Hi AllNeed opinions - 04 rx8 - 159k - 93 gas always - manual - All stock - no mods - orginal engine

My car has been making this noise for a while and I have been trying to figure it out.

Symptoms:

When running car and hitting around 5K in any gear I have a terrible noise that sounds like misfiring... See attached. Also loose power under load (or up a hill). Idol is extremely rough and will stall out.

Got a CEL - P2096 - running lean, fuel issues, etc etc. - has gone off and then three or four cycles later will come back on.

Get the noise on high revs cold or warm - although idol and misfires are worse when warm.

Things done for resolution:

1) Coils, wires, plugs - All changed
2) Clogged Cat - Replaced
3) Clogged Muffler - Replaced Catback
4) MAF - cleaned (more then once)
5) O2 Sensor - position 2 - replaced
6) Removed Fuel Pump - cleaned sock (wasnt dirty)

Other possible causes???

1) Fuel Pump - is this noise possibly fuel starvation happening when the pump cannot keep up - this would cause misfire noise and hesitations and no power??
2) SSV creating some sort of issue - maybe it is not opening - or staying somewhat open?
3) I dont see or hear any sort of vacumm leak - could something like that be causing this?


[URL="http://www.youtube.com/watch?v=awDa_HwIAPM"]

 

Your engine coolant light seems to be on. Maybe fill it up and see what happens.
Just a guess.

 

Collant light goes on and off at whim - check levels and all seems fine - think it is the bottle float indicator. Thanks for the suggestion.

 

The coolant light is due to a faulty sensor - that is common. I had mine fixed under warranty.

I'm not sure if this is it, but it sounds like you might have marbles in a can sound.. ive read about it before somewhere.

 

Aware of the MIAC - this is definitely not that. When car wasnt sick I heard the marbles. Thanks!!

 

vacuum leak? i had a similar issue when the stupid vacuum cap that covers the vfad port(aem/mazdaspeed intake) on the manifold got loose. Mine was just acting crazy as hell though in general.

if the ssv wasnt working it would set off a cel from the switch not being activated though (i say that but ive found unplug coils and the car ran fine with no cel....stupid dealer)

 

this might help. i know i was getting the same problem whenever i would run my car for about an hour or more. i did a little bit of searching and found out that the fuel pump has a sock on it and it gets residue, debris or whatever is in the gas and overtime it clogs it up. even though mine didnt throw a code i thought this might be helpful. il find the thread here in a minute.

 

this will tell you how to get it apart and as you can see it shows the sock as well. that is what you need to clean and it solved my problem. But then again im not sure if i had the same problem bc mine would just cut off like it was getting no fuel at all but it was around the same RPM and i never threw a code either.

https://www.rx8club.com/showthread.p...ving+fuel+pump

 

Thanks Matt - Forgot to mention that - i will update first post - took out pump - cleaned sock already - it wasnt dirty at all...

Thank you for taking the time!!!

 

A bad fuel pump can over heat if there isn't enough fuel in the tank to cool it. Top it off with fresh cool fuel from the pump and see if the problem goes away.

 

Al - so I ran the tank down to 1/8 - then went to the gas station and filled her up with cool fuel.

I have to hand it to you - the misfiring just went away completely. As I drove the car for about an hour or two the sound slowly started to come back....

So - your suggested test has settled this issue. I am ordering the updated fuel pump from BHR and will replace the stock internal pump setup.

THANK YOU FOR SHARING YOUR EDUCATION! I consider this case closed. Wish I had posted this before new coils, wires, plugs, cat, muffler... ugh.

 

Glad to help. I only know because I ran into the problem, 1000 miles from home. Fortunately, it was in February.

 

Would a bad fuel pump also cause the car to act like it's flooded? I have similar symptoms to DHPrx8 on my '05, but I also have the problem of when I park and return to my car within 5 minutes it will not start. I have to go through the de-flooding procedure a time or two before it'll finally fire up. If I wait for 15 minutes it will start up just fine.

 

This case wont be closed till you put that new pump in and see what happens.

 

what is the background of your car? did you replace thae same things too?
I had a similiar issue with the startups taking forever but it was the starter.

 

Well I am back. Winter came and with it the noise disappeared (assumption being the colder temps kept the fuel pump from overheating). Well first warm day here in CT (60 degrees) and its back. Putting in the BHR pump tomorrow night and will update posting.

I want to give a special shout out to BHR - great communication - fast response - and worked with me to get the pump overnight so I can stop limping around! Thanks guys!

 

So the BHR fuel pump has been installed - and the misfiring/starvation/something noise is still hitting me. If I put in mag1 carb cleaner with 1/2 tank it does seem to really help with things - power and pick up comes back and noise goes away - for a little while. Then it slowly comes back. I am no longer getting the lean fuel check engine code - instead I am now getting a P0400 error. I know - Cat.... I replaced the cat last year though. If I dont use the carb cleaner with the Super93 Mobil then I have no power and at 4500 rpm the rattling/misfiring noise begins.

It seems that the issue is preventing the "next" level of kick in when you hit the gas. What is it that kicks in higher up for the next pull of power "a turbo" kick.

