p0300 advice on diagnosing

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02 Protege LX, 03 P5 (x2), 09 Miata, 07 Mazda3, 13 Fit, 09 Ody
Got a p0300 today. No other codes.

Plugs and wires have been recently replaced. One of the coil packs has also recently been replaced.
I am not sure what it could be I've always gotten a 301 or 302 and not the generic 300.

Any ideas?
 

Grendel65

Banned
:
2018 Mazda
PO300 This is a generic DTC. I suggest to re-set the ECU via the OBDII diagnostic connector "directly" and drive a full cycle and recheck for DTC via the direct access of the OBDII diagnostic connector.
There is a misconception on forums with many DIY that a DTC is the actual problem. These DTC's were programmed in the ECU as a starting point for more diagnostic evaluation and testing of components to determine exactly what caused the DTC to be posted.
 
:
02 Protege LX, 03 P5 (x2), 09 Miata, 07 Mazda3, 13 Fit, 09 Ody
PO300 This is a generic DTC. I suggest to re-set the ECU via the OBDII diagnostic connector "directly" and drive a full cycle and recheck for DTC via the direct access of the OBDII diagnostic connector.
There is a misconception on forums with many DIY that a DTC is the actual problem. These DTC's were programmed in the ECU as a starting point for more diagnostic evaluation and testing of components to determine exactly what caused the DTC to be posted.

Yes, well aware that p0300 is a generic code and a starting point for diagnostics.

Other than clearing the code and doing a drive cycle do you have any other suggestions for diagnostics?

The service manual mentions CKP Sensor and CMP sensor as possibilities. Where are these and what do they look like?
 

Grendel65

Banned
:
2018 Mazda
There is NO diagnosis for "GENERIC" Diagnostic Engine Codes (DTC)! Look go re-read what I said and what you seem to respond to know about the generic DTC????
There are procedures to follow to find engine management system possible problems (anomalies can generate a generic DTC that is not a problem and will self clear the dash board caution light with 1-5 engine cycles)and "GUESSING" is not proper procedure. I
Maybe you would rather have help from fellow DIY's and not anyone that is an actual Auto Technician?
Good luck with your problem!
 
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02 Protege LX, 03 P5 (x2), 09 Miata, 07 Mazda3, 13 Fit, 09 Ody
Not guessing. I am looking at the mazda protege service manual and the 24 step procedure for p0300 and the number of possible causes that are listed.

You may be correct that this code will not re-occur or that an additional code will surface. But until then I'd like some help in narrowing the possible causes down.
 
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pcb

The Diagram Dude
:
2002 MP5
You might have just got some bad gas.

I say jyst throw some injector cleaner in the gas and give it some time.
 

Grendel65

Banned
:
2018 Mazda
Not guessing. I am looking at the mazda protege service manual and the 24 step procedure for p0300 and the number of possible causes that are listed.

You may be correct that this code will not re-occur or that an additional code will surface. But until then I'd like some help in narrowing the possible causes down.
LOL You don't even have a confirmed problem yet. Go back to the beginning of YOUR thread and read slowly the posted information. I think you will find the first thing that was suggested to do? ha!


You might have just got some bad gas.

I say jyst throw some injector cleaner in the gas and give it some time.

No this is NOT a good suggestion. Many chemicals in some of those cleaners can create their own set of problems and very seldom cure an extinguishing one especially from a random generic code like a PO300 that is not targeting any specif cylinder. When ever you get a DTC you must look what the DTC is caution and then what procedures to correct the issue are needed. "SNAKE OIL" and seeking advise from a witch Doctor. LOL

https://www.youtube.com/watch?v=cmjrTcYMqBM
 
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pcb

The Diagram Dude
:
2002 MP5
Got a p0300 today. No other codes.

Did your CEL flash or did it just come on ?

If it didn't flash then it's not as serious.

... One of the coil packs has also recently been replaced.

