OMP issues
 

Hello,

First I want to say I am new to the site so be easy on me. However about six months ago I bought a 2004 Mazda RX8 with about 95,XXX miles. Let me tell you I fell in love with this car! Then the engine gave out on me. Blow a seal I guess. Not to familiar with the Rotary engine I decide it would be best if I just purchased a new one from Mazda rather than try to rebuild. This went very smoothly in and out, all back together very nicely. I started it up and it ran fantastic for about 10 seconds. Then the check engine light came on and the car went into limp mode having absolutely no power. I checked the code and I believe it was P1688 (Oil Metering Pump). I brought it to Mazda they looked it all over and said the engine was installed properly and they couldn't tell me what it is. Their guess was the OMP was bad, (on the papers they said the pump had internal pulse?) throwing it into limp mode. I have now Purchased a new pump and am waiting on it, it's on back order. I was just wondering if anyone had any similar issues or an idea to fix it.

Also if i clean the code by disconnecting the battery or with the scanner. It will start and run great for about 10 seconds again then on comes the CEL and the OMP code and limp mode kicks in.

i would check to make sure that the pump is plugged in and the connector is clean.

if the CEL comes on after 10 seconds, it fails the first time the ECU checks.

Check the connections.....if they are all OK..then it is likely the positioning switch

If you remove the switch...and manually turn the pump clockwise till it stops...reinstall the switch..and turn it slightly counterclockwise a little bit until you feel it take up the slack ( about 1/2 way into the adjustment)...then reset the ECU and try and see if it works

Just to clarify, you didn't buy a new engine from Mazda, you bought a remanufactured one. Did you buy a new OMP, too? Those can be quite pricey.

Yea the engine is re manufactured. But Mazda actually checked out all the wiring and I made sure there was power to the pump. I already tried to adjust it all. Looked around on this site for every suggestion that was stated about the adjusting. I did buy a new one, and yes it did hurt the wallet. I thought about buying one used off ebay or whatever but i didn't want to blow money on someone else junk.

Thanks for all the help so far. I hear of people bypassing the pump? How does that work? I understand premixing but it doesn't throw codes then?

Mazda service people won't adjust the switch because there is no official Mazda service procedure for it. There is a thread dedicated to the subject here somewhere

Could it be?

https://www.rx8club.com/major-horsep...tments-120276/

Yea they try to make you buy a new pump for like 1,600 bones. I found the thread at one time and adjusted it. Didn't work. I could have messed up tho

Bought the new pump. Runs great!