P0301 Cyl 1 Misfire Problem

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funkytuqe

Member
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2003 Protege 5, 06 Mazdaspeed6
Driving home from work today and the car began to stutter fairy bad then the check engine light cam on. I checked the code when i got home and it is P0301 cy1 misfire (no other codes). I swapped the coils, no change same code. I replaced all spark plugs, no luck same issue (number one looked quite black). The i checked the wires, the long wire to #1 looks good at 3kohms. Ignition wise, everything looks fine. Could this be an injector problem? It almost feels like a fuel problem, she bogs down when i step on it, but if i go easy on the gas it will ramp up OK. Also to confirm, Cyl #1 is the one on the passenger side right?

Thanks
 
I got misfiring issues even after I replaced my plugs. Then I replaced the wires and coils, still intermittent issues. Then I replaced my EGR. Runs well enough now.
Does it stutter when you're driving or mostly at idle?
 
cylinder 1 is the first cylinder from the timing belt...so yes, 'passenger' side, although the entire engine is on the passenger side haha.

when you say 'no change' after the coils/plugs/wires...did that involve clearing the code, and it returned? Or has the light been on ever since the first misfire condition? Also, when you notice the hesitation, does the engine light blink?...or just come on solid?

What specifically was wrong with that plug? Was it all burned up and melted in some areas, or was it coated in goo and fouled? If you could get us a picture of the bad plug, we could quickly narrow it down...if its melted or obviously cooked in some areas...its probably a lean condition, and i'd point to an injector...If its completely coated in a tar like substance, its probably a rich condition and/or too much oil (or even coolant) is getting into that cylinder, and something else is to blame...possibly a head gasket, valve seal, etc....if the plug didn't look much different than the other 3, its probably ignition related...thats unlikely as you said it looked 'bad', and replaced all ignition components anyway...

One way to quickly check an injector is to switch it with the other cylinder using the same color injector...and see if the misfire follows the injector...if it continues to happen at only cylinder 1, its not an injector...If you follow the FSM, you could try this test in around an hour of work.
 
It could be just a fouled injector. Seafom would clear that up easily for 10 bucks and ten minutes. If it doesn't work,.. move on to the more labor intensive trouble shooting.
(am I correct in assuming that a fouled injector would produce a lean condition, or could it stick open and go rich, or either one ??)
(my 1983 GLC was running rough, Mazda quoted a $400 carb rebuild,... a $3 bottle of carb cleaner fixed it)

When my car starts to stumble a little bit at idle, I know it's seafoam time.
 
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Thanks for your responses guys. The car runs a bit rough at idle, and smoothens out under light throttle. If I step on the throttle the car sputters and lacks serious power.
Yes, i cleared the code and it came back the same after said work was completed, no other codes present. When the code pops the CEL will flash for the first 30sec- minute or so then stay on solid. If i pull the plug wire to #1, the spark archs pretty good, but i might just replace the wire for good measure even though it tested ok. The (old) #1 spark plug was coated in black sut, it does not look oily, gunky or melted. I can post up a picture later tonight.
-With regards to the EGR, i live in Canada hence i have the Canadian EGR, having said that i am at 170000KM and never cleaned it. Would a bad EGR give me bad stumble under load or just at idle? Typically How long can an EGR cleaning take?
- I think my issues are well past a seafoam fix due to the serious stumble under load, but i can dump some in the gas tank for the heck of it so that it runs throuh the injectors (did that about 6mo ago).
- Can anyone point me towards a post that explains how to swap injectors? Never done that before.
- Is it worth checking compression that this point or go down the EGR and injector path first?
 
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carbon build up is ok...so that cylinder is probably running pretty rich, but not so rich that its fouling the plug. you did check the gap with the plug installation, right? Probably not the problem, but ruling it out just in case...

I'm in a similar sitation with what i'm thinking is the EGR...in my case i have no codes, no hesitation whatsoever...and the engine runs great off idle...the car will also start fine, idle after the start perfectly fine...warm up normally...and hold idle if i just stay park and blip the throttle...

but...whenever i drive the car and come up to an intersection or something...revs fall like the ignition was turned off...and it catches, barely, at below 500 rpm...and bumps around for 5 to 10 seconds until it levels out at idle...I do have some afterrmarket cams that seem to have made the problem more pronounced...but i'm pretty certain its not just the cams...

From what i've read...a problem like what i have is directly related to a sticking EGR valve...some people have what i spoke of, some have it with a p0300 code...and some have a little hesitation...I haven't seen one where it was giving a specific cylinder misfire though...I too am at pretty high mileage (157,000), and have never once even touched the EGR...never needed to before...

as far as the injector swap, i'll dig up the threads about it when i get a chance...but if you're plug only had some marginal carbon build up...i think its now less likely that an injector is at fault...you have enough egr like symptoms; i'd say thats the best place to start...

this thread is huge, but goes over tons of people that have done the work...it started in 2005, but continued all the way to very recently...pretty good info if you have the time to read through a lot of it...

http://www.mazdas247.com/forum/show...GR-Removal-and-Cleaning-Rough-Idle-Fix/page76
 
Yes i checked plug gap on the old plugs and on the new before installation.
One thing i think i should meantion is that the car smells kind of sulphery or like a rotten eg smell when i go for a test run. Is that telling me somehting about how the cat is running?

