P0304 after head gasket and DT header install

RoninSwanson

RoninSwanson

Test Drive
so i just finished a massive job, taken me 5 months. root cause was head gasket failure after not fixing minor coolant leaks. lessons learned. took the opportunity to get the heads flattened 0.003, valve seats machined, new seals, pressure tested, no cracks. put on headers, bilsteins, CAI, new wires, plugs, front O2 sensors, supercharged X radiator (mines a 2001). yada yada yada. i got tons of advice and tips after this job. feel like i could take this thing apart with my eyes closed now. #6 spark plug, no problem.

anyways, I'm getting p0304. no other cylinders. i got spark outside of the cylinder. runs intermittently fine. always idles rough. It's only cylinder 4. no vacuum leaks i could find. if it was air i feel like it would show up in other cylinders. Its getting fuel. when i pulled the plug there was fuel all over it. cleaned it, checked for spark. confirmed.

tomorrow I'm going to swap plugs and wires with other cylinders and see if i can narrow it down to a specific connection. i did not replace the distributor, or cap. I don't plan on replacing things until it magically goes away. I'd rather confirm the problem first.

anyone have any tips or tricks? I feel like I'm on the right path, but looking for sage advice from the crowd.

oh i should also mention it had a quarter tank of very old gas. I filled it with premium, and have already drive on the highway for about 30 minutes, so it should have met the 10minutes at 3,000rpm or whatever it is to relearn the air/fuel mixture.
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
I chased a misfire on my Pathfinder for what seemed like forever. Turned out it was a leaking injector. Figured it out by swapping it to a different cylinder. First I tried cleaning in in an ultrasonic parts washer...no go. So I went to the JY and Got a handful of them. I’m thankful it was on bank 2 so it was pretty easy to get at.
 
RoninSwanson

RoninSwanson

Test Drive
Was it the injector itself or worn /damaged o rings? I replaced all the rings in my fuel rail. You're the second person to suggest leaky injector so I might take the intake off and check number 4 today.
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
There was nothing discernibly wrong with the injector. I took the screen out and ran it through an ultra sonic parts washer. To no effect. I believe it was the electronic portion not closing the injector and flooding the cylinder. I swapped the injector to the next cylinder over and the misfire followed. So I replaced it with a used one. Code went away.
 
RoninSwanson

RoninSwanson

Test Drive
Oooookay now we're talking. When I first pulled the plug to check for spark it was flooded with fuel. And it struggles for a couple seconds at start up, as if it were flooded, or full of coolant like when my head gasket was leaking. Only concern is that it wasn't a problem before I took it apart.
 
RoninSwanson

RoninSwanson

Test Drive
Holy ufck. Got off the phone from parts department at my local dealership, they wanted 236 per injector. Per. Not for 6. Good lord. I'ma keep rockauto in business, that's for damn sure.
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
The injectors are know to go in the 3.3 with little or no warning. After cruising the forums for a while I found many people have suffered the same problem. Many people end up replacing all of them when one goes bad as they will all fail eventually....I chose to just replace the one. Never time to a job right but always time to do it twice!
The price for injectors is crazy. Check amazon or your local junkyard.
 
RoninSwanson

RoninSwanson

Test Drive
alright so this afternoon i took the upper intake off, had a buddy hold it at an angle so i could peak down the intake. Since these are not direct injection, I figured I would find some fuel on top of the valve. no such luck. We decided to take your approach, swapping the injector to another cylinder. gonna move it to the passenger side so that if we do identify it, its easy to access when the new one comes. I'm getting soooo tired of taking off this intake.


alas, junkyards where I live are far. 1-1.5 hours each way. Most local vehicles get tossed onto barges and sent to china for straight scrap. Its such a waste. its a better use of time to just order the part and have it shipped. or buy a whole parts engine and keep it in the garage i don't have.
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
Good luck bro.

Ps: after I gave up on the pathfinder rust issues, I bought the X because most of the drive train is the same. I now have my own parts truck. I’d love to rebuild the engine and swap it into the x one day...I’ve also dreamed of swapping in the coil sprung 5 link into the back but that’s just a dream.

Working on my redneck empire...if I don’t cut the lawn no one will notice the derelict truck right?
 
RoninSwanson

RoninSwanson

Test Drive
So. The mystery continues. I swapped injector 4 into cylinder 1. No more misfire on 4. Now I can literally hear and feel the misfire on the passenger side, BUT it doesn't throw a code. Which worries me that my crankshaft position sensor doesn't detect a misfire at the front of the engine... I still get the same idle code p0505, which I am still attributing to the misfire. Because i can feel it at all speeds, I do not think I have an actual idle failure. New injector comes tomorrow. I couldn't select a specific dot, nor could u even tell what version mine were. So I'm just rolling the dice on this one and grateful for amazon's return policy.
 
