Bob_The_Normal

Noooooo....

Well, I've heard about it...

But I went to startup the car today thinking it'd be a lot easier after the idling and driving it did yesterday...

Took a while for it to start up (rebuild so that's SORT OF expected... it has about 2 hours runtime on it and not much load at all) .

When it did it revved and then stalled out about 2 seconds in.

Did it twice.

This could just be rebuild woes, but I pulled the codes and I found 2...

One was the radiator sensor, I knew about that one... had a little air in there, nothing serious... fixed now.

Second is Code 20, which says it's an OMP sensor... searching on it found a thread that said it's when the OMP goes bad and takes the ECU with it. I've read about that several times... didn't think it'd happen to me though... -_-; =(

Anyway, I haven't reset the ECU yet... I have another ECU so I guess that's not a big problem.

But the problem is the OMP... what's going on with it? Is it possible it's not fried?

--Gary

Parastie

If the OMP starts throwing codes, you'll have to replace it. I don't know of anyone who's repaired them, but you can probably pull one from a junkyard or off of the For Sale section.

raising arizona

Thats what happened to me. I had a code 27 which is also an OMP and it took out my ECU. Chris Ott @ rx7.com told me this is what happens.. Not to all, but to most per his experience. I said enough of the OEM ecu, sold the good sensors and bought a Wolf EMS... Its a little work getting it wired, but its so much simpler...

raising arizona

BTW I have an S5 OMP if you need one.. My friend had a good one and I stoled his and now I run a premix so I don't need anything..

BlaCkPlaGUE

A damn good reason to pre-mix with the s5's. I can't believe that they used an electric omp instead of the good old mechanical one. I don't think I've heard of anyone with an S4 omp having it fail, its extremley rare.

F1blueRx7

iTrader: (5)

Yeah it only does that on S5's. I plan on teh premix with my rebuild.

Bob_The_Normal

Yeah the electrical combined with the limp mode BS... *sigh*

Hopefully this is why my car is starting and then falling FLAT on its face... I don't know though.

I pulled the ECU and took it apart, I don't see any fried capacitors, resistors... or any burn marks, scorching.... nothing...

Think my ECU is still good?

EDIT: Oh btw I think I just figured out why my OMP "magically" failed so suddenly.

The first time I started it up, the OMP wires (so conveniently run right next to the belts btw, thanks mazda) got caught... I looked at them, zip tied them and thought nothing of it...

But now I went and took a lot closer look... and it must have caught harder than I thought, it tore a hole throw one of the wire casings... and if my fingers feel right, a little of the wire with it... whiich means that OMP is probably still good, but needs a little wire splicing work.

I don't really want to take chances though, I want to get this running by this Friday (I have a plan to go somewhere long distance to put miles on it!) so I'm going to jack up, pull this OMP off... probably tomorrow... and hopefully tomorrow or the next day I'lll have another OMP... glad I live in SoCal where there's a million people with FC parts.

Anyone want to confirm that its falling on its face due to the OMP code though?

--Gary

George84

When mine went out I got a used one from Rotary Resurrection; OMP and NA ECU $250 shipped. It turned out I did not need the ECU though, he also has just the electric OMP for $150 shipped (tested per FSM guidelines and/or on a running s5 car). Thats one place I know you can get a good one at.

Tierce

yes a dead omp will make the car fall flat on its face. i was bored and decided to see how it did this. i hooked up a multimeter to my o2 sensor and drove around. when limp mode popped up the car fuel cut and it ran so lean the motor basically couldn't run with any throttle. unfortunately you have to have an OMP with the stock ecu or you'll get limp mode no matter what. if you don't mind premix, get a working omp, plug it into the wiring harness and put it off in a safe area of your engine bay away from the vibration and heat of the engine. premix and the car won't be able to tell the difference.

EJayCe996

Banzairacing.net has used OMPs for $50 a pop elec, and $30 mechanical.

Bob_The_Normal

Yeah I know about that, that's pretty much what I'm going to do... get some blockoff plates and bolt that sucker to my firewall... premix... if I ever sell it, just bolt it back on.

EDIT: And I just realized the sad part to that is the 100$ I spent on steel braided oil lines that will now not even get used. ;(

--Gary

BlaCkPlaGUE

Yea thats one reason why I dont want to go premix, I got the SS lines as well and they're nice.

Just for kicks I checked out the price of the S5 OMP. The S4 is all mechanical and around 300$ from what I remembered, I figured the S5 would be cheaper since its electrical. Dead wrong.

1200$USD for a new S5 omp.

Mazda is seriously high to think they can ever get that much. I'd love to have an s5 omp just to take it apart and see what 1200$ gets you. I have a feeling that all it consists of is the exact same setup as the s4, but with an electrical motor or some ****. what a damn waste..

Bob_The_Normal

Alright as an update.

Seeing that an OMP is expensive... and such... I decided to try fixing first.

I spliced the wires and fixed the damaged part... no more code, car runs great. Drives awesome... ;D I broke rear traction at only 3k rpms in 2nd gear! (on a patch of dirt in the road.. ahhaha ;P)

Thanks everyone. =)

I guess now we know if your OMP gets shorted or disconnected, it'll throw a code 20.

--Gary