2003 Ford Explorer Code P0430

Alright so New Years Eve im on my way and out of no where the car spits and sputters then dies. I tryed to restart it, didn't work. Left it and came back the next day to diagnose the problem. I tryed starting it again and it came on for about 20 seconds then died. I got my code reader out and it threw the P0430 code which catalysist efficiency below threshold bank 2. Thought it might be the O2 sensor on the driver side, so i replaced that and still nothing. My next guess was the cat on the driver side, (There are 3 cats on this model). I drilled a hole in that one and it started up fine, i let it run for a bit, shut it off and restarted it to make sure I could get it home. I get on the road and i couldnt go any faster than 20mph. Eventually it died again and i had to have it towed. So I get it towed back to my house and drilled a few more holes in it hoping that it may have just been clogged really bad, but it still wouldnt start up. Im thinking that either that cat is seriously clogged or possibly the others may be. Then i also have a feeling it may be something else. Any ideas about what it could be before I spend all this money to get the cats replaced? ( I have to replace one already) but if im doing one i may as well do them all.

Anything you guys know will help alot.

Which engine does your Explorer have? If the V6, it might still have spark plug wires and if those spark plug wires are original, they may be high in resistance causing poor spark, etc. and contributing to the catalyst efficiency code. I'd start with a tune up if you plan to keep the truck and you plan to replace the converter, which sadly you need to do now since you drilled holes in it.

In the future it's cheaper (although maybe not easier) to remove the sensor 1 oxygen sensor from the exhaust to see if that allows it to start. If the backpressure of the exhaust is causing a no start condition, the small hole from the oxygen sensor will be enough to at least allow the engine to start. If that turns out to not be the issue, you screw the sensor back in and move to the next item, but at least you don't destroy the catalytic converter in the process.

-Rod

All three cats have been replaced along with the IAC valve. When I pulled took the cats off the driver said cat was clogged with the material that they put in them, so they needed replacing anyways. After everything was put back together it came a little closer to starting up but not quit there. You still think it might be the spark plug wires? I almost certain its either spark or air, fuel pump winds up when the key is turned to the on position (unless fuel filter is clogged). Thanks for the help

Also is the V6 4.0L

I still think there is value in performing a tune up if one hasn't been performed in awhile, consisting of spark plugs, spark plug wires, fuel filter, air filter, and a cylinder decarb with SeaFoam or similar would be nice to do as well. I cannot state with high confidence that it will fix the issue, but if you plan to keep the Explorer it will be money well spent.

You'd be doing yourself a favor to find a spark tester and a fuel pressure gauge with Ford adapter to figure out where the likely issue is.

In your original post you said the truck would start but struggled to get over 20 mph. Now it sounds like you cannot get the engine started. Is that accurate?

-Rod

When i was diagnosing it in the begining i could not get it to start, but after i drilled the holes in that one cat it started up and ran a ton better, which made me suspect that that was the issue. Unfortunatley that wasnt it.

After everything was put back together it came a little closer to starting up but not quit there.

Sorry, I'm still looking for clarification with the above statement. Are you currently unable to get your Explorer to start? What happens if you hold the throttle open slightly? Have you made sure all the intake air tubing is secure and correct? You might also try spraying some throttle body cleaner in to the air intake and see if it will sputter like it wants to start. That will help you determine if you are missing fuel and have spark.

-Rod

Heres the update. New Spark plugs, fuel filter, camshaft sensor, Cats, IAC valve, oxygen sensors. The fuel filter was clogged pretty bad, but i got the new one on and fuel is flowing through it well. Main problem now is that i can get it started maybe 1 out of 5 trys, but it runs very rough, and the driver side cat started glowing red. I feel like im getting closer and its going to end up being something really stupid. Going to check yet again for vaccum leaks.

So after all that you still get the P0430 code? No misfire-codes? you could pull the plugs and see if any on the driver's side indicate a dripping fuel-injector (too much fuel, ignition missing, CAT turns red?)
Hope this helps.

no the P0430 code is now gone, just cant seem to keep the car running, i can get it started up but the idle is absolutley horrible, it runs strong at high RPMs but when it drops down to normal idle RPMs it spits and sputters and dies.

