XJ oil sensor question

[Cobia]

The XJ engine, although it has a sensor for oil level, it also has the orifinal XS port for the oil pressure sensor plugged off. I think oil pressure is as much an indicator of oil level as it is of the pressure itself. I mean, if you don't have enough oil you won't have enough pressure if the pump cant pick it up, right?
Well, maybe yes maybe not. But here's where I'm going with this is...
Can I install an oil pressure sensor and connect it to the same indicator circuit that the oil level sensor uses so as to not add another idiot light?
It would seem that if one sensor is not tripping the indicator light, the other one could if something is amiss.
Your thoughts?

[crazy steve]

If the level sensor functions by completing a path to ground, there's no reason you couldn't install a pressure sensor too....

[cywelchjr]

Or replace the level sensor with the pressure one. You can check the oil level in the sight glass, but pressure if lost even with good oil level can be fatal.

[crazy steve]

Not being famililar with the XJ wiring, I should ask this question: is the level sensor tied in in any way that would prevent the bike from starting/running if the level drops too low? If that's the case, adding a pressure sensor may not work as you obviously won't have pressure until the bike is running...

I know the XJ has some 'failsafe' type switches on it, just wondering if this is one of them.

[SFerinTEXAS]

Also the XJ is a 2 wire normally closed and the pressure sensor is a 1 wire n.c that grounds to the engine. If you can find a 2 wire n/c metric pressure then it might be doable, just have to tap into the OE harness wires above the level switch and jump each one to the pressure switch terminals . Then if either one closes it will set off the warning. have to admit I didn't spend a lot of thought on this but I believe its correct.

All things being equal the level sensor sets off the warning before the oil is low enough to fall below the sump pickup which is when the pressure switch gets tripped or a system failure tho rare would not set off the level warning. A redundant system would be ideal

maybe adding a mini oil pressure gauge would be an option as well

[Yahman]

The oil level sensor on an XJ is a single wire, normally closed (at the proper level) switch. It connects to the digital display, not a warning light.

The oil pressure switch on an XS in normally open when under pressure. When pressure is lost the circuit closes and the oil light comes on.

With that in mind, I don't see how you can add a pressure sensor without another warning light.

Larry

[Jerry]

One of our members was making a modified banjo bolt to fit the XJ / XS. It replaces the stock bolt where the oil line to the head enters the engine's lower case. This bolt has a port on it to mount a pressure gauge, either a mechanical unit, or if you want to wire in a gauge, an electrical sensor for a dash-mounted unit. Could also be used to monitor oil temperature. Whatever.

I bought mine a few years back at the Yosemite rally, will have to look at the box it came in to get the guy's name, or maybe he will respond on this thread. Cost was $20.00, included shipping. Very neat solution to the problem of adding an oil gauge without having to modify any existing wiring.

Most common set-up was to screw in a 1/4 inch pipe and have a mechanical gauge mounted where it could be seen on the left-hand side of the engine. Run a wire for the gauge light and you had an illuminated oil pressure gauge. Some have used an electrical sensor and mounted a gauge in a fairing or on handlebars. Just depends on what 'look' you want.

A search for "oil pressure gauge" will turn up multiple threads on this subject, along with several solutions.

I'll try to find the photos I took of of the modified banjo bolt and post them here.

[Yahman]

I think the best place to tap for oil pressure is where the OEM sensor screws into. This is my current solution.





Larry

[Cobia]

Thanks for the input. In looking at the wiring diagram, the oil sensor is not tied in to the starting circuit, so this is not a factor in that regard. As a matter of fact, I had a faulty clutch switch and we figured out that the correct operating condition was a closed circuit. We just spliced the leads together and it fired up. Thanks Phil !!
What is not clear in the diagram is the normal operating condition of the oil level sensor. If in fact a low level condition causes an interruption of continuity and triggers the notification at the console, then I'd have to find a sensor that operates in that manner, unlike the regular XS oil pressure sensor where the normal state is an open circuit.
As far as I can discern, the LCD notification is no different than an idiot light going off. When the condition warrants, via an anomaly in the circuitry where it closes/opens the loop, the LCD lights up and notifies you that there's a problem. I don't know why there would be a difference in the oil level sensor behavior where the normal condition would be an open circuit...???
Don't know how hard it would be to find an oil pressure sensor where the normal operating condition would be a closed circuit. Is that a normal type situation???
My take on this is that by having dual sensors, one for level and one for pressure, you would have a fail-safe system thereby forestalling any catastrophic situations that would lead to total engine failure due to lack of proper lubrication throughout the engine.
And since a warning at the LCD console is really no different than an idiot light going off at the console, it should be a no-brainer to install it and have that peace of mind.
But then again, replacing the level sensor with a pressure sensor makes a lot more sense considering that the bike does have a sight glass where I can check the level of the oil. And actually, as I mentioned in another thread, the XJs like to have the oil level at the top of the full range so as to prevent the warning light from going off!!! Go figure..!!!

