NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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I have searched and searched and read up on alot, but I havent found answers to a few of my problems so...

I just bought a 1985 Rx7, 195k miles, RB intake with holley 4 barrel and RB exhaust, and the rats nest delete. My questions are as follows:

There is a short tube running out the side of my oil filler tube that has nothing going to/ from it. What is this?

My OMP is leaky, and i dont think the previous owner was smart ebough to know it, would blocking it off and premixing be the best option?

This car starts on the first crank, but idles very roughly at 1500 rpm, then dies. after that you have to give it gas to start it, and after maybe 30 seconds of keeping it running with your foot it doesnt die, and when you take of there is a dead spot in every gear, usually when you are a little, not much but a little, harder on the throttle than normal driving... and the car backfires, very very very loudly after about 5 seconds after i turn the engine off if i have been running it for more than 10 minutes.

I traded my Daily for this, and I honestly dont think its a bad car but this stuff worries me, as i am a rotary virgin. I am deeply in love already, but I just dont know what to do. Thanks everyone in advanced for the help

Can you take a picture of that short tube? one each from all three sides.

If the OMP is developing issues, blocking it off and do premix would be a good route to go. To find a good replacement unit is not easy, and new ones can cost you an arm/leg.

Have you checked things such as the TPS, fuel injectors, spark plugs, and some of the regular stuff?

Also, what else has been done to the car?

racing beat intake and headers, rats nest taken off, and its carberated. it has a holley 4 barrel on it. I am replacing the spark plugs as i type ( came in to check email) hoping this will fix it, an I am going to clean the carb out later today. It has brand new NGK spark plugs in it, and it is supposed to have new plugs. thats what the p/o told me.

Tube from oil filler neck is a vent. Many people put a small filter on there (found at most auto parts stores) to keep stuff out of the engine, and so it can continue to vent as needed. It originally pipes into the emissions system, I'm pretty sure.

omp: Block it (and oil metering nozzles) off and premix, or ensure that it's running as it should (replace gasket, measure oil output through tubes, and replace tubes if necessary, as they're usually brittle and break).

The rest sounds like carb/idle tuning issues (which I know nothing about).

Ok, my dad is the carb king so ill let him look at it, but I replaced my spark plugs and OMFG it helped. now just minor hesitation when revving her up but no more sputtering and stalling. Thanks for the input on the OMP because its leaking a pretty good bit. can I just seal it up with some like seal all or something for the time being and premix anyways, so im not really loosing any but im sure i get oil in there?

And I just want to say, thanks for the non biased help here. I traded a VW for this car and on the VW forums everyones got their head stuck in their ass, and in a honda forum everybody argues and calls each others cars stupid ricers, when in reality they all still drive shitty hondas. So thanks my rotary brothers for helping a new guy out.

An OMP blockoff plate is $4.84 from mazdatrix. I would just order that as soon as possible.

I wouldn't want to use any kind of sealant like that, in case some of it gets into the metering lines somehow and makes its way to your combustion chamber. I don't even know if that would happen, but I wouldn't risk it.

Ok thanks a million guys :thumbsup:

OK well the carb was a little mis tuned but now im still having the backfire issue. How can I fix this?!

Carb tuning is my specialty. I can help you more than anybody else. I know how to make them run smooth for the street. I PM you my number give me a call. my help is free.