justinmy300z

I need some input if ya guys can help. My 90 300z n/a automatic did something weird yesterday. it ran just fine the night before but i went to start it in the morning...it fired up fine...then died...and would not restart again. It cranked fine...but no start. I tried that about 20 times with no luck. My buddy came over and repeated the same steps, only he would pump the gas peddle a few times then wait a few seconds and try again. after about 10 times of that...it started to almost sound like it was about to start. finally after he kept pumping the **** out of the gas and flooding it...IT STARTED...but very rough...and it smoked like a banshee. after a few minutes it all seemed fine and drives fine too. It sat over night and i just got home and it fired up just fine. It does sound like a hair dryer is being turned on in the back of the car everytime i touch the gas peddle...i assume that is my fuel pump....could it be going bad? thanks for any ideas.

emo236

I guess it could possibly be a bad fuel pump...but if he was able to get fuel by pumping it...I'm guessing you have fuel pressure. I would try cleaning out the lines and changing the filters. Another thing to look into is the other two aspects of combustion....spark and air. When's the last time you changed your plugs...probably didn't cause it, but would be a smart thing to do if it's been over 30K miles ago.

napoleonzheking

My did something similar to this. Turned out my fuel pump relay came loose and unplugged, i occasionaly got fuel pressure. Check your relay and rule that out first. Then check up top for your fuel pressure. You should only need to check one line (in front of your fuel filter) for pressure. Pull the hose off and point it towards the ground and stuff. turn the key to "on" for just a second (since this turns the fuel pump on) and see if fuel comes out. Could also need a new fuel filter if it's old and grody and clogged and what not.

justinmy300z

I am narrowing it down. it still drives and starts fine now, but i caught it making a weird sound when i shut the car off. It makes a weird motorized slurping sound about every 10 seconds after turning the car off (coming from the back by the fuel tank). it did it about 8 times today, so i started the car again and shut it off immediatly....it made the sound one last time and now has not done it again. Is there some sort of fuel reversal pump that takes fuel out of the line? what ever it is seems to be getting stuck "on" from time to time.....any ideas?

Nycz Z32

hMm interesting...the samething happens to me tOo...i didn't think of it as anything

justinmy300z

so you never did anything NYCZ? it happened once but not again? I just dont know if i should replace my fuel pump...or just wait for it to go dead again.

Nycz Z32

nah i never bothered doing anything about it...because i just thought it was because the car was old and it just made funny noises...i mean it annoys the crap outta me...happens almost everytime i drive...now i found out that you seem to have the same problem that i do so now im curious in what it is and how to fix it...im just as stumped as you

napoleonzheking

if two people have had this prob, that probably means others have. search TT.net see if u guys can find anything.

justinmy300z

well, my car has been fine, so i dont know. my mechanic said that these cars a nortoriuse for getting "vapor" locked....hhhmmmm. I really just want to find out if other people have heard a very faint but audible humming noise coming from under the car near the gas tank after shutting the car off? mine does it at random times...even inthe middle of the night!

emo236

just thought of something...are you sure it's not the auto antenna going down or at least the motor working?

Aphrodite

yeah my antenna humms every time I shut the car off... how about this, try turning your radio on and off with the car in the on but not started... see if u get the noise
Although No reason it should be doing it randomly, or even multiple times... only other motorized thing back there is the fuel pump I guess... dunno

napoleonzheking

1% of all mechanics in the US know what they're talking about when it comes to a Z. just thought I'd throw that out there.... A Nissan dealership didn't even fix my Z right, or know what they were talking about.

entropy31

i fully agree. i suggest you find a Z specialty shop. you would have better luck there than at a dealer.

Nycz Z32

well i've been hearing the humming noise for about a year now...even when im driving i hear it sometimes...and my car seems to be running just fine...i don't think it's my antenna...i hear it coming from the rear left side...but thanx for the suggestions ne wayz...i'll that them in consideration =)

justinmy300z

no, it is not the antenna, i took that totally out the first day i had it. It must be the fuel pump. I will take it in and have the pressure checked. The write up on changing the pump looks really easy. I just wish the damn pump didnt cost 225 bucks...ouch.

bardabe

I have a stock one. from my 1990. WOrks fine. I'll sell it for 100$ shipped. if you want,.

Aphrodite

before you buy a new fuel pump, try the fuel pump diagnostic procedures starting here.

The check for the fuel pump in the electrical components inspection says to disconect the harness and check terminals a to c for approx 0.5 ohms.