Spark plugs, o2 sensor, engine facked?

ITHURTZ

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2006 Mazda 3 S
Short explanation.

Car ran normal. Put on a 2.5" exhaust from the flange back. Took a look at the 2nd cat. EMPTY


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Car ran better.

Over the weeks the car eventually lost its umpf, and bascially moves as stock or worse than stock.

Thought the main cat was clogged. So today cut out a section of the cat to knock it loose and gut it. Well, NOTHING was inside the main cat attached to the header.

In this pic is speaker wire fed through the 1st o2 sensor out the bottom back of the "cat" through the hole that was cut. Nothing there.


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The first point of blockage would be either flex pipe, or the race muffler which has a 1" or 1.5" straight through core. Both clean and free of any obstructions. Which leaves me to thinking that both these cats blew out before I ever put the exhaust on.

For s**** and giggles I thought I would pull the spark plugs out

Spark plugs are in order from looking at the front of the car, passenger to driver side 1, 2,3,4

here is passenger side #1. Oil is on the threads, but it is CLEAN oil. I assume from when I poured it in I spilled some and it gathered there.


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#2


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#3


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#4


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The main sensor before the headercat


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The code I had is PO421
But i have no f'in cats, which means a sensor would be bad correct? Pre cat or post cat?

The tip of the pre cat sensor is white is that normal?

#2 spark plug had white build up on the tip, indicating?

Im really at loss for what this cars problem is. The spark plugs were dry, so there is no indication of water or fluids on them.

Its a 2006 3 s with 52,400miles, mostly town suburb driving the trip computer says I get 26+mpg.
Before all this was happening I could easily move about at 3k rpm, now I gotta get her up to 3500-4k for the same movement but the car sounds funny and doesnt have that get up and go power. Indicating lean?

Someone help me! Im lost
 
The PO421 code is gone, got a new one!

PO139 woooooooooooooooooooooooooooo

Heated o2 sensor H02S (rr) circuit problem


So which one is that pre or post cat? Would solve my power problem?
 
The PO421 code is gone, got a new one!

PO139 woooooooooooooooooooooooooooo

Heated o2 sensor H02S (rr) circuit problem


So which one is that pre or post cat? Would solve my power problem?

I consider myself pretty well informed on our Mazda engines, but I'm not a professional mechanic.....
That said, my take is that the lack of cats has caused your O2 sensors to read that the fuel mixture is too rich (since the cats aren't there to burn off any incomplete combustion). As a result, the computer has been trying to 'lean-out' your air-fuel ratio causing the #2 & #3 plugs to discolor white as they're getting too hot. This combination of fouled plugs and too lean fuel mixture is causing your power loss.
You probably need to get a new primary cat, a new post-cat O2 sensor, and a couple of new plugs.
But I also recommend getting a second opinion before doing anything.

Good luck!
 
Well the other question is, where did my 2 cats go? I never took em out, and when I went to, they were already blown out.


And yes I have a post cat 02 on the way, then next week gonna throw in some new plugs.
 
Well the other question is, where did my 2 cats go? I never took em out, and when I went to, they were already blown out.


And yes I have a post cat 02 on the way, then next week gonna throw in some new plugs.

No idea on what happened to the 2 cats. I have seen the internal element of a cat eventually burn out, break the mounts and rattle around inside the chamber, but never get blown out down the pipe. Even if it could, I would think it would end up trapped at the muffler.

Did you get the car new or used? If used, then the only logical explanation is the previous owner removed them. Back in early '08 guys were stealing cats off cars and selling the elements for cash because I believe they contained small amounts of platinum, and platinum prices were skyrocketing. If new.......... then that's a mystery that may never be solved.
 
The p0421 code is just telling you the cat is not doing it's job. I would replace the second cat and put on a header with the non-fouler 02 fix. The primary cat costs as much as a race header. Replace the spark plugs and check again for the p0139 code. If it comes back replace the affected 02 sensor. A bad 02 sensor can destroy a converter by causing a rich running condition.
 
No idea on what happened to the 2 cats. I have seen the internal element of a cat eventually burn out, break the mounts and rattle around inside the chamber, but never get blown out down the pipe. Even if it could, I would think it would end up trapped at the muffler.

Did you get the car new or used? If used, then the only logical explanation is the previous owner removed them. Back in early '08 guys were stealing cats off cars and selling the elements for cash because I believe they contained small amounts of platinum, and platinum prices were skyrocketing. If new.......... then that's a mystery that may never be solved.

Bought the car new.

The p0421 code is just telling you the cat is not doing it's job. I would replace the second cat and put on a header with the non-fouler 02 fix. The primary cat costs as much as a race header. Replace the spark plugs and check again for the p0139 code. If it comes back replace the affected 02 sensor. A bad 02 sensor can destroy a converter by causing a rich running condition.

I have no cats, its catless (shhh feds dont know) I have a header on the way, should arrive tmw. But to tell you the truth I am dead afraid to put it on now the way the engine is behaving. The post o2 I did the anti fouler 3-4 weeks ago, so when I get my new 02 sensor its already to go.

When I put the new post 02 sensor in do I need to reset the ecu? Or will it "magically" be fine (spark plugs to)

Also here is my primary o2 sensor, does it look ok?


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Put the post o2 sensor in today, as well as 4 new spark plugs. The car still dont feel right. The rpm's just dont climb as they used to before I did the exhaust.

I reset the ecu while doing this so I dunno. Id really love to have ALL my power with these mods back.
 
