Shinronn

I have been a member since 2012. I love my RX-8 or loved... It's a long story but shortened, in 2016 I had an engine swap due to allowing my brother to drive my RX-8 while he had no car. I told him about the levels and managing it however, he didn't listen, he overheated the engine and then it shut down >>> Fastforward a bit >>> got an engine swap from mazda for low compression, changed out clutch and put a stage 1 clutch. and a few other things. I got it back from the dealership and the car drove for about 2 weeks solidly then one day it just wouldn't drive beyond 3rd gear.

The moment I go into 3rd gear I lose all power and the car starts to shake. I couldn't bring it back to the dealership right away due to the fact that I was extremely busy with work. At the time I lived pretty far from the dealership that was able to swap the engine. Fast Forward 2 months, and the dealership closed, I mean completely shut down. Panic ensued, also one of the worst times of my life, couldn't focus on the car etc etc fast forward 4 years later and we are back in the forum. I am unable to identify the issue.

I can accelerate in 1st, 2nd. If I shift in 3rd or 4th or any other gear, the car decelerates and loses power, it caps at 45 miles per hour and pretty much just like hobbles or jerks in between power loss so the car will just go between 42-45. I'm thinking it's a MAF issue but would love the insight from this beloved forum. I haven't started the car in almost 2 years. I replaced the old Optima Battery and bought a new one. Car starts with no issues. I removed the barometric sensor and same thing. I am able to rev high in Neutral, I haven't tried redlining as the car hasn't really been driven in 4 years since the issue started.

I used to spectate heavily on the forum and tons of my issues were resolved due to this, the infamous clutch crumble, airbag change, knowing the compression loss could get me a new engine. Seriously amazing f****ng forum. I am now hoping someone has heard of this issue or experienced it. The only choices I have right now are is it fixable? or Is it Junk?



Also, my first post? (I think my posts disappeared possibly) I was afk from the forum for the last 4 years.

Loki

iTrader: (1)

Is the issue speed, gear or rpm dependent?
If you get to 45 in 2nd, will it continue past it?
If you shift into 3rd/4th/whatever at a lower speed will it stumble?
If you get to whatever rpm 45 is 3rd is, but in another gear, does it stumble (it doesn't sound like it but making sure).
Does the car rpm climb but the car not accelerate? If so -> slipping clutch.

I don't think it's your MAF. That would present at a specific airflow value which you see in every gear, and usually at lower airflow values.

Can you check the clutch switch on the clutch pedal and make sure it's fully pressing and depressing when you action the clutch? If it's noisy, that could cause similar issues (but usually not limited to a specific gear).

More data would help narrow this down. With the car warmed up and idling, get your OBD reader and check the airflow g/sec, short term fuel trim, long term fuel trim. Should be near 0 for the fuel trims and about 5g/sec for airflow. Report back if not.

Shinronn

I'll run the OBD after I get off of work, I will then update you with the readings. I'll Identify if it's speed or gear or RPM based, but I think it may be speed and or gear based. I can rule out the RPM's possibly because I can go into High RPM's no issue while in Idle. I'll check if I can red line in first and second. Or if I can go beyond 45 mph while in 2nd.

CaymanRotary

Sounds like a transmission issue maybe? If it gets to 40+mph in second then you are near the redline. So the problem begins on 3rd gear. You've tried passing 3rd and just shift into 4th or 5th and same issue? Thats really weird. Not sure.

Shinronn

Scratch everything else in the post, I went through a few tests to verify each of the questions.

Rpm Dependent

1st gear caps at 27mph and 6k rpms // 2nd caps at 43 mph and 6k rpms // the weird part is 3rd gear caps at 43-45 mph and just stumbles// 4th gear will hit 50 mph and then caps at 4k ish rpms.

It stumbles if done at a lower speed

it does stumbles a bit but smooths out, it's slow gradual climb to 50 mph starting at 3k rpms in 4th when I go from 2nd to 4th.

Rcpm climbs slowly along with the speed // but rpms don't go beyond that.

No noise on the clutch, replaced clutch 4 years ago along with the clutch pedal to a stage 1, along with the engine. Dealership replaced everything.

Unable to check the airflow, g/sec, my OBD is not that good, I have an Innova 3020 RS. How can I get those levels checked? You think the OBD from autozone would be good enough? or Would I need a better one?

**Current Engine Codes**
P0107 "The (MAP) sensor circuit is out of range, low" // P0443 "Evaporative Emission System Purge Control Valve Circuit"

I will try to see if I can redline while in neutral tomorrow when it's not night time as to not disturb the neighbors.

Shinronn

At this moment from the troubleshooting done, I think it is a failing Catalytic Converter. I haven't changed it since getting it. I remember hearing metal rattling for a few months back in 2016. Not sure if this would be it. Let me know if you guys think I'm headed in the right direction. Also, if it ends up being the Catalytic converter, then I plan on swapping the whole system, catalytic converter and swapping to a catback.

If this ends up being the case:
And I decide to go that route I was thinking the AP RX8 Titanium Colored Catback Exhaust. Because I wanted to replace my current borla anyway. Or if anyone knows any other dual tip exhaust that is beast please recommend. Also, what catalytic converter would be best?

Loki

iTrader: (1)

P0107 is your baro sensor. It's on the passenger side of the engine bay, near the air pump. Make sure it's plugged in. That might actually be the cause.
P0443 could likewise be an unplugged evap solenoid. The dealer might have forgotten to button everything up fully. It wouldn't cause your problems, but it's good to have a working evap system.

Could be the cat, definitely worth inspecting. Cats kill engines and you had a dead engine, so...

Shinronn

Tested sitting in neutral to see how high I could rev, and in neutral it only revs to 6000 rpms. I tried doing the Exhuast test to see if I hear the rattling but I no longer hear the rattling, most likely since it's been sitting for like 4 years. However, the rattling used to upset me from the exhaust so I know I'm not crazy about that happening. It's driving me nuts trying to figure this out. Overall I think it could be a failing catalytic converter. I'll attach a sound clip of how the engine sounds when revving. It his a high pitch whistle like forced air not going through or like it's leaking or something. Engine Sounds

Shinronn

Any Recommendations for who/ what cat I can buy that is solid?