Hello All

I'm based in the UK and now the proud owner of an 1995 Black FD3S Type RB.

She's a beautiful machine and wheels excluded has been kept standard and unmolested throughout.

However.....being new to all this rotary stuff, I've a few concerns I was hoping you could help me with.

I've done a bit of reading and believe the oil pressure gauge should be sitting around 3.5 ish, but mine seems to fluctuate quite a bit. Its still a standard gauge, and don't think its been replaced. While I know these are tempremental at best, was hoping you could give me any info you know on whether I should worry when its changing all the time etc or whether I should just get it replaced with an aftermarket one!

thanks for your help!

Chris

 

stock oil pressure sender craps out pretty frequently and from the sound of it yours has too (join the club). Mine has been broke for about 3 years. The stock sender is kind of pricey so i would just get an aftermarket one if your really worried about it. Also so you dont get flamed read the FAQ and stickys at the top of the 3rd gen forum and search before you post.

 

^^Yup, the gauge itself more than likely is not the problem. It is the sending unit like mentioned above. It is the small black cylindrical unit just below the oil filter. You may try just cleaning the connection with some sand paper or steel wool first. If that does not work then either get a new oem one or just ignore your crazy readings and purchase an aftermarket unit. I think those have been replaced at least once on most every car on here.

Another side note, the factory service manual (FSM) is also posted on here in PDF searchable format. If you have not downloaded it, I would recommend it. It comes in very handy. ALSO do a search on here for Ray Crow at Malloy Mazda, I am pretty sure he ships overseas and is still the cheapest guy to get OEM parts from.

CONGRATS on the new car! You will love driving it!!

 

I'm on my third sender (110k miles). This one has been working properly for several years!

 

fyi, it's not always black. mine has a grey rubber sheath on it. the sending unit itself is cadmium (yellowish color) plated under the cover.

 

Hey Chris

The stock gauge isn't great, and so is worth changing for a more reliable reading.

I recommend the SPA dual gauges. They are digital, rather than analogue, and offer alarms. This is great, as personally apart from a quick glance every now and then, I like to keep my attention on the road! If however something goes wrog then the alarms instantly draw your attention to the problem.

They fit perfectly into the standard gauge position, thus giving you the option of displaying 6 channels without the need to fill up the car with loads of pods

They are very easy to fit...so give me a ring if you want any help or chat through options

 

Hey all,

massive thanks for the advice, has put my mind at rest a little.

Will give the sender a bit of a clean and see if this helps, failing that a replacement might be a good shout!

oo7arkman - everytime I get in it I smile a little bit more! Am starting to get the hang of its handling and its amazing!

 

Congrats on the car and welcome.
I agree with most of the comments... i.e. the spade connector will get dirty, especially due to it's proximity to the oil filter pedestal. I'm guessing that the "fluctuations" your seeing are very low to no readings at idle that will suddenly jump with rpm.
I disagree on just going out and getting a gauge. Personally I prefer to minimize the number of gauges in my interior. And cleaning it frequently solves the problem...which is just the low voltage at idle getting through the dirty connection. I think less frequently it's the sender.
Also remember that indicated pressure is a function of the viscosity rating of your oil, engine temp, ambient temp and in these cars, some fuel dilution between oil changes.

IIRC minimum indicated pressure though is ~ 50 at 3000 rpm.

 

I remote mounted my sender on the shock tower. This sender has now lasted for 5 years and running, before that it was an annual maintenance replacement.

at block 1/8 BSP male x -4AN adapter (Goodridge 741-03-04P) + 7/16 Alum StatoSeal (Pegusus 3245-7/16) at block
-4AN x 18" Hose, I used Autometer Kelvar Hose (ATM-3265 or equal)
at Sender -4AN x 1/8 NPT Female (Pegusus 3254-02-04S) Should be 1/8BSP but never found .. used at least 4 wraps teflon tape + 7/16 Alum StatoSeal (Pegusus 3245-7/16) at sender
Drilled and cut an alum. angle to hold sender to tower.

 

Do you have a picture or two? I am considering getting a SPA oil press/water temp gauge but I'd rather just get the stock oil pressure working and do the water temp linearization.

