Variable valve timing broken?

Nissan 300ZX technical discussion forum: Maintenance, performance, installations, modifications, how-to's and troubleshooting.
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Yardjass
Posts: 14
Joined: Sun Jan 23, 2011 10:24 pm
Car: 1990 300ZX, 1994 Honda Civic EX
Location: Norfolk, Virginia

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Hey everyone,

Sorry, I am by no means a mechanic and I don't know jack squat about cars but I am trying to learn. Hopefully I can explain this well enough so that it actually makes sense. I have a 1990 NA, 5-speed with 67,000 miles by the way just in case you need that info. Anyway, here is what happened.

I was driving through a parking lot at about 5 mph and I ran over a curb that had disappeared under the hood. I know, stupid. I was too busy looking at the line of cars stopped at a light that were blocking my exit and thinking, "hey cool! This parking lot connects. I'll just go down there where it isn't blocked".

The curb was not curved or sharp at the edge. It was more of a 45 degree wedge; a ramp more than anything. I couldn't see it because there was downward sloping grass behind it so as soon as the curb went under the hood, it looked like just all parking lot. After I flew over the curb, I shut the car off to look at it. The part of the frame where the side skirts bolt on was all scraped up at the bottom and the duct tape holding my already broken skid plate was tattered (good thing the body was already in poor shape and is getting replaced anyway). Upon starting the car for the first time, I heard a rattling that I think was from the rear but am not sure. I'm not even sure that it was from my car at this point. I shut it off because I was concerned and then tried again. Everything was fine the second time, which really confused me. This was a few days ago and thus far, here is what has happened.

I have been checking the tire pressure. No decrease in psi other than those associated with temperature changes and no leaks in any tires. The car seems to run fine. No rattling, no trouble starting, no anything other than the valve timing. It just doesn't seem to "come alive" around 3000 rpm like it used to. Some of my co-workers indicated that it is probably an oil pressure problem and that I should have my oil changed. I did this and it is still going on. I also got to look at the underside of the car when they were changing the oil because they said that the oil pan may be damaged. Nothing looked damaged although I am not a mechanic so I wouldn't really know what to look for. I am also going to try to run its self-diagnostic later to see what it says.

Basically on here I am just wondering if anyone has any suggestions or clues. I recently put the stock mufflers back on in place of HKS for legal reasons. I remember shaking black crap out of the stock mufflers before putting them on and it is my best guess that the rattling was a bunch of this stuff that was shaken loose and was blasted out the rear of the exhaust. I know almost nothing about cars though so my opinion is just about as good as dirt.

Sorry for such a long post but if anybody can help, I would greatly appreciate it. Is there an oil pressurizer or pump or something that could have broken? Someone mentioned my cat breaking apart and clogging the exhaust. Would this cause the valve timing to not work? Was the car just held back at low rpm due to crap in the exhaust and now it has just become uniform rather than gotten slower? Is there any risk to continuing to drive it? It seems okay. I realize that this will probably result in some repair work but I don't have much money and I don't want to walk into a garage with no idea what I'm talking about and get taken for a bunch of crap that doesn't need done. I would rather go in with some sort of a clue at least, hence this post.


If anyone actually reads this, thank you so much :)


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Yardjass
Posts: 14
Joined: Sun Jan 23, 2011 10:24 pm
Car: 1990 300ZX, 1994 Honda Civic EX
Location: Norfolk, Virginia

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Oh, almost forgot. Does anybody know of a good Nissan tech in the Norfolk/Portsmouth/Hampton/VA Beach area?

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Ace2cool
Posts: 11650
Joined: Sun Apr 20, 2008 5:21 pm
Car: 1991 Nissan 300ZX TT
1966 Datsun Fairlady 1600
2005 Suzuki GSX-R 600
1974 Honda CB550 Four
2009 Ford F150 Lariat
Location: Murfreesboro, TN

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Sounds to me like you may have dented your oil pan. The smallest dent can block the pickup tube and starve your engine of oil. It's a common problem on JDM engines, since they get shipped over either on a front cut or on a pallet, either of which isn't good news for the oil pan. I'd get back up under the car and look at the oil pan to make sure it's not dented AT ALL.

Other than that, you may have jarred your VTC solenoid connectors loose. Not likely, but I'm just spitballing at this point.

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Yardjass
Posts: 14
Joined: Sun Jan 23, 2011 10:24 pm
Car: 1990 300ZX, 1994 Honda Civic EX
Location: Norfolk, Virginia

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Thanks, I think I'm gonna take it in to the garage and mention this stuff just to see what they have to say. I can replace mufflers and stuff like that but this is totally beyond me. Its at least good to have something to say to them so I don't appear to be completely ignorant. Oh, for the record, the engine is the original one that came with the car so the bump would have had to have done it.

CrazedZ32Owner
Posts: 411
Joined: Fri May 28, 2010 11:59 am
Car: 91 Z32 TT(no motor), 2008 350Z Nismo, 05 Pontiac Sunfire speed machine!!! :)
Location: Lehigh Valley PA

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if you need further help contact Dan at Premier Z in Cary NC he does good work.....he's a little pricy tho

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Yardjass
Posts: 14
Joined: Sun Jan 23, 2011 10:24 pm
Car: 1990 300ZX, 1994 Honda Civic EX
Location: Norfolk, Virginia

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I may have to dispute that: http://www.youtube.com/watch?v=9Fb_H2Qiivg

The ken/barbie one is hilarious though and thanks for the contact :)


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