Failed catalytic converter.

Hot start issue
 

Hey guys I have a 2005 rx8 auto 120k on clock. Brought vehicle at auction 4 months ago I thought it was a great buy. So much fun no start issues hot or cold was a beautiful car still is. Within the last 6 weeks I started hearing a rattle in exhaust system along with lack of power low and high rpm. Checked my plugs 1 had cracked porcelain so replaced. all other plugs looked clean and new. Code read was p0410. Secondary air injection system. I found a vacuum leak on the line where it connected to the intake manifold as an air solenoid valve. I replaced. Real prick to do but fuck the mechanic for what I can do myself After reading alot of the posts on this site I dropped my exhaust to check cat and it had disintegrated. I DIY removed the blockage the correct way lol and reinstalled. Car hardly sounded different but took it for a drive and wow I had everything back under my foot. Thought I had fixed the problem but Maybe 2 weeks later my car developed a hot start problem. Along with stalling at lights etc. In the beginning It would start again luckily. Anyone who has stalled in traffic knows my pain but now I'm scared to slow to an idle no trust and if car is hot there is no way it's gonna start. Ssv has been replaced 30k ago buy previous owner also plugs coils and leads 1.5k before sale as I tracked records. I also have removed and cleaned ess( e-shaft position sensor) maybe helped but idk. I need a compression test but I live isolated and not enough trust to attempt the transit. Help lol. Car will start cold. Used to be easily now getting harder. It will hold idle in Park or neutral. Occasionally struggle but will recognize and Rev up to compensate. Now when car is warm if I try to put in reverse or drive and I don't keep the revs up with handbrake I will stall and I can park it up. Because il be waiting until it's cool. To make matters worse I was investigating and snapped a small radiator hose so now it also pisses out water I'm in the process of repair. Any replys or advice would be helpful thanks.

Appears like you've done well by self-troubleshooting this car while using the forums for guidance.
I applaud you for getting this far on your own.

You're on the right track.
This vehicle came with many defects so knowing the health of the engine is important and a compression test will let you know where its at.

You mentioned the cat had some blockage.
This would make me question the condition of the ignition coils since we've seen those fail as a result of clogged cats.
Being an '05 I'd hope that the coils have been replaced but you can never be too sure.
If those are original or earlier versions of the coils, you definitely should consider that too.

Lastly, see which starter you have.
Again, if original, you might want to consider that too.
When you get the compression test, they can tell you the RPM the motor was turning at.
Would be a way to judge how slow the starter is.

But before you throw too much more at this issue, a compression test should be at the top of your list.
Good luck and keep us posted.

Appreciate the quick reply mate. I believe starter to be the upgraded model as looks cleaner than rest of the engine. Is it worth removing coils for testing. also removed and cleaned maf. And throttle body. Lol anybody who removes cat should go for a small drive without exhaust. Very satisfying noise. I fabricated a radiator fitting from knead it. That plus a little super glue I think has fixed my water leak. Currently trying a can of ametech engine restore. Will keep you updated on results

Hi to update, my warm start problem:
RX8 2004
compression readings were: Front rotor 65, 67, 71 Rear rotor 75, 70, 71, at cranking speed (250 rpm).

Converted to PSI using this

these are apparently

Front Rotor

First Chamber [98.6,120] : 924.52
Second Chamber [98.6,120] : 952.96
Third Chamber [98.6,120] : 1009.86
Chambers Difference [

Hi to update, my warm start problem:
RX8 2004, automatic
compression readings were: Front rotor 65, 67, 71 Rear rotor 75, 70, 71, at cranking speed (250 rpm).

Converted to PSI using this

these are apparently

Front Rotor

First Chamber [98.6,120] : 924.52
Second Chamber [98.6,120] : 952.96
Third Chamber [98.6,120] : 1009.86
Chambers Difference [less than 21.8] : 85.34

Back Rotor

First Chamber [98.6,120] : 1066.75
Second Chamber [98.6,120] : 995.63
Third Chamber [98.6,120] : 1009.86
Chambers Difference less than 21.8] : 71.12
Rotors Difference [less than 14.5] : 56.89

Mechanic advised other RX8s with lower compression start fine.

Mechanic advised the fuel pump was ok and, and spark plug leads have also been replaced, and new larger starter motor fitted. All sensors and electronic diagnostics come back fine as well.

I just experienced today significant loss of power when driving up long steep hills - at one point even stalling when waiting at traffic light. Rev counter very slow to increase while climbing, never exceeded 3500 with my foot down and actually decreased to 1000 after sustained attempt at acceleration.

Is this result consistent with my compression readings ?

Is my engine unambiguously dead/in need of refurbishment?

Mechanic is providing a response that is misleading at best, ignorant at worst. You can have trouble starting a healthy engine, and you can start a dead engine "just fine". The details of each component is what matters.

This sounds like a clogged cat. Rotaries make more compression at higher RPM, so even with a dead engine you would experience the most power loss down low, but as the RPM climbs, it would gain more power, not lose more power.

Power loss increasing with RPM and load is a restriction problem to either air or fuel. If your fuel pump is fine, and your intake isn't clogged up, then check the cat. It clogs easily, and produces this kind of behavior once it gets to near 100% restriction. It can also artificially produce low compression readings in a compression test.

