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A buddy was owner #2 on this car and took decent care of it. The issue below (p0300 and P0421) showed up, they tried to fix it at the shop, failed and he sold it to me.
I’ve done plugs, coils, EGR and can’t find a Vacuum leak. I swear there has to be a vacuum leak but I can’t find one. I’m trying to decide where to go next. So here is the detail.Problem Description: 2002 Mazda Protege5 2.5L 180K
The issue is always seen when driving slowly after a period of driving, usually over 55mph. Car starts to miss on what feels like multiple cylinders. There is shaking of the vehicle when this happens
CEL (check engine light) comes on and usually starts blinking with a considerable Loss of powerError codes:
P0300 – Misfire on multiple cylinders
P0421 – Catalytic converter issue <-installed the non fouler Workarounds: Pull plug wires and reseat. I see spark jump and then the issue goes away when I reseat. I've done this once so far Pull over shut off the car, sit for 20 minutes and restart, light goes solid and power is back. This doesn't always work Pull over shut off the car, and turn it right back on, light goes solid and power is back. This doesn't always work What's been done so far on this issue: Coil packs replaced before I bought the car contacts look new and they used grease Mass Air Flow Sensor Replaced before I bought the car. EGR valve Replaced by me a few hundred miles ago. Spark plugs Installed today with copper OEM plugs. Old plugs had elements that were worn to points but were still gapped close to .044 all of them looked good with light brown / ash look to them. Seafoam pumped into vacuum lines. Vacuum lines-- Not able to find a leak fuel pressure -- Not tested yet Injectors -- Not tested yet compression -- Not tested yet Main ground -- Not tested yet Battery-- Two shops say this is bad (JAN09 install) I'm planning on a new one Crank position sensor -- original fuel pump (filter built in)-- original 02 Sensors-- original Pre Catalytic converter-- original Main Catalytic converter-- original My thoughts: Mass Air Flow?? pull it and clean it? Clear flood mode ?? What does this tell me? OBD2 reader and Torque app ?? Look at some PIDS? Oscilloscope?? Hook this up and try to look at the injector pulse? What would you try next? At the suggestion of Jotmon1, Im adding these links for what I'm going to try tomorrow. Protege5 fuel pump pressure test
fuel sending unit replacement (hope I don’t have to do this)
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Look at the fuel pump pressure. Could be vapor locking (Fuel pump not providing adequate volume or pressure). If the fuel pump pressure is low then none of the fuel is returned to the tank (held by the fuel pressure regulator on the fuel rail). If the fuel pump is injecting a little air, it will collect in the fuel rail and deprive the injector of fuel. If there is a schrader valve on the fuel rail, when the car stalls, depress the valve slightly and see if fuel is present. Be careful to catch fuel with rags etc. to prevent fire.
Wife called to let me know she felt like taking the car for a spin (thought it was fixed) and the light came on. She claims she drove right back to the house as soon as she saw the blinking CEL. She popped the hood, called me up and then asked me if the catalytic converters are always supposed to glow bright red like that. She felt bad and made me a cake to apologize.
I’m guessing the cats are going to have a nice rattle to them when I get home and check them out. I’ll let you know what I find.
Check for clogged or clogging cat. Check fuel pressure. Check for carbon tracking. Google is your friend. If carbon tracking replace wire or coils or boots depending on which type it has.
I would check fuel pressure, fuel pressure regulator and the fuel injector harness connectors at the fuel injectors with a noid light.
Karl
I had a few minutes to check that fuel pressure, and heard a vacuum leak when I played back the video. FYI there seems to be plenty of pressure on the return line
Also I pulled the relay they are talking about in the video and saw this
[url=http://imgur.com/aXqsE6v]
[/urlI’m going to fix the vacuum leak, take a look at those contacts and that relay, and I’ll post another video. I think I still hear a miss but I ran out of time to shoot a video of it.
Car will run just fine for a day or so. Come off the interstate to a stop, take off and press on the pedal and there is almost no power. Then you get about 10 seconds of that before it really starts misfire and shaking, along with a blinking engine light for a P0300. It’s obviously not burning fuel when it does this as it makes the plugs covered in soot when I pull them.
Pull over, shut it off and lift the hood. Start it up and the misfire is still happening. Pull a plug wire from the coil just for a moment while it archs, then reseat the wire. Doesn’t matter which cylinder. Misfire goes away and all is good.
This happened in my driveway as well once before. I originally found that pulling the negative battery terminal would fix it. Then i was pulling plug wires to see if I could figure which cylinder(s) wasn’t contributing. That’s when I saw that pulling a plug wire and reseating it temporarily cleared up the issue.
The car is a 2003 Mazda protege5. It has a coil over plug on cylinder 2 with a plug wire going to cylinder 3. The other coil is over plug 4 with a wire to cylinder 1. I’ve done plugs twice (copper OEM) , coils, EGR. There is also the occasional P0421 in the cat, but I’ve duped the sensor (stacked non foulers on the 2nd o2) for now so it doesn’t come up. Last guy probably drove it with the misfire and cooked the cats. I’ll deal with that later. The battery is 5 years old and tests bad as well. That will be my next purchase for this vehicle.
What happens when I pull the plug and let it arch for a second? Why does that make the misfire go away?
this problem still vexes me.
I swapped the plugs, coils and wires, as well as EGR. this will run great until I come to a stop and try to take off. then it nearly stalls. Runs great on the interstate for almost 30 minutes. I would of figured that a fuel issue would of showed up in that timeframe.
does this lack of power / nearly stalling point to a vacuum leak? I need to regroup and get a new plan.
There might be an exhaust restriction in the CATs since you mention they are cooked.
Eric has great videos on diagnosing this problem: http://www.ericthecarguy.com/fuel-and-emissions/519-how-to-diagnose-exhaust-restrictions
Do you have a generic code reader? If so the first thing i would do is check your short and long term fuel trims when the problem occurs. Your short term will constantly adjust but shouldn’t be more than 10% positive or negative. Long term should be the same although you shouldn’t see it adjust as much. Any number in the positive would indicate a lean condition. Any number in the negative would indicate a rich running condition. Anything + or – 15% I would consider excessive. See what the fuel trim is during the misfire event.
[quote=”ArmedsouthernEr” post=154002]Do you have a generic code reader? If so the first thing i would do is check your short and long term fuel trims when the problem occurs. Your short term will constantly adjust but shouldn’t be more than 10% positive or negative. Long term should be the same although you shouldn’t see it adjust as much. Any number in the positive would indicate a lean condition. Any number in the negative would indicate a rich running condition. Anything + or – 15% I would consider excessive. See what the fuel trim is during the misfire event.[/quote]
Thanks for the tip. Between the fuel trims and experinentation, this came down to bad coils and clogged cats. All hail Eric, the Lord and master, for his brilliant videos.Sent from my SM-N920V using Tapatalk
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