code 34 heelp meeh

[z.Leinbach]

Well i just checked my ecu to see if it has had anything to say and of course I get a code 34 on a loop so guessing that's all its had to say. I have no idea what could cause it other then the normal corrosion and wears and tear of a 25 year old car. But. My guess is the dealership had to of put regular fuel in at some point. I personally run 92 in my car but idk what it could be. Anyone know how to clear it?

[nexus08]

I believe the code is telling you there is something wrong with the sensor, not that it has been knocking. To clear the code to see if it comes back, I'd just disconnect the negative battery terminal and let it sit for a few minutes.

I've heard the sensor is a bit of a pain to fix, and some people relocate it when they do the fix.

[z.Leinbach]

Oh ok. Well I'm gonna be down in that area of the engine in a few months so I'll replace it then. Thank you for little more clarification on that. I don't really have the skills to relocate sensors

[nexus08]

And it could be the sensor is ok, but the connections are corroded. I'd check that first to see if that is the case.

Lots of nasty corrosion problems with the connectors on these babies.

[z.Leinbach]

I hear that all the time. But I haven't seen any. Not on the injectors or anywhere else except the battery cables and that was it

[nexus08]

That's great! Mine wasn't so lucky.

[z.Leinbach]

But the interior hasn't faired so well. Drivers seat side bolster has a chunk missing from it and the same on the bottom end the drivers side door is missing a chunk as well like someone spent alot of time arm hanging. And the paint.. Still cleared but thanks to the neighbors kids... Scratches and small dents galore

[RED_DET]

Replace sensor and sensor harness. Relocated sensor to back of plenum for now to solve the code 34.

[z.Leinbach]

I have never undertaken a sensor relocate.
Could it be attached to one of the on the backside?

[RED_DET]

[z.Leinbach]

I see what you did there lol. Well played

[huntinman13]

Just get this and call it a day. Knock sensor is disabled after 3500rpm's from what I have heard anyway. When you are down there later you can replace and relocate it. https://www.z1motorsports.com/oxygen-an ... -5580.html

[z.Leinbach]

Thinking about a getting a Bee-r rev limiter for fun and launching. Can this be done with a stock 90 ecu or is there anyway to tell if it's been chipped or tuned?

[diplomat 1]

Even tho it's probably your sensor and sensor wiring I would check the continuity of the wire back to the ecu. just incase of a short/open.

[z.Leinbach]

I'm gonna check the codes again tomorrow or Sunday.

[z.Leinbach]

So I'm curious, is it possible to hook up a new relocated sensor and leave the old one where it's at till its time to do the digging for it, when I'm in there replacing injectors and cleaning up years of gunk.?? Or does the plenum need to of to get to the clip on spot?

[MrFeesLaw]

Somewhat off topic... You said you always run 92? Is your car turbo or n/a? The common misconception that higher octane is better for your engine is actually not correct. The only time you want higher octane in on a high compression or performance engine (such as a turbo car). Normally aspirated cars don't usually have a high enough compression ratio to make efficient use of 92 or higher octanes, so you are essentially paying extra for tailpipe soot. you wont fully burn your fuel, which will cause you to have less power, lower gas mileage, and you will be paying more per gallon... If your car is turbo then you are doing the right thing! don't run low octane in a high compression engine (like a turbo engine), but don't waste your money if you have an N/A.

(just noticed your profile says you have N/A. I would switch to a lower octane fuel. The high octane fuel may be causing spark knock and wearing your engine with unburned fuel.)

[z.Leinbach]

I run 92 1) because the car says to both book and gas gauge, 2) how I drive (I'm lead footed and I hoon around alot, and because the spark plugs say it's ok. After 5k of owning it running various brands of 92 the plugs are still clean and clear of carbon build up, car sounds and runs healthy other then the power steering pump leak and rear main. Non turbos have a compression of 10.5:1 which is why I run 92. My mild built 350sbc powered jag had a close compression to that and didnt really have problems till I ran a couple tanks of regular 87 through it.. Also I can't tell if I a tuned ecu in my car or not so better vsafe then sorry kinda if thing and I don't mind paying 2.30-2.75 a gallon for it

[RubyRed300ZX]

don't run low octane in a high compression engine (like a turbo engine), but don't waste your money if you have an N/A.

