removing oil pressure sender unit

The oil pressure switch is connected to the ECM in a 99, according to the wiring diagram. I suspect that the CEL will go on if the oil pressure disappears.

Chas Hurst

Worked fine on a 95 which I think was OBDII(?). Can't see how the pressure switch would be tied into engine management since a loss of oil pressure doesn't shut the engine down (well, it does ultimately but not because of electronics). Poor decision on Mazda's part to put that piece of junk "analog idiot light" in there instead of the real thing.

Tom

Michael Colavito wrote:

There are complete instructions on miata.net for replacing the sender with an analog model. As my JR Whitney sender seems to have crapped out recently (always registers pressure, even with the engine off), my enthusiasm for the replacement is slightly dampened.

The signal out of the analog sender is slightly different from the stock version, but it doesn't seem to bother the ECM. Who knows how sensitive it is, though?

Kevin snipped-for-privacy@bayarea.net

Thanks for the replies. As I was unable to install the oil line connection fittings to the point on the block where the sender unit was, I am still running with the stock "idiot guage". Geez, that is one hard point to gain access too. Saw and read the postings on miata.net and may go that route eventually i.e. installing a stock sender unit from an older miata because that may be easier than trying to attach the oil line fittings. Since i could reinstall my sender, I imagine I could install the old sender although I know it is bigger than mine. Too bad though that this will be more $ for a less accurate but stock guage. Thanks again.

For all the trouble installing a true gauge entails; is it worth it? I mostly watch the road not my dashboard. The CEL should come on if there's no oil pressure. In my 40 + years of driving I have never experienced an oil pressure problem-unless the engine was low on oil.

Chas Hurst

Mech. ga. is much more accurate as the needle sweeps a full 270 degrees thus the markings are more numerous and spaced further apart. In addition it is independent of a cars system voltage.

As far as usefulness, the ga. indicates the condition of an engines main bearings as the car ages, it can also reflect changes in oil temp. (low temps higher psi vice versa), so u can guess if oil level is low or another reason may be causing high temps such as wrong ign. timing, pulling a heavy load, etc. In other words the ga. is not just to tell u when u have low press. but other when is the oil fully warmed up (much later than the water), etc.

Mike

Yup, a gauge can do most of that. When was the last time your car wore out the main bearings? Or the rod bearings? We're dealing with modern engines here. They last the life of the car. My 99 AE has a water/oil heat exchanger. Warms oil up fast. What heavy loads do you contemplate pulling with your Miata? How will the ignition timing change without the CEL telling you somethings amiss? This is a Miata NG. If you realllllyyy need to know the oil pressure, put a mechanical gauge on the engine. That's were it is on a lot of race cars. No need to confuse the driver. But hey, if *you* need a gauge, certainly get one.

Chas

You know, Chas, I'm starting to feel a lot like you. I just started my '95 up after driving the car 250 with three brake calipers attached, letting it sit for approximately six months, and having a friend try jumpstarting it and hooking the cables up backwards.

The car is ten years old and has over 100k miles on it. It didn't even blink. While my father (who longs for the "good old days when cars were "tough") would be praising Jesus to see 100k miles out of a car, it really isn't a big deal at all these days. If this car doesn't make it over 200k miles, I'll be sorely disappointed.

Must be getting a lot of speeding tickets.

You need to look at your dashboard to see it?

Indeed that is one reason to get a true oil gauge instead of something that comes on when the oil supply is already way out of spec or has stopped existing. Does not apply to a Miata since the lifters tell you way before this happens.

However, the true reason that I, and I assume many others, put in a real gauge is that the fake one is disgustingly ricey. I would be perfectly happy with a normal light that turns on when the oil is below spec. But a fake "analog" gauge pretending to indicate actual pressure is much worse than putting a NOX sticker on your Honda. At least the Honda owner only pays a few pennies for the sticker. Here we have such an urge to *pretend* that actuators, working needles, gauge faces, fancy symbols, cases, etc are used. How much more pathetic can you get in pretending?

Leon

I've certainly had my share

Sort of, but there are two other gauges with pointers. The CEL only comes on with no oil pressure.

What can I tell you? My 99 doesn't have hla, hence no clatter from the "lifters".

The fake gauge is hokey, and a light would be more honest. But the rest of the car is just so right I can easily over look the oil pressure gauge. To me it's simply not a concern. As far as pretending, then consider power steering, power brakes, power windows! Air conditioning! Get Real

Chas

Well Mike, you are kind'a correct, but without an Oil Temp. gage, an EGT and a BMEP gage, (and a "Flight Engineer" ) all you are goimg to do, is loose the engine "well informed" Truly if you are driving your Miata and doing engine wear management at the same time, you are loosing out on a lot of fun. With over 122,000 miles on my '91, I can say that the oil pressure gage reads about the same is it did 100,000 miles ago. I am sure that there is wear on the engine parts. The last time I had the intake manifold off (to polish inside and out) the tops of the pistons looked good and clean. The valves looked clean and the spark plugs were clean and the proper color. The tail pipes are clean and dry. When I changed the timming belts last month, the cams showed no wear or galling and the oil (changed every 3,000 miles) looks good. SO, turn the key to the right, put it in gear and go drive. :-)

Yes, a oil pressure gage will tell you if you are going to loose the engine, but its going to go with or without the true gage reading :-)

Bruce RED '91 (10,000 hour comm. pilot and old "flight engineer) :-)

They are not fake power steering, fake power brakes, fake power windows.

Funny you would say that. ;)

Leon

Hey, Leon, *you're* the one with the clear tail lamps. ;)

'95 M-edition, bone stock except a rear window protector and a plain old Voodoo knob.

My clear tail lights ricey?! Just because I, for the most solid esthetical reasons, eliminate unnecessarily offensive BIG *red* spots on a white car which has no other red accents, and replace it by tasteful, subdued, *clear* tail lights, you suggest ricey??

I assume, next time you will complain about my *tiny* chrome windshield washer jets.

Can we talk about this purplish *fake* red and those oversize, 15", shiny BBS wheels. VOODOO knob?? Either to hot or too cold, and then the owners claim it adds 10 hp. How ricey can you get?

And what color is your top, anyway?

Leon

Dang....you mean my Voodoo knob didn't give me the extra 10 hp???! I felt it using the seat of the pants dyno! I know it works! I have an after market bath towel for a window protector on my bone stock

Disregarding my bias as an owner of one, it's hard to argue that the '95 M-edition isn't easily in the running for classiest looking Miata ever. The mahogany mica from 2000(?) is close, but the heavy chrome wheels ruin it for me for several reasons.

How about the 93 LE?

That's right up there for me, as well, but if I had to choose between the black/red and the merlot/tan, I'd still take the one I did. The LE *does* have the right wheels, though.