dan.whyad

i have an '04 73k miles on the body 20k on the motor, i have a magnaflow 3" dual exhaust and a k&n air filter (idk what it is, it came with the car, it just looks like a 3" cone)

i have recently done a seafoaming, used about 3 bottles of lucas fuel system cleaner and just yesterday replaced the MAF sensor, i have been getting this code for about 2 weeks now.

what exactly does this code mean, and what on earth can i do to fix it.

Mr.Mango

iTrader: (2)

Did you put caps back on the intake manifold when decarbing? That would cause a vacuum leak which can set this code.

McKennaR

iTrader: (1)

I don't know man, every single P0171 thread that I found on this site has something to do with a vac leak. I'm guessing thats what your issue is?

There are only about half a dozen places that it could be leaking from, how about you start with the most likely (i.e. the ones you've been fiddling with recently, as mentioned above) and work from there?

It would stand to reason that if you have a 6 port but it has a cone filter, then your VFAD may have been removed. If this is the case, check the VFAD nipple along with the two mentioned above as your first step.

If this doesn't fix it, then trace-out any other vac line you can find from its source to its destination. You can do this while its running, too by listening for a hissing noise.

Shouldn't take more than 30 minutes. Good luck.

dan.whyad

theyre certainly there, i checked them several times. when i pulled them off i used pliers and just put them back with my hands, should i have used some kind of special grease to insure a tight seal, do you think i could have damaged them enough to cause a leak?

dan.whyad

where is the VFAD nipple located? is there a diagram or something with all the vacuum lines that could cause this? that way i can spray some sudds around the suspected areas
my exhaust is too loud to hear any hissing, i have tried this

mrl84

back of the throttle body. on the bottom nearer the fender side. i put a cap on mine when i changed to the RB duct and it fell off after about 1.5yrs. pissed me off cause i forgot about it and it took me like a week to remember and check it lol.

Mr.Mango

iTrader: (2)

If you used pliers it could have damaged them. I would check spots where you recently worked around.

Otherwise check vacuum sources... VFAD, Shutter valve, back of manifold by the 3 solenoids etc.. just be thankful it isnt a FD :P

dan.whyad

i went to the dealer, turns out i have failing rotor housing seals that are sucking in obviously unmetered air. he is regarded as the grand wizard of the rx8 by his peers and what he said along with his title made me question myself. officially procedure is to replace the motor. but he told me to use shitty and low octane fuel to try to build up carbon around the seal to try to plug it. this goes against everything i know. and now im torn

any thoughts?

McKennaR

iTrader: (1)

With 19k on your 2nd engine? I'd find whomever rebuilt it and kick them in the nuts.

Second... rotor housing seals? I mean, I suppose... I guess... maybe but how in the hell did he diagnose that, and furthermore if the seals are crapping out, are you not losing a bunch of coolant?

At this point you're beyond my realm of experience. Perhaps some more educated / experienced folks can pipe in as to the viability of what the dealer tech is saying?

jtspells

iTrader: (1)

You need to find a way to smoke you're system, you could have anything from a bad intake gasket to a cracked vacuum hose.

Good luck!!

JefeSpeed

I'm with you on the leaking coolant... If its sucking in air, it's sucking in coolant. Just rebuild yourself. My 8 I just purchased had the engine replaced. 19k on it too spooky lol and I have the same code. I just put a catless midpipe on though so my own fault. Looking at the work they did.... 1 header nut a cm off the flange, one you can twist by hand, the other one actually was tight, not to mention they mixed up the nuts on it and the midpipe. I haven't checked the other nuts on top yet but... Lets Mazda Japan build it, and don't let Mazda USA touch it lol.

