I did a intercooler, piping upgrade on my newly acquired FD and messed with some emission and vacuum lines and now I have a check engine light on. Code 27 comes up "metering oil pump". I don't know why it happened, I don't even know where this pump is? Any help or suggestions greatly appreciated. Thanks guys

 

I would first clear the code from the ECU and see if it comes back. If not mistaken, this will throw your car into limp mode. And FYI, the pump (OMP...oil metering pump) is located at the lower front of your engine on the passenger side.

 

The Oil metering pump supplies oil to the engine to lubricate the apex seals. The ECU controls how much oil is being supplied to the apex seals by varying the voltage on the OMP according to RPM changes. If something is wrong with the OMP wiring and the ECU notices this, it will put the car in limp mode and you won't be able to go past 4k rpm as a protection for the engine.

The OMP is below the primary turbocharger and is not easy to get to. check the FSM, it will give you much better information about it then I can.

 

Well as a disclaimer, I’m not a 3rd gen owner, but I have had my 91 go into limp mode. There’s more than just replacement of the OMP, it is indeed the same problem. What happens is the ECU or OMP, its unknown which one dose it first, shorts the other one out, causing limp mode. If you replace the OMP the shorted out ECU will ruin the OMP and vice versa.



Here is the second gen limp mode.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/

 

Well did you unplug it? The gigantic plug that leads to the oil metering pump is squeezed between the power steering pump oil tank and engine lift hanger. The OMP is located to the left of the crankshaft pulley.

In the last picture you can see the OMP has the copper gaskets on it. The OMP lines and wires run along the front of the engine. They're tucked in below the water pump and above the crankshaft pulley. The wires end at the OMP plug, which comes from the main harness. The oil lines keep going underneath the alternator to the oil injectors. That's a top view from the driver's side. Notice the OMP is disconnected and hanging from the front of the engine.

 

No I have not messed with the OMP nor the plug at all so that is why im shocked. Only thing I've messed with is vacuum lines when this happened. Does the OMP system have anything to do with vacuum anywhere just so I know so I can rule that out? I'll try clearing the codes tomorrow and see if it comes back.

Got a question, I read that the OMP could be getting stuck sometimes and that would cause the code. Is there anything I can do to help it not get stuck? Or maybe add something to the oil to maybe clean it up? I know seafoam helps regular engines a lot would that be safe in a rotary?

Again thanks for all the help everyone

 

Step 1: Buy Power FC
Step 2: Block off OMP and pre-mix
Step 3: Insert OMP into garbage

 

Check the around the area near the belts. See if the OMP wires which run under the waterpump have rubbed against a belt.

 

If I were getting flash codes for my OMP not working I'd put 2 cycle oil into the gas tank. 1oz per gallon. That would cover my engine until I got the OMP issue worked out. There are two vacuum lines running to the oil injectors. You can see them sticking up. But they are deep down in the vacuum/rat's nest. You'd have to have your upper intake manifold off. I would discount them. Dude e-mail Dave Barninger (kdrotary@ptd.net). His 2 cents are pretty good too.

 

The vacuum lines will not trigger a CEL. The CEL is related to either a malfunctioning OMP or a damaged electrical connection between the ECU and the OMP.

 

+1 check out the link I posted above. The only question I think you have to ask is, Dose the third gen have the same problem as the second gen with the OMP shorting out the ECU?

Do you have hesitation in all gears? Bucking when driving, can’t go above 40mph and messy idle? If so that might be your problem.

 

It doesn't short out the ECU, but it will put the car into limp mode which will give similar symptoms. Unless that's what you are referring to with "shorting out the ECU". When I think of the phase "shorting out", I'm thinking electrical damage.

 

Hey I don't think the ECU is shorted out, but it is most def in limp mode. Wont go past certain RPM, and wont let me boost, but before that it drives just fine. I will def check wiring to make sure its not cut or damaged by the water pump. I'm gonna go do that and clear the codes to see what happens

 

Oh ok. I was unaware if the FD has the same problem as the FC. On the S5 the OMP or ECU, unknown which one shorts out first. My ECU was burnt in 5 places; if indeed this is the same problem as I had, you cannot replace just one, it’s worth checking the ECU I could smell mine through the carpet. I would check it out

Circled one compared to the not circled one.

 

Have you already tried disconnecting the battery and reconnecting it to reset the code? I know it might sound too simple, but one time I had my FD worked on at a shop (my first mistake) and they left a large air hose loose causing the car to go into limp mode and there was a check engine light on. After disconnecting and reconnecting the battery CEL was off and I fixed the loose hose, its worth a shot.