rbti

Hello fellow newbies and experts:

Have a Series 2 with flashing oil light and an obnoxious amount of smoke coming out of the exhaust. I've read oil pressure at the PCM inputs and it's good. Have not read oil level signal yet. However, the flashing and blinking oil light seems to point to OMPs but no OMP DTCs. Any advice on troubleshooting? Manual does not really have info on troubleshooting flashing light from what I can tell.

Thanks.

Loki

iTrader: (1)

What are you using to read DTC's? The OMP codes are specific to Mazda so some readers don't recognize the code and don't display it, even though it's stored. Try a different app, or get the Mazda DTC extensions for the app you have, or try a different reader altogether.

Flashing oil light is usually oil pressure and obnoxious smoke points to a lot of oil entering the combustion chamber. The OMP even at maximum rate can't pump THAT much oil.

The oil pressure sensor on this car is really just a switch. Pressure or no pressure, rather than how much pressure.

rbti

Loki, thanks for your input, I really appreciate feedback from someone experienced with these cars. According to my S2 FSM, the oil pressure sensor mounted on the OMP (#1) is a liner sensor, roughly 0-5V. I am able to read that the car is making good pressure right at the PCM using the pinout in the FSM. I'll see if there are additional codes I'm not getting because according to the FSM, a flashing oil warning light on the S2 should also include either a OCV or OMP fault code which I'm not seeing. It's really stomping me but it may be that I'm not seeing all of the faults.

Regarding your point related to OMPs and the amount of oil. Would a clogged return line or a mechanical internal failure affecting the return to the oil filler neck affect the amount of oil the two OMPs are providing? In other words, I realize they should not inject that much oil, but wondering if a mechanical failure affecting the return would cause the OMPs to behave in a crazy way (maybe even both of them).

Specifically looking for one of these per Ash's post too:

There are 15 New Codes, which are NOT APPLICABLE or Not USED in Series 1.
B1342 PCM malfunction
P0332 Knock Sensor No.2 circuit low input
P0333 Knock Sensor No.2 circuit high input
P0482 Cooling fan relay No.4 and No.5 control circuit problem
P0522 Oil pressure sensor low input
P0523 Oil pressure sensor high input
P0606 PCM processor error
P1680*Oil Control Valve circuit low input
P1681*Oil Control Valve circuit high input
P1682*Metering oil pump No.1 circuit low input
P1683*Metering oil pump No.1 circuit high input
P1684*Metering oil pump oil pressure sensor–oil pressure is low
P1685*Metering oil pump oil pressure sensor–oil pressure is high
P2005 APV stuck open (No.2)
P2101 Throttle actuator circuit range/performance
P2299 Accelerator Pedal spring back malfunction NEW From September 1st, 2010 Production

* No CEL, but Oil Level Warning Light Flashes, also for P1686* and P1687*... Metering oil pump No.2 circuit low input and Metering oil pump No.2 circuit high input .

rbti

Stumped.

rbti

Loki, my prior reply on the oil pressure is related to the sensor mounted on OMP #1....that sensor is downstream of the OCV which regulates the pressure the OMPs see. I don't know what's 'normal' there for the S2 but I've read that the pressures are twice as high as S1 engines. Also two OMPs....so with this higher pressure condition, I wonder what type of smoke one would get given an OCV or OMP malfunction of the 'stuck open' type.

Loki

iTrader: (1)

Interesting. I'm less familiar with the whole S2 OMP set up, never played with one. But let's try.

Can we narrow the problem down to a single OMP? Are the spark plugs wet with oil in both rotors or just one?

If both are oily, the issue is before the OMPs, since it would be weird for both OMPs to fail simultaneously. I'm sort of betting it's that.

What voltage do you see from that oil pressure sensor and does it vary with rpm and load? If S2s really have a proper pressure sensor, let's get an idea of where it sits. If it's 0-5V linear you can assume 4.5V is roughly the end of the calibrated scale for it, and we know what the voltage peaks and troughs are based on rpm, we can guess at the pressure. In fact, does the light flash at idle or all the time or only under some conditions?

rbti

All very good suggestions Loki. Two common items (common to both OMPs):

The Oil Control Valve (upstream) which regulates the pressure could be stuck fully open or jammed somehow.
The Oil return line to filler neck (common to both OMPs) could be clogged.

I have not checked the spark plugs (very good suggestion). I'll do that this weekend and will check back in.....but a common issue like the above would affect both.

The pressure sensor is scaled as follows: .228V - 4.998V corresponds to -7 - 108 PSI. As I reved the car, I saw it go from very low values up to 3V. I was only looking at "am I seeing pressure" so I was not precise. So roughly 60 PSI. But keep in mind this is downstream of the OCV so it's after the OCV has regulated the pressure it's trying to maintain at the OMP inputs. I'm not sure if that's a reasonable pressure for the OCV to be outputting for an S2.

Thanks again for your suggestions and checking back in. I'll take a look at the spark plugs as you suggested.


BTW, did take your suggestion and friend read codes with his reader (he's a Series 1 expert) and didn't see the faults either.....In the FSM, I read that the OCV related overpressure and underpressure faults take 10 seconds to set...so maybe I have to keep the engine speed up longer to get that thing to set.

rbti

Posting my update in the interest of helping others in the future:

So after trying 4 different scanners (including Torque app), I was still not finding one of the OMP DTCs that was supposed to accompany my blinking oil warning light....so nearly ready to send to dealer when I decided to give FORScan a try. Ordered the right HS/LS adapter for current Beta version and voila, it pulled the DTC I expected. P1680.....so lesson learned is none of old diagnostic tools pull the new S2 codes but FORScan does.

Now on to troubleshoot the OCV.

rbti

Geez:

https://www.rx8club.com/new-member-f...xhaust-263879/