I wonder if using di-electric grease on the connection at the sender would help carry the low voltage through. That stuff can work wonders.

 

Sender still ticking 8 years now; this is the longest life of an I have had, Just maybe the cleaner less harsh mounting system.

 

Thread from the dead. . .mine's died again, on to number 4. Wish there were an aftermarket sender that works with stock gauge. Anyone know of such a thing?

 

There is no aftermarket sender that works with the stock gauge. I'm surprised you've had poor luck, mine has been going for at least 4-5 years now.

Remote mounting the sensor is a good idea, that will most definitely help out with life as it keeps the sender away from heat and vibration. But, you have to be VERY careful with the lines if you do so, that introduces many points of failure into the system. If that line bursts you've got a BIG pressurized oil mess.

Really, oil pressure isn't that important. There's a reason Mazda ditched oil pressure on the '99+ engines and put in a boost gauge, that's FAR more important than oil pressure. Typically once an engine is built and running with no oil pressure problems it's good for the long haul.

I've yet to see someone say "gee, my engine died because of low oil pressure, that gauge would have saved me". Nope, it's always blown apex seal or overheated engine with failed coolant seals.

I just like having a working gauge so my car doesn't look ghetto. The sender isn't too pricey, maybe $80 or so. You can replace the sender twice for what a decent aftermarket gauge will cost, then you'll have an extra gauge and a oil pressure gauge on the dash that does nothing. And, again, all that work for a gauge that isn't going to tell you anything terribly important or "save" your motor or anything.

The biggest possible cause of oil pressure drop is sudden oil loss, and there's an oil level light and buzzer that covers that problem.

Dale

 

FWIW my sender is at least 10 yrs old, possibly the original one. No issues with it yet. Just that dirty connection which has to be cleaned once a year or so.

 

I used -4AN Teflon lined Kelvar braided hose, 18" length .. could have used SS braid but I like the lighter stuff. The risk of a burst pressure line is no different than any of the other oil cooler lines. I am NOT suggesting using some cheap-*** plastic line.


Agree but a gauge can show trends over time, oil dilution, pump wear. But rightly as you say the spce would have been better used for a boost guage as in later years and we don't want dead gotto gauges.

 

I've been with this issue since I started the car.. ( purchased a used JDM motor compression is good 100 PSI on both rotors with even pulses on all 3 faces . )

oil has been changed twice.. with 20-50 valvoline synthetic as it was the only oil that was carried at that weight then http://www.autozone.com/autozone/acc...uestid=1146684 at 9 dollars a quart its by no means cheap.. the oil filter is royal purple oil filter first time I used a cheap one and thought it might be the cause so I changed it to royal purple the next time I changed my oil .

at first the oil pressure is good starts off at 60 when cold. as the car heats up .. I have 2 gauges power FC / normal temp gauge .. as the car rises to operating temp the oil pressure lowers .. to under 20 .. then if I give the car gas it will raise to 60.

and when I let go of the gas the oil pressure will lower to 0 or barely readable at idle . using the original gauge .. after having this happen I've checked every single wire / connection from the sensor to the gauge . well like everyone says and blames it either on the sensor , or the gauge .. I went and got an analog oil pressure gauge and fitted it directly to where the oil pressure sensor is .. I started the car and the readings mirror'd the oil pressure sensor / gauge on my car ..


at start its at 60 .. as it warms up it lowers to 20

when I give it some gas it goes to 60 then lowers to 10. on the analog gauge and if I give it gas it once again rises to 60 . but then when I let go of the pedal it lowers to 10, and will go up steadily to about 15 .. then i do the same process of accelerating the car

now I've done this with abrupt accelerating and gradual . ( all done w/o any load as I did not want to take the car out until I had this issue resolved ) so this is done w/o the car moving all done with the car in neutral once again no load .

I will gradually accelerate and it will raise from 10 ( this is on the analog gauge )
to 60 at around 3500 ..

let go and back down to 10 . on the stock gauge it reflected the SAME EXACT procedure ..

