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misfire and 1st bank o2s

Fowler.Alex

NAXJA Forum User
Location
Charlotte, NC
I'm a little stumped on what to do. I have a CEL saying cylinder#3 misfire, bank 1 sensor 1 malfunction, bank 1 sensor 2 malfunction, and radiator fan relay circuit malfunction, and small evap leak. I've had the evap leak for a while, but the others popped up this week. Mind you, my themostat went out last week, causing overheating. I whana think that the O2's are going off cause of the misfire. I checked the spark plugs, they seemed fine, they've 30,000 miles on them. They have a greenish tint on the finger. I'm kinda in a bind with money right now and trying to diagnose this right, hopefully. Thanks in advance.

Alex
 
Sorry to hear but it doesn't sound good.... 01's are known for the head cracking when they overheat, with the most common first symptom being a cylinder 3 misfire. Search on 0331 head and you will find all kinds of posts about it..
 
It is always more helpful if you post the EXACT code numbers, along with the explanation of it if you have it.

Reason being there are a number of codes for different ways oxygen sensors fail, etc. So just knowing that both the upper and lower is not enough info. With codes, the devil is in the details.

Post em up and we'll go from there.....
 
Yeah the infamous 0331 head. I've driven 150 miles since that overheat happened, no water in the oil yet. I'm thinking about doing a compression check to hopefully rule out the head. Maybe bad injector? I might do a fuel pressure check as well.
 
Codes popped up st:

p1491 radiator fan relay circuit
p0303 cylinder #3 misfire
p0130 bank 1 sensor 1 O2 sensor
p0136 bank 1 sensor 2 O2 sensor
p0456 evap small leak ( prexisting from a couple monthes ago)

This is what i interpreted from www.obd-codes.com. Hopefully this will help ya'll, thanks for ya'lls quick responses

Alex
 
Yeah well a little update. Noticed today that the coolant was a little low and the oil is milkshaked, so I'm pretty sure another 0331 head has bit the dust. Any suggestions, little low on funds, maybe rebuilt junkyard head? Its parked for now, can't afford to mess up the bearings.
 
With a misfire on a coil on plug application. The easiest thing to do is move #3 coil pack to another cylinder and see if the misfire follows. If it follows you know you have a bad coil pack. Typically the oxygen sensor codes are popping up due to the engine misfire.

Maybe see what a shop would charge to do a hydrocarbon test to confirm a blown head gasket. Or if you have access to a leak down gauge you can confirm the blown head gasket yourself. Good luck.
 
Yeah well a little update. Noticed today that the coolant was a little low and the oil is milkshaked, so I'm pretty sure another 0331 head has bit the dust. Any suggestions, little low on funds, maybe rebuilt junkyard head? Its parked for now, can't afford to mess up the bearings.

I would have to agree with you. Low coolant and "milkshake" oil are the primary clues for the 0331 head cracking.

Many guys (most) can see this crack(s) if they remove the valve cover. The weak area and the spot that almost all of these heads fails is between cylinders 3-4.

I would start with a visual inspection to confirm.
 
A leak down test most likely won't show the 0331 crack. Pull the valve cover, pressurize the cooling system and look for coolant seeping from between cylinder #3 and #4 valves. Of you could do it hot and watch for the leak.
 
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