Cat glowing red would suggest a rich condition. The catalytic converter is trying to convert the unburned fuel to water vapor but get overworked due to a whole bunch of fuel making it through.

Make sure all the plug wires are installed securely at both ends. If they all snap on nicely, then with a set of insulated gloves you might try pulling plug wires for bank 2, one at a time, to see if there is one that doesn't seem to change the way the engine runs. If you find one, then you know what cylinder to focus on. Try swapping that plug wire with another, then try swapping spark plugs with another cylinder to see if the misfire follows the plug or the wire. If it stays with the cylinder, then you're probably looking to check compression or for a fuel injector that doesn't close. This could be seen with a fuel pressure gauge on the fuel rail. Turn off the engine and if the fuel pressure drops quickly, you've got something that's allowing the fuel pressure to bleed off, likely the injector on the cylinder that's not firing.

-Rod

I checked the fuel pressure late last night, and it was about 60psi, and dropped pretty steadily (not real fast or anything). Although this morning my dad did go out and got it started with the rough idle and sprayed some brake cleaner on the back side of the engine compartment and he said it seemed to try to run a little. Would it be plausible to suspect the intake gasket or vaccum hoses?

Certainly, a vacuum leak could cause a rough idle that isn't noticeable at high engine speeds.

-Rod

Another thought: Is the temp gauge working? Maybe your ECT sensor is dead, ECM thinks engine temp is like -30F; so puts "choke" on (richens fuel mixture). It's only driver's-side CAT that gets hot?

Also; If your code reader can show "live data" you could check to see what the reported engine temp is.

And, quick way to check the MAF is to get engine running, then unplug the MAF. If engine performance doesn't change, then you're not getting good data from the MAF. (however, your problem might be so bad that it overrides this test). You could search around for a way to measure and validate the MAF output.

Another thought: Check the fuel pressure regulator (should be on the fuel rail, with a vacuum hose going to it.) With engine running, see if there's any gas leaking around it. Pull the vacuum line off, and see if there's any gas in / on the vaccum line. Sometimes the FPR diaphram breaks, allows gas to get sucked into the intake mainfold. That would account for it being only one CAT, assuming the vacuum line goes into the manifold on the driver's side.

Isn't the 2003 Explorer (both V6 and V8) a returnless fuel system with a fuel pressure sensor rather than a fuel pressure regulator?

-Rod

Found the source of the problem. Some how there was a hole melted into the the top of the intake, therefore causing to much air to come in at low RPMS and not burning the fuel, which them dumped into the cat causing it to turn red. New question though, any idea why there would be a hole in the top of the intake. Ford was retarded making half the intake out of plastic.

Im extremely certain that the intake was the cause of all the problems, so ill be replacing that. Thanks for the help guys.

I don't know why there would be a hole in the top of the intake manifold, but you'll definitely want to understand that. Is it at a location where if you take the throttle body off you'll be able to see the inside of the hole? Could you have had a backfire that set something on fire in the intake and it burned from the inside out? There would need to be a delicate match of air through the throttle body though to allow such a thing to occur. If the throttle plate was closed air to a flame inside the manifold would be limited, and if you were under throttle the air movement may be sufficient to snuff the flame out....

As for plastic intakes, it's not just Ford that uses them and there is good reason for that. The plastic is lighter than comparable metal and it doesn't transfer thermal energy from the head/block like aluminum or other metals so you get a power benefit from that. Plus it's likely cheaper to manufacture. What you experienced is rare and the root cause is probably not the plastic intake, although hopefully that's all that will be needed to fix the issue you're fighting.

-Rod

Vehicle is fixed and running like a champ, finally! After this whole ordeal i believe I have a conclusion. The catalytic converter was clogged at the "Y" causing exhaust and an enormous amount of heat to build in the intake eventually melting a dime size hole in it. Although I did spend a ton of money on the other parts that were replaced the vehicle needed a tune up. Hopefully this will help other people having similar problems. Thanks shorod and skeeter123 for the help, I would have had no idea what I was looking for.

I'm glad to hear you got it all figured out and the truck is running well again! Congratulations, and thank you for keeping the forum updated on your progress and findings.

-Rod