( I DO NOT KNOW THE MOTOR'S PEDIGREE ) but i know that its not leaking oil the car also has premix in the gas . klotz tw-30 sorry I cant be bothered to go check just for the name of the premix .

and I dont even know if its boosting .. but all the vacuum lines seem to be connected correctly .

I restored the car I bought the shell from a shop the shell itself was involved in an engine fire .. so I've redone alot of the wiring .. and everything has been soldered NO, once again NO cheap connectors have been used ..

idle which will be at around 800 750/900 at times . it starts up practically turn key .

only issue I have is the stupid oil pressure pressure issue..


I'm at a loss as to what ... I can do .. short of taking the engine apart ..

thanks for reading this mess hopefully I'm overlooking something stupid ..

 

Agreed

 

Minimum of 50 psi at 3k. Sounds like your OK but your oil pump COULD be getting worn. I'd also check to see if you still have the wax thermopellet. If so, it could be changed out for one of these http://atkinsrotary.com/store/produc...cat=643&page=1 After replacing my thermopellet I saw an increase in indicated pressure across the board, but especially when cold.
Note: Be careful when doing this. The thrust bearing can drop and get fubar'd when you re-tighten the hub-bolt.


Personally I think the OEM oil pressure gauge has utility. Even though my engine is pretty tight, I can get fuel dilution over time...especially in spring and fall when it's cool and the car idles richer longer. I can usually see it's time for a change in oil pressure even without looking at mileage.

 

hmmmmm my oil may be diluted then because I've only let the car idle pretty much .. I warm it up every day . until the FP dips to 0 ( well even though at hte time I thought it was a faulty sensor I'm just paranoid )

 

Smell it. Does it smell stongly of fuel? If so, change it and see what you get. If not, it's probably something else.

 

it does.. its one of the things I noticed .. It spelled of klotz . the 2 cycle oil additive I put i the gas.

so wait that means I shouldn't idle the rx7 very much ? lol

 

You're way over-thinking this. No, it doesn't mean you shouldn't idle the car. And if it smells of your pre-mix oil, that's expected.
I asked if it smelled of FUEL. Fuel dilution of the oil, to one extent or another, is common on a rotary. It's aggravated a little when the car idles during warm up in cooler weather...like you see here in the midwest.

 

well my fuel smells of premix LOL but it doesnt smell of fuel itself no.

I changed the oil a week ago , and the car hasn't been driven one mile so Idont think its that.

 

I'm going to revive this because I very recently tackled it and feel its worth adding what I went through for others in the future. I bought the car with this issue, though I didn't know about it until I investigated further more recently.

My gauge would show a pretty static 60psi on startup and then drop down to about 50psi where it would then sit. It wouldn't change based on rpm at all, maybe a few tiny movements but mostly just sat at ~50-60psi. Eventually I got nervous and started to look into it. I first replaced the sender since mine was covered in oil, but that didn't change anything. The next step I took was sort of unrelated - I swapped in a new cluster because mine was in rough shape. That served as a test of the gauge(s), again with no change. At this point I verified the readings with a brand new mechanical gauge while driving (long hose up to gauge taped to the windshield like a boss) and found that pressure was actually decreasing to close to 20psi as rpms increased. What I ended up doing most recently was dropping the oil pan and checking the regulators and pickup tube/screen. There wasn't much to see, but there was a lot of excess rtv all over the place so I cleaned everything up and put it all back together with a new pan and a more sparing dose of rtv ultra black. Either there was more clogging things up than I thought as I cleaned or I didn't notice something because that clean-out and reassembly seems to have done it. I now get a solid ~100psi at startup, which settles to about 70psi at idle and then jumps up to 120 when I get on the throttle and continues to be responsive as I vary rpms - as it should.

Dropping the pan, cleaning and reassembling is a ****. Not terribly complicated, but time consuming, messy, and a bit of a chore. This is the best write up I could find and I recommend doing some searching before you embark: Oil Pan Removal

-Note I couldn't get the pan out without dropping the subframe. Others have claimed its possible, but I'm dubious.. My car is very much not-stock so there's a lot of 'junk' removed and there still isn't space to get it out.