Hi guys, this is my first post here, but I've been lurking since I got my RX8 in June. I've got a 2004 RX8 with 596xx miles on it. I bought it from a guy who tunes rotaries, (He had 2 built RX-7s behind his house and another 8), it ran great for about 2 weeks after I got it, and started dying. I'm not sure if that's a crazy coincidence or if he did something I've never heard of to temporarily fix it.

Sometimes it will idle when it's warm, but typically it will shoot up to around 1500 RPMs then fall back down, shoot back up, and repeat. Soon enough it will go down too far and die. It's like the ECU is over-correcting itself and the fuel flow is cutting off, it hasn't ever flooded while doing it.

On to my efforts, it has a new engine courtesy of Mazda at 593xx miles, a gutted cat, a new Bosch front O2 sensor (post-gutted cat, pre-new engine). The dealership told me that the muffler was clogged, so I took it off entirely for a couple of days, no change. I cleaned the fuel filter, MAF, accordion hose, ESS, and the throttle body. I've been trying to avoid the SSV as I haven't had the MIAC sound, but I do have a brief hesitation in 2nd gear around 4600-5000 RPM. Of course the new engine has 4 new plugs and coils. The plug wires are performance ones put in around April. I ran Seafoam through everything about a week before engine replacement.

I called the dealership back after getting the new engine and taking off the muffler, they told me that the only thing that stood out to them was the throttle body looked like it was from a junkyard, but after I have cleaned, polished, and sanded it for more airflow, there's no change other than slightly improved throttle response (It used to hesitate on takeoff, not anymore). With the air intake off and the key switched to on, it doesn't visually seem to have any issues. Still dying, though. With the dealership I went to, they were good people, but tried to get their money for the throttle body and muffler, I would think if the SSV or motor mounts were having a problem they would have tried to pursue that. They also told me that the new engine compression tested well and was verified good before it went to me when I asked.

I'm honestly at a complete loss for what to do, I love the RX8, but I haven't been able to drive it without revving it at idle and working on it multiple times a week since I got the car in June. If anyone has any ideas on what I should do I would love the help.

On to my other problems, my power-steering went out in July, I hard-wired the connections under my air-box and put in a longer overflow hose, still no change. I couldn't find a good way to get to the other connections, though. My air-bag light is on for the passenger-side curtain, not sure how to fix that, I tried the connections under the seats last time I vacuumed, no help. I also have an evap leak and P2401 evap pump low voltage code, though the mechanic said my fuel system looked okay. The car doesn't like to take gas, it takes me about 10 minutes to put in 5 gallons, the bottom of the tank looks as if it could have been ditched, but I didn't see any damage to the tank internally when I had the pump out. If anyone could give me help with that I'd appreciate it.

Yeah, I know this post is too long and over-done, but I really have no idea what to do after searching this forum so many times, so I thought maybe making my own thread would be better. I love the car, I just wish it would run. I appreciate you guys, and hope to get this fixed soon. Thanks, Seth.

 

Also, I get a white-smoke out of the exhaust, not Sea-Foam thick, but more than I ever remember seeing before the new engine, if that helps anyone. I haven't done any pre-mixing or fuel treatment since I got the new engine, and have ran through 3-4 tanks since then.

 

Ummmm wow, crazy stuff in here ..

This puts up a red flag in my mind right away. Have you tried contacting him about your issues?

This sounds like a vacuum leak to me, or bad Maf, you said you replaced the Front O2 sensor. Are you sure it was the front O2 sensor and not the rear O2 sensor. Are you sure you replaced it with the correct O2 sensor model?

A clogged muffler? OMG, I'm glad you're not buying that.

How did you clean the fuel filter? Never-mind.

[quote=Seth749;4365696]I've been trying to avoid the SSV as I haven't had the MIAC sound,

SSV has nothing to do with MIAC, it's caused by a issue in the coolant lines going the cabin heater. The fix was something to do with the heater hose.
Unless there has been some new development. I've not been following the MIAC as I don't have that issue in my 2005 MT.

