Ok, here goes.

04 rx8, no mods.

I've had problems with the idle for quite some time now, dealership doesn't seem to think is unusual to idle under 700rpms, and then stall. I, on the other hand, disagree.

First start the car cold, it seems to run well, once you put a load on it, I have low idles, car shakes pretty bad (I know mounts are worn, but not in dire need of replacement). Apparently I had an animal under my hood at some point, which chewed through an air hose, mazda replaced.

I replaced all coils, wires, and plugs yesterday; did an oil change as well.
She started up beautifully, and ran like a champ, until I took in on the highway, pushed 3rd to 8000rpms. Was fine til I stopped the car off the ramp, idle dropped to 750ish, and started to stall.

Today I took the airbox out, found oil on the filter and box itself, took the hose out, found oil pooling in the hose, took the throttle body out, no wet oil, looks like either carbon or oil buildup on the backside of the butterfly.

Cleaned everything out, cleaned battery terminals (thinking power issues, if it idles low once the fan kicks in..at a stop...), put her back together, and started it up.


...perfect start, sounds great, no misfire codes, no codes at all for that matter.
Drove about 10 miles with no issues, took it on the highway, died as soon as I stopped.

I'm out of ideas. I ran logging data for the drive home, if that helps. I tracked mph, calculated load, timing advance, MAF, and intake air temp, if any of that helps. Any ideas or even somewhere to start would make my day. Thanks guys.

 

post your log

 

Did you also clean the MAF?
I know you mentioned cleaning "everything out" but I just wanted to make sure this was also covered.
Also, did you clean out the resonance chamber on the intake accordion tube?

 

I seem to not be able to upload the log, its in a spreadsheet format, and is too large to try to post as a word document.

I cleaned the chamber as best I could, until oil stopped pouring out, and I tried to clean the sensor, but was terrified I was going to break it. I cleaned the oil out of the airbox, and the accordian tube. and used TB cleaner to get the residue off the throttlebody.

on a side note, i forgot to mention that after I cleaned the battery (which I did before everything else), I reconnected the wires and the DSC OFF light was flashing, and the traction light came on. Once I drove the car, DSC stopped flashing, but traction ligt is still on, and the car slid out a bit on a curve.

I really feel like I'm fighting a losing battle, and this is my first rotary, so I'm flying blind here. Thanks guys

 

For cleaning the MAF, follow this guide:
https://www.rx8club.com/showpost.php...71&postcount=9

Whenever you disconnect the battery, you'll need to reset the DSC by turning the steering wheel all the way to one side, then all the way to the other.

 

Would the MAF being dirty cause my idling issues, and stalling?
And wouldn't it send a code if it was having issues reading?

I'll take it apart again tomarrow. Any contact cleaner reccomendation?
Thanks again.

 

If an excessive amount gets on the MAF... yes, it'll throw a code and your car will make a real ugly sound (hard to describe).
But a tiny bit of contaminate on the resistor wires may be enough to not throw a code, but enough to give an inaccurate reading.

You can purchase contact cleaner or MAF cleaner at the local Autozone.

 

ok, thanks for the tip. I'll try to get this done tomarrow or friday. I'll post my results...thanks again, much appriciated.

 

Jon...could it be just as simple as he needs a couple drive cycles after disconnecting the battery to clean the terminals?

 

Engine and/or TB is bad. 99.99999% positive

again. A perfectly functioning car will NEVER drop it's idle below 700 rpm. Or stall at stop light

 

Don't tell me that!!! Mazda swears the cars fine, they can never "duplicate" the problem. Is that just a cop out??

 

^ Likely..



print out the TSB and take it in and make them do the procedures....tell them it runs rough and is hard to start sometimes...especially warm

 

Ok, cleaned MAF today, doesn't seem to be any more oil in the accordian tube or the air box, so good signs.

The car seemed to run better today, I took it out for some stop and go, then highway, then stop and go again, and I ran same testing I did the other day. Never stalled, idle stayed around 800s, so I'm getting there.

