Nopstnz8

iTrader: (6)

So over the past week I've been having a very odd power loss problem toward the top of the powerband in my '04 Touring AT Rx8 (4-Port Motor). With a rebuilt engine 20k miles ago (when the car hit 40k miles) that was religiously broken in and has never given me a problem since.

My car recently hit 60k (currently at 62k), and I have just completed the entire 60k service including: diff fluid, oil change, transmission fluid drain and fill, filled both engine mounts per the DIY, coolant flush was done 10k miles ago, brand new ignition coils, spark plugs, and plug wires.

My car has been running great since doing all these things, and after each thing I noticed massive performance gains due to two softened engine mounts, and recently found out my ignition coils were shot after only 20k miles (replaced with rebuilt engine), and my spark plugs were fouled pretty bad after only 20k miles. Surprisingly, my car didn't seem to be running as bad or even misfire with how bad the plugs looked.

Now back to last Friday night. I'm heading to a car meet with my buddy and his girlfriend and I get on the freeway and redline 1st and 2nd, and I noticed something very odd... When the revs reached around 6k, I noticed basically an enhanced tone coming from my Mazdaspeed intake. It sounds excessively louder starting at 6k rpm all the way to redline at 7.5k. Also during this, my engine stops pulling and it feels like fuel cut, but the revs climb all the way to redline, just a little slower and with this loud raspy tone. I did notice my coolant was low too, but I topped it off after, so that's fine.

I thought for sure either my intake boot came loose, since my car sounded like this without the power loss the night I replaced the engine mounts and then went for a test drive to discover the intake boot came loose, so I reseated it and that was that. Otherwise, I was certain I was probably getting a misfire because the mileage for the ignition system (coils, plugs, and wires) were all due for replacement.

Last week I replaced coils, plugs, and wires, and notice a boost in low end performance, but still am exhibiting the same effects from 6k to redline. I've never gotten a CEL the whole time my car has been acting this way, so I'm starting to run out of ideas as to what is wrong?

I'm almost certain compression loss can be ruled out the engine pulls strong from idle to around 6k, where it feels like it wants to pull all the way to redline, but something is cutting power along the way.

With my last engine, compression loss was clearly obvious when my car started bogging like crazy until 4k, until it finally moved of the line. My car now with the rebuilt engine doesn't exhibit bogging at all, and outside of the symptom from 6k and above, it's probably running the best it's ever run since the rebuild, as long as I shift right before 6k the car runs perfect. My idle is smooth as butter outside of the intermittent "birds chirping" while sitting in drive at a light, but I'm thinking it's the heatshield under the cat because I get a loud metallic rattle right when I go into gear or am just above idling speed and sitting at a light every now and then. Really embarrassing.

I've been doing extensive research across the board this past week, and have tried to narrow down possible problems.

I'm thinking it's either:

-clogged cat (although no CEL or rattle from inside the cat itself)
-Bad fuel pump (power problems at high rpm are the same regardless of fuel level and if car is just at operating temp or has been driven for a while, but the pump not being able to flow fuel fast enough at high rpm does make sense)

-SSV (possibly stuck closed, and the noise does happen around the RPM this valve opens, but I redline my car a lot, so I'd be shocked if there was carbon buildup, especially on a rebuilt engine of only 20k miles)

Other things I have done:

-Took apart intake and checked throttle body for oil. Oddly none has been observed.
-Cleaned ESS position sensor and did the 20 brake pedal stomp to reset it after
-Cleaned MAF sensor and connectors

Sorry for the long explanation, but I've been searching the board non-stop for the past few weeks trying almost everything, but I can't find any real answers yet that have worked. I really want to figure this out on my own instead of take it to a shop (Rick's Rotary Performance is local) because I don't want to pay for them to diagnose something I could do myself, outside of a compression test only if necessary. I just want this solved before anything bad happens to the car because I'm planning to sell it in the next 6 months, and can't afford really dump any more crazy unnecessary money into it.

RIWWP

iTrader: (2)

I'd point the finger at the cat before everything else. ESPECIALLY because you recently had coil failure. Coil failure kills cats quite quickly.

Intake tone can and will change when the housing is packed with exhaust and you aren't getting much more air in...

Nopstnz8

iTrader: (6)

Yeah both of those make sense. I took the intake off today to check if there was oil in the throttle body or if a screen in the intake it self might have been damaged, but both were fine so that's off the list.

