Ok......I started my quest to find the root to a new ticking noise that is intermittent.

Here is the thread that shows others with the same or similar noise, and the reason I stumbled across the following.

In short, it is a slight tick tick tick sound that is speed dependant on engine RPM. Many people are reporting similar sounds. Mazda Maniac's description is much like mine.....first noticed after the engine is good and hot.

I started to read my shop manual about the lubrication system and found info about the metering pump. This is responcible for lubricating the side and apex seals, and is a newly designed delivery system for the 13B MSP. The shop manual did not go into detail about the pump itself, but I discovered something almost horrifying. A dry oil line to one of the four oil nozzles!!!.

I'm assuming it was an intentional effort by Mazda to make the nozzle line clear for diagnostic purposes. I will also bet it is not normal for one of these lines to be dry. I actually was able to get a good photo of exactly what i am talking about.

The photo shows a cluster of the clear plastic oil nozzle lines from the metering pump. All of which are full of oil except for one. It is obvious in the photo.
What I dont know is how the metering pump works. Does it use only 2 nozzles until a certain RPM or calculated load is reached......in which case the line would charge up with oil ( I hope to hell that it is this scenario) or is a seized or clogged nozzle which could explain my new ticking sound.....?

 

Now that is a little scary. Have you called the dealer yet to clarify the operation of the oil metering pump?

 

where is this located in the car?

 

In one photo one line looks empty, but in your second pic they all appear to have oil in them... Is there a bubble in the line perhaps?

 

Jason...... It is bolted to the front lower portion of the engine on the passenger side (US spec).
Looking down into the engine compartment, you can see it just left and down from the water pump pulley. Then you can clearly see the clear plastic oil lines.

Roy...I havent called my dealer yet. I'm dreading trying to explain this to the service writer who hates his job and rolles his eys when you talk to him...

Sferret... There is a combo of air and oil in the line itself.

 

OK. This is troubling. I have the exact same oil line situation.
I am researching the function of the oil metering system as I type this, so stay tuned.

EDIT - There is no info on the operation of the metering oil pump in the shop manual, just diagnostic information and I just checked for codes and I don't have any.

After the car cools off again, I will check the metering oil pump and switch using the diagnostic procedure as outlined in the FSM.

I just don't know when those lines are supposed to have pressure and when should they not.

 

The lines are supposed to be full of oil when the engine is running. After the engine is shut off the oil typically drains back down out of the lines. After startup it takes a couple of minutes for the lines to fill back up. They should all be full after about 5 minutes.

 

A note to those new to this post...

Both Mazda Maniac and I have noticed a new ticking sound from engine and a dry oil nozzle line from metering pump.




uh oh....

 

Mine does NOT fill up, even after the motor has been running for miles. I can't wait to try to explain this one to the service writer prior to the actual engine failure.
Acording the FSM, this isn't an actual problem until it sets a code...

 

in the shop manual it describes how to test the oil nozzles....

You pull vacuum on the inlet and it is supposed to hold at about 10 psi. How would oil drain back against a good nozzle ?...unless air is entering from somewhere else.

 

I'll ask about it from my dealer this week too. They have always been very knowledgable and cooperative about my past questions/concerns. If it really is a problem the more reports the better for us getting a solution right? (after checking my lines for oil once warmed up of course..)

 

OK. New observations:

I just took the car out and flogged it. 9000 RPM in every gear to the 7-11 and back for a total of 3 miles.
Upon return (with engine idling), the clicking was gone and the oil lines from the MOP were full. After 10 or 15 seconds, air bubbles began to appear in one oil line and after another 10 or 20 seconds, the ticking returned again.
The ticking noise comes from the immediate vicinity of the front leading plug area of the rotor housing.

I also have a new noise - a "laser gun" type descending whine as I go from gear to gear. Probably just the normal sound of the synchros, but I never noticed it before.

 

Hey Snap on,

What is your thought on this issue? It does explain why the nosie comes a goes. I will check mine tonight after I make a quick run for pizza

 

Jeff, Is it the same line that is going dry as it was the first time you checked?

 

Hrm.. I had finally given up on worrying about this noise, figuring it was normal, and now I see this thread.

Question for those experiencing the noise: Would you compare it to a sewing machine, (schick schick schick) or is it more like a heat shield (dee dee dee dee) ?

Oh, and MazdaManiac; I notice that sound intermittently as well. (The "lazer gun") Usually it occurs on the 3-4 shift while driving in town. Sort of a soft, high pitched "Eeep!" when I move into 4th. I assumed it was synchros.

 

Yes.