You should consider replacing the other coil pack.

Coil packs can be a real problem with our car. They can test fine on the bench but fail on the car.

They are a leading cause of engine misfire with our car and can be bad brand new out of the box.

... I am not sure what it could be I've always gotten a 301 or 302 and not the generic 300.

It's possible that if the coil is misfiring on two cylinders (1&4 or 2&3) it might register as a "random" misfire.
 

pcb

The Diagram Dude
:
2002 MP5
.... "SNAKE OIL" and seeking advise from a witch Doctor. LOL ...

I've been using "Snake Oil" (Seafoam) since the day I bought my car 9 years ago.

I originally put half a can in the gas and half in the oil.

After washing out the engine sludge (3-4 flushes)
I put half a can in the new oil and leave it in till my next oil change.
I put as shot in the gas at every fill up.

My car has never been a problem, idles smoothly an doesn't burn a drop of oil.

I'm sure I'm keeping my oil rings clear of carbon buildup.

 
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02 Protege LX, 03 P5 (x2), 09 Miata, 07 Mazda3, 13 Fit, 09 Ody
What I have done...
1) traded both coil packs with my other P5.

2) Cleaned the MAF, checked the air intake hose after the MAF for cracks, and checked for Vacuum leaks as best as I can.

3) can of seafoam in gas.

4) pulled a single spark plug. It looked good, a very little oil around the top but no oil down into the threads.

5) Cleared codes. Did drive cycle Mode 1 and have driven it a little.

No codes yet, but all DTC haven't been checked yet.
 
:
protege5
LOL You don't even have a confirmed problem yet. Go back to the beginning of YOUR thread and read slowly the posted information. I think you will find the first thing that was suggested to do? ha!




No this is NOT a good suggestion. Many chemicals in some of those cleaners can create their own set of problems and very seldom cure an extinguishing one especially from a random generic code like a PO300 that is not targeting any specif cylinder. When ever you get a DTC you must look what the DTC is caution and then what procedures to correct the issue are needed. "SNAKE OIL" and seeking advise from a witch Doctor. LOL

https://www.youtube.com/watch?v=cmjrTcYMqBM

You appear to be new here, but no need to be a d!ck. We're all just here to help.

And yes, there are more ASE master techs than just you on this forum. Some of us just don't feel the need to advertise, bragging about passing a couple tests. I know several ASE master techs who have never spent one day in a shop actually working on cars. And I know other ASE master techs I wouldn't let touch my bicycle. So you passed a test. That's good, but doesn't mean it's a license to be a jerk.



To the original poster...
P0300 isn't a "generic" code. It is a code for a random multiple misfire. This code will come up with you have misfires is more than 1 cylinder long enough to trip a code, but not long enough or consistent enough in any one cylinder for the computer to single out any particular cylinder.

Did you replace the plugs and coil pack because of an issue, or preventative? Did you use OEM coil pack or cheap generic? Did you gap the spark plugs? Never trust the gap when they come out of the boxes. Are the connectors on your coil packs connected securely? The locking tabs get brittle and tend to break or crack on the harness connectors.

It could be something as simple as bad gas, maybe a bit of water got where it shouldn't have, or could be about a thousand different possibilities. I would recommend clearing the codes, and just drive the car. Sometimes there's just fluke things that happen for no reason. If the ONLY code in your car was a P0300 then I wouldn't worry about it too much right now. Clear the codes, and drive it. See if it comes back. If it does then maybe next time it will be accompanied with another code that can help in troubleshooting. I wouldn't spent too much time, or any money trying to diagnose a P0300. All you'd be doing is throwing a dart in the dark after a few drinks and hoping you find the target.
 

pcb

The Diagram Dude
:
2002 MP5
Plugs and wires have been recently replaced.

One other thing...

Use regular NGK V-Power copper plugs.
They give the the strongest most reliable spark.

They wear out and have to be gapped/replaced more often but they only cost $1.50 a piece.

