2001 Protege 2.0 random misfire - symptoms
- Thread starter rtrussel
- Start date
No problem Ian. Hope your Protege runs fine now. I am saying GOOD-BYE to my Mazda this weekend.. It runs OK, but i am ready for a new car of a different make. It also starts with M...
Maserati? ^_^
Rubberspoiler
Member
- :
- '99 323 FP-DE
...no-no.
It must be a Maybach!
It must be a Maybach!
Oh, the infamous P300 Code(random misfire). The Shop Manual for the Protege has a list of 25 diagnotics procedures to run through to pin point the mismfire. It ranges from fuel issues to sensors, to electrical wires and connectors. It's a nightmare to run through. And if fuel isnt the probelm it gets worse cause all electrical components can check out ok, which makes things even more frustrating. I'm going to list some of the most common fixes assuming your vehicle is up to speed on routine maintanence.
I personally just went through this on my 2002 Protege DX that had only 78k miles.(Fuel pump and regulator faulted at the same time...luck of the draw)
- Random Order -
*1st check for any vaccum leaks. Check all hoses, and inspect the intake hose. They're known for cracking at the bottom.
To see if your intake manifold or throttle body gaskets are leaking spray some carb cleaner around the maiting surfaces when the vehicle is idling, listen for the rpm's to fluctuate...if nothing then you're good...well you should be.
*Fuel PSI...if the PSI is under 40psi then you need either a Fuel Pump or fuel Pressure Regulator. If the PSI is above 65psi then most likely you'll need a pressure regulator(99-03 psi specs). This is based off of normal operating levels. The min psi and max psi levels are different, that's another story. If you replace the fuel pump I recommend that you replace the Fuel Pump unit as well. This has the high pressure filter built into it. But it's your call.
* EGR Valve....Just replace it, cleaning it can be a temporary fix, and you'll end up replacing it anyways.
*Spark - Ignitional Coils are common, assuming your wires and plugs were routinely replaced.
* CMP & CKP sensors are not likely, only b/c if those go then your vehicle would consistantly run like crap. But if you notice any visual signs of wear, like melting of the wires, or a cut in the wire exposing the copper, then it could be the issue. The CKP sensor is located by the crank pulley. Measure the gap between the sensor and the teeth using a feeler gauge. The gap should be between 0.5mm and I think 1.5mm. If more than 1.5mm either replace the crank pulley or the sensor. Inspect the teeth attached behind the crank pulley for any serious signs of wear. Any chipping, cracking, or missing teeth. The pulley is cheaper than the sensor it self. The sensors are magnets....your basic trigger sensor setup.
* Fuel Injectors are possible cause. But typically if any one of those go bad the issue is continuous. Not at random....I would recommend an injector flush before replacing these. Only b/c they're pricey and if they are gummed up its an easy fix, and less costly. Plus, check to see if you see any fuel leakage around them. If one of the O-rings went bad this can be a cause as well. Plus, your vehicle would run abnormally lean.
* MAF - I hate these things, they can cause so many issues. Clean it first, and when the car is idling like normal knock on it to see if it is faulty. You will notice the car will stumble. This is the easiest way to test it if you dont have a higher end diagnostic scanner that will read it in real time.
* PCV Valve - pull it, if the check ball doesnt rattle, then replace it. $2! If your's does rattle, hit it up with a little carb cleaner while it's out. Keep it operating smooth.
Hope this helps, when I get around to it I will post the whole diagnotic steps for this code. Just the list of common parts to fail and cause the P300 code it self. And they're in order from most likely causes to least.
I personally just went through this on my 2002 Protege DX that had only 78k miles.(Fuel pump and regulator faulted at the same time...luck of the draw)
- Random Order -
*1st check for any vaccum leaks. Check all hoses, and inspect the intake hose. They're known for cracking at the bottom.
To see if your intake manifold or throttle body gaskets are leaking spray some carb cleaner around the maiting surfaces when the vehicle is idling, listen for the rpm's to fluctuate...if nothing then you're good...well you should be.
*Fuel PSI...if the PSI is under 40psi then you need either a Fuel Pump or fuel Pressure Regulator. If the PSI is above 65psi then most likely you'll need a pressure regulator(99-03 psi specs). This is based off of normal operating levels. The min psi and max psi levels are different, that's another story. If you replace the fuel pump I recommend that you replace the Fuel Pump unit as well. This has the high pressure filter built into it. But it's your call.
* EGR Valve....Just replace it, cleaning it can be a temporary fix, and you'll end up replacing it anyways.
*Spark - Ignitional Coils are common, assuming your wires and plugs were routinely replaced.
