So, as I continue to familiarize myself with this new to me FD (but not FD's in general), I noticed something, the oil level in the car has not gone down, at all. I've checked it over the course of 3,000 ish miles, and nothing has changed. Thankfully I've been premixing the entire time. The car is running a PFC, and I did check the VMOP voltage, and it does change depending on throttle input.

I can see the omp lines when I look at the car, so it has to be there, but I'm kind of stumped by the fact that the oil level hasn't depleted whatsoever. Any thoughts?

Edit: I'm considering the possibility of a higher capacity oil pan, but based on the images of the underside of the car before I bought it, I don't see anything that looks aftermarket.

 

Fuel dilution? How does the oil smell? A little like gas?

 

oil injectors may be blocked up. the best way to fix it is to remove the omp and lines entirely. never worry about it again

 

I actually haven't sniffed the oil, worth a try.

 

I'm trying to retain the factory OMP system. Can't remember off the top of my head if the 92-95 USDM and JDM OMP's are the same, I believe the later FD's had a different one, though, so I'm not sure what to go about as finding a replacement if it is bad, once I test the lines.

Anyone happen to know the omp compatibility between USDM/JDM Series 6 OMP's?

 

I think probably every rotary engine suffers from SOME fuel dilution over time. Probably about the same amount as the OMP puts out. It’s one reason oil change intervals should be a little shorter.
And I’m in the camp of keeping the stock OMP. In the FD it’s metered for both load AND rpm. If you just premix, lubrication stops during decel. And that is often for extended periods and at higher rpms. Like you, I do both, but it can be hard on a stock cat and passing emissions.
Your OMP is probably fine if you’ve checked the sensor screen and it’s not highlighted. Lines and injectors can plug up, leak or restrict but not sure how common that really is.

 

its the same N3A2-14-600.

i like to keep the metering pump too, if i choose to add a little premix its fine, and if i don't its also fine. i like the flexibility

 

Most likely it is due to fuel dilution. I've seen the dipstick level actually rise in my '94 after a winter of cold starts and short trips.

 

What injectors do you have? Stock?

 

I believe the injectors are stock. I haven't pulled off the UIM to take a look yet, though.

The car is also likely on the PFC basemap as well.

 

Either you are experiencing fuel dilution or the oil injectors or the actual ports in the rotor housings are clogged. Its very important to test the oil injectors and replace if they are bad when doing a rebuild or major service. In the meantime I would premix.

 

I've been doing 1oz/gal since I got it, luckily. Going to be a nice trip through the car getting to the omp injectors, might just do that at the same time I do my solenoids.

 

How often have you seen this clogging issue? I have 75K on my FD with the original engine and haven't driven it a lot in the last couple of years, so it's hard for me to tell if there's an oil-injection problem I'm missing.

 

Not that common but it is important to blow through the oil injector openings in the rotor housings to make sure they are clear of obstruction when cleaning a motor prior to rebuild. The injectors themselves have a check valve that fails more often.

 

Don't know if this is relevant, but we recently had our engine replaced with a Mazda crate engine. The original used about a quart every 3K miles (just enough that my 3K mile oil changes took care of that). But this new engine for its first 3K miles has shown no usage at all. I understand that the oil metering nozzles have been changed by Mazda and the new ones are smaller in diameter, which I would expect to reduce oil usage. If the engine in the OP's car is relatively new, maybe it has the new oil metering nozzles.

 

No way to tell for sure. the car has about 49,000 miles on it, engine compression is about in the 100's when warm.

 

Random update on this. I had the engine oil changed, and it has been steady at the F mark on the dipstick before and after the oil change, a few thousand miles now. (Ive been premixing since I bought the car, to be safe.)

When I took the car to get the oil change done, the rotary tech did mention he thinks my rear main seal needs to be replaced because of an oil leak.

I found this odd because I've never seen the car leak a drop of oil. I got under the car on the lift with him, and there is a very thin but very large amount of oil coming off the bottom of the rear rotor housing (looks like the right side, near where the transmission mates to the engine & oil pan area roughly) and this has found its way onto the transmission cover, too.

I figured if it were a rear main seal, it would likely have gotten onto the clutch disc, I've had no issues there. Also, I haven't had any oil go down, the level has been the exact same this entire time.

I'm just rambling here trying to figure out what could be causing it. Any chance the OMP lines are broken or cracked? I figured if that were the case he would have noticed when the solenoids were being changed.

 

ive replaced the lines and nozzles on mine and noticed level not really dropping either. i havent boosted the engine or gone over 5k rpms either so not sure if the omp is really injecting awhole lot either. i dont reallly see any oil in the new oem mazda lines

 

If by some miracle the engine is original, after 25 years, wouldn't be surprised the rear seal and O ring is leaking - usually fail far earlier, clutch contamination is unlikely, still has to get past a flywheel flinging oil away. I'd expect your injectors would fail the suck blow test as well in the unlikely case they're originals.

If the lines are intact, primary turbo elbow state will probably give a good indication of the oil injector condition.

Unless Mazda have done something new in the last 10~15 years, only injectors available now, are the late small diameter ones, which have the rubber donut underneath to reduce oil use.

 

Well, it has 52,000 miles on it, so it likely could be the original engine. Compression was all in the 100+'s prior to purchase. So I guess at this point do I bother cleaning the injectors or just replacing them? I've seen threads on both, but I'm curious as to what the chances are of the one way valves failing inside, I don't want to potentially R&R a part that could go bad after its cleaned.

 

Any engine number on it?

Seems typical to throw a complete engine at them when they die over there, 100,000km on the imports here seems to be when they strike trouble and you're virtually there. For the price of them, I wouldn't bother trying to resurrect old injectors, anyhow, as said, I'd look first in the elbow for lots of oil.

 

Where would I find the engine number? I'd be happy to look. I haven't seen any oil when looking except just in the areas I've described. That's whats confusing me.

 

Some disassembly required! It's stamped on the top of the front plate near the alternator and probably under the wiring bundle leading down to the crank sensors, should be an E with 6(?) digit number.