On a side note, I did the coolant throttle body bypass mod while I was in there and again noticed more slightly more throttle response from the engine throughout the rev band, and I didn't go above 5k. This to me says once again make me feel it's something limiting the engine from producing power up top, not the engine itself, because if compression was bad, replacing all these things wouldn't yield the positive results I've gained, and my car never ran like crap really at all.

Also, I might not have actually filled the coolant tank to full two weeks ago, because it was already almost low when I checked it today. It's hard to tell since my expansion tank is so yellowed, but if I did in fact fill it completely a few weeks ago, then we might have yet another possible problem.

Right now I'm trying not to redline really at all unless I have to until the issue is fixed so I don't cause any potential engine damage. Just every now and then (like every few days min) I'll do it once to see if the symptom is still the same.

I still have the old plugs and coils in my garage because I figured maybe they could help in diagnosing a potential problem. The plugs looked pretty fouled for only 20k miles on them, but my car honestly didn't seem like it ran that horribly at all till this high rpm symptom came about. That should imply my car is running pretty rich, which could wreck that cat if it hasn't already? If my car is still running rich, how do you usually fix that on an NA car on a completely stock tune?

I feel right now the only two big things left to check are the fuel pump and the cat, but it's odd that I don't get a CEL for either of these.

Nopstnz8

iTrader: (6)

^^Thanks for that. I've been wondering the same about the intake solenoids failing, but can't determine for sure this is my problem or not. My friend said maybe I should get my car dyno'd to get an AFR readout to determine if anything is out of wack from that side to maybe pinpoint the issue closer. What do you guys think? I still wanna try other things before I get a dyno though

Nopstnz8

iTrader: (6)

Anyone else have any ideas?

Nopstnz8

iTrader: (6)

Bump

Nopstnz8

iTrader: (6)

Anyone?

RIWWP

iTrader: (2)

Have you addressed or tested anything in the 'could be' list? You aren't really giving us anything to go on other than a list of stuff you might attempt to do.

Nopstnz8

iTrader: (6)

^^I've been really busy lately and had hoped to pull the cat this weekend, but didn't get a chance. I'm hoping to be able to do that Friday or Saturday though. I was just hoping for other ideas that I haven't tried yet outside of the fuel pump or cat. How do I check the pressure of the OEM fuel pump on my own?

Nopstnz8

iTrader: (6)

Took my cat off yesterday and ran my car open headers to test if my cat was clogged, but while it was off, I still had the same powerloss symptoms above 6k, so the cat isn't the problem.

My only other idea is a bad fuel pump, or possibly the intake solenoids, but outside of that, I'm fresh out of ideas.

Can I unplug the SSV to test if it is my problem because I heard you can do this?

Nopstnz8

iTrader: (6)

Bump. Still looking for some help.

paimon.soror

iTrader: (15)

I hope you dont mean you drove around open header. Pop a good flame = no bueno down there.

I would check the SSV actuator by hand to see if it moves freely.

Ricky SE3P

iTrader: (10)

rather than that lucas stuff (because i never noticed it do anything at all), get to having a low tank of gas (almost warning light) and run a 12oz bottle of chevron techron through the car. its really high concentration i know but that should help do some cleaning for sure. might run weird when it breaks free some gunk and goes through the motor, but afterwards after you top off the tank it should hopefully make a difference.. also like others said check the SSV is working well and able to move freely

Nopstnz8

iTrader: (6)

I did, but I only did that once over a two mile trip, just to verify that my cat wasn't clogged, then went back home. Can't be that bad, right?

paimon.soror

iTrader: (15)

Lol, well ... it could especially if you are living above 6k to diagnose the issue.

Nopstnz8

iTrader: (6)

I literally did it for a quick second then let off. I'm more concerned as to what the cause of this issue is honestly. The car still runs exactly the same as before.

Hoodster

Guys,
Well, I'm not sure where to start exactly but here it goes;

My 04' Mt, with new warranty engine, 5000km on it, died about 12-15 times on me yesterday while driving on the highway on a 300km trip.
Previous to yesterday, I had been following the Raingbeat breakin procedure which is about double what Mazda asks for and therefore had not been able to WOT my engine for the 1st 4000km.
Over the past month, while opening her up under WOT, she starting acting up around 6000RPM and would not give me any power regardless of how far down I pressed the gas pedal(under load). However, I attempted this 300km trip on the highway because I knew her limitation and did not exceed 5000rpm. At idle, you can rev the engine under WOT to about 8500rpm and to redline under a gentle push of the gas pedal.