 
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'02 Mazda Protege5
I've been using "Snake Oil" (Seafoam) since the day I bought my car 9 years ago.

I originally put half a can in the gas and half in the oil.

After washing out the engine sludge (3-4 flushes)
I put half a can in the new oil and leave it in till my next oil change.
I put as shot in the gas at every fill up.

My car has never been a problem, idles smoothly an doesn't burn a drop of oil.

I'm sure I'm keeping my oil rings clear of carbon buildup.


I was thinking about using Seafoam. I can see some black stuff on the pistons when I peek through the spark plug hole. but it runs fine so I suppose " if it ain't broke don't fix it" I'm afraid Seafoam will ruin my cats and o2 sensors... it turns into smoke but it can't be good to have all that engine gunk shooting out the exhaust...
 

pcb

The Diagram Dude
:
2002 MP5
Did you replace the plugs and coil pack because of an issue, or preventative? Did you use OEM coil pack or cheap generic? ...

You might want to invest in quality coils.

When I first joined this forum I replaced my coils after reading about all the problems they can cause.

I went with Beck-Arnley and they have been working fine since then but if IIRC Hitachi was the OEM supplier of coils for our car.

It might be the only part on my car where I will spend the money to go OEM.

 

pcb

The Diagram Dude
:
2002 MP5
I was thinking about using Seafoam. I can see some black stuff on the pistons when I peek through the spark plug hole. but it runs fine so I suppose " if it ain't broke don't fix it" I'm afraid Seafoam will ruin my cats and o2 sensors... it turns into smoke but it can't be good to have all that engine gunk shooting out the exhaust...

I haven't had any problems with Seafoam.
I'm on my original O2 sensors and cat.
It's been in my engine and gas since I joined this forum.

If you're worried about releasing too much crap at once, you could go slow with it and just put a couple of shots in the gas at every fill up and 1/3 of a can in the oil to wash out the sludge.

I suppose you could release a huge chunk of gum or carbon and send a huge "blood clot" down the pipe and give your car a heart attack or stroke but no one here on this forum has ever said they wrecked their car.

Seafoam also has a guarantee and will replace your engine if it kills it.
(although you might have a hard time proving it and collecting)
 
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Mazda P5
Seafoam is healthy for your car. I put it in my oil every 3-4 oil changes, some people do it more. Same with gas, when I start to lose MPG(20 or so) I put some in gas and get my mileage back.
People put it in their brake booster line and let it sit in there to clean out the IM and that's when it gets smokey
 

Grendel65

Banned
:
2018 Mazda
You appear to be new here, but no need to be a d!ck. We're all just here to help.
Calling a memeber a dick (which is a forum guideline inappropriate and they do say they deal with members that violate the guidelines...will see?) for correcting bad information? Did I insult you or respond to you personally in this thread or any other yet? ROLMAO you just only made me curious as I hope other do to go look at what you contribute to this forum?
ROLMAO.
 

Grendel65

Banned
:
2018 Mazda
One other thing...

regular NGK V-Power copper plugs.
They give the the strongest most reliable spark.

They wear out and have to be gapped/replaced more often but they only cost $1.50 a piece.

Wow I impressed, finally something almost worthy of not commenting to correct you on?
But it is the other parst of the electrical system not the spark plugs for the plug energy output. LOL
And the reliability of the spark is also from the other ignition components not the spark plug.
All spark plugs wear out only some have material that tend to help them live longer. If spark plugs start or begin to show signs of any wear that is the time to replace them regardless of there recorded mileage.
I really have never ever read any professional racer, performance engine builder or crew chief in the world comment that they seldom change spark plugs because they still looked good. LOL

