Oil pressure switch

[Darren69]

Ok, just thought I would post up because the part from post #2 turned up yesterday afternoon. I checked the resistance of it off the bike and if was low to virtually nothing so I conclude from that the switch is closed in static position.

I removed the one I that was fitted and the differences were obvious but not so much. The one I removed was stainless and much heavier than the cheapo one. No surprise there. The copper washer supplied with the cheapo one was a very thin brakeline banjo bolt type and the one from the bike had a large aly flat washer that fitted nicely into the flat machined into the cover, so I re-used that. If it leaks a bit I will replace it but it will do for now. The only other differnce was the threaded part was 2-3 mm shorter than the one removed and I don't know if that would have any impact.

Upshot is that the even with the replacement unit the light still stays on just the same, so it looks like I'll be chasing an electrical issue or I really do have no oil pressure, which I don't think but who knows2

I should have mentioned in my previous post that if you use the washer supplied with the Vauxhall replacement it will **** oil every where I found out the hard way I done the same as yourself replaced with the original flat washer, as for your light staying on mine went out immediately the second I turned it over so you seem to have another issue.

[Darren69]

Yea, I know. I think my switch will probably be Ok after all. I've been messing about with the wiring, just moving it around so maybe I broke something along the way. Deep joy!

Originally Posted by Darren69

Yea, I know. I think my switch will probably be Ok after all. I've been messing about with the wiring, just moving it around so maybe I broke something along the way. Deep joy!

If I understand you aright, you must have a short to ground somewhere, not just a broken wire. Good luck finding it!

Nick

[manwithredbike]

Just be careful Darren, if your oil light stays on esp with a new switch then you might actually have low oil pressure. The oil pressure switch should be low/no resistance when static, allowing the circuit to 'earth' to light the oil light. Starting the engine should operate the oil pressure switch, opening it to put the light out.

[Darren69]

The light stays on when the switch is unplugged so unless it's supposed to do that then it is shorting somewhere? I'll look at wiring diagram to confirm.

[mickj]

Originally Posted by Darren69

The light stays on when the switch is unplugged so unless it's supposed to do that then it is shorting somewhere? I'll look at wiring diagram to confirm.

If the light is staying on with the switch unplugged you have a problem elsewhere, it should go out.

[Darren69]

yea, thanks for confirming. I thought that it should but I wasn't 100% sure with the S4 if there was another circuit involved. I think most likely it's a problem of my own making. I tidied up the wiring recently and fastened everything to the frame and there was one bit of it that was a bit bodged tbh by the DPO.

[manwithredbike]

Originally Posted by Darren69

The light stays on when the switch is unplugged so unless it's supposed to do that then it is shorting somewhere? I'll look at wiring diagram to confirm.

Ah, so prob a short to the frame upstream from the switch somewhere. Sorry if i missed that earlier. Wouls do no harm to put a meter on the oil switch, start the bike and see the resistance drop anyway, just as a check, in case you want to ride it before sorting the wiring issue.

[Darren69]

Yea, that's the most likely scenario. TBH even though I posted about the light staying on you were the first to pick up on that and I had assumed that it went through the ECU or some weird stuff like that. I expected the light to go out but when it didn't, I was like oh Ok.

But I wasn't sure how the switch setup worked on this bike, but once I had checked the state of the new switch it became more obvious and makes total sense now.

[manwithredbike]

Originally Posted by Darren69

Yea, that's the most likely scenario. TBH even though I posted about the light staying on you were the first to pick up on that and I had assumed that it went through the ECU or some weird stuff like that. I expected the light to go out but when it didn't, I was like oh Ok.

But I wasn't sure how the switch setup worked on this bike, but once I had checked the state of the new switch it became more obvious and makes total sense now.

BTW, i should've said in my previous post, if you check the sensor with a meter the resistance should rise (not drop) when the engine is running i.e. switch opens

So, as I suggested before, a short to ground, i.e. a bare wire to the frame where you tidied it up?

Oh boy, right again! (with apologies to Laurie Anderson)

Nick

[Darren69]

Right! Quick update on this issue. I had all the wiring off that side and checked everything and sorted the oil light issue when it was staying on when disconnected fairly quickly but what then took me a lot longer was getting it to come back on when connected. Turns out that cheap Vauxhall replacement doesn't work, it's not grounding through the switch somehow. Glad I kept the old original one as that works perfectly. I need to replace the batteries in my multimeter now, but they worked just long enough for me to find this issue.

So, if anyone has a Vauxhall Aquila and wants an oil pressure switch I've got one you can have that might work! Not even sure what an Aquila looks like so it's doubtful if anyone even has one.

Right I'm off for a few beers!