Thoro'Bred

Apologize for the old bump, but I'm unable to create a new thread. However, it's in relation to this same exact issue and I'm in need of quick help. I am getting this code which I have never had before. I have a 04 RX8 with 57k miles (manual trans.) and have had her for a little under a year. I've installed the BHR Mid with a Greddy muffler and have had that for going on 5 months now. This past Memorial Day weekend my vehicle stalls on me on what was supposed to be a pleasant roadtrip. I have to get it towed back home for $400... dealership informs me I have a bad fuel pump... fine. $750 later before I even get her home (15 mins away) the check engine light comes on and shoots me this code [p0171]. The following day, I have the Mazda Tech come to take a look at it and informs me it's because I have a "cat-back" and it will not go away. I refuse and still refuse to believe this as I've stated, I've had it for a good 4 months prior to the stall and never once have I ever had any code appear. I find it very ironic how a code such as this decides to shoot once they start messing with "fuel" related things. I decided to take it back this past Monday to the dealership in demand they figure out what exactly is wrong with it because I did not bring it there with the light on and never have. After an hour and a half, the same tech again, informs me of the same exact thing; "It will not go away until you put the catalytic converter back on." Perhaps I am overreacting and he is right, but my issues is with the possibility of it not being what they're claiming it is. I do not want to continue riding with a "System to lean" and increase the odds of further damaging something more. Unfortunately, there is only one Mazda dealership within my area and the next one is a good two+ hours away. I called them anyway to see if they could shed some light on the issue and they informed me it's usually a vac. leak, but he can't say for certain. He gave me a Mazda hotline number to contact if I'd like to state my complaint(s) and before I do so or go over to the dealership and raise Hell, I'd like to know I'm not in the wrong.

tpb7463

iTrader: (1)

The second dealer is correct--this is typically a vacuum leak. But, you can still get p0171 from a leaky exhaust system north of the O2 bung (possible considering you have replaced the midpipe). In my opinion, the first tech's belief that a missing cat will throw that code is absurd. Other sources of P0171 can include, but not limited to:

Dirty/bad MAF sensor. (Search MAF Cleaning)
Loose Accordion Tube / Connectors (3 in total)
Missing LIM Nipple Caps (Passenger-side, search "Seafoam")
Broken VFAD connector / Missing Cap (Aftermarket Intake)
Weak / Dying Fuel Pump

Considering that they just replaced the fuel pump and this code crops up, I doubt is coincidence. I would double check for vacuum leaks and see if there is any noticeable smell or audible noise around the connection between the midpipe and exhaust header--also consider replacing or checking the gasket there. After that, I would take it to a Mom & Pop. See if they can verify there are no vacuum leaks and pressure test the fuel system.

Kvothe1318

2004 Manual. 15K on engine 68K on body. Stock. KN air filter. ( I removed the baffles from the stock airbox about 4 years ago.)


Ive been having a Po171 for a about a month now. Initially it only popped after driving 100+Miles and would go off after a few days of driving to and from work, just to pop again after another long drive. I initially changed MAF, plugs/wires and ran a Fuel system cleaner. (Lucas brand). Light went off for about a week. I took it to a mechanic in town to check Fuel pressure, Vacuum leaks and O2 sensor readings. Only thing he found was the Downstream (after Cat) O2 sensor was reading nothing at all so he recommended changing that. He couldn't confirm if the Upstream O2 sensors readings were correct and didn't think it was malfunctioning. I replaced the Downstream O2 Sensor with a Denso OE replacement. Drove 50 Miles and cranked engine 2 times and still getting same code and rough idle. To the point the Tachometer would jump between 1.5k and 300 while idling if it would even idle. Mostly it would die the second the engine dropped to idle speeds. I decided to change the Upstream O2 sensor as well ( Denso OE also) and still having issue. I have more power and its driving like normal at any speeds above idle. Im wondering if the code didn't get cleared from the ECU fully if that could still cause issues or if I'm missing an underlying cause. Im honestly at a loss of ideas.

dannobre

iTrader: (3)

Clear your ECU...see if it comes back

You could have a leaky injector seal, there could be leak in the Jet air lines, a missing or damaged VAC cap...lots of areas to look for Vac leaks. The o-rings on the manifold could be leaking as well

Kvothe1318

I tried both brake and odometer methods to clear vram and kam?? And CEL is still there. Only goes away if I remove neg battery cable.

I removed neg battery cable when I replaced upstream o2 sensor. After 20miles CEL came back on with p0171. That's what made me finally make a post instead of just browsing.

I had a vacuum leak test performed by a mom and pop shop nearby before I changed either o2 sensor since that seems the most likely cause. They said there were no leaks found. I'm not sure how they tested it.

Come to think of it when issues first presented I was cruising at 80mph and if I gassed it above 5k it started to sound weird. Only way I can describe is like a cheap ricer exhaust or a snowmobile. Could I have an exhaust leak north of my o2 sensor? If so where from? The manifold or is there other seals than just that? Ideas on how I would confirm a leak there?