RoninSwanson

RoninSwanson

Test Drive
p0304 came back on this morning, but didnt trip the CEL. cleared it, came back on in the afternoon definitively, tripped the CEL, showed up in multiple code readers. cylinder 1 never actually showed an error. now im flabbergasted.
 
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Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
I reread the op. You’ve had the whole thing apart. Have not replaced the rotor, cap or distributor. Have you inspected the cap and rotor? Try running a little fine sandpaper on the contacts. Is there a build up of carbon? Have you checked the gap on the plugs? Let’s do the obvious first before throwing more money at it.
 
RoninSwanson

RoninSwanson

Test Drive
Compression is 150 spark plug is good, cleaned cap and rotor with fine sandpaper.... Still there. It actually got worse.. And it's definitely on the driver side... Feel like there's a poor connection somewhere, everytime I reconnect everything something runs a little different.
Edit: compression 140. Checked two instead of 4 at first.
 
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RoninSwanson

RoninSwanson

Test Drive
I cleaned it out pretty good. I don't have much faith right now, its getting detailed thursdsy then Friday I finally get to go camping again. If it doesn't misfire in the next couple days I can rest easy
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
Glade to help??? I hate it when you have an issue with your ride...you tend to loose faith in it. Hope things go smoothly from now on.
I get to tackle a leaking lower coolant hose tomorrow.
 
RoninSwanson

RoninSwanson

Test Drive
Oh I feel ya. I have a leak in my radiator.. Behind the plastic. Not on the
hoses. Might be unfixable, and it's a brand new supercharged version, I just think it got dinged while sitting next to the truck and all my tools for 5 months. One thing on the distributor cap, it was actually pretty caked with oxide. Here's hoping that is what did it
 
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RoninSwanson

RoninSwanson

Test Drive
Cylinder 4 misfire came back last night. Distributor is the last thing to replace, it's coming Monday... ufcking hell man. Compression is good. Swapped fuel injectors, can't be fuel, can't be air or it wouldn't be isolated. Has to be something in spark.
 
Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
Before you go full Dizzy, try cap and rotor. It’s interesting that it is only cylinder 4. If it was the dizzy you’d think that you’d have multiple misfire. I wonder if there is a crack in the cap? Or maybe that particular electrode is bad.
 
RoninSwanson

RoninSwanson

Test Drive
once again, thanks to amazon prime, i'm just ordering the whole thing. then i'm going to swap cap and rotor first, see if i can isolate the problem. then return it, or keep it. unfortunately the only one on amazon is pretty poorly reviewed. the Cardone one, lots of people have had duds.
 
RoninSwanson

RoninSwanson

Test Drive
I'm going to try swapping the plugs around too, just in case I got a bad one. but faulty new parts seems least likely.

a buddy of mine that works on bikes thinks its the condenser on the distributor thats gone bad, just cause they can go bad without warning and give spark issues. but its still weird that its just #4. hope its just the cap.
 
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RoninSwanson

RoninSwanson

Test Drive
misfire code never showed up again after friday night. very noticeably rough idle remained. I swapped cap, no diff, rotor, no diff, full distributor, no difference. replaced the Idle Air Control Valve, just in case it was bad, even though i had tested it. problem solved.
 
RoninSwanson

RoninSwanson

Test Drive
Been good for almost a week. P0304 came back literally at the end of a 400km road trip, a few blocks from my house. Replacing the cap and rotor now, because they're cheap. Gonna rack my brain on this one. I'm running out of things to check now
 
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Bushnut

Bushnut

First Fill-Up (of many)
Location
Fredericton NB, Canada
So the question is why the misfire on cylinder 4?
Plug check.
Wire check.
Rotor check.
Cap check.
Injector check.
Compression check.
Dizzy check.
I’m stumped man. The only thing I can think of is to pull the plug again and see if it’s sooted up.
I recently watched an Aussie show on youtube about miss fires....ended up being caused by leaking valve seals. MadMatt 4x4.
We’ll get this just have to think it through.
 
RoninSwanson

RoninSwanson

Test Drive
almost certainly not in the head. was rebuilt by a local shop that does race engines. new seals, machined everything.
plugs new
wires new.
rotor cap and distro were all swapped, no difference. returned the complete assembly. felt like it ran a little better, so im just gonna throw new cap and rotor on just cuz.
injector and plug swapped to cylinder 1. no misfire on 1 since rebuilding.
compression is good.
 
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