* CMP & CKP sensors are not likely, only b/c if those go then your vehicle would consistantly run like crap. But if you notice any visual signs of wear, like melting of the wires, or a cut in the wire exposing the copper, then it could be the issue. The CKP sensor is located by the crank pulley. Measure the gap between the sensor and the teeth using a feeler gauge. The gap should be between 0.5mm and I think 1.5mm. If more than 1.5mm either replace the crank pulley or the sensor. Inspect the teeth attached behind the crank pulley for any serious signs of wear. Any chipping, cracking, or missing teeth. The pulley is cheaper than the sensor it self. The sensors are magnets....your basic trigger sensor setup.
* Fuel Injectors are possible cause. But typically if any one of those go bad the issue is continuous. Not at random....I would recommend an injector flush before replacing these. Only b/c they're pricey and if they are gummed up its an easy fix, and less costly. Plus, check to see if you see any fuel leakage around them. If one of the O-rings went bad this can be a cause as well. Plus, your vehicle would run abnormally lean.
* MAF - I hate these things, they can cause so many issues. Clean it first, and when the car is idling like normal knock on it to see if it is faulty. You will notice the car will stumble. This is the easiest way to test it if you dont have a higher end diagnostic scanner that will read it in real time.
* PCV Valve - pull it, if the check ball doesnt rattle, then replace it. $2! If your's does rattle, hit it up with a little carb cleaner while it's out. Keep it operating smooth.
Hope this helps, when I get around to it I will post the whole diagnotic steps for this code. Just the list of common parts to fail and cause the P300 code it self. And they're in order from most likely causes to least.
Canadian-ES-GT
Member
- :
- Protege
I had the same problem (it turned out to be EGR) and yes, the diagnostic only said multiple misfire. I as well had problems starting my car and had to give it gas to keep it going. When I did get it going, it ran rough, slow and had terrible MPG. EGR cleaning isn't worth it like someone else said, mine lasted 2 months and it was back to the way it was. Thankfully, either Mazda or a parts company made a new version of the EGR which runs coolant to it to keep moisture from settling in and causing it to rust. Get that version of it. It has been about 5000KM's that I have been running with new EGR and not once has it let me down.
Here is the diagnotic info for possible causes of the P300 Code. Straight from the Mazda workshop manual.
DTC P0300 Random misfire detection
• CKP sensor malfunction
• CMP sensor malfunction
• Ignition coil malfunction
• High-tension lead malfunction
• MAF sensor contamination
• Excess air suction in intake-air system (between MAF sensor and dynamic chamber)
• Fuel pump malfunction
• Fuel pressure regulator malfunction
• Fuel line clogged
• Fuel filter clogged
• Fuel leakage in fuel line
• Purge control solenoid valve malfunction
• PCV valve malfunction
• EGR valve malfunction
• Vacuum hoses damages or improper connection
• Related connector and terminal malfunction
• Related wiring harness malfunction
• Poor fuel quality
DTC P0300 Random misfire detection
• CKP sensor malfunction
• CMP sensor malfunction
• Ignition coil malfunction
• High-tension lead malfunction
• MAF sensor contamination
• Excess air suction in intake-air system (between MAF sensor and dynamic chamber)
• Fuel pump malfunction
• Fuel pressure regulator malfunction
• Fuel line clogged
• Fuel filter clogged
• Fuel leakage in fuel line
• Purge control solenoid valve malfunction
• PCV valve malfunction
• EGR valve malfunction
• Vacuum hoses damages or improper connection
• Related connector and terminal malfunction
• Related wiring harness malfunction
• Poor fuel quality
made in china
Member
- :
- 2002 Protege5
Well, we just bought a 2002 P5. I FORGOT to bring my code scanner when we were looking at the car, otherwise I would have known it had a pending P0171. On top of that, second day after buying the car, it started idling horribly, would accelerate erratically and threw a P0300 code on top of the P0171 code.
The P0171 was due to a vac line falling off behind the throttle body, and the air intake tube being loose. Someone had been fiddling around back there.
The P0300 was due to bad coil packs.
I would like to share some tips about determining what can cause a P0171 and/or a P0300 as I spent a lot of time troubleshooting this car:
P0171 is mix too lean, basically the ECU has done all it can to make the exhaust stoich (air/fuel at 14.7) but it is needing more fuel than the maps allow. So yeah, a loose (or broken, common) intake tube or stuck EGR seems common for these cars.
How to know if it's a stuck EGR? Well, the EGR will cause hard starting as that is a bigger hole than a vac leak. Even with 2 intake leaks our P5 started fine. I would bet that it wouldn't start well if a EGR was stuck open.
P0300 is multiple misfire. Basically, the coil pack shorted out somewhere. A wet plug can cause this due to engine damage. Bad plug wires can allow spark to chassis ground which will cause this too. A coil pack with a path to ground (same as if a plug wire goes bad) can do this too.