Could this be fuel injectors that are not working properly and maybe flooding things so it can burn them completely - therefore CAT is getting to much fuel dump and creating an issue?

Does the SSV kick open and maybe its not completely working - or its worn out and not working properly? What would someone experience if the SSV isnt kicking or working correctly? I know if it is stuck a CEL will kick in and have checked and it is not sticking. Wondering if maybe it can just get worn out and not "operate" properly?

Looking for any suggestions!

Same background - now 173K - 2004 - orginal engine - super93 always

First post tells you everything I have changed out using deductive reasoning on this one.

 

I believe secondary injectors kick in around 5250 rpm? Maybe run some fuel injector cleaner through? Also if it is misfiring shouldn't the CEL throw a P0302 or P0301 code or something along those lines? I know if you had a misfire it will keep it in the codes (happened to mine)

Also have you replaced your fuel filter recently? I noticed you have quite a lot of mileage and if your filter is clogged/dirty when the secondary injectors open up and demand more fuel they might not be getting correct pressure.

Just throwin ideas feel free to point out where I'm wrong.

 

I saw your post on Jon's SSV thread.
I don't think you would get a rattle like that from an SSV malfunction.
So I'm interested in what Jon has to say, he's good.

However, Darkbrew and I just went through diagnosing his SSV problems, which ended up being a bad actuator so thankfully we didn't have to rip everything a part (ie Jon's video)

Geeesh ... I see the MIAC response in post#5
If I had not read that and just listened to your clip I would have bet the farm that it was MIAC.

As we are in troubleshooting mood (ideas):
- Clean Eccentric Shaft Sensor then do 20 brake press reset procedure
- Vacuum leaks?
- Check actuators like the VFAD and the SSV
- Air filter

You know ... you could spends lost of money replacing parts.
I think your best bet right now would be to buy a Cobb AP with the MM service.
This way you have an excellent tool to monitor all the operating conditions of your vehicle.
Plus you get the MM tune, and if Jeff notices anything strange in the data logging he WILL help you out.
Jeff will defiantely be able to tell from the data log if the car is running to lean up top or not enough gram/sec of air from the SSV not opening (or worse).
I say it's a win win ... do it.

BTW in your first post you mentioned changing the second O2 Sensor.
It's the Front O2 sensor the changes the parameters of your engine during closed loop.
The Rear O2 only monitors CAT efficiency and has no effect on the car operating parameters

 

You can check your vacuum system and actuators for leaks with a vacuum hand pump. (My SSV actuator leak was very small but had a very significant impact)
You can have your injectors tested and maybe even flow rated. A bad injector could easily be the problem.
+1 on the Access Port to help you monitor and diagnose the problem.

 

Personally I would first stop "Throwing Money" at your car....IMO you have spent enough trying to find 'an issue'.

Your engine has done a lot of miles for an 04, have you had a Rotary compression test done??..

Looking at your injectors 'may' fix, but after all the $$$'s you then find compressions are crap?.

Spend the $$'s on a Comp Test...then make a decision.

 

sounds like a cat problem.

 

My first question would be... can you replicate this sound at idle or is it only under load/while driving?
Is this only in gear or can you disengage the clutch and produce the same sound by revving it?

You mentioned replacing the O2 senor in "position 2", so I assume you mean the rear O2 sensor.
That one only monitors the cat efficiency... I would have replaced the front one if anything.

What intake setup do you have?
Check to make sure nothing is blocking part of the "ducting" and also verify the screen(s) are still upright.

If you want to check for a vacuum leak, hook a pressure gauge to the VFAD nipple behind the throttle body and let us know what it reads.

 

Thanks for all the suggestions. (except for grumpy ASH - haha- i love playing with my Rx8 no matter the miles!)

FYI I replaced the rear O2 sensor because heat buildup from my first cat screwed up the wiring and kicked a CEL.

Jon - No I cannot replicate the sound at idle or with the clutch disengaged - problem becomes the greatest at load or up hill but is happening all the time to some degree.

Intake is stock and duct is all good. Filter is new too.

I have looked and looked - cannot find any type of vaccum leak happening. Going to do what Jon suggested and get a reading with the pressure gauge. Any chance someone has a picture of where the nipple is behind the throttle body? I can look it up but on the chance that someone does... :-)

Yesterday the car was absolutely fine while driving - I had put in Carb/fuel injector cleaner and half tank of gas and off I go. Then put in more gas (always 93) without the Carb/fuel injector cleaner and Im right back to the noise and no power up top at all. Makes me suspect of the mix - so either fuel or air - which means injectors or SSV air mixture. This Access port could help determine this?

DarkBrew - you mention that I can get the injectors tested - how do I go about doing that?

When we figure this all out its Beers on me!!!! :-)

 

I didn't find much on our site...

Here's a little explanation of what's involved

http://www.skylife4ever.com/2011/03/...aning-and.html

Please chime in if you know where to get your injectors cleaned and tested in your area

The VFAD vacuum nipple location.

follow the hose from the check valve back to the UIM


You can also run the vacuum gauge on the rear vacuum chamber to check for leaks in the air solenoids and vacuum actuators... (after the rear one-way-check-valve)
Thanks to Jon316G