But, low and behold, while on cruise control at around 110KM/HR(65mph). my speed started to drop and i hit the gas and nothing. Pulled to the side of the road and she shut right down. RPM's were only at 3500

This kept happenning to me yesterday and it sure made for a hectic arrival to the city during rush hour traffic.

While pulled off to the side of the road, I unplugged the battery, 20 pedal pump reset, no bueno.

While at highway speeds when the revs dropped out and pulling off the road, I released the clutch several times with it in gear and it would temporarily bring the revs back up and the instrument cluster would unlight, but again, no response from pressing the gas pedal until I shut off the car and let it sit for a bit.

Like I said, this issue has been creeping up on me but now I am worried I can't even get my car home and a tow job is $600. I also have the racingbeat midpipe so that rules out bad CAT. As well, since I have the catless midpipe, I do not want to take it into the local Mazda dealership because if this does narrow itself down to a faulty warranty engine, I don't want anything on file about aftermarket parts.

Something to note, I have changed the oil every 1000km since getting the new engine with 5w-30 conventional.

Guys, is there any suggestions here to at least get me home to my garage 300km away? I do not want to take her in to a dealer as last year they convinced me to spend over $2000 on an APV valve and new computer before my last engine finally died on me. Those guys are brutal at City Mazda in Halifax and I am done with them working on my car.

This is what I expect;
1. Bad fuel pump or fuel component.
2. My coils and plugs have about 30000km on them, sparks look good, haven't had the coils off since the newbuild.

I am at a loss here and after loosing my DRL module, cd player and power steering in the past year I am really getting bothered with this continuous decline of my once proud and unstoppable 2004 RX8 which I have owned since NEW.

Any suggestions would be greatly appreciated thanks!

Nopstnz8

iTrader: (6)

^^Ugh... Start your own thread instead of jacking mine. K thanks.

Nopstnz8

iTrader: (6)

So I think my car is either burning or leaking coolant. I noticed small remnants of dried coolant on one of the hoses in the bay near the bottom of the serpinetine belt pulley from underneath the car when I was under it the other day. There is no puddle, so I don't think if it's leaking, its huge. If it's burning coolant, it sounds like the engine could be on it's way out, although performance still hasn't changed outside of the original reving problem. And no, my car is not overheating or blowing out white smoke.

Over the last two months, I now have filled the reservoir up from the low point to full, and never was aware since I unplugged the defective sensor months ago.

Looks like it's time to sell my car since no one can figure out what is wrong with it...

Denztrasion

I know whats wrong with ur 8.

Sephitrask

on the coolant leak, check the pressure fitting on the thermostat housing. Sometimes it will fail and you will get a small seep from it; see if you can spot a dried trail of coolant down the side of the housing. But if you are loosing coolant and can't find were it is going, yeah, you may be loosing the engine.
Did you ever check the ssv?

Nopstnz8

iTrader: (6)

My engine has been fine for the last month other than the coolant leaking issue. There's dried residue on one of the hoses that you can see from underneath the car, but no puddle. Obviously a very small leak, but there's a leak I can't find. I already ordered a new thermostat just to be safe, and will be doing a coolant flush and heater core flush this weekend.

I had a compression test and the numbers were in spec and no where near failing.

Lately my heater hasn't worked at all, but the engine temps are fine, so I think I'm having a problem with the heater core. I'll start a new thread if I can't figure it out this weekend.

Ricky SE3P

iTrader: (10)

good to hear your compression is good, after all my issues (some of them somewhat similar), turns out my engine compression is shot. im in the last 25 days of warranty luckily and im getting a reman... i hope you are able to resolve your issue soon so you can get back to enjoying your 8 (hopefully much sooner than ill be)

NewtoRotary

Im having the exact same problem with my rx8, i recently got a re manufactured engine in august this year aswell.
As for the heater problem, turn the **** all the way to right for full heat, then tightly turn it a little more as if your turning it all the way around. It may sound wierd but it worked for me. If anyone has any ideas on this thread on what the problem could be please respond.

NewtoRotary

Also forgot to mention, When taking it to the dealership because of a check engine light, they informed me that it was due to an air pump issue and to fix it was 800$. Anyone ever heard of this issue?