Anyone have a extra position sensor please pm me
Wcs says he has one but I haven't gotten a response from him since he posted

Wow - one of the best threads I have had the pleasure of reading and after 3rd read its starting to make sense.
Someone said make this a sticky and I totally agree, theres nothing like this on any other forum around the world.

Did anyone actually finally prove that they could increase (or decrease) oil consumption to the rotors?

many thanks guys - Mark

It is easy to adjust the MOP table with the correct tool...either a Cobb AP or a programer like MazdaEdit. There is a very evident changes in the pump outputs

The Racing Beat pump modification was stopped soon after implementation for an unknown reason....but likely it was a lot of work and irrelevant after the software programmers allowed us to modify it electronically

And the $1k+ cost ... I wouldn't be surprised if someone got into a limp mode issue with the swap and didn't understand the switch position adjustment procedure back in those days either

Ps: unfortunately there's a substantial amount of false info in this thread along with the good info

Duh - I give up what is AP and STU ?
 

OK, Please pardon my ignorance - what is an AP (is this the PCM, a kind of ECU)?
- what a STU project?
Thanks :confused:

Ap=accessport it is a tool that allows you to adjust settings in the cars computer.

Thanks Logalinipoo; STU?
 

Thanks logalinipoo; sometimes I get lost w/ the abbreviations. :rolleyes:

Any ideas about what is a STU? :dunno:

Dazed & Confused - set screw and position sensor adjustment
 

Sorry if I'm dense - I know the preferred method is to use a COBB, MazdaEdit, etc. to adjust the oil flow rate; maybe I missed this - but - anyone tried out / has comments about the suggestion that the set screw in the OMP/MOP be screwed in a bit, then the position sensor adjusted a similar bit counterclockwise? :sad:

Doesnt really work that way... the pump supplies more oil by increasing the movement of the pistons

The position switch tells the ECU where the stepper position is

STU is an autocross class

Thanks dennobre; some other questions
 

Thanks! :wavey:

Thanks dannobre, I (believe) I understand about how this all works. :rolleyes:

(1) Just to confirm I understand - So maybe the only way to physically adjust the pump would be to leave the position switch alone, leave the stepper motor in its original position, somehow take the curved toothed rack off without moving anything including its pivot point and the pinion gear, reinstall the rack a few teeth down, screw the set screw down to the new position, and close up?

Of course, to avoid the cost of a Cobb or MazdaEdit, the physical adjustment would just be a guess as to the oil flow change, such physical adjustment would be hard to do, and any mistake might screw up the OMP.

(2) I notice MazdaEdit is much less expensive than a Cobb. Can you change the oil flow rate of the OMP with MazdaEdit?

(3) What's the advantage of a Cobb versus MazdaEdit?

Thanks :worship:

Its going to cost you a lot more if you screw up the pump ;)

Cobb or ME they will also allow you to change a lot more parameters. .. so worth the cost IMO

Thanks again dannobre
 

I agree. I'll take your advice. Thanks for your help and expertise.

I've not used ME but have been trying to stay informed by following

https://www.rx8club.com/series-i-eng...daedit-239275/

1) The Cobb AP is an actual device that you receive, and used to upload or reflash the ECU map vs the ME which is software that is loaded on a laptop and the laptop is used to flash the ECU map.
(EDIT: The ME requires the use of the Tactrix http://www.tactrix.com/ which I believe is actually doing the heavy lifting of the ECU flashing)


2) The Cobb AP is a handy device that also allows data logging and general monitoring of your cars vitals vs the ME which I believe can do the same but would require you're laptop which is more awkward than the Cobb AP

3) The Cobb AP as a product seems to be more mature and less buggy vs the ME which still seems to be working out issues (this is purely speculative on my behave as I've never used ME but I know Brettus was having issues in the early days. Things by his account are better, but just how much he would have to say)

4) The Cobb AP is only a reflasher tool it has no ability on it's own to adjust anything, for that you need to use a piece of software called the Access Tuner Race (ATR) vs ME which is all in one

5) ATR software is ok by means of offering you enough tables to get things done (while still wanting more) and the tables are titled ok with some strangeness that isn't a very long learning curve. vs. ME which has access to a great deal more tables however the tables (my understanding) are not labelled which means you need to know what you're looking at or experiment slightly.

6) You can be ready to go using the Cobb for as little as 300 usd vs ME which I believe has a initial purchase price and a yearly software support fee.


