P0300 and P0304

[Phlingwinger]

Okay, here I go...

My 98 rolla with the cursed 1ZZFE (undersized pistons, about a half a quart of oil through the exhaust per tank of fuel) threw P0300 (multiple misfires) and P0304(misfire cylinder four).

What did I do prior to the codes: I replaced the exhaust donut at the downpipe, which required me to remove and reinstall the forward O2 sensor, and I put an O2 sensor spacer on the after sensor to fool the ECU into thinking the CAT is good (which it isn't).

About a hundred miles after that job I throw the misfire codes, the engine runs hard at idle but will accelerate, CEL, flashes instead of coming on solid.

What I've done so far: Check the air intake system for leaks (none obvious), pull the plugs (not fouled, but cleaned and re-insalled anyway), double checked plug wires routed properly for firing order (they were right), checked resistance of injectors (all four were around 14 ohms, engine still warm), used the old long screwdriver to listen to the injectors with the engine running (the clicking varied with engine speed), swapped ignition coils (coil 1,4 into position of coil 3,4, making sure to swap input connectors as well as plug wire positions) and still threw same codes. Removed the injector harness and fuel rail, then put the injector for cylinder four in the position of cylinder three (and vice versa), checked secondary coil resistance (right at 14 K ohms for both coils)...

Again, still threw the same codes...this one's stumping me, any help would be awesome, thanks in advance!

Phlingwinger

[Phlingwinger]

Well, took a day off from work, pulled the head, and found:

#4 cylinder wall scored badly, ring missing about 1.5 inches of material.

The fix:

Called "Donate Your Car" charity for free disposal of vehicle. They take your old car to a high school Vo Tech shop and teach the kids how to maintain, repair, and even customize cars.

Replaced 98 Rolla VE with 2004 Rolla S.

On the road again

[2001corollaDRL]

Sorry you had to call in the donees, but glad you're back on the road again

My girlfriend's 2000 Sentra has bad Cats and we're trying to shop around for a decent price to replace them (I'm no mechanic) but I hope her engine doesn't end up fragging in response... I presume your cats weren't fine because of the engine sending all the oil down the pipes?

[Phlingwinger]

Yep, you just can't blow oil past your rings and expect the platinum in the cat to stay alive forever...

If nothing else I really have a good handle on how emission systems work now, from the MAF to the resonator assembly, I see how the auto manufacturers have put a $60 to $120 part every 12" inches or so!!!

If I can offer any advice on buying a cat at this point it would be this: There are "discount" cats on the web that look very inviting at less than $100, but the precious metal content in these items is low, so the effective life of the cat would also be reduced. Given that it sounds like you don't want to do the install yourself, you could end up buying a cheap cat and paying a mechanic several times over to install your part when you could just dig in and pay for that $350 cat and be done with it...

The 2000 Sentra only comes in a four cylinder ( I believe), so you should only have one catalyst. Don't let anyone charge you for two catalytic converters unless your GF actually has a V6 engine... good luck


Phlingwinger