Hey all...got a nagging question that has bothered me for YEARS, litterally. My 93 R1 has been in the family since new. It's got close to 95,000 miles on it, but the engine was replaced by the dealer around 70,000 miles. For al long as I can remember, the oil pressure seems scarily low at times...like the guage will read ZERO at idle when warm and I come to a stop and have it in neutral. It doesnt happen every time, but often enough that it has been a concern...but it's been that way for many many years. I asked dad about it long ago, and he told me he had the same concern but that the dealer had reassured him that it was normal. Is it really NORMAL? Maybe it is, if it really had an oil pressure problem, wouldnt it have died by now? Thoughts?

The idiot light never comes on nor does any buzzer. The car is totally stock except for a cat back stainless system from RacingBeat (was cheaper than the stock one at the dealer).

Oh, if it helps diagnose the problem...the exhaust smells REALLY rich and she does blow a bit of smoke upon cold startup if she hasnt been driven in a few days and the exhaust tips are pretty black on the inside. Otherwise she seems to run perfect.

Pic for views:

 

I have the exact same problem..I'm running very rich and blowing off a ton of smoke on a cold start,and even still smokes a little while idling before it gets warm..My oil pressure is awfully low sometimes,I have it read 0 occasionally but I wasn't quite sure what to do about it..So i'd love for someone to come in here and tell me that it's normal..

 

The oil pressure sending unit is under the oil filter pedestal. That area tends to get a little dirty and cause its readings to be off. It also does have a tendency to fail.

If its really bothering you, try cleaning the contacts on the sender and see if it clears up. If not, then its time to replace the sender.

 

Like Mahjik said.

I had oil pressure of 0 at idle when my car was warm, a replacement oil pressure sender unit cured my problem.

BTW i used a miata/mx5 pressure sender.

 

If it habitually runs rich as you've described, watch for fuel dilution in your oil. A little over time is not uncommon, especially when it's cool out and the car runs richer for a longer period of time after start-up. But it's something to keep an eye on.
Nice looking car btw.

 

My stock oil pressure gauge did the same thing. I just replaced it with a faze gauge and it's reading the way it should. Once you replace you'll see a difference (I did).They do tend to fail (oem). The smoke that comes out when you first start has to be from the turbo's (blue smoke). Normal wear from the turbo's.

 

was the miata sender a direct fit? what is the benefit of using it? is it cheaper?

 

your car is supposed to burn oil. if it dosent, then you have problems.

The instruction manual says that you should put in a half a quart every fillup. Rotary Engines are oil injected, and this is why at cold startup, you can see smoke. Its because your oil metering pump is injecting oil into your combustion chamber, for lubrication.

If you havent been putting in oil every fillup, then start to do so. Make sure you dont use synthetic (it dosent burn).

 

Thanks for the info, but most of us are well aware of the OMP pump and it's function. The issue being discussed was indicated oil pressure, usually sourced back to a bad connection at the sender, and/or a bad sender. It's also affected by engine temperature, rpm, the oil's weight and fuel dilution, but not burning oil. He mentioned some smoke on start-up, but that's not generally an OMP issue. More likely turbos if it's blue smoke. And many owners have used some synthetic oils with success. That debate is long standing and a search will yield alot of info.

 

This is wrong. Synthetic also burns cleanly. It also has nothing to do with oil pressure.

 

The miata sender required splicing in another connector, which isn't a big deal because it's a self-grounded sensor and so you're just connecting a single pin.

The 2nd gen rx7 thermoswitch does the same thing but is a direct fit. Price is about the same.

 

These cars usually run quite rich at startup. It's a combination of rich stock tuning, possibly some gunk in the idle control and cold start systems, and a little varnish building up on the injectors. It's generally not a big deal.

If you do the big 'rats nest' job or other major engine work, consider having the injectors removed and ultrasonically cleaned. This can eliminate much of the richness at startup.

 

+1. my car never ran as smoothly as it does with royal purple. of course i only got about 800 or so good miles before i switched.

 

I had a similar problem with low oil pres. After cleaning the sender nothing much changed. I replaced the oil pres send and I also added an additional oil pres send & gauge (defi D-series). Both work great although my defi gauge responds better and gives a more accurate reading.

 

+1, i usually get about 20psi at idle but the oil pressure rises as my right foot falls.



For a laugh ask them how much it would be to replace the t/t assembly. You'll notice that the dealership is not your best solution for many things when it comes to replacement parts.

 

royal purple is a synthetic meant to burn. by synthetic, i meant the usual, like pennzoil or mobil 1.

 

What? So which is it?
And before you answer, I don't think any synthetic is meant to burn. One of the obvious advantages is better tolerance of high temperatures. You really should do a search.

 

i dont need to do a "search" because I know what im talking about.

synthetic dosent burn efficiently. its meant to withstand high temperatures, therefore when its injected into your combustion chamber, it dosent burn efficiently.

i blew my first motor because of it.

 

royal purple is also safe for "two stroke" engines, so its designed to burn. pennzoil, mobil 1, chevron, etc. they dont design thier oil to burn. therefore it shouldnt be used with rotary engines since they are oil injected.

maybe you should do a search.

 

the question was that he was concerned about low oil pressure.

...and low oil levels (due to not filling up with a half quart of oil every fillup) can display low oil pressure on your gauge.

maybe you should do a search...

 

Yes, you do.
No, you don't
Not only did you post mis-information, or as degessaman so succinctly put it was "wrong". But it wasn't even on topic. What the hell does the OMP have to do with anything when the author is asking questions about indicated oil pressure? Then you contradict yourself......synthetic doesn't burn, well OK, maybe only Royal Purple is OK because it's "made to burn", now it doesn't burn efficiently? Make up your mind.
Is this documented? Because If it is, I think you'd be the first one to do so.
And that part about needing to add oil between changes because the rotary burns oil. Wow, who would've thunk?
Have you been licking the dipstick? Your the first one to suggest adding a half quart of oil with every "fillup". And I've been low on oil before but never enough to lower my indicated oil pressure. Not sure where the threshold is, but I'd bet it's a more than a half quart.

 

the simple suggestion to his question was that he may not be filling it up with oil every fillup, therefore it would be low on oil, which can eventually lead to low oil pressure, if you dont have any oil in your car. (duh)

"regular" synthetic car oil is NOT Designed to burn.

good one...

 

That's not so much the case these days. Oil makers realize that pretty much all performance cars these days inject/burn oil (nope, it's not a rotary thing) and also want the benefits of synthetic oils. So, pretty much the majority of synthetic oils today will burn effectively during a combustion cycle. The BMW M cars have been using synthetics for a while and they eat oil like nobody's business.

 

http://www.pennzoilplatinum.com/

click on the "20 facts" page and check out the section about the "resistance to burn off" tab

 

Who told you that oil blew your engine? Pennzoilplatinum.com?

Dave