If anyone using ME would like to correct me, please do. I'm rather curious about the exact differences as well.

Thanks WCS - Cobb vs MazdaEdit
 

^
Wow WCS - Great synopsis and information - just what I was looking for! Thank you and thank God for Canadians.

You get :score: and my :worship:.

Most of the bugs have been resolved - there are still the odd glitches which requires the user to just be persistent and not give up every time they get an error message. Not a biggie - for me anyway.

This was the case in the beginning - these days it isn't.
All the tables that are labelled in the Cobb are also labelled in M/E plus a few extras.


The support fee should not be necessary for anyone with an RX8 . It applies to those that buy the full pro version and are actively using the software to tune multiple models across the Mazda range including any new models as they come into service.

*One huge advantage with M/E (pro version only) is that you can tune multiple cars (so long as you can physically have access to it) with the same software . With Cobb - every car has to have it's own Accessport.

*Another huge advantage with M/E is that it is available for ALL model RX8s including S2 . Cobb can only be self tuned (via ATR) on North American RX8s (excluding S2).

* The logging software is better on M/E : Much easier to manipulate logs and view all the parameters visually as well as compare with previous logs.

* The monitoring software is better on M/E : You can monitor multiple parameters in real time and customise the gauges to suit . With the Cobb you just get one digital readout .

*One big drawback with M/E - it has virtually no resale value .
Cobb on the other hand ...does.

Nice ^^^^ Thanks Brett

Cobb vs MazdaEdit
 

^^^ Ditto. Great information, Brett! Covers all rest of the questions and more. :score:

(Between tha Canadians and New Zealanders, we got it covered!) ;)

Since I installed a Sohn adapter on my car, there is a recurrent fault : under high loads, high engine speeds, the car gets a CEL and defaults to a very slow fail mode. DTC is P1686 : OMP circuit low flow side problem.

I suspect one of the following as the root cause for the DTC :
- slight modification of the position switch position with regards to the stepper motor assy following the installation of the Sohn adapter
- bad contact in the position switch connector because the wiring is (or was) a bit stretched due to the thickness of the Sohn adapter
- faulty switch

I'll try to slightly rotate the position switch clockwise as a first step in fixing this issue.

Fabrice

System has no way of knowing that.

Yes, my bad.

What does it perceive to be a low flow side issue then? Is it not positioning that plunger correctly or something?

i would think the word "circuit" is a hint that it's not liking the electrical read out, it may just be a bad stepper motor sensor circuit. it's been a while since i've dug into it but is there a specific reading on a scan tool/data logger for omp position? stretched wires is a good clue, if only could could monitor the readout while jiggling the wires to see if it fluctuates...

I just spent an afternoon trying to unravel the mysteries of the omp. Upon doing this I realised this thread has a lot of incorrect information. I'm not sure if anyone else realised this back when the thread was done and I can't be bothered re-reading the whole thing so :

Correct

Incorrect .
The stepper motor adjusts the position of the cam . Thus allowing the brass sleeves to move up and down further as they are rotated. The needles don't move but effectively form the piston of the pump as the brass outer sleeve moves.Oil doesn't "get by", it enters the pump as the sleeve holes align with the pressurised engine oil holes and is then pumped into the exit holes by the sleeve action.
There are four pumps effectively . Two small ones tied together and two larger ones tied together (via the needles). These pumps are all connected in such a way that they provide equal flow to each exit hose. The smaller pump is activated sooner than the larger one to give the ecu a means of effectively and gradually increasing flow. The larger pump rotates (pumps) at almost twice the speed of the smaller one.



It also highlights a couple of potential issues with the Sohn adapter :
1/get air into the pump and it's highly likely it wont self prime.
2/even if there is no air the pump output is likely to be less than the stock setup . This is due to internal leakage that will exist in this type of pump.

Armed with the knowledge above... I believe I have worked out a cost effective way to increase the omp output by up to 50% whilst retaining a similar flow at low rpm/load.
Thread to come soon once tested.

once again, NICE.

beers :beer:

Here is a pic of components as they are (exploded) inside the omp .


https://cimg1.ibsrv.net/gimg/www.rx8...0d6849a3da.jpg

Isn't this why it is recommended that the Sohn reservoir be mounted at least 6" above OMP so as to take advantage of hydrostatic pressure?

