I've been searching and reading up on the failure of the OMP. In a car that I'm thinking about buying, it is believe to have an OMP failure which throws it into the limp home mode. I have not been able to find any guidelines on swapping out the omp with a new one. Where would I find either a writeup (hopefully with pictures) of how to replace this device? Where is the omp/how do I find it, and have we figured out a way to just bypass the omp and use premix instead? I figure, if I'm gonna purchase a new omp, I might as well install it correctly. Thank you very much.

 

there is currently no way to bypass the omp without your ecu going into limp mode (unless you go with a standalone ecu). my omp died and i connected another used one that i acquired from a friend...but did not install it. i just zip tied it in the engine bay away from heat and vibration so it wouldn't die. i now premix. there have been people speculating on how to build a "black box" that could connect to the omp spots on the harness and fool the ecu into thinking the omp is there, but no one to my knowledge has done this yet. as for replacing the omp itself, it is below the water pump area on the front of the engine. it's a pain to get at unless you remove the radiator fan/shroud.

 

ok, so you're saying, that all I really have to do is unhook the omp from the ecu, and hook the ecu to the other omp and just tie it down somewhere safe and it should be fine? I have no problem with premixing, in fact I hear it's better anyways.

 

Just to add to what Bingo boy said.

The omp is also below the radiator hose that goes into the bottem neck of the waterpump housing. It is attached to the front cover.

To make things easy you would have to remove the airpump and the lower radiator hose. Not to say bingo's wrong but, after removing those things you'll be able to get to the omp without removing the shroud and fan, plus its easier this way.

The biggest note of caution is that you would have to be very careful discontecting the injector lines' banjobolts, before removing the bolts that hold the OMP to the front cover. The injector lines are very very brittle after being exposed to the heat of the engine compartment for years. If you're not very careful and patient you'll be replacing those lines.

 

well, couldn't I just leave the old omp intact, considering if it's not leaking or working at all, then all I have to do is transfer the ecu wires to the new omp.

 

well, couldn't I just leave the old omp intact, considering if it's not leaking or working at all, then all I have to do is transfer the ecu wires to the new omp.


Yeah.....But, in my opinion (and I've owned 4 fc's) premix isn't a good idea. Aaron Cake mectioned just the other day that the motors he has taken apart that are premixed are more worn/damaged then OMP lubbed ones. Aaron does this on a regular basis.

Simply put, The FC rotary is not a lawnmower or chainsaw...

I won't dog on it too much, cause there's alot of forum members who love it. To each his own....

IMHO, I say just replace the omp if you're going to go through all that trouble anway.

Airpump 2 bolts. Omp 8 bolts radiator hose 2 clamps.

 

you will find people who swear by both sides of the premix issue. i premix because my omp died, and because i know people who have been around working on and around rotaries for many many years and do it too (street cars and race as well), not to say that the people who like the omp aren't knowledgable. i choose to premix, and their arguments one way or another aren't going to change my mind so i don't argue the points.

i have a friend who has started premixing even though his omp is still working. he broke a couple of the omp lines, so what we did is we got bolts and replaced the oil injectors and banjo bolts with them. if i remember correclty the oil injectors are m10x1.25 pitch and the banjo's on the omp are m8x1.25. be sure to cut the oil injector bolts to the right size so they don't stick out on the inside. we locktighted bolts in with washers and lock washers on both ends rather than having to buy a new set of lines, and he was premixing already so it wasn't much of an extra burden. you will also want to plug the vac lines on the spider under the intake manifold that run to the oil injectors if you do something like this.

as for me saying that you could get at the omp without the fan/shroud, i was basing that off of a car i've worked on that has an E-fan. i didn't think to take other things out of the way since the omp is right there to work on without the shroud/fan so do whatever works for you.

oh and as for my zip tying a working omp on the side of my engine bay, i would have replaced the working one, but well i killed one omp already and heat/vibration is what kills electronics so i figured that the further i could get it away from the block the better since i was going to be premixing anyway.