I'm new here. I have a 1993 300zx n/a the car is running rich more at idle than higher engine speed. I know i checked the HCs about 500-1000 at idle. I found the Passenger side O2 to be flatlined at idle and come to life at about 2000rpm. replaced the right O2 and the car is still the same only more toward 500 Hcs. no know exhaust or air leaks, new plugs, preformance chip removed, not a leaking injector. At idle the left O2 is rich the right is alway flatlined (lean) the car runs good but you can feel almost a miss at idle from time to time. not sure if anyone has had this problem? Thnks

 

Welcome to zdriver.

First off I'll assume that you have no ecu codes. when the o2's are working properly they shoiuld be bouncing back and forth from rich-to-lean. They will settle down at idle, but if you give it gas, they should start bouncing around again like crazy. If you r o2's aren't reacting properly, I'd ohm test them, even the new one, and then check and clean all of the connections.

Once you're sure the o2's are o.k. and they are, you might then have two seperate problems........ with the lean on one side and the rich on the other side.

Keep us updated.

 

Im not a retarded I am A certified Tech, But the 02 is not ranging properly, the a/f alpha is around 100% which it souldn't be at idle. I wasn't sure if anyone knew the MAF spec for idle and 2000 rpm. I have the shop manual but there is no real spec. I know bank 2 is fine and the O2 on bank one sould never go below .01v, i was not sure if the maf could cause one bank to go rich and the other to go lean. I haven't tested the new 02 yet i will at work on monday. i didn't know if anyone had came across this before.


By the way as soon as it stops raining next week i'll get some pics and post them. I have a 1993 300zx peal white black top, full ground effects kit, full pacesetter exhaust. stillen intake, preformace chip, nismo custom made short throw, locked rear diff, koni shocks nice clean car.

 

sorry dood.

 

Noone called you retarded,

Where you from in Pittsburgh I was up there not too long ago.

 

Hey are we on TTnet? Man nothing like biting the hand that feeds...great start Goreack! You seem to have the FSM but I will say that if one bank goes rich and the other goes lean I would just chalk it up as expired parts and replace the faulty part. Why did it go bad...I am sure that would matter on the condition of your car, how you drive it, humidity and so on and so on.

Parts break and bears sh*t in the woods but rarely need a reason to do so.

 

I resently bought the car and it is has done it since i have owned it. That is why i got it soo cheap. I'm sorry about being a dick, but i looked a old posts, the advise given is always the same. my problem isn't the same as a exhaust leak or intake leak. I do work on nissan's every day of my life. sorry about that.
I think the right bank is telling me the truth, i checked with consult(ie nissan scan tool) the car it kida primitive compared to what i am used to working on, anyway the left is rich and the hcs on the emissions machine is saying the same. The right always says lean till you hit the gas pedal. i ran a power balance test and the mechanical part of the eninge is fine despite the high mileage, I'm really thinking of the TT front clip conversion since i can't get the car to run right. I like the N/A but my engine is old and does have a internal noise that worrys me. My issue is a control one so I need to fix it before i mod the car anymore and add more varitables. I can't spell.

 

Since you say it's a high mileage motor, have you run a compression check? If it's running rich and the compression is o.k., have you pulled the injectors and powered them up to see if they're leaking? Plugs are new...... how are the boots on the coil packs? If they're cracked, they could be arcing to the valve cover...... causing week spark, hence unburnt fuel.

Nobody is going to figure your problems out for you from a computer screen. All we can do is suggest things to check, that you might not have thought of, certified tech and all.

 

I checked the compresion and it was fine. The leakdown test was good to. i didn't think about the coil boots arching. I look at that today. Do you know where i can get interior part some of mine are damaged. Nissan want's a forture for them.