Thinking it through some ... I don't think the difference in output will be significant, but it will always be less than stock . As stock you have a significant positive pressure on the inlet so any leakage will flow towards the engine vs the Sohn where there is next to nil pressure and any leakage will flow back towards the inlet.

Started a new thread on this :

https://www.rx8club.com/series-i-tec...cation-268559/

I believe the oil input location to the OMP on the front cover is not pressurized at all. It looks like an oil return, and a gravity one at that, and has a what looks to me like windage passage slow the flow down to eliminate air from the oil flow. I could be wrong, however, I didn't spend a lot of time understanding the front cover oil routes. Also, I had no problem with my Sohn self priming the pump after multiple disconnections of the feed line, and disassembly of the pump itself while on the car, and using a gravity feed only on another pump on a test stand with multiple times disassembly/reassembly.

Feel free to chime in if I am incorrect in any case. It would be nice to have an accurate record on the forum of how this thing works after only 15 years since the first one rolled off the assembly line.

Just checked this out .
Pressurised oil goes through hole at bottom left then comes into the chamber via that nozzle (approx. 1mm dia.) .There is also a hole that would relieve the pressure of oil heading to the nozzle. It would then fill up the chamber which looks like it's designed to take the air out of the oil as you mentioned. Oil then flows to the hole in the bottom of the chamber and off to the omp inlet. There is also a small hole approx. same size as the inlet, at the top of the chamber cover (not shown) which is probably there to to let the air out of the chamber .So .......... it looks like you are correct . The oil flows to the omp at a very low pressure .
Good to know that the pump does self prime . Looks like I was wrong on both counts ....

https://cimg4.ibsrv.net/gimg/www.rx8...b168036a69.jpg

Hopefully this thread isn't dead. Just picked up two 8s (for 900, a steal) and found that my '05 is smoking like a freight train. Disassembled OMP, tested POT, found that it's faulty. Supposedly the POT (potentiometer, i.e. the position sensor) is the same as a throttle position sensor on some other Mazdas, but I can't seem to find the right one. A little assistance? Go easy on me. I may have missed it in the 14 pages of this thread.

This thread is fantastic. I have been reading these pages for 12 months. Got myself an 05 project car after a bit of a break from rotors. The 8 has been going well other than a couple of codes to chase down. Mostly resolved or or just learned to deal with such as the pesky p0139.

Had a couple of p1688 codes that until now i have been able to clear ok. Now i have a rock solid code so i will attempt to clear by adjusting the mop. I suspect that the mop has forgotten its zero point to end up at this point. I will report back with results when i can.

Thanks to OP and all other posters for this thead that took a long time to chew through! Amazing.

Just a follow up. Had a mini win after adjusting MOP switch. After one failed attempt to set switch that instantly set off CEL. Happy spot was full travel towards firewall then forwards a whisker.

Reconnected neg terminal then winner winner. No more CEL. Did full heat Cycle while still on stands. Shut down then reset again via batt terminal to ensure it was not a fluke. All good so far and done about 6 full heat cycles and still no CEL. But still on stands so time will tell.

Will report back if any problems after decent load testing on road. Hope this helps someone else!

Nobody has ever found a replacement sensor switch that I’m aware of. If it goes bad the only known solution is to buy another MOP, either used or new. Seems kind of dumb, but perhaps Mazda considered the assembly too critical to be swapping sensors. Plenty of people have done it, but we don’t really know the true outcome.

Dragon,

Chances are you fixed it. But the OMP switch can also be bad. Some say its a potentiometer, but it isn't, its a switch.

I have mine adjusted on a knife edge apparently. When it is very hot here (over 110 approx) and I shut the engine down and then restart within 5-10 min, the sensor (switch) and the OMP assembly heat soaks enough that when I start again it goes into limp mode. If I shut down again, after running for about 30-45 seconds, the system cools down enough from the fans running, I am assuming, to restart and not go into limp mode. When its cooler outside, or if I let the car sit for longer than 15 min or so, I never have this trouble. Its a pretty fine adjustment apparently. I need to go under there again and fiddle with it a bit so this doesn't happen anymore, I doubt its a bad switch, its probably from my guesstimate initial adjustment.

Someone else on here is getting limp mode when warm and it might be the same thing. Kind of a guess, but I was thinking the same as you; switch might be right on the edge of adjustment. It could just be bad internally. Only one way to find out; try adjusting it.