Hello everyone,
I have turned to you folks over the years and have never been let down. I am just about to throw in the towel on my 04 Wagon, figures since I just put HID lights in. This always happens to me when I do a non necessity upgrade to an older car...they die right after.
Back story:
2004 Mazda6 Wagon 3.0 v6 5spd auto. Bought 3+ years ago with a misfire. Someone installed Autolite copper plugs in it.
Replaced:
Both warm-up catalysts (pre-cats)
Plugs (Motorcraft)
COP's (United brand)
PVC
Plenum gaskets
Air cleaner
Trans fluid (x3)
Ran great. Lots of power 19mpg average (17-26, town/highway)
Only code since that time is p1410 and it stays.
Currently:
The car has been feeling like it is misfiring in 4th-5th gear (below 2000RPM) Very light throttle
Add throttle and it feels like I am driving on a windy day. Like there is some external force slowing me from outside and it is not regular or rhythmic.
When I start the car after warming up and press the accelerator to go it feels like there is no power. No jerking or stumbling just I have to keep pushing the pedal down and nothing different is happening. After driving a mile it feels normal.
Current Gas mileage 12mpg
So I replaced the Plugs (OEM Motorcraft platinum) x6
Denso COP's x 6
Check all hoses and vacuum lines. All Fine
Drive today: Traveling down a highway, I rarely drive anymore, it was appalling the difference. I used to be able to drive up the hill in 5th gear and 60MPH. I could not accelerate without downshifting but it could hold it. Today I could not do better than 42MPH and it wanted to go to 2nd gear at 5000RPM but then dropped down to 4200RPM. I cannot seem to push any faster than 4000-4200 RPM on flat in 3rd.
Incidentally the car has been smelling like sulfur all the time for around 6-8 months, no matter how hard I drive. Generally I will rev to 4000RPM once or twice a year so not hard. Even on flat highway it wants 4th gear all the time
MIL ON:
p1410 (for some time but does not illuminate MIL)
p0300 (first time ever)
p0302 (first time ever)
The sulfur smell would lead me towards your cat. You've replaced the pre cats but perhaps the rear cat is getting clogged. This is just a guess so temper that with your other responses. Don't give up yet, the wagons are a rare breed!
The Sulfur smell was telling me that the catalyst was overwhelmed. I did not think about the rear cats however.
Addendum. For a while 2 years ago the Spark plug at the #1 position (I think. Pass side rear, bank1) was loose enough to pass gas (he he) and sound but I didn't clue onto it for some time. That was the manifold that I had to extract a stud from and repair so I thought it was an exhaust leak. The smell of raw fuel in the cabin from fresh vent should have clued me in.
Anyways, the coil at that position was badly discolored, both on the boot and the inner conduit. I cleaned it up and moved it forward to #4 (pass side front, bank2) so I could get to it if it acted up but I never noticed anything.
My LTFT1 (bank1/rear) is showing a NEG(-) number indicating rich running. (CMP sensor?)
LTFT2 (bank2/front) is showing a POS(+) number indicating a lean burn. (vac leak, clogged injector, blocked exhaust?)
I don't know what my number should be as I am at work and do not have access to my Manual but I am fairly confident there should not be a 25 point spread between the two.
I will read curves when my new Bluetooth scan tool comes and can tell if there are inversions in the O2 sensors. This will at least tell me if the front cats are involved.
This is the most fragile car I have ever owned.
I'll stick with it for now...unless I find a nice TSX wagon before I figure this out.
It may have something to do with transmission differences, mine being a sluggish automatic, and what is invariably advanced age of the vehicle in general. I have taken it WOT twice both times backing off at 500RPM. The first ended up with oil on the exhaust (from somewhere)and smelly for a bit. The second was recently downshifting to 2nd on the freeway trying to accelerate past 42mph (auto shift in D). Now it is definitely off in power. 500RPM is probably past its functional limit at the current mileage. I suppose this would not make it fragile but rather owner abused. Oops.
Gotcha... my 04 6s wagon just rolled over 100k last week. It was a little sad to cross that Mark but it was really a mental difference than anything specific to the engine.
I finally got some more numbers. Incidentally the car will "ping" so bad after 4000RPM while driving I have to back out. I can rev to 5000+ easily in neutral.
Idle:
LTFT1 -12.5
LTFT2 -9.4
MAF (lb/min) 1.75
2500RPM:
LTFT1 -5.5
LTFT2 10.9
MAF (lb/min) 0.54
Exhaust system comes off tomorrow [groan] as right now I am operating under the impression that I have an exhaust restriction.
You might also want to do a compression test before dropping the exhaust. You can also pull both front O2 sensors out and take it for a quick ride and see if there is more power. The bad smell for a prolonged period is not a good sign for the cats. Doing the compression test should be 1st on the list.
