I have a 2004 G35 with 116k miles that recently threw a P0328 code for a bad knock sensor. While I am replacing the sensor, I am also replacing the sensor harness. Now that I have the engine apart to get at the sensor, I am wondering what else I should proactively address while I am in there. Spark plugs were replaced at 99k miles, so I think I am good there.

Main focus is on the injectors. I have the fuel rails out with the injectors exposed. Do I take the opportunity to replace them? The car definitely does not have the pep it once had. The only issue I can recall having with it is occasional hard starting when it has sat for an extended period of time. To get it started, you have to crank it with the pedal mashed to the floor, then it starts, idles rough for a minute or so, then gets a regular-sounding idle with some momentary additional carbon out the exhaust pipe. I guess that could also be fuel pump-related or something else, but it happens very infrequently. Looking for any advice on the injectors so that I can avoid getting it all back together only to find out I need to take it apart again.

Thanks

 

If it were my car then yes I would replace the injectors with new Bosch injectors while I had it apart simply because of preventative maintenance, I'm sort of a sucker for anything preventative maintenance at 100k miles or more and I would also replace both fuel dampers on the ends of the fuel rails.

I also STRONGLY recommend doing the ECM and Idle Air Volume resets after getting it back together.

https://nicoclub.com/archives/g35-35...procedure.html

I suspect you have a poorly firing cylinder since the rough idle clears up after a minute or so, first take a torque wrench and check to make sure they are all properly torqued, if one is loose then there's the problem. Inspect each spark plug well for any oil accumulation which could hamper spark. Next pull all the spark plugs and make sure they all look the same, pay close attention to the ceramic insulator right where it connects to the metal spark plug housing, if one cylinder has a lot of carbon scoring and the rest do not then you've probably found the bad cylinder (replace that spark plug and coil pack). Thoroughly inspect the coil packs as well for any scorching of the spark plug tube rubber, look up inside it and make sure there's no corrosion on the contact spring that touches the spark plug, also check the epoxy resin encapsulation (shiny black part on the top) for any blistering or scorching.

 

Thanks so much for the response and feedback. Great info. Will do as you describe.

There is so much good information on this forum. The more I read, the more I want to do. Going to be busy and costly, but a lot of fun. Thanks again.

 

Well, I pulled the first coil pack and, guess what? Oil pooled around the spark plug. I assume the correct play here is to replace the valve cover. Haven't pulled any others, but plan to pull from other side to see if I can get away with just replacing one cover. Any other suggestions or options?

Thanks

 

I recommend doing both covers at once, it doesn't add much more time and the other is surely going to fail soon.

 

You should pull all the plugs and take pics of what they look like on the ends. It would be a good idea to replace them but it might not necessarily be your issue, mine's had a leaky well for over 25k miles and the only engine "quirk" is a bit of extra roughness (possibly a misfire?) when started in temperatures under 15 degrees F that's been happening for years before and after replacement of spark plugs.

 

Same situation on the other side. Rear spark plug has oil around it.

That brings up a different question. 2004 G35, 116k miles. I am about $650 in on parts so far. No labor expense other than my time. Valve covers are going to be another $300-$400. At what point is this a lost cause?
Next, I was going to tackle the radio issue. Display comes on but no sound. I have read about the circuit board issue. Replacement with aftermarket, given the additional dash parts, runs another $300+.
Didn't want to give up on it with the relatively low miles and it is paid for. But, also don't want to end up with a money pit either.

What would you do?

 

Depends on your financial willingness and willingness to fix it. It's an old car with the potential to be a money pit, albeit a reliable one. Any car of this age is going to have problems with rubber wearing out in the engine seals, mounts and suspension, but if it's had the oil changed and not been abused too much there's not much else major that typically goes wrong.

 

I tend to agree with you. Just wanted to gather some opinions from other owners who have been through it.

It has been a great car. Bought it new. Had a Maxima before it and wife has an 8th Gen Maxima now. Recently got rid of an '07 Mazda 3 with almost 200k on it due to needing a new transmission. Couldn't justify what it was going to cost for that one. I am leaning toward continuing the fight with the G though.

 

Order the cheap valve covers from Rockauto.com, they're like $60 apiece.

Another option is to simply remove the valve covers and apply Permatex Ultra Grey RTV sealant to the existing spark plug well gasket surface and bolt the valve covers back down. A lot of users have had good luck stopping leaks by just doing that.

There's also the option of drilling out the retainer around the existing gaskets and replacing JUST the gasket. It's like $30 for a pack of 6. If I did it again I would use a holesaw to cut a piece of wood that fits snug inside the opening in the valve cover, then slide that core you made over the drill bit of the larger holesaw.

This thread from MY350Z has a video using a kit by another manufacturer that essentially mirrors what I'm talking about, instead of that yellow plastic alignment tool instead picture it being a round piece of wood.

I also STRONGLY recommend using a battery drill with a clutch instead of a corded drill, just in case it binds up on you it's not scarring the VC up. I also recommend taping off the inside of the valve cover so you don't end up with a bunch of plastic chips in the baffles.

 

Thanks. I will check it out.

I saw the cheaper covers at Rockauto, just wasn't sure how good they were given the large difference in cost.

 

Looks like this is the kit you may be referring to. Know anyone who has used it with success?

http://www.rndfactory.com/Web/NISSAN-vc%20kit.html

 

No clue, honestly I wouldn't pay that much though, you can get cheap replacement VC's for less then that kit. I'm sure it made a lot more sense back when the ONLY option was to buy new OEM VC's but there's a lot of options out there now.

Personally I went with a set of Fel-Pro spark plug well gaskets and called it good. I made a jig to hold the entire VC and drilled them out on my drill press. Next time I have to do one of these I'll be making a pilot with the correct diameter holesaw to have a piece of wood fit into the spark plug well in the VC similar to how that install tool works.

 

What does the tool/wood do? Keep the hole saw stable and prevent it from moving around as you drill? You are just drilling a larger hole to fit the seal into?

 

Yep exactly, keeps it from walking around. There's no way you can hold it steady by hand.

Some folks have chosen to completely forego the hole saw and instead used a hammer and screwdriver to just chip out the retaining plastic, others used a pair of channel locks to grab the edge and break it off.

Lots of options depending on how you want to tackle the issue.