Cybaster

Hello everyone,
basically I was planning on getting a MegaSquirt to replace my ECU. From the megasquirt forum i notice that I would need to go premix because the MS does not have a output that can control the S5 OMP.

now some say its POSSIBLE to leave the stock ECU in, and just controlling the OMP. What I want to know is, what requirements in the ECU is needed to run the OMP? (ie rev, a/f ratio, manifold pressure, etc....) In theory, if i install the Megasquirt, and then plumb the lines for rev signal, a/f ratio ( just saying in theory if i need those info) in the stock ECU to operate the OMP, then it would work right?

Its a big project I know, but also I want to understand more how the OMP works,
and I know premixing is good, its better and cleaner burning, but for the sake of knowledge I want to see if i can get it working without premixing ( just for the sake of science) so please everyone, post what you know, (and not that premix is the way to go, cuz i know that. i just want to see if i can do this)

thanks
Jonathan

classicauto

iTrader: (3)

you could use a S4 MOP...

but Im not sure if all the mechanical components would swap over, I would assume it can be made to work (perhaps easier then making the electrical one operate after disabling most of the ECU's jobs) in the S5

Cybaster

I actually read up on that when I wanted a Wolf EMS, it seems converting the S5 OMP to S4 is a REALLY tough job, more so than figuring out the ECU wiring.

i would assume that if i got all the required parameters right and have them in the stock ECU, i can control the OMP (and cruse control for that matter)... but then of course, it really depends if my "theory" works or not

slpin

iTrader: (9)

i used the stock ECU to take care of the OMP.

let the ECU have all inputs, just dont allow it to fire the injectors
for ignition, same thing, except you use it to send signals to coil...

Cybaster

YES! thanks Slpin,

i'll PM u later to see what u did, but just to ask
did u split the signal into a standalone, like say a Y adapter of some sort? so all the air temp, oil pressure, coolant temp etc, connects to BOTH the ECU and the Stand alone?

and how well is that working for you? ^___^

one more thing i just thought about is that the ECU would want a signal from the MAF, if i use the MegaSquirt, the MAP sensor will be used and the MAF will be gone (yay!) so "if" the ECU needs that signal, then would i have to rig something up to fake the signal?

and i guess i want to try to run as LITTLE wiring into the stock ECU as possible ( just less confusion i guess )

so anyone else know what parameters the OMP needs in the stock ECU?

slpin

iTrader: (9)

I did a Y..

there isnt much you have to wire..
i.e. i used a new AIT sensor because it is on the intercooler piping, I think that is probably a better idea too. megasquirt or the ecu doesnt know oil press... coolant temp, i used that recalbibration tool, and i ran a NEW rpm signal from the leading coil... that one with the little plug on it.

it worked really well, along with my hks to4e setup and reamemiya fmic... but i ran out of money, so my piece of **** is stock now...

From my experience, the ECU doesnt really need the MAF for proper mop operation... i would take that out if you want. do keep the press sensor and the fullrange tps though. tap the fullrange tps (y adapter) for the throttle on megasquirt....