30 is the same as 10w30. The first number only makes a difference at startup as that is it viscosity when cold and then it transitions to the 30 weight as it becomes warm.