monkeyposeur Posted October 3, 2012 Share Posted October 3, 2012 My friend has a '97 22E L wagon w/5MT and about 200k. He had a bad oil leak so I stopped by and took a look and all I had to do was replace the valve covers. However, I noticed his CEL was on so I had him get the codes pulled today. I have read the links the CEL sticky provides, but could still use some help. Codes are: PO301 (cylinder #1 misfire), PO420 (catalyst system effeciency below threshold Bank #1), & PO440 (evaporative emission control system malfunction). He said that he was told about a year ago that his cat was going bad (don't knw if it is front or rear) and possibly had his O2 sensor(s) replaced. He's looking through his records and I am about to go over to his place and check out the plugs. Obviously the first thing I will do is to check his plugs and wires, and possibly the coilpack (although I don't know how to check the coilpack, lol). If needed I'll just swap a salvage coilpack on. I will also see if I can find any vacuum leaks that may be causing the evap problem. However, I have read that a cat going bad can cause the misfire code. Possibly all of these codes are related? Any and all advice is appreciated. My friend saw how awesome my leggy is after I did all the body work and paint, JDMs etc, and now he wants to keep his car running and get it looking good like mine, so I'd like to help him out if I can. Link to comment Share on other sites More sharing options...
monkeyposeur Posted October 3, 2012 Author Share Posted October 3, 2012 I checked out the plugs and wires, they look great. They are OEM plug wires and have been replaced relatively recently along with new plugs so I they are probably not causing the misfire. I looked for vacuum leaks again and couldn't see any cracked lines or anything like that. The PCV valve is the original, so that should be replaced. Perhaps the purge control solenoid is bad, but before I replace that I would like to fix the other codes. How would I decide which cat to replace? Should I replace both? Link to comment Share on other sites More sharing options...
monkeyposeur Posted October 4, 2012 Author Share Posted October 4, 2012 Anyone? Link to comment Share on other sites More sharing options...
SpecBamf41 Posted October 4, 2012 Share Posted October 4, 2012 the front cat is most likely to cause the code. BNR18g on 93oct Link to comment Share on other sites More sharing options...
monkeyposeur Posted October 5, 2012 Author Share Posted October 5, 2012 Thanks! Link to comment Share on other sites More sharing options...
ehsnils Posted October 5, 2012 Share Posted October 5, 2012 Notice that the misfire should also be checked - manifold gaskets, valve adjustment and injectors are suspect. Fresh spark plugs, cleaning ignition coils and possibly fresh ignition cables. Of course - the oil leak could also have been the cause for the misfire, but since the cat is bad then I would certainly check the other things to avoid killing a new cat. Link to comment Share on other sites More sharing options...
monkeyposeur Posted October 9, 2012 Author Share Posted October 9, 2012 Thanks ehsnils. I didn't check the ignition coils. How could the valve covers leaking cause a misfire? His head gaskets were replaced a few years ago. I would have hoped the valve clearances would have been checked. I'm trying to find out, but the service records may be lost. Link to comment Share on other sites More sharing options...
ehsnils Posted October 9, 2012 Share Posted October 9, 2012 When oil leaks onto the ignition cables and spark plugs it can cause the spark to go the wrong way on the outside of the plugs and/or wires. Keeping all high voltage parts clean is important for a trouble-free life. And use brake cleaner or pure alcohol when cleaning them, NOT WD-40 since WD-40 will leave oil residue that attracts dirt and causes problems very soon. I know that from experience. Link to comment Share on other sites More sharing options...
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