Are you sure... your CAM gears are not rattling?? They can make a metallic rattling sound when coming off throttle... Having experienced both in my old NA, I can have a listen on Sunday and see if thats it. Or do just a quick test now. Disconnect both VTC plugs (one at back of engine, near DET sensor connector, one on drivers side of plenum; its the plug that has the wire with the white sheath material). If the sound goes away with both of these disconnected, its your CAM gears rattling.
I can't make it Sunday now, maybe on the cruise, sky des like a good test to do tho... You really are the ping king, new name? Lmao So if it my cam gears, how do I shut them up?
CAM gears... If it is CAM gears, you either live with the sound. Or replace them. Its only the intake gears, not the exhaust gears as they are solid metal. The intake clears can go bad after years of use, and allow the innards (the VVT components) to rattle inside. New CAM gears are expensive so you can try and buy 2nd hand ones. But by buying 2nd hand ones, you dont know how long they will last either. But rule them out first by doing the simple test I described. Also, do you get this "rattling" sound if you rev it to say 5000 rpm in neutral?
I havnt noticed this sound at idle or lower speeds till tonight... Usually it's 80ks + before it happens. I will try the revs to 5000 rpm and listen out for it. Tell me tho seeing as though I havnt noticed the sound at idle or revs, can I drive it with the vct's un-plugged? I'm guessing no, but it's the only time I notice it :/
Yes... You can drive around perfectly well with the VCTs unplugged... You may feel a little down on power, but thats it.
Best way i can describe it is . when you look up the hole on the coil extension that pushes over the end of the spark plug cap there should be a little carbon piece that pushes against the spark plug cap , it has the spring on the coil side to put pressure down on the carbon piece against the spark plug end. If this is missing you can get some weird ignition (spark) things happening. Hope fully someone can post you a photo. Cheers Dave
Well that is interesting. When i bought my Zed i did a plug change and just happened to look in there and spotted them. On closer inspection i found 1 missing. I had a slight miss on idle and after getting one off a member i found the miss go away. If you are missing them all maybe it is your problem so defiantly worth getting some. They could possibly be on other cars. I just looked on conceptZ and they are not on their site. Cheers Dave
Cam ... PM "brisz" ... describe the part/location and get him to do a parts search ... Brisz is a wiz with this stuff.
Found it. Was bloody hard to find . http://www.twinturbo.net/nissan/300zx/forums/main/view/1099253/On-Coilpacks-Part-Two.html Explains a lot and some have them and some don't. Pictures and description should help you see if your should have them. Read it well as it says what part number they are. Also interesting about back firing. Cheers Dave
Today I set the TPS to .45v and adjusted the idle screw for 800-900 rpm's Took the cover off the plenum so i could have a good listen for any air that sounds like its being sucked in where it shouldn't and I could here a induction sound upon rev, but couldn't 100% tell if that was at the throttle body or not. I think it sounds about mid way to the back of the engine, Im thinking my el-dodgo gasket may be leaking. I took it for a test drive and found the gears to be shifting at 4000-5000 rpm's now! I know thats to do with the TPS but I have it perfectly set to .45v as per the link that was supplied earlier in the thread. Does and Auto need to be set to a different setting? I waited for the "dingling" sound to start again, pulled over, and disconnected the VCT's...but the sound still continued I have heard a bad VCT on youtube and thats not the sound I get....I read another thread and they described a sound which is like a couple of beer bottle caps rattling around, and thats what it sounds like to me too. Key thing today was it didnt make the sound until say 10mins of driving, sometimes only 2mins. This is sooo frustrating! the engine feels strong, but just something is a miss. Still hoping for a plenum pull to solve the possible vac leak but i need more bits to make the pull more worth the effort. Keep the ideas coming people
If you suspect there is a leak, first thing to do, fix the leak. Unaccounted for air may cause the engine to ping.
Yeah i know thats the most obvious job to do for the pinging but Im not sure about the other sound I describe... it drives me nuts! because I spend so much time and money looking after the old girl but it all feels in vain when there is a jingle sound that makes it sound unloved lol [TIS]