 

After sitting for 18 Hr all my lines looked dry. After quick run to get some chow, all lines looked full. It is hard to tell as oil is so clean. I think Mazda has some type of dye the can put in oil for diagnostics. Will keep checking this thread.

 

gyro check your pm's

 

This is from the Technical Training Program from Mazda.

The metering oil pump supplies a measured quantity of oil to the injector nozzles to lubricate the apex seals. Two nozzles per rotor are used in the RENESIS Rotary Engine. The quantity of oil is carefully controlled by a stepper motor, so oil consumption in the RENESIS engine is less than half that of previous rotary engines.

The stepper motor is cycled from minimum to maximum as a self test every 12th ignition-on cycle, and each time the battery is disconnected. When the engine is started, the stepper motor starts at the minimum flow position, then steps up to the desired flow quantity for the operating conditions. When a fault occurs, the failsafe oil flow is at the minimum setting. Engine power and speed are limited to prevent engine damage.

 

Thanks NavyDood. I had read that in the TTP, but had completely forgotten about it.

Note to those following this - the MOP from the AT operates at a higher flow rate than the MT and is a direct bolt-on replacement for the MT MOP.
I might try that. If it doesn't up the oil consumption too much, it would be a good thing to increase the oil flow a bit.

 

Here are some things I have learned.

After the initial finding of dry MOP lines, I have been checking them for a couple of days. They have remained full ever since. This tells me that the dry line must not have an obstruction. The question of it being normal for air to enter the line itself and cause a dry line still was a mystery to me.
I called MNAO to see if there was any resource for RX8 owners to ask a very technical question and be answered by someone who actually knew the answer.
Of course I was referred to my local dealer. I was trying to avoid this because I didn't actually have an apparent issue or problem that they could verify. My MOP lines were full, and the ticking sound was gone. I looked at a trip to the dealer to be a waste of time.
The shop manual as Mazda Maniac stated was very limited when it came to detail on the Metering Oil Pump, so my only option was to try to talk to an experienced Rotary tech that had knowlege in this area. This could be harder to do than you may think. I called one dealership and they said "our techs dont come to the phone".....
Another dealer was more receptive and asked me to call back after an hour and ask to speak with a specific person that has the most RE knowlege. I did talk to him today about my concerns.

• The MOP is supplimental and not crucial in the very short term. It is designed to increase engine longevity. For this reason, even a pump failure or line malfulction should not cause immediate abnormal engine noise.
• It is not a concern for the lines to drain out after engine shut down. This is more common after extended engine use when the oil is very hot and very thin. It may not even fully pump up at idle due to low demand as perceived by the PCM.
• The stepping motor in the MOP uses a signal from the PCM based on three things; Engine rotation, coolant temperature and amount of intake air.

I'm continuing to monitor my lines and odd sounds. If I hear the sound again I will check my MOP lines to see if there is any link betwwen the noise and a dry line. I guess this is all I can do for the moment.

Thanks Zoom44 for the very useful scans regarding the MOP detail.



[sidebar]

It is a fact that the Metering Oil Pump uses singnal from the MAF sensor to decide how much oil is delivered to the side seals of the engine.
This makes me worry slightly about all of the Canzoomer piggyback ECU users. The CZ fakes the PCM into thinking it is getting less air over the MAF than it really is. This skews the input data to the MOP, telling it to give slightly less oil. How much is less? I guess thats the magic question.

 

your welcome but i was merely the go between. they were sent by a freind who read your posts. much thanks to him. what i read from the scans if i remember correctly is that at some point the maf signal is taken out of the equation and the temp and engine rotation controlled the oil metering. i think from that that the cz unit will probably not cause much difference but maybe you can look at that part again and see what it says.

 

The only time that the MOP uses only 1 signal input to determine oil flow is when it is in "Fail-safe function". At that time it uses only RPM. It is in Fail safe when the PCM senses a failure to the oil pump. Flashing CEL and a rev limit of 3500 is set, or limp mode if you want to call it that.

Under normal circumstances, it uses info from the MAF.

 

Even if the Canzoomer ecu causes the OMP to pump in less oil, it can't be much less. Look at how much oil is consumed in a thousand or two thousand miles. It is hardly anything. It is really a very slow drip at best. It is also going to get more oil during heavy loads or high rpms which is where you aren't at most of the time. I wouldn't worry about it.

 

I'll have to log the duty cycle of the MOP in relationship to the MAF, but I doubt it has much correlation.
I suspect it is simply a load/no-load issue. If the rpms are high and the engine temps are high, the MOP sprays more or less depending on if the motor is under load or not.
.1v under isn't going to trigger the PCM to think it isn't under load. We are talking upwards of a 3v swing to a "no-load" condition at 8000 RPM.