Blue Demon

Just curious if it is normal for my oil pressure reading to be steady no mtter what the speed or rpms? It stays just to the right of the middle mark throughout the driving range. Doesn't seem to flucturate with revving the engine either.

Roy

Racer X-8

Normal.

It's not analog, it's a discrete signal which sweeps the gage needle to where you see it. Without the signal, you get zero on the gage. In other words, its a very impressive idiot light.

darkducati

That is correct. And we can thank Ford for that wonderful idea.

eccles

No, we can thank the fact that Mazda are targeting this car (and the Miata) at more than just the enthusiast market.

Generally speaking, enthusiasts know how a real OPG works, but Joe Sixpack has no clue, and Mazda changed the Miata OPG to be an "analog idiot light" after too many idiots kept complaining about the fact that their oil pressure was fluctuating. The RX-8 inherits that same gauge behaviour.

I just wish that there was some way to return it to full function through a sensor and/or firmware upgrade.

Blue Demon

Thanks, I had not thought of that, now it makes sense (bad sense!!).

darkducati

Far more likely that they inherited it from Ford, because it is cheaper. Mazda and Ford don't care if customers call the dealer with questions, they care about money. That and the fact that the company is compartmentalized to the point that the engineers likely would never even here about what the customers think about the OPG. But they always here about saving money.

A perfect example is Volvo. They have a computer on all new models that controls sunroof, gas door, and such. These computers will go to sleep after awhile. When this happens, the fuel door will not open. Now, this wouldn't be a problem had Volvo not decided to eliminate the manual overide cable. They did this to save money, nevermind the fact that they eat tons of money from roadside assistance towing. The reason this happens is that the department saving the money on the fuel door release doesn't have any contact with the department that handles road side assistance. What does he care, he just got a bonus for saving the company XYZ per car. Stepping over a dollar to pick up a dime.

Gord96BRG

You might think so, but it was in fact Mazda by itself that did away with the real OPG in the Miata for the 1995 model year. Ford didn't assume controlling interest until 1996.

Customer support calls DO cost money. That was a definite factor in the decision - the customer support calls, the dealer visits for warranty requests to "fix the oil pressure" (or gauge), etc. The fact that they sender and gauge head were cheaper for the on/off version was significant, of course.

Remember, in the 1990s, Mazda was bleeding red ink. Without Ford's intervention in 1996, there is little doubt that Mazda would not have survived as an independent company. By 1995, Mazda was looking for every single way to reduce production and operating costs.

Rather than blame Ford, you should be thanking them for rescuing the company! Without Ford's help, there would be no RX-8.

Regards,
Gordon

darkducati

Hmmm, iteresting. You could very well be right. I am not however, blaming Ford in a negative manner. I just know how they operate, and they are cheap. The bottom line for Ford, is the bottom line. Thanks for your input though.

rxphink

The RX-7's have had dummy pressure gauges since the 2nd gen RX-7

It's a Mazda thing, same with the water temp gauge.

Omicron

Sure wish someone would look into a replacement sending unit (which I think someone already has, just can't recall where!) and gauge unit that mounts in the factory location. I may have to run this down in the future...

rxphink

On the RX-7 at least it wasn't a problem with the sending unit. The problem is actually with the gauge.

It takes the signal from the sending unit and goes to the middle of the gauge if the signal is within a set range.

A couple of guys on the RX-7 forum made a mod for the RX-7's temp gauge that allowed the user to adjust the sensitivity of the gauge and make it into a full sweep gauge.

rotarynews.com

Here's an idea: campaign Mazda for a "Real Gauge Cluster Option" or "Enthusiast Gauge Option" - IE no idiot light gauges, and more gauges like the MazdaSpeed gauge cluster.

Omicron

Yeah, that's what I'd heard. Hope someone tackles this for the RX-8...

Now THERE'S a thought!!!

Mazda, are you listening? Of course, this won't do it for all of us who already HAVE RX-8s unless they come up with a retrofit. Sigh.

Jag

These gauges are available as a mazdaspeed part through japanparts.com

Sports Meter Link System

I'd love to get these, and they can be yours for the bargain price of $1355(US), gotta love the mazdaspeed mark-up price....they are cool though.

Racer X-8

The water temp gage? How do you figure that?


Uh, so the pressure GAGE is what would need to be replaced. The sender is indeed analog. Correct?

rxphink

The water temp gauge is a dummy gauge too.

It points to the center when it gets a certain range of voltage from the temp sensor. It's not linear by any means.

Correct the gauge would need to be replaced. The sender is fine it pumps out a voltage based on the pressure/temp it sees.

I Have not scoped the sender so this is all based on my past experience with Mazda rotary engines. I would imagine the part is the same as on the FD RX-7

sferrett

The oil pressure gauge in the rx7 (FC or FD) is not a dummy gauge. The temp gauge is, but the oil pressure gauge reads in psi and it does fluctuate on engine rpms and such.

It may not be very accurate, but that's not the question - it's not a simple yes/no gauge like the rx8's oil pressure gauge - it does attempt to read actual pressure and it does fluctuate.

Simon.

khoney

You must have a NA FC??? Maybe the Turbo was different, because both my oil and temp gauges were analog - I know, I watched my temp gauge move into the danger zone when I blew a coolant hose once :D.

sferrett

Indeed the FC is a NA..

The temp gauge in the FC will start to move upwards past center when the water temp starts going over 230F (I have a real temp gauge in there also, and when my heater hose developed a leak I had a bit of an overheating moment also).

Both gauges are analog, in that they have a needle which sweeps over the gauge face. The temp gauge is not linear in that the temperature range for the center position is quite large - so it's in effect a 'dummy light' having three positions - cold, normal and pull-over-now. The oil gauge is not a 'dummy light' in that it actually reads oil pressure in psi and the gauge is marked in psi. It's not super accurate and the senders have a tendency to go bad but it does read your oil pressure none the less.

The temp gauge in the rx8 I would suspect is similar to the rx7 in that the range of temperatures for which the needle stays in the middle is wide and if you ever see it starting to head north it's likely indicating that the engine is quite out of spec temperature wise. The oil gauge, as far as I can tell, on the 8 only has two positions - zero and just to the right of center. Even when you do a self-test of the dashboard the oil pressure gauge only sweeps from zero to it's normal running position and doesn't sweep the full range of the gauge.

Simon.

MEGAREDS

I'd also like to see real pressure readings off the tires.

rxphink

What I meant by the oil pressure gauge being a dummy gauge is that it is not a linear gauge. A couple of guys back home in Texas tested thiers and found that it has a range just like the water gauge, it has a smaller range and fluctuates the needle within this range. We were thinking of replacing the water and oil gauges with aftermarket gauges, but I don't think anyone wanted to cut up the PCB in the cluster.