Hey everyone, new user, new owner. Just purchased my 03 g35 almost 200k on the od. Drove it maybe 200 miles before I started getting trouble starting. I've gotten misfire codes, camshaft codes, pulled my plugs and had oil on most of them. Now it sits and won't start anymore. I've just read about the cats causing ceramic dust in the motor and was JW if there's anyway I can test for this? Seems pretty pointless to get any parts if that's the case. If it ends up being necessary to get a new engine, I'll (sadly) have to give up the car as I'm still paying for it. Hope to find some help here. Thanks in advance.

 

Does it crank but won't start? Pull the plugs and check for spark, if there is no spark it's probably a cam or crank sensor (only use Hitachi or OEM sensors, other brands are highly notorious for not working). If you DO have spark I would perform a compression test and check for fuel pressure, Z1 Motorsports sells a sandwich adapter for the fuel damper so you can hook up a gauge.

 

As for cat dust in the engine I've never seen it personally and as far as I know it's more of a "working theory" that's never been proven.

 

It cranks for days, occasionally starts then dies. See, that's what I'm wondering I guess, is if there's any truth to the dust thing. Claims it would cause all the things I've experienced but then ive never seen anyone mention it on these forums. In the end I suppose with 200k how long I could even expect the engine to keep running if I got it up again. Not trying to continually throw parts at a motor that's all but done for. I'm on a very tight budget and barely have the cash to make my payments.

 

The only engines I have seen with the catalytic problem are the 1st gen QR25 cars. Pretty sure the VQ series never had that issue.

 

P1128
P0345
P0304
Those are the codes I'm currently dealing with. Any advice to get this sucker running again please. Honestly if there's anyone experienced with these things in my area and willing to take pity on me, I could really use the help. But advice is a good start. Thanks.
just realized, I'm located about an hour south of Springfield Il and east of stl mo

 

P1128 probably the throttle body

P0345 bank 2 cam sensor, use only hitachi or OEM Nissan Genuine Parts. If the harness has a lot of oil on it spray it clean with electrical contact cleaner that's safe on plastic.

Fix those two first and hopefully the cylinder 4 code goes away (P0304) but I would still pull the spark plug and see how it looks, inspect the coil pack as well for any damage like blistering on the epoxy resin encapsulation (black shiny on the top) or scorching of the well tube or corrosion of the spring inside the well tube. If you have access to a digital multimeter you can read resistance across the pins and compare it to the other coil packs (make sure they're fully unplugged from the spark plug when testing).

 

The coil pack seems fine from what I can tell, I do have oil about halfway up on 4 of my plugs. Should I just replace that cam sensor straight away or is there something else I should be testing first?

 

That much oil is DEFINITELY causing problems since the spark plug electrical connection is literally submerged in oil.

 

I figured that was the most likely cause of my misfire. Plugs need changed, they seem pretty old. I was hoping I could change the gaskets and fix the oil issue, but I've heard that the only way I'd get the oil like this is if the plug seals need replaced, ergo having to change valve covers. Is there a simpler explanation I might check before doing all that? Can't really afford new covers so I'd likely buy new gaskets and rtv the hell outta the seals. As per someone else's suggestion on here.

 

You can always try the RTV trick, remove the covers, clean all mating surfaces thoroughly with Brakekleen to remove any oil, including on the spark plug well tubes (spray the cleaner on a rag then wipe down surfaces, not directly into the head...).

Next apply a thin layer of RTV sealant to the gaskets, the well tube seals, and the well tubes themselves, reinstall the VC's, sit for 24 hours to cure.

Usually works.

 

Yep, make sure to use scotchbrite pads to clean the metal sparkplug tubes before the RTV. It gives the RTV a good surface to hold on to. Done it to two cars so far with no leaks. Make sure you get the new Fel pro brand valve cover gasket set, the new ones are bright blue and easy to see. The older black ones are really hard to see if they fall in on the back lower corners.

 

So I use rtv from the top side where the plugs actually go in as well? And you're talking the basic green scrub pads right?

 

Yes, the green scotch brite abrasive pads. They make them in different colors and abrasive values. Green is very good for lightly scratching up a surface and red is good for polishing stainless out.

Here is what I wrote up on another thread about sealing valve covers without buying new ones:

The spark plug holes are a molded gasket in the valve covers. It slides over the spark plug tubes and makes a seal. They shrink over time and heat cycling and leak oil into the spark plug tubes. They are built into the covers so you cannot replace them. You know they are leaking bad if you have your car in a quiet area idling and hear it miss every once in awhile. When the oil fills the tube enough to get the spark plugs wet they will ground out instead of fire every once in awhile. The lower cover gaskets are replaceable.

I have done this on 2x 04'-06' VQ35DE cars and 1x 07'-08' VQ35HR car and so far permanently fixes the leaks. Only costs about $50 in parts to do.

Pull upper intake, pull valve covers, put paper towels in all 6 intake holes so you don't drop anything down there, wash the valve covers and then carb clean them really really good, use a scotch brite green pad and clean the spark plug tube gaskets then cab clean again, use the scotch brite pad on the head surface until completely clean and carb clean off, Use scotch brite pad on top of the spark plug tubes and then carb clean. Make sure all gasket surfaces are completely clean with out any oil or RTV will not stick. But Permatex Ultra Grey RTV silicone. Buy Fel Pro valve cover gaskets. Clean gaskets with carb cleaner to remove and mold release on them. Use the ultra grey silicone in about 8 spots so the gaskets will stick to the valve covers, let it tack up and partially dry for 1-2 hours. This will make your life much easier because they can fall out while trying to install and then it will leak everywhere and you will have to do it again. Silicone the head surface where the gasket mates and make sure you use a bunch on the front corners buy the VTC area. Silicone the spark plug tube gaskets and wipe a thin layer on the spark plug tubes. Reassemble.

I have re used the valve covers on 3 cars this way and not had 1 leak yet, not even on my 10psi boosted car. Be aware this is a permanent fix and if you have to remove the cover it will probably crack since they will be stuck down pretty good and the covers are very old. But it will allow you to get another 80-120k miles without buying valve covers.

 

Scumbag (still never feel good about saying that), basically it sounds like what you do is the usual procedure for replacing the valve covers, except you add some extra rtv sealant to the mating surface of the spark plug tube gaskets?

I replaced my valve covers a few months ago, everything I did was the same except I didn't put any silicone on the area where the tube gaskets mate to the head/tube. Checked a couple months later and I'm in a worse situation I was in before; I have oil up past my spark plugs in every. single. cylinder. However, no misfires, no odd noises, and I'm still getting above average MPG. I'm looking to fix this in the future.