Just so you know, The N/A has a higher compression ratio than the TT.

[z.Leinbach]

TT is 8.5:1 NA 10.5:1 as I've seen around here. Which is why either way you should be running atleast 91 octane in your car.

[nissanfreak12]

Stock ecu is tuned for 91 octane from the factory to prevent detonation in both NA and TT engines. Yes, you can run below 91 in NA cars, it will create a lower performance and a possible chance for detonation. It will also cause a reduction in MPG, not that anyone really cares in a sports car.

Mrfreeslaw, you are correct and incorrect at the same time. The engines that are not tuned or designed for higher octane will cause issues like unburnet fuel and soot, but Z engine are designed for higher octane. Just because high comp doesnt automatically mean higher octane. I have a Jeep Grand Cherokee with the 5.9, it requires higher octane because it was tuned for it. I can get a flash for the ecu and lose 20 hp so I can use lower octane, but that s why we have high performance engines. I think mine has a comp ratio of 9.5:1. Its all about the tune, not just the compression ratio.

[z.Leinbach]

Exactly, most Lexus cars will say premium fuel only as well it's how they are built and tuned, same with some toyoters

[MrFeesLaw]

don't run low octane in a high compression engine (like a turbo engine), but don't waste your money if you have an N/A.

Just so you know, The N/A has a higher compression ratio than the TT.

You do realize that compression ratio does not calculate the turbo right?... and that a turbo engine has to run a lower compression ratio because the forced induction raises the compression ratio while boost is being made... so it may only be 8.5:1 at idle... but may be 13.5:1 going down the road... Just so you know.

[MrFeesLaw]

Stock ecu is tuned for 91 octane from the factory to prevent detonation in both NA and TT engines. Yes, you can run below 91 in NA cars, it will create a lower performance and a possible chance for detonation. It will also cause a reduction in MPG, not that anyone really cares in a sports car.

Mrfreeslaw, you are correct and incorrect at the same time. The engines that are not tuned or designed for higher octane will cause issues like unburnet fuel and soot, but Z engine are designed for higher octane. Just because high comp doesnt automatically mean higher octane. I have a Jeep Grand Cherokee with the 5.9, it requires higher octane because it was tuned for it. I can get a flash for the ecu and lose 20 hp so I can use lower octane, but that s why we have high performance engines. I think mine has a comp ratio of 9.5:1. Its all about the tune, not just the compression ratio.

Maybe the Z is different. To be honest I haven't even used the gas that is in mine yet, so I didn't really think about what to put in. But in most modern N/A vehicles that are not a performance application (such as an accord with a 3.0 v6) running 91 is a waste of money. A higher compression ratio will cause the engine to have a higher temperature. If you know anything about diesel engines, then you know that high enough compression will cause fuel to ignite, even without a spark. This is why high compression engines (such as a turbo car) need higher octane fuel, because it is harder to combust higher octane fuel, which lowers the chances that the high compression will cause detenation in the engine and lower performance.

Maybe the Z is different, but most cars with 10.5:1 will only use 87, because 91 and 92 are harder to combust, and therefore you will not completely burn your fuel, and will be wasting money.

I can't stress this enough!!!! That the Z is probably different. I wouldn't put it past nissan to tune to higher octane to make more power, but on most N/A 10.5:1 cars you will LOSE power with higher octane, because it will not completely burn the amount of fuel your injectors put out. whereas it will completely burn 87. so if have a 200hp engine, and you make 10 more hp on 91, but you only burn 90% of the fuel on 91, you actually would make about 190 horsepower, because you can't burn it all.

FOR THE FINAL TIME!!! the Z may be different... But I feel like many people aren't fully understanding what i'm trying to say. Not saying the Z won't run 91. just saying the MAJORITY of N/A cars will not completely burn higher octane fuel for the reasons stated above, and will therefore, lose economy and power.