This was before cleaning MAF
MAF RPM Calc Load
5.05 821 40.8
19.4 2538 42

And this was after
MAF RPM Calc Load
4.64 823 35.7
16.8 2534 18.4

Numbers still seem off a ways vs shop manual, and still has a bad vibration at idle, which i've attributed to the worn motormounts. I'm gonna drive it for a couple days, run some more tests. Here's to staying hopeful! Thanks again guys.

 

JD,

i'm chasing the same problem. Runs fine cold then after its run on the highway it will idle low and stall.
I'm not sure either what it is. I also don't have any codes (don't have your level of diag software though just a code reader). I will try the MAF clean process. If you figure anything else out let me know. I will also look for oil in the intake.

jtdwab

 

I do have one other thought which is a bad fuel pump which is not able to send enough at low output. If somebody has knowledge about that it would help. I'm still hunting.

 

JD, since it is a 2004.

Disconnect the tube from the oil filler neck. place a filter from auto stroe at that end. Also buy plastic caps. Cap off the end on the intake tube.

No more oil will get in now.

Since you still have oil in the accoridian tube and intake(never can get it all out)

You will need to clean the MAF more often.

Since it is working better... drive it for month then reclean the MAF.

 

JTD I'm still having issues. I do reccommend the MAF cleaning, it did wonders. Worked great for a while after I did all the cleaning, started having issues again, some seeming worse than before. I'm going to take her apart again today and check the intake, hoping its not full of oil again. We'll see.

Razz, I like the idea, but I'd like to figure out why so much oil was sitting in there. I could understand a small amount. Again, gonna take it down today and take another look.
I also...kinda...broke the vaccuum elbow from the oil filler neck at the point where it connects to the accodordian tube. No one seemed to have any, so I put in a "T" fitting and capped the open side...which in turn leaves me with a nasty vaccuum leak at about 3K rpms..lovely. Checking NAPA to see if they carry it, iff not I guess I'll be calling Mazada...boooo.

Good luck Jtd, if you find anything please post, maybe if we bang our cars together we'll figure this mess out.

 

Ok, well no more oil in the intake, so thats a good sign. I removed the line from the oil filler tube completely, and capped it. We'll see.

I've been thinking about my exhaust system...thinking my cat is melting. I'd had issues with it before, was glowing red around the O2 sensor, and backfiring at cold start. Mazda replaced an air hose that was leaking, and it hasn't glowed since, to my knowledge. I do have backfire still. I was under the car today as well, and noticed that the heat shield has a ton of scratches all in one direction, I'm wondering if something got run over, (something in the street...a curb...), if it could have jolted the pipe enough to break any seals. I do have a leak somewhere, considering the smell that comes every now and then. So I'm thinking I'll have to take the cat down, see what it looks like...no back pressure = bad idle...

this is like a really expensive truth or dare project.

 

Scratches..
Damn... was wondering what happened to the neighborhood cat.

 

You do need to vent that oil filler tube to somewhere...to build pressure there would be bad. If you are under warranty still you can get the tube that goes from there to the maint. ports on the side of the engine under a TSB.

 

that cat had it coming.....lol

Dev, I was hoping to just be a temporary fix until i can find an elbow the right size. I still have a vaccuum leak though, which seems odd since everythings capped. wondering if the leak isn't where i think it is. So now I get to search and destroy that, amongst everything else.

Don't get me wrong, I love this car, its probably the most comfortable fit for me, and its a beautiful bodystyle. On the other hand, I have two kids, so I might have to bite the bullet soon if I can't figure this out.

and yes, I have two carseats in the Rx..sporty, I know...

I'm thinking supercat...doing a search now for reviews.

 

If you saw your cat glow at any point, it is probably fried.

And since youre in NJ, head up to Wayne Mazda.

 

Where's that located? I assume its a reputable dealer?

 

its located in wayne, nj.

 

I probably should have guessed that...