Sort of normal but doesn't mean the SSV isn't sticking. The SSV's don't open at a predetermined RPM. They are load based and won't open until the P2 fuel injectors come online (or is the Secondary Injectors .. mmm can't remember I'm going to have to check)

Hold the PHONE! Seafoamed everything? Ok you need to expand on this.

Ummm you don't think that this might also have a negative impact on the idle quality?


[quote=Seth749;4365696]
On to my other problems, my power-steering went out in July, I hard-wired the connections under my air-box and put in a longer overflow hose, still no change.

I couldn't find a good way to get to the other connections, though.

My air-bag light is on for the passenger-side curtain, not sure how to fix that, I tried the connections under the seats last time I vacuumed, no help.


Don't think this has anything to do with the fuel system. Unless they think its a gas tank cap.

There are two side to the gas tank. I don't believe you can visually see the other side from where you remove the fuel pump. (Can't remember to be honest).
You may have pinched the hose the crosses over to the other half when you re-installed the pump.

 

This is not a good sign.

White smoke is typically an internal coolant leak which is getting burned off on the combustion cycle.

 

Wow this is long ..


Focus on a single item.
1) Stop spending more on this car until you discover what is wrong, and boy do you seem to have a list of issues.
2) Get the EVAP leak fixed.
3) Inspect for vacuum leaks, there are lots of good methods have a look around the forum
4) Check your fuel pump installation, I don't know maybe the EVAP might be caused by this.
5) Check that the plug leads are on correctly
6) Has someone actually done a fuel pressure test?

edit: And you don't have a Catalytic Efficiency cel due to running catless? You would have one of the rare RX8's that don't get that cel. Unless, that Rotary expert has put a custom tune in the ECU to suppress the cell.
That is another thing I would suspect.

 

A few weeks after I got the car when it was still running fine I put the paper with his number on it up, and I've since lost it. The O2 sensor was the Bosch front O2 O'Reilys had in their system for my RX8, I'll get the model # off the box. I was getting a CEL for it, which went away after install. I installed it myself, and checked it for any obvious fouling when I did a clutch swap in August and had the midpipe off. My intake has one screen removed, but putting it back in didn't help. I would get a CEL for a bad MAF, right? I Sea- Foamed per the Youtube video using vacuum line and the ports on the intake manifold with slightly less than they used, and put a few ounces in my gas tank before my next fill up. I didn't do much with the throttle body, I had a really heavy bit of oil residue that I cleaned with carb and choke cleaner and sanded with 400 grit then 1200 grit until it was gone. I didn't alter the dimensions or anything, just particularly hard to remove oil buildup. Plug leads have been checked several times, evaps are both pre-fuel pump removal. It has Mazda's newest flashes from the dealership, and they didn't even know it was running with a gutted cat until I said something. No fuel pressure test done AFAIK. I'll try to call Mazda about the white smoke today and follow up on some vacuum stuff. Thanks for taking the time to write all that, bud.

 

Let me know if / when you get it fixed and how you did it. I had my engine rebuilt and ported in the process and have "issues" with idle and low rpm operation. My accessport comes in tomorrow and am hoping that will take car of it. These issues include perfect idling for 9 sec, then it dying as if someone cut the fuel supply. Low operation issues include attempting to hold engine at 2k rpm and having it vary between 1k and 2.25k. This hunting happens when trying to hold at any rpm below 2k.
Good luck finding out what's wrong with yours.

 

was about to say MAF, then reread.

White smoke is scary. Pressure test the cooling system. That will rule out, or validate a leak. Are you losing coolant?

Also, go through all of the engine grounds. One or more might be loose. Tighten them, or better yet put a stainless start washer under each one. There are 2 on the motor, one on each fender, and one under the air box.

Does it have a catch can? Is it vented, to atmosphere, or tied back into the tube? Did you get all the tubes sorted back out after you cleaned everything. I agree with wcs, sound like mother of all vacuum leaks. Did it run find until, say, the batter died or you changed the battery? ECU might have been able to hand old configuration, but not new one. Try starting it cold, and letting it idle until it warms up. Does it hunt and search for idle, or settle down. If you have a leak, or something weird for a tune, or a big vacuum leak, or anything else wrong, it will take a bit to learn to idle again.

Do not assume new plugs and coils with new engine unless you have seen them.

