Help on 85 300ZX please

I need some major help please. the car idles fine for a few secs then it starts flooding out it seems. once you get the car going it seems to run fine but i still dont think it has the power it should. any suggestions on what may cause it? Throttle position sensor? idle up valve? O2 sensor?

Does this happen only at startup or everytime you bring the engine to idle? When it 'floods out' do you get black smoke out the exhaust?

Try checking the ecu for fault codes. To do this, just get down in the passenger side kick panel, unscrew the ecu, and using a flat head screwdriver, turn the little screw thingo all the way counterclockwise. Then turn the ignition on. Now turn the screw selector thing fully clockwise. Start her up, making sure you keep your foot OFF the accelerator while the engine's trying to start. Drive it around a bit and then turn the engine back off. Now check the flashing lights on the ecu. Here are the codes:

code 11 (1 red flash, 1 green flash): fault in crank angle sensor
code 12 (1 red flash, 2 green flashes): Fault in Air flow meter
code 13: fault in cylinder head temp sensor
code 14: fault in vehicle speed sensor
code 21: fault in ignition signal
code 22: fault in fuel pump circuit
code 23: Idle switch circuit is open
code 31: ECU input signal is beyond normal range
code 32: fault in EGR control valve
code 33: fault in exhaust gas sensor
code 34: fault in detonation sensor
code 35: fault in exhaust gas temp circuit
code 42: fault in fuel temperature sensor
code 43: fault in throttle sensor
code 45: Injector leak
code 55: normal operation

Hope this helps,
-Mike

THANKS For the HELP!. I just bought this car, if I could get this lined out it would be a real good car. dont smoke and the engine sounds tight and runs pretty good after you get moving. JUST WONT IDLE.

This happens everytime i bring the engine to idle. bad bad gas smell out the exhaust.

Here is what I have done so far. I found four cracked vaccum hoses so i replaced those, i have also replaced the plugs, plug wires, distributor cap and rotor, throttle position sensor (TPS). The TPS that was on the car was corroded pretty bad.

Seems like when you adjust the TPS so that it is in the closed position for idle the car starts to stumble. Sounds like I can hear that Fast Idle Control Device (FICD) clicking but that may be due to me not having the TPS adjusted correctly. Also, when I disconnect the vacuum line from the fuel pressure regulator it idles faster.

Any suggestions on how to adjust the FICD?

I checked the codes last night and it displayed 23, 31 and 41. I think 41 is the fuel temp sensor, would that cause the problem?

the FICD isn't really something you can adjust. You can adjust the idle screw on the AAC, but this is put in such a stupid position, you cant actually get to it because the intake piping is in the way.
The fuel temp sensor could make the engine run rich or lean, but you cant just replace that. You have to replace the whole pressure regulator. Thankfully these are pretty cheap as they are also used on the RB30E engine.

I'd try what the ECU suggests first, and then if that doesn't work, go about replacing the FICD, AAC etc.

Have you remembered to get the injectors replaced by nissan? I got burned (metaphorically and literally) because I didn't replace mine in my 85 z31. Engine fire, caused all the electrical system to melt, as well as destroying half the sensors in its path. I still have a big black mark on the underside of my hood now. Cost me $2300 to fix. Check on z31.com about that leaky injector recall.

Def get the inj recall checked. All you have to do is call a nissan dealership with your VIN and they'll run it and tell you for free.

My Celica does the same thing yours does. I'm surprised the vac hoses didn't fix it. I think that's what's wrong with the celica, but it's just a beater so I don't really care. Mine does it REALLY intermittantly [sp.] and only when it's hot out. If it's cool out, it runs fine. Yours do this?

Mike...why would you want "twin centrifugal superchargers"? Unless you have a very large engine, this is completely pointless. What kind of engine are you wanting to do this to, anyway?

From what i know about the car the injectors have been replaced do to the recall.

here is what i did yesterday. i checked everything over again and worked my way down to the MASS AIRFLOW SENSOR (MAS). when i unplugged it the car idled GREAT, of course it wont rev over 2000k. when i would plug it back up it started missing again. i removed the MAS to check and see if it had any trash on it and it appeared to be clean. i did notice an adjustment screw on the side of it, so i replaced the MAS and tried adjusting it and it SMOOTHED IT OUT ENUF TO IDLE. I still have a small miss but it is 90% better than it was before.


MAN THAT FICD is in a bad place fo sho!!!!!

Appreciate all the advice!

Def get the inj recall checked. All you have to do is call a nissan dealership with your VIN and they'll run it and tell you for free.

Heh, in Australia we didn't have this recall, so even if i did know about it, i'd still have to fork out $$ to fix it. It would just be a fair bit less than what i did end up paying.


Mike...why would you want "twin centrifugal superchargers"? Unless you have a very large engine, this is completely pointless. What kind of engine are you wanting to do this to, anyway?

I like the idea of twin intakes being separated on the VG30DE. I guess it just kinda clicks for me. I love symmetry.

I would love to chuck a twin turbo on it but if you saw my engine bay pics in one of my previous posts, you'd understand why this isn't feasible. Besides I love a big grunty roar that supercharger + tuned length headers gives.

Running two smaller superchargers (cheap ones that I'd be able to get off little 1.6L engines etc.) is going to require the same amount of power to spin as one big one (This isn't turbos we're talking about here, the only power draw is going to be compressing the air and insubstantial parasitic friction power losses). So, rather than forking out big dollars to get a supercharger big enough for a 3L engine, I'd rather get two cheapo superchargers from the wreckers for little engines and run them in tandem on each intake separately.

This is still a pipe dream though, i've kinda run out of cash for this z31/z32 hybrid project, thankfully just as I'm finishing it, so I'll have to save up a bit more before i start doing any additional performance mods to the engine. :)

-Mike

That was a better answer than I expected. What it boils down to is basically you wanting to do two "belt driven turbos" instead of doing two turbos. If this seems easier to you, go for it. I would think that would be a massive pain in the nuts. Plus, I'm yet to find ANYTHING that sounds cooler than turbo spool...add a BOV and it just gets better...you'll never find me putting a S/C on anything.

Plus, I'm yet to find ANYTHING that sounds cooler than turbo spool...add a BOV and it just gets better...you'll never find me putting a S/C on anything.


You know whats cool about centrifugal superchargers? They still have that spooling sound, its just aligned with the rpm of the engine.
ie. I'm still going to have the 'wzzzzzzz' but its going to go up with the engine rpm. :) I can't add a BOV though, because with superchargers, the throttle body is before the supercharger (whereas with turbos, the tb is after the turbocharger) so there isn't going to be a pressure build up that I can release. Aww well, I'd be happy with a nitrous purge for 'cool' points.
:)

-Mike