A couple of enine problems; help if you can

[dantesdoom]

i have a couple of issue with my car that i can't seem to polish out and i was wondering if someone could try to figure out whats wrong.
1.) My car cranks, idles and runs perfectly with decent power. The computer has also been clear of problems for a while now.
The first problem is that if the car warms up SOMETIMES when i push the clutch to shift, the idle won't catch and it will die..it will continue to that for the rest of that day. I tend to think IACV. Also, at idle it will eventually lower itself from 800-500 at which point a intermittent skip will show up on the left side of the motor

2.) I have that piss a** noise on the top side of the motor. Rattle noise, that sounds like a person trying to intimidate a cat purring lol. I can only hear it at the 1500-1800 rpm range both during giving gas and allowing it to return to idle. Note i only am able to hear this when not moving...the exhaust may be too loud to hear when driving idk. Also it might be important to note that it quiets down a good bit upon an oil change. It doesnt sound like knock. VTC springs???...this is the problem that worries me the most.

3.) Finally, the exhaust is very sooty, it looks like i colored my finger with a marker when i wipe it out. I tend to think the high test gas, but could it be an oxygen sensor....or is that an unreasonable assumption?

I plan to clean MAF and disassemble IACV and clean. Also the PCV valves have never been changed to my knowledge, 173,000 miles on the car LMAO....i rebuilt the motor....what symptoms do they cause?

[dantesdoom]

ummm....bump?

[marty1mc]

For the fist problem, I would check the MAF, temp sensor and TPS. Make sure the connectors are clean and have good contact. Test the temp sensor per the FSM and the same for the TPS.

Here is a link to the FSM.

http://www.300zx.co.uk/cgi-bin/manual.cgi

[FlogWaffle]

2) What does the rattle sound like exactly? Is it almost like a creaking type of rattle? (if that makes any sense) Because mine did the same thing, rattling when you would rev the engine to a certain point in the RPM band, and then it would rattle on the way back down past that RPM again. You could also tell it was coming from directly under the timing belt cover if you paid enough attention to it. I bought a set of JWT "heavy duty" VTC springs, and it fixed it completely for me.

http://www.importpartspro.com/jwtheduvtcsp.html

The only s*** part is having to rip apart a lot of stuff just to replace two little springs...but to me it was worth it, not hearing that damned noise every time i drove around...it was a little embarrassing at times haha. Hopefully that will solve your problem and your sound!

[300ZXttZMAN]

it sounds like some sort of sensor

[es.biggs]

The noise could be VTC springs

The blackness on your exhaust may be a sign you are running rich - could be a sign of bad 02 sensors. This link (below) shows how to test the O2 sensors for each side. Read it thoroughly and you can figure out how to read the test and it will tell you if they are good or not. It's not difficult. Also check for trouble fault codes while you are in there.

http://www.nicoclub.com/archives/nissan ... ostic.html

[dantesdoom]

Thanks guys...the noise sounds like its under the timing belt cover...i was thinking springs....will it cause any problems if i don't replace yet (other than embarassment)? I was never too sure of the O2 sensor check even though i have pulled the codes as mentioned in that article. Ill go back and check that. Thanks for the info thus far guys!

[es.biggs]

I can't imagine bad VTC springs causing any damage...your VTC won't function the right way, but it shouldn't affect driveability.

[dantesdoom]

sounds good...i dont really have the time to rip it apart right now....the only thing i was unsure of is why it would quiet down when i change the oil...