NEED TO FIND OBD I PORT AND READ CODES ON 91 300ZX NONTURBO

Blanco 300Z · Oct 13th, 2005, 10:16 PM

I just recently purchased a 91 300ZX 5-spd(non-turbo) that has been slightly modified. as far as I know, it has eibach lowered springs and adjustable struts, a 2 into 1 air intake system with a K&N cone burried low to the bumper, a custom H-pipe and some kind of aftermarket japanese cat back system. There is alot more smaller things but the point I am posting is............

Car runs rough for the first 3,000 RPMs or so then takes off like a rocket after that. Rev limiter is set to approx 8,800 rpms ( tach reads 9k ) . upon starting it seems to have a miss and smells a little like gasoline. and oh yeah, gas milage it terrible!!! although the car runs like a ROCKETSHIP!!!
The car was garage kept for over a year, and with myself purchasing it I am about to clean the air filter, change the fuel filter. (already changed the oil and tranny fluid)I am wondering how bad these cars need plugs replaced .

Also, the check engine light has been on since i got it. I have not yet been able to find the OBD port and need to find out where to start on this new project... ANY input is greatly appreciated. thanks alot!!

westpak · Oct 13th, 2005, 10:59 PM

The OBD port is on the left side of the drivers foot well by/over the handle to open the hood.

And congrats on purchase.

Blanco 300Z · Oct 14th, 2005, 08:45 PM

Quote:

Originally Posted by westpak

The OBD port is on the left side of the drivers foot well by/over the handle to open the hood.

And congrats on purchase.

Great! I thought that was it but not sure. Now how about any info or web pages with data codes and how to pull...

BTW, latest I can figure....about 16 MPG ( sucks! ) and kinda runs like on 5 cylanders or something till high RPMs... any one know of common problems with these engines???

Damnit! I knew I should have stuck to Chevys and Fords...

snowcrash1984 · Oct 15th, 2005, 10:25 PM

I just sold my Firebird and purchased 300zx. LOL. Reliability on the late Chevy sucks man. In your case, I think you will be buying new oxygen sensors, may be some others. If the car was running on 5 cylinders, you’d know it. Most likely, some other sensors are dead or disconnected. You mentioned it has aftermarket exhaust on it. I wouldn’t be surprised if the guy installing it, disconnected something.

snowcrash1984 · Oct 15th, 2005, 10:28 PM

It’s just struck me. I can guarantee that they fucked up intake sensor seating behind CAI! It’s very sensitive and you looking at about $300. People do this shit all the time.

Blanco 300Z · Oct 16th, 2005, 09:53 PM

OK.... I installed new plugs (platnum of course) found 1 wet plug amoung the bunch. car runs and idles much beter. upto about 22 MPG or so and runs ALOT better!. I was thinking about the O2 sensors but I wanna get the info I need to check the (check engine) light. anyway... CAI??? I see the mass air flow sensor and it is plugged in well ... as befor.....

ANY HELP on doagnosing the (Check engine light) would be GREATLY appreciated. thanks ALOT for the info thus far guys !!!!!

my350z8 · Oct 17th, 2005, 04:03 PM

Go to http://forum.ztechz.net/ and find this post “Summary of available software”. Everything you want to know about diagnostic software from Free to $$$$

apudapus · Oct 17th, 2005, 11:18 PM

you can check the codes without a scanner.

get to your ECU (below the passenger side kick panel). unbolt the brace from the ECU. there's a round screw in the ECU with a flat-head cut.

turn the car on (2 clicks). be sure your Check Engine Light (CEL) is on. take a flat head, turn the screw clockwise, wait 2 seconds, and now the CEL should be off. turn it counter-clockwise then clockwise just a little. the CEL should now flash you the codes. slow flashes are the first number, fast flashes are the second number.

if it flashes 5 times slow, and 5 times fast, that means you have no codes.
if you turn the screw in the same manner (clockwise -> counterclockwise), you'll reset the codes. be patient, read all the codes and write them down before you restart the car or reset everything.

can the engine rev that high? 8800 rpm?! i know an S2000 can. i don't think there's much power to be had past 7500rpm. please check that.

i get 16mpg on the city and 18-20mpg highway... and i don't push my car.