I determined that if the OMP position switch isn't turned far enough clockwise into the switch position range it causes the the PCM to go into the fail-safe/limp mode with no code. The condition is that on start up you have throttle for several seconds until the PCM decides there's an OMP issue, throws limp mode, and then you only have 11% throttle/4500rpm max in neutral. It stays in limp mode until you clear the PCM, but this situation will repeat until you adjust the position switch to the point the PCM is happy. This is an issue encountered by dannobre and several others and there's nothing in the service manual about it. The confounding part is no CEL code

and now you know the rest of the story ....


.

 

Did it work??

 

There's nothing in the service manual about it because the OMP sensor is deemed to be a non-serviceable part.
The end result of any of the 16xx DTCs is to replace the entire ($1400) MOP.
Kinda weird as far as I'm concerned since calibrating it is fairly easy. 2 7mm screws and some patience.

I had a similar problem the other day - the thing was working fine forever, but when I went to run my "max-oil" program, it cycled the OMP and got the same error/limp-mode.
When I reflashed back to a regular calibration, it continued to fail. Watching the OMP do its thing, you could see that the PCM swept it from 0 - 60 3 times, failing it during the second sweep and setting the limp-mode.
I just loosened the two screws, bumped the sensor a bit one way and then the other until it passed the test.
Because of the way the MOP is constructed, it isn't possible for it to damage itself by over-ranging, so it really is a no-brainer.

 

It's worked like that for me 3-4 times over the last couple of years...but I have had one pump that wouldn't calibrate for whatever reason. It kept setting limp mode no matter what I did.....so I either didn't get lucky...or there is something wrong that I couldn't scope out...or correct with the position switch

It is a super simple pump..there is nothing difficult about it...the logic is all supplied from the PC...just wish I knew exactly what it was looking for

 

oh yeah, baby check your email

IMO it is serviceable, otherwise why are the switch mounting holes slotted for rotational positioning?

It may not be intended for normal service, but apparently it is intended to be adjustable for a reason. Pretty stupid to dump a perfectly good pump and then sock the customer for a new $1300 OMP + labor, retarded actually. I didn't test the other end of the range (the max end), but it definitely mattered on the low end. I was just happy to resolve the issue.




.

 

If I had a lift I'd play with the one I couldn't get to work...to see why.

I did get pissed at it and that didn't help

 

I did mine through the engine bay and just the switch only. Being NA and not having all that factory crap over the radiator made it a breeze.

 

Even FI, its easy to reach, though I found I could measure how much I rotated it more easily from under the car, looking straight up at the connector.
From the top, it is hard to judge the rotation since its rounded.

 

Mine had a white paint alignment mark on top between the two parts. I assumed it was done at the factory. Had no problem judging it from up top with this on there. Ended up slightly clockwise from the marking to work. Anything prior and it was a no-go.

however, what I posted last night was reported by Jax on the first page of this thread except he said a CEL code was thrown whereas I and several others had no code indicated - weird


.

 

Mine does throw a CEL.

It would be weird to get a P16xx/limp-mode and have no CEL.
I don't think you are alone in that experience, though.

 

I'm on an extremely old flash so this may make a difference, probably from early 2006 since that was the first & last time a dealer touched it from the original purchase about a year earlier

 

Oh! Wow!

lol

Yeah, that might do it.

 

Interesting..

I'm curious reading some of your comments Team and MM. When you say "adjustment" it makes me think you can actually adjust something in relation to the contribution of the OMP itself. However the understanding I'm coming across from everyone's postings is that this adjustment really is just a way of getting the OMP to a solid connection with the ECU to not throw it into limp mode? Or is this actually something that could be manually done to increase the pump rate of the oil which from last I recall looking into this deeply it can only be adjusted via tool software such as the COBB

FYI I'm speaking of before any modification is done to the OMP that was shown in this thread earlier. If I per say did the mods noted earlier, would the SOHN adapter effect the rate any or be at whatever the fixed rate is on the OMP that you manually set yourself?

 

We are talking about adjusting the position switch so that the pump functions in a way the car doesn't go into limp mode

BTW...I have a much more recent flash...and I didn't get a CEL...or a code of any kind the iDS could read....so it wasn't even a code the "scanner" I use could have missed...

 

That really sucks.

I'd love to get an understanding on why that is.

I've only been able to simulate this failure once on my own and it immediately threw a code.

 

Look at the first page, specifically MMs posted pictures. Look closely and you can make out that the position switch mounting holes are radially slotted. This allows the position switch to have an approximate 20 degree rotational mounting position range on the metering pump. This is explained in the thread. I understand wading through all the subsequent BS posts can be tedious, but fully reading a thread is the only way to find the diamonds amongst the coal.

Apparently the flash is so old that Cobb can't even generate a copy of the last AP flash they did for my STU project into a newer flash version. Both their program structure and Mazdas fueling strategy changed since then.


.

 

It really sucked..I had just done an install and had changed a number of systems.....didn't really have anywhere to look. I went over the wiring harness for the whole PCM with a meter, including the MOP..and found nothing wrong. Had a dealer buddy hook up the iDS to see if it could see something that my scanner couldn't...nothing
According to the iDS the MOP was functioning fine

It took a month to finally just pull the MOP and replace it with a spare...it was the only system other than the DBW throttle that I knew would cause instant limp mode....

Turned out that's what it was.....put the old pump back on and limp mode again...so I knew that was the problem.

That's when I figured out the reset thing with the position switch....Problem is it doesn't always work...and I never figured exactly what the PCM is looking for......Funny thing is the original pump worked for about 2 years with no problems....and then for some reason it "lost" the position again...and I couldn't get it to work.....never really tried that hard though..I just put in the spare

It seems to happen when the PCM has been disconnected....not sure why that would be......I had been told that sometimes if the PCM was removed it needed to be disconnected and restored to get all the systems to work to work properly

Has everyone with this problem had it after they disconnected the PCM wiring IE after a new engine install or unplugging the PCM?

 

I've had PCMs disconnected numerous times and never had an issue before. When the local shop did an engine swap in 2008 no issue then either.

I can see if the MOP is removed and the switch is on the edge of it's acceptable position range that there might be enough slop in the mounting holes such that it bolts up out of position enough to require adjustment. Otherwise

 

Sorry to bump, but do you guys think the slop in the mounting bolt holes would be enough to throw the OMP off enough to reduce what it is pulling from my SOHN reservoir?

Ray has suggested I clean the oil injectors and test the check valves for clogs. I plan to do that but now that I think about it, I have removed the OMP to replace the SOHN gasket and I am wondering if when I put it back on it is rotated slightly enough to throw it off. It does seem that it stopped pulling the usual amount from the SOHN reservoir after I did that. But I am not getting limp mode so maybe not

 

...

 

Thanks. I guess I will be checking for clogs this weekend.

 

did you reset the arm position as discussed in this thread or just slap it back on unchecked?

 

i just put mine back on, but I dont think my car is in limp mode (?)... I dont have any issues with reving in neutral or anything.


But I think that the omp is not taking any new oil in.

 

try re-reading the thread from the beginning again

 

Honestly, I just slapped it back on without checking it. I will remove it again this weekend and check the position of the sensor.