Put the post o2 sensor in today, as well as 4 new spark plugs. The car still dont feel right. The rpm's just dont climb as they used to before I did the exhaust.

I reset the ecu while doing this so I dunno. Id really love to have ALL my power with these mods back.

Have you (or do you have access to) run a scanner and see if it's throwing up any more codes?
 
I have autozone for my code scanner haha. Right now I have no check engine light



WELL GOOD news and bad news.

After about 10miles of driving this morning, the car seemed to be "reborn" and I now have full power again.

BAD news, arrived at one job and got out to do something. I come back maybe 1 min later and my temperature gauge way pretty well above normal :( From browsing the forums one guy had this problem and everyone told him to check the fan. In park, checked fan NADA. Put ac on @60 full blast, fan..... NADA. So is this safe to say I have a bad connection or a s*** fan? I can spin the fan easily with my finger if that makes any difference.

I drove 30miles before arriving at my destination before the temp thing happened. So paranoid as s*** I put the heat at 90 and blasted it for almost the rest of the work day with the ac button on. :(

Well I turned it all off my last 10miles before home, and no temp change on the dash meter at all, stayed at normal. Checked the fan at the last house, nada. So I am confused.


Problem #2 that has dazzled me. Sitting at a stop light my car likes to "jerk" moving me a few inches then stops whatever it was doing with the rpm's. So bascially I stop 750rpms, then after a few seconds it goes to 550-600 or whatever norm is. Then jumps to 750. What it does to jerk me a few inches I dont know as I am not paying attention when it does it. The one thing that made me notice it was I was at the mcd's drive through in the morning and it felt like a 1/4 second earthquake. Shoot me?
 
I have autozone for my code scanner haha. Right now I have no check engine light



WELL GOOD news and bad news.

After about 10miles of driving this morning, the car seemed to be "reborn" and I now have full power again.

BAD news, arrived at one job and got out to do something. I come back maybe 1 min later and my temperature gauge way pretty well above normal :( From browsing the forums one guy had this problem and everyone told him to check the fan. In park, checked fan NADA. Put ac on @60 full blast, fan..... NADA. So is this safe to say I have a bad connection or a s*** fan? I can spin the fan easily with my finger if that makes any difference.

I drove 30miles before arriving at my destination before the temp thing happened. So paranoid as s*** I put the heat at 90 and blasted it for almost the rest of the work day with the ac button on. :(

Well I turned it all off my last 10miles before home, and no temp change on the dash meter at all, stayed at normal. Checked the fan at the last house, nada. So I am confused.


Problem #2 that has dazzled me. Sitting at a stop light my car likes to "jerk" moving me a few inches then stops whatever it was doing with the rpm's. So bascially I stop 750rpms, then after a few seconds it goes to 550-600 or whatever norm is. Then jumps to 750. What it does to jerk me a few inches I dont know as I am not paying attention when it does it. The one thing that made me notice it was I was at the mcd's drive through in the morning and it felt like a 1/4 second earthquake. Shoot me?

I can't help with the jerking as it sounds like your car is an automatic and all of mine are manuals. However, engine temperature issues are nothing to fool around with as many things can get damaged if the engine is under-cooled.

Personally, in your situation I would start with the basics:
1) Verify you have the right amount of coolant.
2) Verify the water pump is working.
3) Verify the fan temperature switch (and fan motor) are working.
4) Verify (not exactly sure how in our cars) or replace the main thermostat.

Again, good luck!
 
Id go with #3, but how do I check it?

Went to the gym tonight, had zero issues.

I also forgot to state, that at the stop light it wasnt jerking all the time, but sounds like something would turn on, then turn off.
 
Took it to the dealer, they said ac compressor was bad, blah blah called extended warranty to see if they will cover it. They also say there is a short in my fan harness somewhere. Long story short I picked my car up today

Hey got my car back!

Hey they denied my extended warranty!

Why? CAI and catback exhaust! I have to return it all to stock before they will fix it. But heres the catch, they WILL fix it IF i bring it back to stock HAHAHAHAHAHA.SO ya it isnt going back to stock.

So heres to self fixing. I dont give 2 s**** about the a/c compressor right now, Ill take the belt off and call it a day. The fan I need to do. I found the 40amp fuse under the hood and put a multimeter to it and heres what I got

Fuse panel lid


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Mr fuse himself (on left)


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Ok so car is OFF, keys are NOT in the ignition and the battery is connected. I tested the fan fuse


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I tested the fuse next to him


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ALL other fuses read ZERO except that fan fuse, why? Is this my no working fan problem? Does that mean the fuse is blown?
 
ALL other fuses read ZERO except that fan fuse, why? Is this my no working fan problem? Does that mean the fuse is blown?

Yes, the way fuses work is that when they're working it's the same as a straight piece of wire. Your meter is measure a potential (or voltage drop) between the 2 leads. If the fuse is good, then (just like a piece of wire) the voltage will be the same on both sides and the meter will read zero.
When the fuse is blown, there's no longer a connection between the 2 ends of the fuse, so you read the voltage drop.
As a side note, testing it this way only works when there's power to one side of the fuse. If you pull the fuse out to test it, or disconnect the battery, then use the Ohm Meter function to test for continuity. If the fuse is good, there should be no (or very little, like less than 1 ohm) resistance.
 
Fuse was blown, replaced fuse now fan and a/c work perfect. Only problem now is even with a anti fouler and diode I keep pulling a P0139(hand)
 
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