You mean exhaust back pressure right? I agree. Seeing if there is excess pressure would be ideal. I am uncertain how pulling the upstream O2 sensors will affect my mixture during the test. Possible damage?
I took the O2 sensor (bank 2) and visually checked it and it looked (okay) even if I couldn't back light it. I realize this will be my only real way of showing restriction since I cant see into the downstream converter for bank 2. My dilemma is not wanting to pay $100 for the equipment to check. How many more times in my wrenching future am I going to use it? although if I keep this car I may get several uses out of it.
Can anyone think why the fuel would suddenly go lean (bank2) after about 1200RPM? And if bank 2 is leaning out (possible obstruction) why would I experience a misfire code on Bank1 (cyl 2)?
My Shop Manual says this: for P0171, P0174 (Fuel system trim lean [RH], [LH])
Misfire
HO2S Deterioration
HO2S Malfunction
Leakage Exhaust System
MAF/IAT sensor malfunction
Air suction in intake system
Fuel Filter clogged
Fuel Pump Malfunction
Fuel Leakage on fuel line from fuel delivery pipe and fuel pump
Pressure regulator Malfunction
Fuel Hose Return Clogged
Fuel Injector Malfunction
VVT control system malfunction
Purge solenoid valve malfunction
Purge solenoid hise improper connection
Insufficient compression
PCM malfunction.
I suppose it is better than not knowing what to do next.
That accordion hose is pretty much shot but my repair was through. Gorilla tape for strength under and about half a roll of stretched electrical tape.I did just check it on your suggestion but it has been holding strong for years. Still looks plenty sealed. You cant even tell unless you look close.
That air hose is common to the plenum, both banks. I can't figure how it would only affect one.
I am going to go with b1lk1's suggestion once my body aches let me. My fever broke so maybe today. My brain can still wrap around the possibility of a bank 2 restriction. This manifests as enough back pressure the computer see it and switches the fuel curve for that bank from rich to lean.
These cats were melted when I bought the car. The pic shows what came out of the rear bank. What was in the front bank??? I couldnt see the cat and there wasnt much that dropped out when I removed that front manifold but...
Update:
Cleaned MAF/IAT, CMP1 (522 Ω), CMP2 (542 Ω ), CKP (293 Ω) All within spec, but a bit dirty.
Intake vacuum test shows 17 in Hg at idle and 18in Hg at 3000rpm - restriction unlikely
New Values
Idle:
LTFT1 = -8.6
LTFT2 = -3.1
I checked the resistance on the starter when cranking and it shows even resistance over the whole crank cycle. I have not done a plug out trial of that test however.
I suppose a 15% change in mixture is within specifications. Maybe I am just need not perceverate on this and look elsewhere for my pinging/power/gas mileage issue.
Thanks everyone who has been sending ideas. I would love you all to keep them coming.
EDIT: On further thought I realized that a more accurate compression test would be in order. I tried both of the compression test kits that Harbor Freight sells and neither fit. Does anyone know for sure of a brand of compression tester that will fit the 3.0 v6?
Summary: Loss of power, P0300 and random P0302, P0304, etc... Felt a misfire at low RPM (<2000RPM) light throttle, surging in 4th and 5th gears (ATX), pinging beyond 2500RPM under moderate acceleration, low MPG (12 mpg city).
I finally got a scan tool that interfaced with my laptop and was able to read wave forms. The downstream O2 sensor in bank 2 was reading flat
(nearly... 0.02V) and smooth in curve. I bit the bullet and ordered all four catalytic converters and all four oxygen sensors. After installing them this weekend I must report that Mozzie is back like I have never felt. This fix has eliminated all surging, rough idle, low MPG, and loss of power. Starts are faster and exhaust sounds better. Ladies and gentlemen, I am in love again (and that's saying a lot since it is an automatic).
What I learned. When I replaced the melted pre-cats (Three-way catalyst/warm-up cats) four years ago I did not also do the downstream converters or the oxygen sensors. The condition of the catalysts was nominal at best and it contributed to an increased back pressure that reduced my ignition efficiency. This reduction in combustion (sub-clinical misfire) resulted in increased temperature due to nu-burnt hydrocarbons and caused the "new" pre-cats to fail along with the downstream cats. Whether the downstream catalytic converters failed completely and thus precipitated the failure of pre-cats is unknown. Regardless, after inspection, they are all plugged (the exception is rear manifold which is still open). I wasted $700 on pre-cats when I did not buck up and do the whole thing. This says nothing about working on the garage floor (albeit on cardboard) in the middle of what had been a solid winter here in the NW. Lesson learned. Don't be cheap! Dealer wanted $7000USD (2017) to replace all 4 cats and O2 sensors.