Did you seafoam the new engine or the old one? If the new one, are you positive the vacuum lines or caps went back on right?

When it is running, look at the $100 thread in my signature for what to do with an older 8.

 

If you've gotten oil deposits on the throttle body, you probably got them on the MAF wire too. Clean that for sure. Is the fuel line sock for the pickup in the tank clean? If you have to fill the gas tank that slowly, likely the rollover flapper valve is mostly closed. There was a TSB on that - I think the cure was to replace the tank.

 

Okay, I'm sorry to necro this thread, but it is still relevant, so I hope the mods will forgive me. I've been swamped with school and work and have had the 8 in the shop to save some money on insurance. I still run it up and down a few times a week to keep the engine from sitting, but it was on the back burner for a while.

I'm still thinking it might be the purge solenoid, as I'm getting a 443, but I'm not sure. I'm getting 2.5V to it and it has about 23 ohms of resistance in itself, that seems off to me, coming from an electronics background, but I really don't know enough about solenoids to know if that's out of the ordinary. I'm also concerned it could be my charcoal canister is filled with fuel, but I don't know how to check that without dropping my rear differential. Cleaning and adding washers to the grounds didn't change much. I also have a "Whooshing/sucking" sound when I take my gas cap off, which I've heard is associated with a sticking purge valve.

I think I fixed the not taking fuel part, I believe it was the flap sticking, but it slowly went away after I started premixing. A few weeks later it would take gas full speed. The white smoke settled down with the new engine, I believe what's left is just because I'm running so rich, (My LTFT was at like 14.x when the mechanic I bought the car from came to my house to help me.)

I'm also hearing a sucking sound from around the throttle body that I just noticed tonight, I think it might be my big vacuum link, but I'm not sure how to locate it. The VFAD lines are good, as is the one across the top of the engine by the purge valve, they're both drawing good vacuum. My elbow connections on the accordion look okay, one is brand new. Are there any lines I'm missing? Otherwise, is it safe to use starting fluid to check or will it hurt the rubber lines?

Thanks in advance guys, I can tell I'm close to fixing this, I'd appreciate if someone could check their purge valve's electrical properties before I spring $100 for a new one.

 

EDIT: Sorry to rebump this thread. I didn't realize it until after I posted.

Why are you going to call Mazda? You'll get just as much, actually probably more, help here. Hell, someone already commented on the fact that there's a high probability of cooling seal failure.

I feel like you've got about 10 different issues and you need to address them one at a time.

 

I'm going to assume you don't have access to a smoke machine, so grab a can of brake parts cleaner and spray around the throttle body with the engine running. If it begins to stall, then you've found a vacuum leak which allowed the parts cleaner to enter the manifold.

 

I'll check that tonight, can a regular shop with a smoke machine check a rotary? I know that the guy I bought my car from can, but his shop is almost 2 hours from my house. As some extra information, the car idles perfectly for about 4 minutes after starting cold, then starts to hunt as it warms up. Newest Mazda flashes were put in with the new engine.

 

So it idles fine until the RPM drop to normal idle level (850)?
Then I'd suspect MAF, since that is the time the car starts taking into account measured airflow.

You can run the first few minutes even without an MAF plugged in.

To confirm, get an OBD reader and log MAF readings.

 

Just skimmed the inspection quickly.
Looks like you're testing just for continuity and air flow

MazdaRX8_04-05_PurgeSolenoidInspect.pdf

 

It might just be a bad MAF. I unplugged it and it will idle all night, but if I plug it back in it goes back to the same old thing. It drives without near as much pep, but it doesn't die. I guess it's limp mode. I am still getting a 441, 442, 446, and 2401. Any ideas as to what would cause that combination?

 

Replace your MAF Sensor, then.

If I remember correctly, at least the first three of the codes are related to your evap system, so the first step is to check the exact codes (there is a thread here) and start checking for a leak (most probable cause).

 

Can vaccum leak cause miac throughout rpm range from cold to warm, stalling when warm and hard start when warm? Also a hunting idle when up to full warm temp?

 

I have a 2004 rx8 and when idling its very low. I put a/c on and it wants to die'what I did was turned up the idle and reset the throttle.

 

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