However, my P0300 was pretty obvious: When the coil packs warmed up, the car would start running on 2 cylinders. Pretty much at the same spot every day on my way home. A coil pack sits on top of your engine, and the internal components get hot from the engine heat. If the coil pack has an electrical defect, the heat will reveal it. I even pulled over once to remove the packs just to let them cool down and re-installed them to get home. Also, bad coil packs will present driveability issues like a on-off switch. Trust me on this, bad injectors or EGR will have a less abrupt power issue. It's pretty obvious when it's an electrical failure. EGR or bad injector would be a softer loss in power, not like the on-off effect bad coils give you.
It has been several days now and my car runs fine, finally. Let this be a lesson to me: "I should have bought that nice Honda I looked at before this P5(hand)"
I hope this helps somebody!
The P0171 was due to a vac line falling off behind the throttle body, and the air intake tube being loose. Someone had been fiddling around back there.
The P0300 was due to bad coil packs.
I would like to share some tips about determining what can cause a P0171 and/or a P0300 as I spent a lot of time troubleshooting this car:
P0171 is mix too lean, basically the ECU has done all it can to make the exhaust stoich (air/fuel at 14.7) but it is needing more fuel than the maps allow. So yeah, a loose (or broken, common) intake tube or stuck EGR seems common for these cars.
How to know if it's a stuck EGR? Well, the EGR will cause hard starting as that is a bigger hole than a vac leak. Even with 2 intake leaks our P5 started fine. I would bet that it wouldn't start well if a EGR was stuck open.
P0300 is multiple misfire. Basically, the coil pack shorted out somewhere. A wet plug can cause this due to engine damage. Bad plug wires can allow spark to chassis ground which will cause this too. A coil pack with a path to ground (same as if a plug wire goes bad) can do this too.
However, my P0300 was pretty obvious: When the coil packs warmed up, the car would start running on 2 cylinders. Pretty much at the same spot every day on my way home. A coil pack sits on top of your engine, and the internal components get hot from the engine heat. If the coil pack has an electrical defect, the heat will reveal it. I even pulled over once to remove the packs just to let them cool down and re-installed them to get home. Also, bad coil packs will present driveability issues like a on-off switch. Trust me on this, bad injectors or EGR will have a less abrupt power issue. It's pretty obvious when it's an electrical failure. EGR or bad injector would be a softer loss in power, not like the on-off effect bad coils give you.
It has been several days now and my car runs fine, finally. Let this be a lesson to me: "I should have bought that nice Honda I looked at before this P5(hand)"
I hope this helps somebody!
Last edited:
made in china
Member
- :
- 2002 Protege5
Just wanted to follow, all of this P0300 trouble is officially in the past. But the CEL came on for P0421, which means the upstream cat failed. Makes sense as it is a victim of raw, unburned fuel being dumped into it while I was trying to drive on a random misfire. Common on Mazda's to have cat failure after a P0300 event.
Yay!! What an awesome car!
Yay!! What an awesome car!
not tryin to sound like a jacka** or anything but dude any car u buy will have troubles at some point.. u just had bad luck.. get it fixed and get over it.. or sell it.. simple as that
made in china
Member
- :
- 2002 Protege5
dude something ain't right with these cars. I know what you are saying, I own a newer full size truck and on those forums there's a lot of unhappy owners who expect their trucks to be as reliable as a their old Civic. I kinda roll my eyes at them but at the same time I cross my fingers that those things don't happen to much to mine......
This Mazda, well dude they are designed poorly. Rust is not uncommon on them, and I find that unacceptable. I can deal with the occasional break-down, if the rest of the car holds up. But I already found rust at the bottom of all 4 doors. Common problem. And of course the whole pre-cat thing is BS too because this is only a common issue on these cars.
I've owned a bunch of Craigslist el-cheapo daily drivers. Some required some work, but ran excellent for years after that. Something's wrong with these cars, very weird that P0300 and P0171 are so common around here, followed by P0421.
Normally if it wasn't me saying it, I'd be inclined to agree with you.
This Mazda, well dude they are designed poorly. Rust is not uncommon on them, and I find that unacceptable. I can deal with the occasional break-down, if the rest of the car holds up. But I already found rust at the bottom of all 4 doors. Common problem. And of course the whole pre-cat thing is BS too because this is only a common issue on these cars.
I've owned a bunch of Craigslist el-cheapo daily drivers. Some required some work, but ran excellent for years after that. Something's wrong with these cars, very weird that P0300 and P0171 are so common around here, followed by P0421.
Normally if it wasn't me saying it, I'd be inclined to agree with you.