I want to thanks everyone who gave me input. Your feedback (esp Scott with the "...don't give up") spurred me on.
Wonderful news and great information for the archive here on the board! Thanks for posting it up.
I've always been a bit dissappointed with my fuel economy. I check it regularly and haven't been above 24.6mpg yet. I've seen others report 28 (IIRC) and your post makes me wonder if the cats play a role there. What do you think?
Wonderful news and great information for the archive here on the board! Thanks for posting it up.
I've always been a bit dissappointed with my fuel economy. I check it regularly and haven't been above 24.6mpg yet. I've seen others report 28 (IIRC) and your post makes me wonder if the cats play a role there. What do you think?
I would agree. Anytime the engine is running more efficiently it makes more power per unit fuel. That means I use less fuel to do the same work. Gas saved.
I never used to have to worry about spinning tires unless I really flogged it. Now it is quite easy making a curb lane turn (right), especially on an incline. I fear I will now be eating tires. (a good problem considering the alternative).
Glad to hear you saved it ! Hate to see them go to the scrap yard just because the owner didn't want to do CPR (spend some time and money) on them. :smile2:
For future reference, please post where you order from and if you don't mind, share how much you paid for all of it.
Hi. I want to do this to my wagon soon. The front Precat and 02 sensors were replaced before at 108k. The rear precat is now cracked at 134k and I want to replace that along with the other 2 oxygen sensors sensors, spark plugs, and COP.
Is there a write up to replace the rear precat? Can't seem to find a write up.
I found the write up on the spark plugs (sticky DIY), but there are no pics, so if you could also point me in the direction of a post with pics that would be wonderful.
Hello, it's not fun the first time but the reward is great. Start with a nice spray down with thread lube. I use mostly Blaster but liquid wrench or WD40 or anything will help.
Start forward of the resonator and learn the ratchet/extension/elbow/socket dance one bolt at a time.
I wrote a few steps down here.
A now largely defunct site 6crew, which also happens to be a goldmine of info, has a step-be-step
Thank you! I am ordering parts today and will start this work once they come in.
I just read through your instructions and that does seem like a lot of steps. I had no idea you had to remove the alternator and belts. I've done it before on my old Subaru, so I'm not worried; I assume I do this for space issues. Guess I will add the alternator belt to my list of parts since I'll already have I off
Also, about the bolts: I dont want to break them off. How long did you soak them? And did you get replacement bolts from Mazda? Somewhere else? Will they come off with hand tools? I don't have a torch to heat anything or air tools.
I'm sure I will have more questions, so thank you in advance for offering to answer.
Thank you! I am ordering parts today and will start this work once they come in.
I just read through your instructions and that does seem like a lot of steps. I had no idea you had to remove the alternator and belts. I've done it before on my old Subaru, so I'm not worried; I assume I do this for space issues. Guess I will add the alternator belt to my list of parts since I'll already have I off
The alternator needs to be removed to take the manifold nut off the #1 cylinder (mine was broken and had to be drilled out). It comes out after the exhaust. (remember to re-install it before you bolt the exhaust back up, I did this, oops) The only sticky points are getting the belt off. I purchased a 1/2" breaker bar with a swivel head to do this (then it was easy), and getting the alternator plug off (lots of grunting and sore fingers).
Squeeze the green plug tab near the base
I did not have to remove any suspension parts. When the belt is off spin the idler pulleys for the serpentine. Mine were bad. Cheap and easy to replace at this point.
I did not have to lower the sub-frame. I did it the first time but soon realized it was not necessary with the right counter-clockwise twisting motion to get the curvy twin flex pipe over the steering rack heat shield. The EGR required an adjustable clamp and 3' breaker bar (before loosening the manifold bolts of course).
I soaked the exhaust bolts the night before (I am west coast on unsalted roads) and used almost all the bolts over again. I have an impact and used it when I could but with the extensions and swivels I mostly ended up hurting myself and used mainly hand tools as a result. Replace the manifold studs/nuts with Mazda OEM. PLEASE. It is an aluminum head and drilling one out below the mating surface was a nightmare.
The remainder of the exhaust bolts can be replaced with whatever fits well (use anti-seize).
Ok thank you for the pics. Before I order anything I'm going to take off the old pieces first before I get myself in debt
I'm in no rush to do this, but I'd like to get this fixed before the summer comes around. The car is just sitting now.
I'm on the west coast too (SF), so hopefully the bolts will come out after being soaked over night.