I currently am running an OBX header (no pre-cat) with non fouler on the O2, so i'm not sure if that would affect lean/rich O2 readings or hide posible codes.
 
funkytuqe said:
-With regards to the EGR, i live in Canada hence i have the Canadian EGR,
Click to expand...

Do you mean the EGR with the coolant lines? commonly referred to as the "Canadian" EGR,... if not then I'm willing to blame your EGR. Just put on the true "Canadian" version eh, and be done with EGR problems for good.


Here's the Canadian part: http://www.rockauto.com/catalog/moreinfo.php?pk=1515368
It's $109.01 plus shipping. (It's a bit of work to install but you only do it once)

Here's great info about it: http://www.mazdas247.com/forum/showt...-valve-exposed

Quote from Megazuel:
The Canadian Egr mod is completely compatible with US models. Not only did I put one one my personal P5 several years ago and have not had the random misfire/low idle BS that the US Egr valves caused, but I have installed the Canadian variant on several of my customer's P5's to correct the same issue over the years and not one has come back with a problem. For some reason the Canadian version is also cheaper, even with the extra cooling lines and such, go figure.
 
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Well, i bought my car new in Canada at a Canadian dealer so i would assume it has the Canadian version but, if this was not a stock item on a 2003 protege5 sold in Canada then i would have the US variant EgR i guess.
 
Yea, the "Canadian" egr was only available a few years ago. It was first introduced in Canada because of our climate and we had the most problems with the EGR. The guys in the states had to phone Canada to order one. That's where the term "Canadian" came from. They're a little harder to install (connecting the coolant lines) but you only have to do it once. No more annual cleaning.
 
Ah ok i understand. Thanks for the clarification.

I have an update, i just changed the plug wires with new ones and the car seems to run fine now. I'm a little surprised since the old wire checked out fine and I'm not entirely convinced that it has been fixed, but for now she purrs nice. I think i'll plan some wrench time to clean or even just block off the egr just to save further headache down the road. So for now I'll just monitor and hope that awful stumble and lack of power does not come back.
 
Pmazda5 had almost the exact same problem only it was p0303. Turned out to be his short wire.
 
funkytuqe said:
Ah ok i understand. Thanks for the clarification.

I have an update, i just changed the plug wires with new ones and the car seems to run fine now. I'm a little surprised since the old wire checked out fine and I'm not entirely convinced that it has been fixed, but for now she purrs nice. I think i'll plan some wrench time to clean or even just block off the egr just to save further headache down the road. So for now I'll just monitor and hope that awful stumble and lack of power does not come back.
Click to expand...

What a lot of people don't realize is that a milliohm meter tells you very little about a high tension lead. The only thing a milliohm meter is going to tell you reliably is if you have an open. What is really needed megaohm meter or a megger as it's often called. I megger uses a higher voltage on the wire you are testing and can tell you if there is too much resistance (if you know the specs) on the line when it's loaded down. Most people have never seen a megger and for the cost of one versus the cost of new wires, it's just not worth it.
 
I don't think that Megger could even replicate real world on the bench test. If there is a bad spot in the wires coating that might not even show to look at or measure, it might "leak" or "arc" randomly when conditions are just perfect. I think the best way (and easy) to test for arcing is to park the car indoors with the lights off at night or with the windows blocked, then spray the top of the engine down with soapy water, covering all wires and coils. (I guess you can leave the lights on until U spray everything). Then start the car and watch for blue arcing that shows up in the dark. This is especially true if the car's missing when it's humid out but runs better after it warms up (and dries out).
 
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Yes that is a good point. Not to meantion the frequency characterisics of a spark pulse. Most ohm meters just use a DC current to measure resistance, what is realy needed is something that can measure true Z impedance in the frequency ranges in that the spark pulse is active in. That and like you said, the higher voltage measurement would give more accurate results. This equipment costs thousands of dollars so yah not for my garage!
The car ran great on the way to work this morning again. I'll post agian if anything changes.
 
pcb said:
I don't think that Megger could even replicate real world on the bench test. If there is a bad spot in the wires coating that might not even show to look at or measure, it might "leak" or "arc" randomly when conditions are just perfect. I think the best way (and easy) to test for arcing is to park the car indoors with the lights off at night or with the windows blocked, then spray the top of the engine down with soapy water, covering all wires and coils. (I guess you can leave the lights on until U spray everything). Then start the car and watch for blue arcing that shows up in the dark. This is especially true if the car's missing when it's humid out but runs better after it warms up (and dries out).
Click to expand...

Good point. I megger will not cover all real world issues; it is however much better than a simple ohm check. I've seen people check for arcing in the dark before but not with soapy water. Nice tip!
 
I'm not sure but if you spray that soapy water on a running engine and your stream hits the weak spot, your water bottle and you may become the path of least resistance. I would suggest gloves, boots and to not touch the car when you're hosing her down.
 
Haha might be in for an electrifying experience!

I was focusing so much on the continuity of the plug wires it never crossed my mind that the failure could have been in the breakdown of the dielectric insulator. Likely the rubber boot or wire insulator it's self broke down letting the spark go through sraight to ground somewhere on the valve cover or spark plug cavity, there is no visible brakage anywhere on the old wire but I suspect the continous heat cycles broke down the integrety of the insulation. I'll keep the "in the dark" test in mind for the next ime i have problems like this.
 
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