Anyone get the S5 OMP to work with the squirt 3? Thinking about going megasquirt on my latest project since the n370 ecu's seem to be in short supply, and would like to know if the OMP system can be left in place, or if there are no other options than going premix..

Let me know what ya'll think

 

just to let you know, you can get an n374 ECU and send it off to Rtek for an Rtek 2.1

 

Yea I'm also thinking about going that route, although I'm not familiar with the rtek system.. time to read up. Will that "fix" the n374/USDM harness issue?

The megasquirt has always interested me though, so I definitely wouldn't mind going standalone just to say I did it.. I very well may go with the rtek in the end though. Thanks for the recommendation.

 

I have no firsthand experience but I believe the answer to that is yes.

 

As far as I know, nobody's built the proper stepper motor controller into the Megasquirt.

Check out the Megasquirt section of the standalone forum here on the RX-7 club. I used to build Plug and Play units with Ken (muythaibxr).

He's more involved with the Development aspect now and works with the producers of the units; he'd know better.


What I do know and can say for 100% certainty is that someone has built an aftermarket controller that will both operate the stepper motor in the OMP and read the sensor.
http://eomp.info/

The older Megasquirt (MS 1 on a V2.2 or V3.0 board) was pretty limited and I think we used up most of the input/outputs on ignition control, reading the CAS, Controlling the BAC valve, controlling 6 ports and the VDI on the S5... The MS2 and MS3 processors might be able to interface with a controller like what I've shown above to provide OMP control.

 

The eomp looks pretty cool... Seems like it could be used in conjunction with the MS so that i don't have to ditch the omp, and I won't have to rack my brain for weeks on how to reverse engineer the system.. Hell I might pick one up just to play with it.. Thanks Pele!

Do you have any experience with the EOMP?

 

None specifically, no...

I have pulled one apart though. It's your standard stepper motor like on an old floppy disk drive. It's got an encoder on it to determine position.

It shouldn't be too hard to control, provided the right software on the MS.

My solution, back when I was gonna build up an S5 engine was to put an S4 front cover on.

 

yeah its a simple stepper motor, but the trick is the position sensor. there is a separate 0-5V position sensor so the ecu knows where the MOP is, and then if it doesn't work the ECU can go into a limp home.

if you're going to run the MOP, the feedback part is kind of KEY, if something DOES go wrong it needs to turn on a light, or the ecu should limit power or something

 

Ok.. I was actually referring to the eomp controller at http://eomp.info/ .. That info is very helpful though if I decided to give it a shot the hard way. Thanks

 

I'm considering ordering one and reverse engineering it.

I like the idea of the electronic OMP because you can have it inject based on RPM rather than throttle position.

I still have to study the reliability of it. What causes it to kill the factory S5 ECU when it dies? What are its common failure modes?

 

there is a HARNESS ground that fails, and when it does the ecu tries to ground everything thru the metering pump, which fries everything

 

I have an N370 I will ship you for $150 brotato.

 

PM Sent.. Thanks!

Still alot of good info in this thread.. One of these days I might lock myself in my garage for a week with a case of beer and try to reverse engineer the OMP, and then post my results here on how to control it.

Thanks all

 

goodluck ,, the code used has several million permutations,, the rest of it open source stuff any-hows

jason makes them for a reasonable price,, though shipping is from far away for just about everybody reading
( nowhere is close to WA Australia )

they can cover a basic need or a complex one if you wish your ECU to drive it with complex mapping
they allow the user to offset trim adjust the flow for any extra lube needs if they have dry fuel or aftermarket seals
( ie it will pump more at minimum flows and achieve 100% flow at less load if desired )
they have a user adjustable loop rate to make them fast or lazy in response rate
they have auto calibrate modes and will work in two tune modes to allow use with early style and also the later FD and rx8 EOMPs



the latest versions have ditched the 3 d mapping to make the unit more user friendly and capable for use with ECU aux out , TPS , and even unused map sensors for those with no ECU ( LPG mixer users )

as always was,, the OMP itself has RPM "mapping" as a mechanical function of its drive gear anyhows
( ie the rpm quotient of delivery curve always has been a mechanical variable )

if you wish to map it for RPM V load then you can use the aux out function on decent ECU's to write a map for it

the earth thing is a good possibility
,, also the motor at the EOMP is prone to poling one of its step phases and causes the motor to jam
alternately the feedback sensor can get covered in oil and effect the linearity of its response
,, and amount to dead spots and full signals at part strokes

similarly the plugs connections at the thermoneck can be effected by heat and corrosion and make for some trouble with the feedback loop causing hunting that may effect motor pole life

 

I forgot that the mechanical pump was also eccentric shaft driven.

In the interest of keeping things simple and reliable, I will be going back to my original plan of using an S4 front cover with a mechanical pump.