Another questions if you don't mind: you mentioned removing the egr valve and intake manifold. Should I do that first? For example:
Remove IM, egr valve
Remove most of the pre-cat exhaust bolts, then alternator
Finish removing pre-cat
I tried reading the thread about exhaust removal on 6crew but the link says I'm not allowed to read it (I don't understand why both Mazda threads I'm trying to learn from block users from reading information, but thats another story).
Thanks!
I'll post pictures (or start a new thread) when I start , which will be in about two weeks (I'm in holiday starting this weekend).
I understand waiting to see what you have before spending money. I usually have to minimize downtime and sometimes that comes at extra cost (still cheaper than professional garage)
You can do everything from below. Unless you change the coils and plugs there is no need to take off the intake manifold. The EGR tube is unbolted (un-nutted really) from the bottom. It is big and mine was stuck but eventually relented.
The alternator comes off after the flex pipe and before the rear manifold. Start at the collector/resonator where the pipe becomes single, then just work your way forward, unbolting one section at a time. The flex pipe comes out easier if you unbolt the all the brackets holding the cat that is next to the oil pan. Drop the rear of the flex pipe down as you rotate counter-clockwise and wiggle. The heat shield for the power steering rack gets a little bent but it makes putting everything back together easier. The only thing that you really need to do from the top of the engine is torquing the front manifold nuts when you are done.
Working on you back is tough and freeing old exhaust nuts is not fun but otherwise it is a pretty straight forward job. Make sure you have leverage.
So I managed to remove 8 bolts last night. The first pic is what I saw when I first got underneath the car. The second pic has green circles around the bolts I took off. The red circle is the piece I can't understand how to take off. It's a bracket that looks impossible to get to. The precat is free from the bottom, but I feel stuck now. What do I do next? You said you didn't drop the subframe, but it seems impossible to go any further. Also, the steering rod (?) is in the way. What am I missing?
In your directions, you said to remove resenator bolts and then remove the 02 sensor. I can't even see the 02 sensor from here.
Hey there, did you figure it out? Sorry, I had e-mail notification off for this thread by accident. The upper bracket stays put. Everything forward from the resonator comes off in segments, working forward. That pipe (with the 180 degree turn is what needs to come out to gain access. It is called the flex pipe. that flex pipe needs to be lowered from the rear (where it attaches to the rear catalyst). While you are lowering it you will also leed to move the rearward end towards the drivers side at the same time you are rotating it counter-clockwise. Drop (wiggle) move left (wiggle), rotate (wiggle). There may be some levered prying of the pipe and as long as you are only contacting the power steering rack heat shield it is okay. DO NOT PRY AGAINST FLUID LINES. The heat shield however is not a problem it it gets a bit deformed as long as it does not impede the movement of the tie rods.
I've managed to take off the center resonator, the twin flex pipe, and the front right passenger side converter! Yay me. It was really difficult to remove the flex pipe and converter, you have to really squeeze the pipes past a shield, but you don't break anything.
Now I can clearly see the exhaust manifold and the 6 bolts that hold the manifold in place. This weekend I plan to take off the EGR pipe, alternator, and the exhaust manifold. I think it's safe to order the part about now
I've managed to take off the center resonator, the twin flex pipe, and the front right passenger side converter! Yay me. It was really difficult to remove the flex pipe and converter, you have to really squeeze the pipes past a shield, but you don't break anything.
Now I can clearly see the exhaust manifold and the 6 bolts that hold the manifold in place. This weekend I plan to take off the EGR pipe, alternator, and the exhaust manifold. I think it's safe to order the part about now
Congratulations! Put some lube on the EGR nut. You are almost there. Don't shortcut the parts. I recommend doing all the cats, OEM exhaust studs and O2 sensors. I would also go with a quality exhaust manifold gaskets (like Beck Arnley for OEM or Felpro) rather than the ones that come with the catalysts.
Project car Finally finished! Replaced the exhaust manifold/cat, 2 oxygen sensors, 6 spark plugs, PCV valve, the egr purge valve and valve solenoid, air filter, oil change, cabin air filter, and all wiper blades. Passed smog today!!
Thanks for your help!! I've attached pictures of the car.
That is fantastic news! I am glad you got it back together and I bet it feels pretty satisfying. May you have many miles of trouble free motoring. If I could suggest one more thing. If it is an automatic I would recommend doing a 3x trans fluid replacement (I use Mobil 1 multi vehicle in my 2004 5spd auto) as transmissions are no longer made and 2-3 thousand to rebuild. You use special fluid if you are 6 speed Aisin.
Nice! Glad to see another saved, these cars are meant to pile on the miles if you can avoid the rust.
I am getting ready to install a set of gently used CP-e headers with a catted mid pipe so I am just gonna cut off the old pipes, dreading those manifold to engine bolts though, lol.
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