Mazda switched over the Miata around '94 to a dummy oil pressure sender and gauge, and it's been fairly common amongst enthusiasts to add an aftermarket oil pressure sender (JC Whitney sells one, VDO sells one you can get at some autoparts stores) to solve the problem. The gauge should work fine, but it's missing the PSI markings that might be more useful. I don't know if any of these senders will work the the '8, but with all the other similarities to the Miata I would bet they would.

I seriously doubt Mazda will ever offer a real working OPG again, considering there's probably less than 10% of the owners would understand what the data meant... and dealers would be overwhelmed by calls about 'fluctuating' oil "level". Sad, but true.

 

In keeping with the refined simplicity of the oil pressure gauge, perhaps the speedometer should be changed to read either "stopped" or "moving" :p

 

Nubo

Yes - But should be "Moving !!!" and "STOPPED !!!" (As per police)

John

PS Love plays on words.

 

Okay. Thank you.
Actually, psi markings aren't all that necessary. What you want to do is make sure that the oil pressure is basically where it is supposed to be. If one happens to need actual PSI values, then one should probably look into one of the many datalogging solutions out there. That's why I checked with Overload on the process. If the Miata trick would work, then the tech wouldn't have to have an external guage. He would only have to hook the sender right back up to the stock wiring.

---jps

 

It really would be nice to get that oil pressure gauge functioning as it should...

 

I think that the entire dash cluster connects to the ECU via it's own bus.. not the CAN bus.. which I can confirm from the shop wiring diagram. The Gauge cluster has its own microcontroller.

see below...

The main bus lines from the ECU look like A & B.. but on the next sheet they have a ton of info on the actual warning lamps having their own dedicated wire from the ECU, oddly enough instead of being just another bus message. Perhaps they wanted to ensure that those warning lamps would work even if the gauge cluster somehow was not working.

EDIT: I take that back.. the A/B lines are the same lines (color wires) that the TPMS uses to communicate, so that almost certainly is the CAN bus.

 

Also, the warning lamps,

 

More lamps...

 

The locking switches and the turn indicators:

 

And the TPMS module..

From a related thread, it looks like to disable the TPMS temporarily for testing, all that is needed is to pull the room fuse. Then find a way to cut the power from tpms later if it works.

OverLOAD

 

I don't know much about the RX8 OPG, but I know alot about pressure guages at out power plant...


from what it sounds like, we have a oil pressure switch. A pressure switch goes between true and false at a set pressure. It is not capable of delivering a full range analog signal.

to get a full range analog signal you need a pressure guage which will probably deliver a 4-20 miliamp signal which an analog indicator can be hooked up to. Unfortunetly, the RX8 guages are digitally controlled as far as I can tell, so you will need a analog/digital converter to make the stock guages work. So its not exactly an easy thing to do.

 

Further digging has the gauge cluster controller aware of its surroundings, and able to throw a MIL/CEL if the gauges don't respond the way they should.

It seems as though the best/only? way to get this done, is to replace the sending unit, and a PCM code change.. Mazda? Want to do this as an option? I'll pay, and so will hundreds if not thousands of others at the dealerships.. are you listening? You should be... An informed decision on the OPG would be a remarkable custmer response from Mazda

Regards,

OverLOAD

[I can dream can't i?]

 

I gladly would also pay for that option - and include a voltage/battery gage too in the package!

:D

 

amen

 

I join to those who want a real oil pressure gauge and am willing to pay for it too.

 

I agree with you but education is the key. They have a manual, put it in there. educate the consumer and he will be a better happier customer

my
.02