QuestionQUESTION: Good evening Von-
Thanks for your help on the oxygen sensor question a week or so back. Well, I got into the thing and found a cracked exhaust manifold, so had to wait a bit while the new part came from South Dakota. Now that's here, do you know the torque setting for the manifold bolts? I don't want to mess it up. Thanks!
ANSWER: Eric,
The manifold bolts shoudld be 20 pounds. The thing that is most important is to make sure everything lines up and nothing is binding.
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QUESTION: Well, the saga continues. I got the manifold on, no big problems besides getting the EGR tube back on, I wound up cutting it and patching it. So now the exhaust is tight and the oxygen sensors are new, but I'm still getting the same OBD codes, the PO705 (Park Neutral Position sensor) and the PO420 (catalyst efficiency). I'm guessing that now I need to replace the cat? Thanks for your help...
ANSWER: Eric,
Replace the neutral safety switch and the converter. I would also check the fuel pressure since that is a usual cause for the converter overheating and melting internally. You do not want to replace the converter twice.
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QUESTION: Thank you. How do I check the fuel pressure? Do I have to hook up a pressure gauge at the throttle body, or is there some other type of check I can do? The truck has 217K miles, most of which was city driving (it was a service truck for an alarm company), so I can see the cat being bad. Or is that too soon?
AnswerEric,
The fuel rail, on the engines intake manifold is where you check the fuel pressure. Most newer Nissans require an adapter. So, if yours does not have a pressure port you will need an adapter. If the engine was running rich it could have cooked the converter. But, you will need to get the fuel working properly as not to damage a new converter.
