Pretty much what the title says, the question, is the pump mostly dead? or is it something with the wiring?
It reads zero the vast majority of the time but every so often starts to hop up and down, Yes there is plenty of oil in the car. The oil somewhat suspiciously is very very clean. The temp gauge is pretty much dead center so no over heating.
92 Mazda Miata
Low oil pressure is usually due to worn bearings, but it’s possible you have a bad sending unit. If your pressure is really zero, your engine is on its way to the great scrapyard in the sky…
Replace the sender.
Agreed, it’s more likely than not the sending unit. Easy fix.
If it is a 3 wires sensor it should also control the low oil pressure warning switch through the computer module. If the warning light is not comming on and you do have a 3 wire sensor my guess would be th gage or a connector going to the gage.
You guys, as usual, Rock. Thanks for the tips.
It is a problem with the gauge. If the oil pressure was really zero for any time at all, the engine would be seized. The problem is most likely a bad sender unit. I would look up the troubleshooting procedure for your Mazda on a Miata forum. Then you can find the problem and only buy what you need and only do the minimum work necessary to have a working oil pressure gauge. Heck, it may just be a loose wire connecter. Total cost, Zero dollars and some time.
IHTH, 48.
As I understand it, the first indicator of no oil (or almost none) would be a very loud engine. All that metal on metal would sound like a loud bunch of metal parts being dragged across sand-paper (so I’ve been told). The camshaft/valves should be particularly noisy.
When my wife’s Audi had oil problems - she got an engine flush and after that the oil light would come on when she let off the accelerator. We were told (but not by the dealer) that the first few years Audi did not recommend synthetic oil, the dealer did not use it, so the oil at high temperatures would burn, gum, and plug the intake screen and the oil channels. The constricted oil channels meant not enough oil to the engine, the guess was the worst problem was the crankshaft bearings wearing excessively. The clogged channel made the oil sensor think there was pressure, due to back pressure.
Flush out the channels, the oil runs more freely, and there is not enough back pressure when idling or low revs (letting foot off accelerator) and the oil pressure light comes on.
We could replace the engine but the car was old enough it was hardly worth it. We could get the crank bearings replaced, but what if that was just part of the problem? Spend thousands on an engine that could already be crap?
For the OP - if it’s the sender - cheap fix. If it’s actual oil pressure, then odds are you’ve screwed your engine. If so, then odds are you might as well drive it until it fails if that’s not too inconvenient.
Yeah, electronic gauges are teh suck when you start getting weird readings and don’t know whether they’re real or phantoms. I’ve replaced too many senders under crappy conditions because I couldn’t tell if there were real oil or temp problems. All of which is why I prize the mechanical gauges in my other cars…
Gauges jumping around randomly are almost certainly an electrical problem. If it runs OK I also suspect the sender - could be a bad connector in the wiring or the dash which could be expensive to troubleshoot or fix. I’d inspect and clean the connector at the sender, then replace it.
I really did post a thank you on this thread, I thought I did anyway.
You guys rock, thanks for the tips. sorry if my million restarts ate my first attempt at a thank you but I also had to re install the OS this week.