,........ I can see you have no real idea about spark plugs and why some wear faster then others and why some types will help support better MPG or engine output, etc. ? But hey I am going to let this go because I recomend the use of single ground electrode on most very application.
I use plain old Champion Copper spark plugs that I changed out at between 5-10,000 mile on my new 2018 2.5 Skyactive engine. Ran a couple of oscilloscope tests and found that the factory plug was actually less efficient for performance. However if getting all the wear possible without concern for diminished MPG and engine out put I would have stayed with the factory spark plug.
[url=https://postimg.cc/YhcYFQX4] [/URL]
[url=https://postimg.cc/XX5ynpVn] [/URL]
[url=https://postimg.cc/qzzMx779] [/URL]

And speaking of ignition parts what a crock of s*** about the quality of these coils for a MAZDA. REALLY! LOL
First I don't see anyone that tested or at least posted testing results that should that they were not to at least the specification for that type of coil. Next no one has posted any analysis by way of using electrical testing equipment to see the wave pattern of any of these coils to make a statement about quality? This is just another forum MYTH about these failing often with no one considering how many units are actually out there and the predictable and mathematical probability that a sum number of any electrical parts manufacture may fail. If it were an epidemic there would be at least reasonable and repeated TSB's reported which there is not. Most of the coils that fail are directly due to DIRTY FRICKEN ENGINES and no preventative maintenance servicing. Just like computers if you dont keep the fans cleans something is going to fail because of it. LOL

But off my rant really, the MAZDA coil ar as simplistic as a coil can get. There just is not much there that can go wrong and improving the material used may extend the life of the eletrical componet but the design and what are used by almost all the OEM as well aftermarket coils are all the same. Just because there are some that offere a 7 dollar coil from a generically packaged supplier and another in a POP bright Bule box with lightning Bolts on the box at 3 x times the coat does not make it better then the 7 buck coil.


PLEASE NOTE I am not talking about PERFORMANCE coils which are total different from OE< as far as martial and engineered output when we start considering the quality and what the specification are which are also generally a bit Hyped for those retails customers that dont really know what the best engineering specification to consider are


On a personal note ...pcb how come looking at your response history I can find many pictures of things you actually do and mostly internet stolen pictures from other people to post with your responses??? Hmmmm!? LOL

Want me to post my spark plugs changes on my MAZDA, or how many spark plugs I keep around my garage for all my engines? ;)
You know it really helps other when you show that you do s*** instead of only look stuff up and post about what you r found?

Here you go just a container I could easily get to. And please note the note and also I took the picture in my kitchen just so there is no question that they were not from my garage. I also want you to notice that I have a set of NGK for my FORD Truck that I am doing an ignition service on. Even had to replace two coils. LOL but that was because the boot were cause arching and it was cheaper to replace the coils that to but a boot kit. LOL

[url=https://postimg.cc/dD7wL9Br] [/URL]

[url=https://postimg.cc/XrWb160k] [/URL]

[url=https://postimg.cc/qtbH7t61] [/URL]
BTW have have many other spark plug but I am currently building shelves in my garage and dont have good access to all of them or I would have posted more. LOL
 
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Grendel65

Banned
:
2018 Mazda
Any EMTs on the board? If so you like myself can accesses the none posted (proprietary) ingredients of SEAFOAM and can post it? Because I am an engineer and manufacture of performance automotive parts which are distributed through many suppliers all over the world which also offer seafood in their line of item sold , so I have been reminded legally and maybe more ethically I should not really post to many negative information other then recommendation not to use it. Maybe if more knew what was in it they would waste their money on "SNAKE OIL" products.
Honestly the introduction of water while the engine is running will work better then almost any so called cleaners and faster. Smoking up the neighborhood with seafood more to piss off your neighbors then cleaning your engine.


I will say that peace of mind using some chemicals in your vehicles you think works even though they may really be more placebo in nature sometimes is worth using them for some people. I can't totality argue this point and even keep a couple cans for some that insist I use it when I work on their vehicle. Think about that. They come to me with a problem and then tell me what they want me to use to correct the problem? hahahahha
 
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