Nissan 240sx exhaust problem

[fgp]

I drive a 240sx, the car have never have any problem til a few days ago. The car started to fail and I thought were the spark plugs. When I took the off they were black, like covered by a black dust. I surprised me because I've never seen them so black. I purchased some bosh platinum 4+ and got rid of the problem. A couple of days after that, it happened again. I lost my new expensive spark plugs and I decided to take a better look at the exhaust system. I noticed a problem a few months ago but never paid attention to it, it was like a pssssss in the exhaust side of the motor, constant and now more loud, now I think it;s part of the problem. I also noticed some of the black dust coming out of the muffler and falling in the floor like little drops, no oil, just dry powder. Does anyone know what the problem could be? do i need to clean the muffler, a broken recirculation valve? I don't want to take it to a shop but I really don't know too much about the exhaust system. Thanks.

[nissan_240sx]

Id say your its your cat

[David_NISMO]

Originally Posted by nissan_240sx

Id say your its your cat

It's the only thing in the exhaust that could increase restriction from build up enough to cause problems
. . . unless your muffler bearings siezed.

j/k, First of all, stop buying bosch and spend even more money on a good set of NGK's. Most of the Nissan guys I talk to hate bosch plugs, our motors don't seem to like them either.

Secondly, if you're fouling out plugs, it's more likely to be an A/F mixture problem. You said recirc, so I'm going to assume you haven't switched to a BOV, assuming again that you have a turboed engine.

[sidewayzS13]

yes ngk iridums are the shit.

[stang805]

i got hks iridiums, tee hee

[fgp]

It's the first time I get bosh, wanted to give them a try. Might be a A/F problem, but once again I should check the oxigen sensor I guess, and the cat. The psssss sound in the manifold makes me think about a clogged cat.

[sidewayzS13]

what engine do you have? how much do those hks iridiums cost?

[David_NISMO]

Still don't know what engine you're running

Turbo would probably provide enough back pressure that at idle a small exhaust gasket leak would create that sound.

[fgp]

Mine is a ka24de. I took off the cat, but seems clean to me, I run the car without the cat and I still listen the pssssss in the manifold side, so I would say the manifold gaskets are fucked up as well as the o2 sensor. I got a new o2 to see if I dont have to take off the manifold, doesn't look like an easy job.

[fgp]

Nop, I thinks is a ka24E, it's the one with the spark plugs at the side, not on top.

[nissan_240sx]

Try spraying carb cleaner around your intake manifold (gasket area) if the engine sputters then your gasket has a leak

[fgp]

I will try that. But for what I see, the manifold is the problem. I was taking a look at it, and the top left side screw has a broken head and the bottom right one is not even there. Might be a previos owner great job. Any recommendations to take off that shit? Is it easier to unscrew with a hot motor or cold? What if I just use some hi-temp silicone? I really don't wanna do that shit, even less after seing those 2 screws.

[fgp]

I did the job, I use w40 to loosen the bolts and everything worked ok. When I turned the car on, after a minute of doing just fine, smoke started to come off all the manifold so I turned it off and waited. I guess it's just probably the w40 burning, but just in case I will get an extinguisher before trying again. I don;t thing could have messed up another thing. Any advice?

[nissan_240sx]

so you fixed the prob?

[fgp]

I'm not sure, I'm not sure the smoke is the w40 burning from the manifold (even thou I can't find a better reason for the smoke), and I didn't have an extinguisher, so tomorrow will buy one and turn it on again.