[z.Leinbach]

The Z is different by nature has been since birth, they are a breed of their own, hence why they are an acquired taste, I believe by design of the vg30de and it's tune for the 300 it needs the 91 octane # run the way it's designed to be drove. I for a face know I'm getting a complete burn, id almost be money, that after I replaced/relocated my knock sensor my foul smell issue would disappear

[nissanfreak12]

Mrfeeslaw, just so you know, I probably know more about diesel than gas engines. Am I a master mechanic, no, but schooling, yrs of rebuilding maintaining in a shop environment(factory repair for volvo diesel). I do completely understand what you are trying to say, generally NA cars will not require 91+ octane. These are for fuel economy, basic everyday vehicles that soccer moms use. The Z is not your basic car, it is an over-engineered vehicle to squeeze as much HP as possible. Why do you think aftermarket parts do little to no HP gain on a NA engine? You also have to remember that this is 20+yr old technology. Not the same as modern day cars.

Take the Chevy sonic, 1.3 turbo engine. It dos not require 91+ octane, they actually tell you to use 85/87. Ford Eco boost 3.5 TT, same thing. These are designed this way because the general population do not understand what the wrong octane will do to a turbo vehicle. But take a 2007 dodge Dakota, 4.7 NA 9.5:1, requires 91+ to run effiently. All engines will run with lower/higher octane, but with the outcome you stated.

Personally, this thread has gotten way out of hand and way off topic, I apologize because I have not helped that either. Z's were engineered to run 91+ octane NA and TT, if you want to run lower, that is your decision. Lets leave this at that. If you want to start a new topic on octanes, by all means do that. Lets get back on topic please.

Z.leinbach;

You mentioned foul smell. Knock sensor will not cause that, What is going on? What kind of smell? Is there a running issue? I know you said code 34 is what keeps coming up, but what issues are you having?

[MrFeesLaw]

^^^I agree completely. Again. The Z, I'm sure, is different, because of its engineering. I just felt like many people were trying to say that ALL cars run better on 91. Which is not true. And I felt like I was being attacked for disagreeing. I apologize for taking this thread so far off topic. I did not think it would become this big of a deal to say that not all cars run better on 91.

Back to the point of this topic, I think nissanfreak is on to something. The knock sensor is a fairly common issue from what I have heard. I believe Z1 makes a kit for the knock sensor, which is the most likely cause for code 34 (but not necessarily the only cause).

[z.Leinbach]

Smells sulfury or phosphorusy, nothing like a raw fuel smell, only engine oil leak I've found is a rear main, and the driver pcv hose is split. Only running issue I've had is poor gas mileage, lopey feel at idle that's, aggressive, to moderate. Car has 2kish on the oil change, 4500-5000 on the pcvs, plugs, and fuel filter, also believe the fuel gauge to be off to about 1/8-1/4 tank, gonna replace that seal either this week or mid February (where paycheck and delivery fall) cause I've had some fuel smell in the cabin and around the car

[nissanfreak12]

Sulfur smell is your cats, period. You need to check the ohms of your injectors. Your knock sensor will not cause your car to emit bad smells. All the knock sensor does is detect knock and determines if the engine needs to retard the timing. If the sensor is bad, it wont do anything like detect knock or make the fuel change to a richer or leaner condition.

Things you need to check is;

Injectors- these should ohm between 10-14, no more no less. Replace if out of range, look for phase 2 style, better with ethanol blends

Coolant Temp Sensor-Make sure it is reading correctly, these are cheap enough to replace

O2 sensors-Even these only work after 2k rpms, they will still dump a ton of fuel if they are bad or reading incorrectly, don't go cheap, get the OEM type, NGK I think, otherwise you may chase a lopey idle as well

TPS-make sure its in the correct reading

Timing-13 degrees BTDC

Fuel pressure regulator/dampner- Mainly the FPR, check the fuel pressure.

MAF-make sure its functioning


Your car is dumping too much fuel cause a rich condition. This is causing the cats to overheat and melt, which creates a sulfur smell. Bad cats will cause all sorts of issues, poor mileage, poor performance, unable to rev high, smells. Anyway you look at it, you need to fix what caused the cats to go and replace the cats, if you want. If your area doesn't require cats or emissions, test pipes.

[z.Leinbach]

The smell honestly comes and goes, which I find odd. It's was super bad when I first got the car after some very aggressive driving (to speeds which should not mentioned... Lol) it's gone away and comes back ever so slightly, I'm already looking to replace all the injectors with phase 2s' what size should I get as to avoid any lean conditions, and it probably wouldn't help that I almost drowned the car with intake cleaner when I got it should've mentioned that, but I digress, I've been using the red bottle of heat (which is a fuel dryer, and injector cleaner) seems to have dampened the smell.