duowing

Alright, car is an 87' 300ZX Turbo 5-speed.

Here's a pic of when I brought it home:


Tokico Adjustable Shocks, Eibach Springs, pretty much new brakes, tires, etc. Car handles really well, but man is it a hard ride with the tokicos on even the softest setting.

Anyway the car runs great, except for one small issue. It's the one thing that Zs always have the most problem with. The cold start. Anyway from a cold start the car will kind of sputter to life and only idle say around 900-1000 RPM. It kind of pulses almost as if the AAC is maybe saving it? Anyway it still seems to rev fine, but when I put it in gear and drive it at low RPMs or light throttle it kind of hesitates and gets a little jumpy, a little more throttle and it's fine. It does this for about the first 30 seconds or so, then it drives fine. No problems at all. My thoughts are on the Air Regulator. Ran diagnostics and got code 44. So that was a good sign. Ran the car a few more times from cold start and checked again to make sure, still no codes.

This only occurs from a dead cold start. Restarting after warmed up, or even after partially warmed up seems to result in no problems. So any thoughts? I want to pull the air regulator off and check it, but I didn't know if I would need a new o-ring or something when I put it back on? The lower cold start idle almost seems like an indication of the air regulator, but I'm not quite sure what these cars are supposed to idle at. I'm used to the S130 roaring to life to nearly 1500 RPM due to the air regulator.

Oh and does anyone happen to know the bulb type for the dome light? I went to the auto parts store, looked through their listing and they didn't have the bulb number for the dome.

xenonxiii

http://www.xenonz31.com/Lampreplacement.html

duowing

Yeah, I actually found that after I posted. Thanks for that info. I've been working through your site for all kinds of stuff at this point.

reddzx

Have you replaced the CHTS?

duowing

No, I haven't. I wouldn't think theres any problem with it since there are no ECU codes, and that with a little extra throttle the problem seems to not be an issue. I maybe wrong, but my thoughts are that the CHTS isn't bad. When the CHTS was bad on my 280ZXT the car was almost undrivable when cold. Although I guess it's possible this is a sign of a CHTS that's failing, but hasn't gone bad to the point that it gives me a code.

Like I said, I want to remove the air regulator to check it, but I don't know if I'm going to need a new O-ring once I pull it off? If so, where can I get a new o-ring for the air regulator? My main concerns with the air regulator are the lower cold idle, and even with a bad CHTS I've never seen it affect the initial startup of a car.

UPDATE: Ok, I don't know how much of a difference the air regulator makes on these cars. Unfortunately I didn't have anyone to watch the tach while I did this. Anyway, I started up the car from a cold start. It kind of sputters to life and then settles down idling right at just a hair or two under 1000 RPM. So I quickly ran around the car and pinched off the hose going to the air regulator. I did this a couple times, and there was no audible change in engine speed when pinched or unpinched. I have a fairly quiet and tame exahust, but it doesn't sound bad even when revved up, but I still think I should hear a change in engine speed. I'd say that's a sign of the air regulator. I know on my 280zx turbo if I leave the air regulator closed off, the car will do a similar thing. Sort of stumble to life, although I don't have an AAC to provide extra air so it will either stumble to life or die, but it'll make a big driving difference even on warm days having the regulator closed off.

duowing

One more question I wanted to throw in. I may need a new valve cover gasket. Looks like it leaks some. I was wondering if they all use rubber gaskets? I was thinking about going with the Beck/Arnley gasket as I hear their stuff is usually the Nissan stuff, but I can't tell if it's a rubber gasket or not.

johnZboy

I've bought a bunch of rocker cover gaskets from a bunch of vendors, and, not once did I get a set that was cork. I'd say betting on rubber would be a safe bet.

duowing

I'd assume that they are in fact leaky rubbers. Alright, well that's good to know. I'll order a set. I'll have to order that and the intake collector gasket, because the thing that leaks is always the one that requires the most crap to be removed.

Niku-Sama

this is a problem i havent been able to figure out since i got my maxima.
the AAV doesent kick on untill the car warms up some. with the car warm pinch it off and it should die.
i have changed the CHTS, MAF, O2, and other various things and i for the life of me cant figure it out.

the only thing i wasnt able to change was the crank angle sensor because it was so damned much.

but yea i feel your pain, its all sputtery and you step on the gas and its faster sputtery untill it gets higher revs. mine will acually die some times idleing. adjusting the timing helps untill you can fix it

duowing

my AAC works fine, it's what helps the car idle when cold. As on first start it sort of pulses it and the idle rises in pulses until it's stable. The car idles fine warm and cold. I've noticed though that if I make sure to keep my revs up while I shift like over 1000 then I don't have any problem.

duowing

I checked my ECU's flashing lights to see if my O2 sensor was working or not. It wasn't working. Then I started looking around my engine bay and noticed that the O2 sensor wasn't even connected. The sensor connector was laying down by the exhaust. I have to wonder how the thing did not become melted. Anyway, plugged it back in and now I have a working O2. Still waiting on my air regulator, and if I should need it I'll get a CHTS. I think the weird hesitation was my bad clutch work.

duowing

Alright got my air regulator in, that's definitely helped the cold starting. The car still seems to on and off have the issue. I checked the codes again and I'm getting code 21 now. I see that's related to the coil and ignition. Anyone have any advice on this or where is cheapest to buy these? Some of the tests it looks like I can't perform as I'd need some sort of logic tester? Anyway I was thinking I should maybe replace these anyway as I've already ordered new Cap, Rotor, Plugs, and wires. I like to start off with all that stuff new.

banana944

MAF might be worth a check. Not sooo familiar with these cars just yet however.

Car is beautiful by the way.

duowing

If the distributor zaps you while setting the timing would that indicate something leaking spark? I was messing with the timing as it was a bit retarded, and I got zapped by the distributor. I've never had that happen on my 280ZXT.

xlpbodily

now when you say air regulator do you mean the idle air control valve or something else? just wondering because i have the same problem and i know its not the CHTS because i've already replaced it and checked the resistance of the sensor and checked wiring goin to the computer. thanks for the help

PooFlinginMonke

If the distributor zap, you need a new cap.