[crazy steve]

...What is not clear in the diagram is the normal operating condition of the oil level sensor. If in fact a low level condition causes an interruption of continuity and triggers the notification at the console, then I'd have to find a sensor that operates in that manner, unlike the regular XS oil pressure sensor where the normal state is an open circuit.
As far as I can discern, the LCD notification is no different than an idiot light going off. When the condition warrants, via an anomaly in the circuitry where it closes/opens the loop, the LCD lights up and notifies you that there's a problem. I don't know why there would be a difference in the oil level sensor behavior where the normal condition would be an open circuit...???
Don't know how hard it would be to find an oil pressure sensor where the normal operating condition would be a closed circuit. Is that a normal type situation???

If your oil level sensor has more than one wire connected to it, this will be far more trouble than it's worth...

Two wires means it's being 'powered', i.e. it needs a voltage supply or is switching a supplied voltage. While the 'low level' lights' basic function is the same, the means is very different. If the 'light' is part of a LCD display, this may not be at 'line value' (12V), but may be operating at a reduced voltage or through a specific resistance, possibly variable. If one or both of the wires to the sensor go to any sort of 'black box' containing electronic bits, this is almost certainly the case.

Virtually every automotive/motorcycle 'oil pressure' sensor I've ever seen is one wire; either a simple open/closed switch (for a light) or a variable resistance (for a gauge), but both 'switch' to ground. This won't work for you. What you need is a pressure switch with isolated contacts (so you can connect two wires). They do make them for non-automotive applications, but I couldn't find one specifically rated for contact with hot oil. Matching switching pressure will be an issue too; most 'normal' oil pressure switches close when the pressure drop below 5 psi. There's also adjustable switches, but you're back to fluid rating. Be prepared for sticker shock, as the cheapest one of any kind I found was $70, with prices going up from there. Size will an issue too, as many of these are the size of a cigarette pack or larger.

Adding a simple 'extra' light will be the easiest fix...

[Jerry]

Larry:

Your solution works for an XS, but not an XJ as there is no sensor port in that location on an XJ. The XJ oil level sensor is mountd in the oil pan. One would need to drill and tap the case on an XJ to do the same mod, where as the modified banjo bolt just replaces the standard bolt, a clean conversion for XJ owners not willing to drill into the engine cases

Nice install, though. I prefer gauges to idiot lights.

Have not found my photos yet...SWMBO had me doing yard work last night, mulching leaves and raking the yard. Will look tonight if I have a chance.

[Cobia]

Steve,
I guess a good idea was once again thwarted by the japanese design geniuses!! Thanks for the great info, I appreciate it. Darn!! Oh well.

Jerry,
The reason why I even contemplated this possible redundant solution is because I saw the oil pressure sensor port capped off on my XJ. The hole is there, it just has a plug in it.

Thanks guys.

[Yahman]

Larry:

Your solution works for an XS, but not an XJ as there is no sensor port in that location on an XJ. The XJ oil level sensor is mountd in the oil pan. One would need to drill and tap the case on an XJ to do the same mod, where as the modified banjo bolt just replaces the standard bolt, a clean conversion for XJ owners not willing to drill into the engine cases

Nice install, though. I prefer gauges to idiot lights.

Have not found my photos yet...SWMBO had me doing yard work last night, mulching leaves and raking the yard. Will look tonight if I have a chance.

Hi Jerry,

The photos I posted are of my XJ1100. It has the port for an oil pressure sensor, I just had to unscrew the plug.

Larry

[Cobia]

Yahman,
Is that an oil filled pressure guage? I kind of like that setup, very utilitarian looking. Do you remember make and model of the guage? I suppose you fabricated the mount for it??

[justme1100]

Here I was just going to ask if anyone has installed a gauge on an XJ and low and behold here it is. You could use a braided flex line or there is chrome hard line. I will be playing with this in the coming months as I want a pressure gauge.