Just bought RX-8 sight unseen, maybe not the best decision of my life...
 

Hi everyone, I'm new around here. I've recently bought a 2007 RX-8 GT / 6-Speed Manual at a car auction. I've wanted an RX-8 for a long time, but bidding on the auction was based purely on impulse and not rational though.

So, I take possession of it and have to replace the battery to get it started. When I start it, it is dumping white smoke from the exhaust and idles rough, frequently dying. The check engine light is on and has a P0300 Random Misfire code. So I search these forums and find that the likely culprit is a coolant leak, which will require an engine rebuild at best. Well, that isn't promising so now I'm trying to decide if keeping the car is worth it, or if I should just cut my losses.

Some of the threads of apparent coolant leaks as well as P0300 codes suggest changing the plugs/wires/coils as that is a big issue with this car. So in the mean time, I've changed the plugs/wires/coils. I also found a test for checking for a coolant leak by watching for bubbles in the coolant reservoir. When I did that, I didn't see any compression blowback in the coolant.

Changing the plugs/wires/coils helped a lot, but then I started getting codes P0506 "Idle Control System RPM Lower Than Expected", P0171 "System too Lean", and P0111 "Intake Air Tempurature Circuit Range/Performance Problem". Further searching indicates an issue with the MAF sensor, so I follow one of the DIY to clean the MAF sensor. After I clean it, I cleared the codes.

Now the car is low on power, but the white smoke is either gone or almost gone and overall the car seems to be improving. However, it still doesn't idle well. In the process of cleaning the MAF, I was going to clean the throttle body but I found a crack in the intake hose and I don't want to damage it further by removing it. I'm curious if that is likely the culprit of the running too lean code, and possibly the trouble idling.

I'm sure all of this has been answered before, but I've been reading through numerous threads and my brain is mush. Any insight is appreciated. Thanks.

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Heh, yes that would def cause issues... If you have a vacuum leak after the MAF sensor then the engine is pulling in more air than the MAF is reading and it will run lean. Don't stress too much too quick. Take it slow and fix what you can find, like this cracked intake. This could be the root cause for a lot of things. Check your local wrecking yard for a cheap replacement and see if it clears things up, then go from there. You could wind up with a pretty nice ride for just a cheap fix :)

Thanks slash,

I'm definitely taking it a bit at a time, chipping away at the faults and trying to remain optimistic.

I've searched the inventory of the local wrecking yards and none of them seem to have any RX-8s, at least none advertised. I may have to stop in and check myself. Either way, I think I may have sourced the part from the classifieds on here, assuming my offer is accepted.

Thanks again for the feedback.

Np. Do you have a way to check your fuel trims? If you have high positive fuel trims at idle this is an indicator of a vac leak, but I think that crack is pretty obvious. As a temporary fix to check things you could repair the crack with some RTV. If that fixes the idle then pick up a used cold air intake for cheap and be off and running!

A cold air intake doesn't eliminate that accordion rubber piece. Should be easy to find in a junkyard or eBay though. Definitely get it fixed, but I don't recommend rtv on the chance it comes loose and goes for a trip around your engine. Just replace the piece.

AEM does...

My Mazda Speed CAI replaced it as well, with a decent silicone piece that is more robust than that accordion piece. And the RTV was mentioned as a temporary fix just to check idle, not to drive around with. Of course also letting it cure completely before starting up. And don't squirt a bunch in to where it makes a big mess inside. Sheesh Loki now you got me putting in a bunch of common sense disclaimers... He mentioned he had already checked the local wrecking yards so was just trying to offer up a way to test without shelling out for parts. But agreed the best way would be to just replace it. Or get a cold air intake that comes with that section and let the modding adventure begin :)

I have the Torque app. I can use it to check the trims. However, I was using it already to check the temperature of the cat because of all the threads saying once coils/plugs/wires go, the cat isn't far behind, and I'd much rather replace the cat than the entire engine. :-)

I'll check the fuel soon to see what it is saying.

Thanks again for the suggestions.

Yeah.. Don't stress too much. Take one step at a time.
I had some serious idling issues with a tiny leak I could imagine how nasty your idle is with that crack lol. Get that piece replaced, even check with some rx8 owners in your area who are running aftermarket intakes, they may have stock pieces sitting arround.

All the best!

High fuel trims confirmed, though not surprising. I've bought a replacement accordion hose from another member and I'll see how it goes once that arrives.


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Happy to see you may have gotten a lucky break! Keep us updated, definitely looking forward to seeing if this turns out to be the ride you hoped.