Hello!

so I just recently bought an 1999 rx7 FC GXL with about 150k miles on it. When I bought the car. The owner warned me that there had been a check engine light coming on when giving the car a lot of gas. And the car would go into what I call a “limp mode” where it’ll start to choke out when giving it a lot of power. The owner before me had put in a lot of work to this car, replacing the o2 sensor, radiator, struts, pretty much everything in this engine bay has been replaced or worked on other than the OMP and rotaries themselves because the shop apparently wouldn’t touch them since they didn’t know too much about it.
I put some work into the car and also some premix to help the car out a bit and discovered that it can run fine sometimes! With a little bit of warming up and if the check engine comes up, pull over turn it off clear the codes. It runs perfect. But it’s starting to eat at me whether or not I should be premixing or how much premix I should even put into the car since I’m not entirely sure If my omp pump is working correctly… any advice? Or recommendations as to how much premix I should safely put into my tank? Thank you- there is screen shots and descriptions of the codes told my previous owner^

 

welcome to the board.

unfortunately, premixing will not solve the issue with the ECU. you are going to have to deal with it one way or another.

here are some links:

FSM: Foxed.ca

https://www.rx7club.com/2nd-generati...p-mode-195733/

 

I'm not sure if there is a language barrier happening here but, are you trying to ask which is better? The OMP or premixing, and what experience the poster above you has with premixing vs.using the factory OMP? Also which one results in better engine life?

If so here are my thoughts from what I've read mostly as, since I have series 5 premixing only isn't currently and option. More on that later. Premixing an oil that was meant to be mixed with gas and burned in the combustion chamber is always going to be better than using the same motor oil that's being used for engine lubrication. Partly because as the oil gets used and dirty you're now also burning the contaminants as well. How much that effects engine life I don't know. Premixing a two-stoke oil in theory should be better for engine life. The con of course is you have to do it at every fill up which is why Mazda did it the way they did. The average car owner wouldn't be willing or may not remember to do it.

As for the original poster. Premixing alone isn't an option as the factory ECU on a S5 won't allow the engine to run properly without the OMP connected. If it doesn't see the OMP connected and also receives the signals it expects to see from it, it puts the car in limp mode which is what they are experiencing in the original post. The OMP could be bad or there could be a problem with the wiring to between it and the ECU. Either way the problem will need to be corrected for the car to run properly. Once repaired they can premix some additional 2-stroke oil or get the Rotary Aviation OMP adapter that allows you to inject 2-stroke oil supplied from a separate tank into the engine. I've been wanting to do this but just never have.

 

Not really. It depends on what kind of car you have. with a S4 you can just delete it and premix only. I can't remember the ratio. I think 100:1. With a S5 if you install the rotary Aviation kit you don't need to pre-mix as 2-stroke oil is supplied from a separate tank. The SOHN adapter is for an Rx-8, but same as the S5 Rx-7 oil comes from the seperate tank. If you want to pre-mix in addition to the OMP I think the ration is 400:1.

Also are you even a real person? Most of your posts are word salad that has almost nothing to do with the thread they are posted in. This thread is the closest you've came to being on topic.

 

^^Had to ban that user. Spammy links in their responses.