Hello,
I have an 03' 350z with headers, testpipes, nismo exhaust, cold air intake, kenetix intake and 440cc injectors and a nismo fuel pump. I am in the process of tuning it through Uprev. I have been getting the same to codes, knock sensor low circuit and bank 2 running rich. Just recently I had the fuel temp sensor go out on me after I replaced it, no lights for three days. Then those two came on. I have an afr gauge in bank two which is reading about 20 at idle, I know its supposed to be around 14.7. So my question would be is this a bad knock sensor causing these codes or does it need to be tuned more? 🤔

 

Get your injectors checked. 20 is lean not rich. To lean can certainly cause knock.

 

No reason to have bigger injectors. Put the stock injectors back in and check for leaks on plenum.
The knock sensor would retard timing. I don't think it adjusts fuel(someone correct me if I'm wrong)

 

it retards timing not advances. It also does nothing with fuel.

 

I wrote "pull" first then changed it to advance for some reason. Yes it pulls the timing back(retard) Thanks for the correction.

 

Okay if its a P0327 knock code, circuit low input, is it related to the running lean on one bank and to rich on the other? Is it just the knock sensor and/or the injectors causing the afr to be flopped like that or would it be a tuning issue? Cause I haven't had these codes until the injectors, which I presumed it needed tuned, and its been on and off during the tuning process.

 

So update. Pulled the codes again and both banks are running rich and it seems there's an exhaust leak right before the afr gauges sensors. Still having that knock code though.

 

Remove the injectors and retest, you don't need them anyway or the pump for that matter. I have headers, HFC, exhaust, Kinetix velocity, NWP TB, intake and Okada coils tuned on stock fuel system and it runs flawless so far.

 

LINDA, LINDA, LINDA...IF YOUR WIDEBAND IS READING 20:1 YOU ARE LEAN NOT RICH! That is 20 parts air to 1 part fuel. Rich would be 10:1 or so.

You need to put the stock ~290cc Injectors back in, if you don't have any PM your address and I'll send you the ones I have laying around. Exhaust leaks right before your O2 sensor is not good it can cause untrue readings.

 

Did you ever get the tune sorted? The Nismo fuel pump operates at a different pressure than the factory one so may or may not be part of the problem.

 

The pump should not determine pressure, it is Fuel Pressure Regulator that does it.

 

Yes, exactly. The factory FPR is part of the fuel basket with the fuel pump. Nismo drills the orfice out to lower pressure back to 3 bar which also raises the fuel flow. This is assuming the factory return system is still being used.

 

Ahh your talking about the swirl jet. Got ya!

 

Not yet but the exhaust leak was fixed turns out the shop that claimed to be a high performance shop didn't tighten the test pipes down causing a massive leak turns out i need a new y-pipe too, their welds for the bung are ****, and it leaks at the flex pipe. I get the p0172 every three drive cycles now that i fixed the test pipe issue. I am however leaning towards it being the tune though. Since the gauge wasn't properly installed to begin with and it messed with us.

 

Oh and also the knock code was just the wiring harness from the sensor.

 

Oh and also the knock code was just the wiring harness from the sensor.

 

I understand. I had such a problem when I still owned a Nissan. When I was on a longer route, I heard strange sounds emitted by the engine, I was scared, and I could not understand what the problem might be. Then I went to a service specializing only in Nissan, and to my great happiness, they immediately found the problem. This speed is because they used a very good application for diagnosis. I saw it on google once. It appeared randomly with a standard caption: Click here for more information. I didn't pay attention when I first saw it, and I didn't even think it would save my car. Spontaneous thins are sometimes crucial.