1991 300zxTT New Owner/Problems!

[liamwynn]

So I have been running into a few funny problems with my new Z. (Just purchased 4 days ago, already deeply in love, Pearl white 1991 Twin Turbo w/ Pearl interior leather trim).

- When driving in third gear, and I let off the throttle, my shifter seems to move back halfway into neutral, causing a little hiccup in acceleration. When I get back onto the gas pedal it moves back into third. I know these cars can be touchy at partial throttle, but I was wondering if anyone knew about this, or if it's supposed to do this, as I'm new here.

- There seems to be a shaking/buzzing noise coming from underneath my shifter boot. I haven't looked at it myself yet, but it's getting worse and worse. Feels like maybe my shift rod itself is hitting against the outer wall and causing a buzzing sound.

- Also my car seems to have a water leak, but I can't pinpoint where it's coming from and haven't had the time yet to get under it. Seems to be right in front of the steering column. Any ideas what could be leaking water there?

- One more thing I am having MASSIVE amounts of white smoke coming from my exhaust, which of these issues seems most likely the cause?
1. The guy before me installed BOVs on the car, causing the engine to run rich, unburned fuel gets burned by exhaust.
I don't know much about how blow off valves work.
2. The water leak I mentioned = no water in my car. My car is using coolant instead, which I think burns white.
3. The previous owner has turbo back exhaust and high-flow cats. Could the high flow cats just be causing the issue?
The smoke smells like normal exhaust, not sweet or tangy in any way.

- When my car is in second gear, sometimes I hear a grinding or scraping sound. Usually in lower speeds.

Sorry for any amount of incompetence, or newbieness, I just bought this car and am still learning the workings of the most complicated and crowded engine compartment I have ever seen. Any help is much appreciated.
And glad to be here!

[Ace2cool]

Sounds a lot like a broken shifter bracket to me. I bet if you pushed down on the shifter while driving, it would scrape against the driveshaft. I'd replace with a zspeed upgraded bracket and never worry about it again. This car doesn't have a shift rod like you think. It's just a rod out the back with a yoke on it.

As for the smoke, I really can't tell without seeing it myself. If it smells like normal exhaust, that leads me to think it's a fuel issue, but excess fuel is usually black. White is coolant and would usually have a sweet smell to accompany. If it does it all the time, it's not a BOV issue. It could also be oil, but that has a bluish tint to the white, and to be as much as you're describing, would be a huge loss of power, as the compression would most likely be toast.

Water "leak" may just be condensation from the A/C compressor. The lines run right in front of the steering column.

[liamwynn]

Awesome, I'll look into that. Thanks for the tip. How difficult of a fix is that?

I'm not sure about the exhaust. I'm having a mechanic look at it tomorrow. It could be a number of things but we'll have to see.

And as for the water leak I did think of that, but it was a surprising amount of water. Decent sized puddle about half a foot wide. Which would possibly explain the exhaust smoke, without water it would be coolant being burned. Not sure though, haven't had any heating issues or anything since the leak.

Another problem I have been having as of today is that my car seems to want to stall. When I let it idle, it will bounce back and forth between 1000 and 500rpms, and stutter a little. Which could be caused by the BOV installed, causing ECU confusion and excess gas. The stuttering happens when I slow down too quickly too.

[Ace2cool]

BOVs would only cause problems when they're actually working, AKA going "psssshhhhhh." Don't think that's your issue. If your idle is bouncing around, I'd look to the idle air circuit. IACV and FICD, to be exact. They're on the back of the plenum near where the brake booster connects. They make rebuild kits, but most of the time they jsut need a good clean and lube.

I had my A/C on in Florida once for about an hour and a half in the same parking space, and got out to find I had filled the entire space and half the neighboring spaces with condensation. I was terrified I had broken something, but I gave it a very good inspection, and everything checked out. Then I had the "DOH!" moment where I remmebered condensation was a thing. These can put off a surprising amount.

And as far as the coolant vs smoke thing, if it was coming out the tailpipe, it won't also be leaking on the ground. (well, it could be, but that would be a completely separate issue). Coming out the tailpipe means an internal burn.

Shifter bracket isn't hard. All accessible through the interior. Don't have to pull the trans or anything like that.

[liamwynn]

I'll give those a good look. Thanks for your help.

My only other issue with the AC condensation thing is that my AC wasn't running at the time, and I had just bought the car. I had only driven about 3 miles, and there was small amounts of light colored smoke coming from my engine compartment. At first I was thinking thermostat but I don't think that's it. I pulled into my driveway, and looked around, but it was all still foreign to me. When I pulled out, there was a large puddle where I had been.

Might sound weird but it tasted like antifreeze. (being on asphalt, it was the only way to identify the liquid.) And It definitely wasn't coming from my radiator so I assumed water, not coolant.

[Ace2cool]

Coolant cycles through the whole engine and even through the dash. Just because it isn't in the radiator doesn't mean it isn't Coolant. Places to look would be bypass hoses, heater core hoses, and upper and lower radiator hoses. There's also a ton of hoses under the plenum that can be deleted.

[Ace2cool]

Oh, and check the coolant lines on the turbos. Pita to get to, but a common leak point. These turbos are oil and water cooled.