Oil metering pump testing
 

is there a way to see if it is doing its job properly? i looked at my lines and it looks like there are small air pockets in them. same as when your drinking from a straw and your close to the bottom. is this normal?

but either way, how would i know if the omp is 100% functional? are there signs i should be looking for that may indicate failure or not proper operation? i dont have a cel or anything btw...

also, how would i know when to replace the lines or start paying attention to them before they cause my motor to go away...

In my experience, the lines are perfectly fine until you mess with them. Replace them when you go into or rebuild the motor, and you're good there.

Bubbles are normal, not sure why, but that's normal.

The pump is working properly if you're not throwing any codes or anything, when the ECU sends a command for the pump to move there's a feedback to confirm that command. If it doesn't move or has some sort of electrical issue, you get a code.

Dale

got it... have you heard anything about an output deficiency? maybe it doesnt pump as well as it used to type of thing? or is ANYTHING outside of normal operation gives a code?

also, whats your opinion on the conversion that removes the pump and replaces it with that thing that pumps 2 stroke fluid? is it a pointless upgrade? ive been reading that the ss omp lines are pointless but i dont see how considering how fragile the stock plastic ones are.

As DaleClark mentioned, the lines are usually fine if left alone. If you have to remove/move them for anything, that's the time to replace with stainless or new OEM...along with new copper crush washers at both ends.
The OMP has three different CEL codes associated with it, each will put you into Limp Mode. So it's a pretty well monitored component. If you don't have a CEL/not in limp I wouldn't worry.
As for the adaptor to source 2 cycle, IMO that's a great upgrade IF you have the room for the reservoir tank and the discipline to keep it full. As for many things under the FD hood, it's the packaging that can be the biggest hurdle.

Great.. then I'm way good. I'm interested in doing the adapter conversion. What kind of reservoir are you supposed to use? Would a vented oil catch can work with only one hose running to the pump and some sort of fill port on top?

I saw the write up on how to do the conversion. It doesn't seem to hard. Is filling the reservoir an as needed thing or should there be a consumption rate..

there's a test in the FSM for volume if you want to be sure the output is sufficient.

if you have disassembled the system and there are large air pockets in the lines then you should premix for ~2 full tanks of fuel until the lines have primed and expelled all of the air from the system, this takes time and is unavoidable. small air bubbles aren't a big deal but might indicate an issue with the check valves in your nozzles.

^^^^^ + 1.... I was just going to say that air pockets are caused by blow back. This is another reason why I wouldnt replace my OMP lines for SS lines. I could be wrong but This is what I noticed from my own testing.

they do make it more difficult to monitor for air, i agree. but i do dislike very much that you have to work around the unprotected lines with kid gloves even if they are only a few years old.

with every pro there seems to be a con.. heh

If you really care about your engine and are a real enthusiast you'll ditch the whole OMP assembly and premix. The factory OMP injectors fail quite often. Not only that but even when working IMO it does a quite poor job of lubricating the entire chamber. Save yourself the trouble, time, and money and block it off and premix...

To do that you must have a standalone. The OP has one, but for many that's not an inexpensive proposition, especially if there's no other reason for doing it. And if you're JUST premixing, when your duty cycle goes to zero, so does lubrication.

I use my OMP but do not depend on it to keep my motor lubricated at our HP range, I still premix in tank.. My OMP is there for extra lube, The OMP is the only thing i can monitor unlike pouring oil in gas tanks and hope the mixture is correct.

The nozzles absolutely have a decent fail rate. At 38k original miles on mine, both had failed. I plan on rechecking my new nozzles every oil change to monitor their life span. In the event they fail though, I plan to externally run one of Daleclark's check valves to remedy the situation as opposed to replacing the nozzles again. The factory nozzles use rubber "stoppers" to prevent blow back under pressurized chamber conditions. If these nozzles fail, then you have no omp lubrication under boost! Bad news. But as for blocking off the OMP completely? I do not agree. The OMP itself does not necessarily fail as often as the nozzles, I believe supplementing your omp with premix is the best fail safe for engine that you can possibly do.

What is the result of total failure of the OMP system? Premature tip seal wear?

There is a lot of misinformation in this thread. So to qualify the the below please consider and reference this work:
OMP (oil metering pump) Declassified threads by ttmott https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/

• The metering oil system is hugely reliable to include all of it's components in stock or near stock engine configuration.
• The oil pump when in good repair has a zero percent failure rate. The only failure issue in the pump is the feedback potentiometer and in one case that I can find the stepper motor.
• A failed OMP sets minimum oil flow (ie oil flow never shuts off). With a nul PCM the pump still delivers oil.
• If you want a superior metering oil system get the Mikuni OMP. Forget premix and other solutions unless you are subjecting the engine to massive amounts of boost and really need the additional lubricant; but then such an engine combination is specialized from top to bottom.
• A PFC with the Mikuni OMP opens up a world of lubrication options and adjustment.
• The nylon oil lines are no different than any other rubber or plastic hose or tube; they need to be serviced and changed - I would say at 90K mile intervals maximum.
• The air bleed check valves (what someone called the "nozzles") are the weak link in the system. They are designed for stock boost levels and are extremely sensitive to dirt. The air lines to them are tied into the primary turbo inlet for a reason; that is clean filtered air. These check valves are designed to crack open at very low differential pressure and consequently it is suspected they have a problem tollerating the higher boost levels we tend to want to develop. Several of us are working on a suitable replacement for them but with that said if you maintain a clean air source and boost is less than 18 or 19 PSI they should provide good service.
• The air bleeds are not in effect at above atmospheric engine conditions and consequently are isolated by the check valves. Conversely, if the check valves fail then under boost conditions the critical oil is blown into the primary turbo inlet rather injected into the engine. And many wondered where that oil in the intercooler came from..... The air serves several functions: one is to emulsify the oil for better lubrication under low engine loads, helps in the combustion of the oil for emissions reasons, and prevents the engine from scavanging the oil from the OMP system under vacuum conditions thus starving oil when oil is needed under engine load conditions.

The bottom line is this system is robust and reliable - consider how many recalls Mazda did on the system; none that I know of, and how long have they been putting the system on the engines? Nuff said.

To address the OP's question - If you have the factory ECM the system constantly checks the operation of the OMP otherwise you will get a CEL and a limp home mode will set. The air bubbles in the nylon lines is most likely due to engine vacuum drawing air in from a source like loose line fittings but with that said I've seen it more than once. Remember also, the oil flows are small, very small, like 0.004cc/E-shaft Rev under full engine load and may not be enough to move the air bubbles down the tubes. Now in my case with the Mikuni OMP and PFC I double the oil flow at 100% engine load from the stock condition and there are no bubbles shown in the nylon lines.

Spot on and very descriptive and clear post ttmott. As stated I also disagree with blocking off the omp as it is a very "robust" system. I personally use premix as a fail safe for my nozzles (air bleeds if you will). The nozzles correct operation are imperative to the proper metering of oil from the omp. To reiterate what has been stated: If the valves leak, oil will be blown back into your primary turbo inlet; if they stick closed, the engine will drink oil under less than atmospheric conditions.

I know this is an old thread

But Im a new fd owner, and I was wondering if anyone could tell me how to check the nozzles are working well?


thanks

^^ to answer your question. Basically you should only be able to blow through them one way. There's a test in the FSM that will help you out. If they're on the car still then it's obviously harder. You could probably use a vacuum gauge to test if they are shutting off but I don't know. They aren't that expensive for new ones and if you're running the OMP it would be worth having them replaced.

does premix help with a newly rebuilt (low compression) bridgeport engine startup when hot?