daem0n

Ok, here's the deal:

I charged my battery and replaced/topped-up all fluids after storing my car for the winter. It seemed to start fine and everything seemed to be ok. So I took it for a drive and in 2nd or 3rd gear, the car can drive with about half-throttle (or not even) but as soon as you try WOT or anything more than close to half-throttle, the car just constantly backfires and there is NO throttle at all. This is extremely dangerous, because if there are cars behind you they don't know that you're slowing down but it's as if your car is stalling (while still running).

Is this limp mode? I didn't think limp mode was this bad. Anyhow so my car seems pretty useless to drive so I decided I better park it to figure out what this problem is as I can't even really make it to any shops without being towed. I pulled a couple of codes from the ECU. I know that the codes are represented as long = 10 and short = 1. I pulled the following:

L S
L S S S S S S S

So, I got 11 and 17 from my calculations.

Now, these seem pretty odd to me. The 11 code has been there for a while and I believe it has to do with the connection to the ECU as I've already replaced the thermosensor (code 11 is for thermosensor). So, I'm not worried about that code at the moment. I'll work on getting a PFC and get correct readings soon. The 17 code is new. 17 = Oil Metering Pump?...So I will need to check the OMP.

So yes, the OMP might have something wrong with it, but I can't see it causing problems like this? I've already been premixing for the first batch of gas in the car at the moment so that doesn't worry me.

The only scenario I can think of, is maybe the OMP malfunctioned and caused the car to go into limp mode...and I'm not experiencing limp mode?

Any other ideas?

daem0n

Ok, so I've been doing some research on the site and found out that the OMP can put the car into limp mode...so this makes sense. Now my question becomes...what can I check on the OMP for failure? What causes the ECU to read an OMP problem? Is this a mechanical or electrical problem? Can it be both? Basically, what can I do with the OMP without replacing it (to fix it)?

Thanks for any and all help!

hanman

17 is the O2 feedback system.

j-specfd3s

correct, 17 is feedback for the o2. Did you do anything else like take the manifold off or something like that, something that your forgetting about. I cant really think of anything that would cause your issues to happen from charging the batt or changing the fluids.. Reset the ecu codes and see if it happens again.. Could you have mice in your car they like to chew on wires. What you are talking about sounds like limp mode but it doesnt make a difference what the tps see's it just rev limits the car @5500 rpm and puts the wastegate in fail safe at 7psi

Sgtblue

iTrader: (16)

As far as I can tell, the OMP...the sensor, pump and stepper motor, are designed to be changed out as one assembly. For more info on the inner workings...
https://www.rx7club.com/showthread.p...&highlight=omp
If you want an idea of how-to...
https://www.rx7club.com/showthread.p...&highlight=omp

daem0n

Well first off, thanks a lot for the replies. You are correct, 17 is O2 sensor. I must've made a mistake in writing the message because I believe it was 27 that I got (L L S S S S S S S). As background, I haven't done anything to the car since storage (to the manifold, etc.). It is possible that mice were in something, I have seen them in the garage before but this winter I didn't notice any so it is doubtful, but anything is possible. I will have to check for broken or chewed wires.

Wow, thank you for those links. I just browsed over them now. They have a ton of information in them (and thanks for taking the time to do your own write-up on the repair).

Have you (Sgtblue) or anyone else figured out a checklist in the FSM or "other" to follow for the repair of the OMP? I mean, say for instance a shop took in a car throwing the 27 ECU code, they must follow some procedure before deciding to replace the OMP module...no?

I found this in one of the links:
"When the OMP goes bad it is usually the stepper motor or the potentiometer that malfunctions, unfortunately Mazda does not sell those parts separately and they are not exactly off the shelf parts so you are forced to replace the entire assembly when this happens."

But would still like to know how to check these items...

Thanks again for all the help!

Sgtblue

iTrader: (16)

The OMP (Mazda refers to it as a "Metering Oil Pump") diagnosis begins on page D-14 of the FSM, a flow-chart of inspections continues on D-15. I'm not good with things electrical but as mentioned in the write-up, once I got to the plug below the alternator I tested resistance and voltage. Everything seemed to be in range so I figured it must be a damaged sensor or motor and pressed on with the replacement. Good luck.