AchillesGr

iTrader: (1)

Hi,
i have a mikuni newer OMP from a 97+fd and my car uses the older version since it is a 92 model.

i checked the resistance at the terminals per FSM and there are some diferences.
here is the diferences:

Vc-E 5.1 KOhm the mikuni and 1-2kohm the recomended
Vo-E 1.65 KOhm the mikuni and 0.4-12kohm the recomended
B1-S1-S3 33 Ohm the mikuni and 16-31ohm the recomended

do anyone of you guys use this nerer pump with the older cars?
i have a pfc instaled and i wonder if these mesurements can cause damage to the pfc .

are these pumps considered upgrade or these are only for specific ECU?i know that the car witch the OMP pulled of is a 97+ car and the ECU had diferent harnes than mines.

both the mikuni and the older pumps have the same connector but can i use it?

thanks!!

Supernaut

iTrader: (83)

There is alot of info on here about it...

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/omp-declassified-part-iii-mikuni-897507/

AchillesGr

iTrader: (1)

thanks,
i already read this . great info but i wonder if someone have expeirene or if there are any updates about this issue. the conclusions in this thread are not yet cleared.
there is an issue about the position sensor resistance out of range (resulting faulty signals to ecu?) and an isue about the smaller 0.8mm nozles compared to the older 2.00mm

thanks

Supernaut

iTrader: (83)

I'm running the mikuni on my car with the Sohn adapter. Everything has been aOK. That's the best I can offer. Also running PFC ECU. I had alot of questions before the install but in the end, I just jumped into it because everyone else seems to be having no problems with it. I'd post in the old thread though. This is kind of a waste to post here.

GL

RotorMotor

iTrader: (5)

How do you know it's working better (or more importantly, worse) than the stock unit?

The stock unit uses different oil injectors than the mikuni... did you upgraded the injectors as well?

Supernaut

iTrader: (83)

Good question. Never said it's working better. I didn't upgrade the injectors. I assumed at the very least more flow through the same injectors would be better. I asked about this to but it became more of a leap of faith. I've put alot of miles on the car and haven't had any problems so far but then again, I guess it's been modded enough where my experiences wouldn't count.

red_dragon

iTrader: (10)

I agree with this. I don't see how more flow through the same injectors could be worse. So even if we assume that it flows the same, it fits better with the RA adapter.

AchillesGr

iTrader: (1)

guys,
thank you all for the replies.
i am thinking to throw away all these pumps and go with premix.it seems that the oiling of the chamber is done better (not only a spot on the seals) and i will not have any wories if my oump fail over the time and riun the engine. i have a pfc instaled and there will be no indication that the pump is faild(if it will fail).

this small difference in the positioning sensor voltage wories me and i am afraid to install a pump that is 20 years old on a newe engine.

thanks!!!

ttmott

iTrader: (1)

I would think twice about not using the Mikuni pump; it's an excellent design. The position sensor is compatable with the Mazda ECM and as you are using a PFC you can taylor the oil injection - it's a win-win.

If you run the numbers on position sensor voltage there is essentially no real difference from the Denso unit. Additionally, the sensor output is not used for pump injection volume; it is used for failure detection; at least we know that with the PFC. Jury is still out on the factory ECU.

Regarding the injector hole sizes, it is the pump that determines oil volume not the hole size in the orifices; the pump is a positive displacement design. The issue with the pre 95 designs is there was a comapratively large open area at the orifices and the engine would scavange the oil from that area leaving it up to the pump to refill it. The pump volume could not maintain that area full of oil and in certain cases the engine was starved of lubrication. Mazda modified that design and plugged the area and made the orifice slightly smaller to correct the issue. The FD engines I have seen all have had the rubber plugs installed under the check valves reducing the open volume so somehow much of the issue was corrected.
The real benefit of the Mikuni is at low engine loads the oil flow is minimized but as load increases the oil inject rate is greater than the Denso.
So, unless you are running 100% competition with huge chamber pressures I would stay with the pump.