Gut ur cat mate. Or check it out at least. If it has disintegrated you need to remove or replace

2005 Rx8
Having hot start problem - have to wait 15 minutes to restart. Starts fine when cold.
Mechanic did compression test, reported 98,97,98.
Is this compression reading good or low ?

Also did sea foam, waiting time for hot start reduced to 5 minutes but after about a week, restart time increased back to 15 minutes.

Any recommendations on what to try next?

You should have 6 number, not 3, as well as the rpm at which the test was done. It makes a difference in the interpretation of the compression numbers. 98 psi could be failing, borderline or still has some life left depending on rpm. I assume mechanic used a rotary tester, not a regular one? If not, go get your money back ;)

interesting
 

i am having a hot start issue myself compression is good thought it was fuel pump changed that changed plugs tested coils, coils came out good I'm going to change regardless no cat singled out exit thinking battery can't change till next week. But could it be vacuum leaks making it not want to stay running after 5 miles at running temp that fluctuates from 185 to 210 in 90degree weather with high humidity.

I kept my '04 RX8 with marginal compression going a year or 2 with a faster starter motor (but even so had regular warm starting issues). In the end I had to bite the bullet and get my engine rebuilt. Cost me $8k from RE Sinclair here in Christchurch NZ - almost the nominal value of the whole car (without compression problems), so going ahead was a hard decision - but in the end I theoretically recover all of that in terms of resale value, so came out ahead compared with the alternative - which was to scrap the cars & walk away with maybe $1K towards my next one....

OP: you said you replaced the old starter with what ?. You said a new one but what new one?. I ask because there are some old 2004 /2005 starters that are remaned but the issue would be that a reemaned N3H1 is still a 1.8KW and weak even remaned. Did you make sure you got an up graded starter which woulkd be a N3H1-A or N3Z1

I have the same issue, my 8 won't start when hot:

https://youtu.be/-Sw4MGK7qu4

any advices?

going to change starter next week, someone knows where to buy it in japan?

Updated video with cold start:
https://youtu.be/3PyQ9eq1se8

Read this

https://www.rx8club.com/series-i-tro...t-here-222584/

Beating a dead horse...
 

Hello all, I finally broke down and decided to register for rx8 club. I've been amazed by this community.

I believe this to perhaps be the most appropriate place to post this.. If not, I apologize.

I'm pretty mechanically adept so I don't need spared on terms or sequences/procedures.

I just recently purchased a very nice 2006 rx8 automatic with 144k miles. (I know) GEEZ. It runs decent, however I have a lack of power it seems... Along with a starting issue that gets worse with the heating up of the engine. Here are some of the checks I've done and replacements I've made...

1. Compression test at Mazda. Tested good.

2. Replaced 1 dead coil with new OEM coil and replaced plugs.

3. Cleaned ssv and actuator.

NOTICED ISSUES

1. Glowing almost BEAMING red hot catalytic converter.

2. Engine overheats only with AC on.

3. Misfire on startup and redline.

4. Intake tuning valve CEL. (Mazda did it)

Starter cranks real good. Battery seems very healthy!

With all that being said, I was hoping someone had a similar issue. Any advice or ideas would be greatly appreciated!

Thanks in advance!

Regardless of your other issues, if your cat is glowing you need to replace it asap. Either with another cat or a mid pipe if that's an option. Otherwise your engine which tested good will fail, quickly.

When was the compression test done? What were the actual numbers?

Test was dine last week. Didn't get the numbers. I will go back and ask for another test in order to get those.

Gutted cat and got instant power gains. However hot start issue remains. Checked coils again, and they are all sparking good... But removing the "#2" plug wire does not change idle at all? Scratching my head here... Bad plug? Or perhaps they didn't do the compression test properly.

Any ideas y'all?

Okay so rather than asking to be "spoon fed" I decided to take it upon myself to clean and reset the ESS. No luck.

The dealership in my town refuses to give me another test without charging me again. (Jerks)

Perhaps a reasonable assumption that compression is my issue.

Still throwing codes for intake tuning valve sensor and MAF.
Could these even cause hot start issues?
By hot start I mean drive the car down the street and back.

Sorry for the multiple posts.

What are the codes you're throwing? If your MAF isn't working correctly that could cause a variety of problems.

Have an 04 rx8 mt(I think) and I had a hot starting issue until I replaced my 1.4Kw starter with a 2.0Kw starter from bosch. You need a really powerful one to hot start the car, and that was the most powerful starter I could find and it works great, kind of expensive tho. I feel so sorry for the people who believe others when they tell them they have a bad engine when 9 times out of 10 it really isnt the problem. If the car runs fine, and the only problem is the hot starting, then maybe look into your starter/ignition system

if you havent felt an loss of power, chances are it's not bad compression or a clogged cat, I would look to see how powerful your starter is, I have an 04 rx8 and a 1.4Kw starter wasnt enough to hot start it, after I changed to 2.0Kw starter, never had the hot start problem again

The upgraded starter is not fixing the problem, only covering it up.
You can have a failing engine with the OEM starter and no hot start issues.
Just because you can start it hot doesn't mean it's not a failing engine.

When is a problem not a problem ....
Sure an engine might be tired and worn out .... Does that mean it must be rebuilt ? If you are into competitive motorsports , you have a problem and it must be fixed.
When it's just your daily driver, you don't have a problem so it doesn't.