CEL code 34 and wont idle, just stalls... Knock sensor? MAF? Plugs? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DUBCITY · 09-15-2005, 10:07 AM

I have a 1992 SE with the stock KA and I was driving to work yesterday morning, stopped for gas, then got back on the freeway when all of a sudden my check engine light comes on. I pulled over and looked everythign over and it seemed fine so i kept driving and the light would keep coming on then going off. really weird, but the car was running ok. On my lunch break i pull the code from the ecu and its a 34 = knock sensor. So when i drive home now the car wont idle and keeps stalling when i come to a stop. It is also pretty stuggish when accelerating. My question is could all of this be related to the knock sensor? Ive also heard that the CEL wont even come on for the know sensor? but i dont know if this is true. Could it mabey be a bad ground and that is why the ecu thinks the KS is bad and could be the reason for the car stalling? could a clogged/dirty MAF cause all of this? Any help would be great.
thanks

*MELLO*SOS* · 09-15-2005, 10:36 AM

A few quick suggestions...

Check all your vac + elec connectors, wires, hoses for shorts or leaks
Check engine grounds
Clean battery terminals
Clean your MAF with TB cleaner

I had a code 34, ended up being a short in the wiring from the knock sensor to the ECU, in the harness from the ECU to the KS Subharness connector. This made the ecu believe the engine was knocking, so it would pull timing and cause the car to bog and just generally drive like shit. Here is my thread on the topic you might find something in there that helps you...

http://www.zilvia.net/f/showthread.p...ht=serious+bog

GL

aznpoopy · 09-15-2005, 10:38 AM

code 34 knock is on my car. it doesn't affect the idle or anything.

however, iirc according to the FSM, the knock sensor will retard timing when it senses knock; so maybe its reading inaccurately and screwing with your timing, making your car idle funky and run like shit.

i have to reiterate that just about every 240sx will throw a 34 at some point; and in three years of forum whoring and talking to people ive never heard of it causing issues like yours.

DUBCITY · 09-15-2005, 02:08 PM

Quote:

Originally Posted by mello88

A few quick suggestions...

Check all your vac + elec connectors, wires, hoses for shorts or leaks
Check engine grounds
Clean battery terminals
Clean your MAF with TB cleaner

I had a code 34, ended up being a short in the wiring from the knock sensor to the ECU, in the harness from the ECU to the KS Subharness connector. This made the ecu believe the engine was knocking, so it would pull timing and cause the car to bog and just generally drive like shit. Here is my thread on the topic you might find something in there that helps you...

http://www.zilvia.net/f/showthread.p...ht=serious+bog

GL

thanks a lot man, that is a great write up. I just had one question, how exactly did u measure the resistance from the ecu to the knock sensor? using an muti meter? I have one, but i dont think the wires are ong enought to go from teh cabin to the engine bay. Please let me know.
thanks

09-15-2005, 10:07 AM	#1
DUBCITY Zilvia Junkie Join Date: Mar 2003 Location: Redondo Beach, Ca Age: 41 Posts: 596 Trader Rating: (9) Feedback Score: 9 reviews	CEL code 34 and wont idle, just stalls... Knock sensor? MAF? Plugs? I have a 1992 SE with the stock KA and I was driving to work yesterday morning, stopped for gas, then got back on the freeway when all of a sudden my check engine light comes on. I pulled over and looked everythign over and it seemed fine so i kept driving and the light would keep coming on then going off. really weird, but the car was running ok. On my lunch break i pull the code from the ecu and its a 34 = knock sensor. So when i drive home now the car wont idle and keeps stalling when i come to a stop. It is also pretty stuggish when accelerating. My question is could all of this be related to the knock sensor? Ive also heard that the CEL wont even come on for the know sensor? but i dont know if this is true. Could it mabey be a bad ground and that is why the ecu thinks the KS is bad and could be the reason for the car stalling? could a clogged/dirty MAF cause all of this? Any help would be great. thanks

09-15-2005, 10:36 AM	#2
MELLOSOS* LAID OUT Join Date: Mar 2004 Location: LAS VEGAS Age: 43 Posts: 2,015 Trader Rating: (1) Rides Gallery: MELLO*SOS Feedback Score: 1 reviews	A few quick suggestions... Check all your vac + elec connectors, wires, hoses for shorts or leaks Check engine grounds Clean battery terminals Clean your MAF with TB cleaner I had a code 34, ended up being a short in the wiring from the knock sensor to the ECU, in the harness from the ECU to the KS Subharness connector. This made the ecu believe the engine was knocking, so it would pull timing and cause the car to bog and just generally drive like shit. Here is my thread on the topic you might find something in there that helps you... http://www.zilvia.net/f/showthread.p...ht=serious+bog GL

09-15-2005, 10:38 AM	#3
aznpoopy Post Whore! Join Date: Mar 2003 Location: New Jersey Age: 44 Posts: 5,013 Trader Rating: (1) Feedback Score: 1 reviews	code 34 knock is on my car. it doesn't affect the idle or anything. however, iirc according to the FSM, the knock sensor will retard timing when it senses knock; so maybe its reading inaccurately and screwing with your timing, making your car idle funky and run like shit. i have to reiterate that just about every 240sx will throw a 34 at some point; and in three years of forum whoring and talking to people ive never heard of it causing issues like yours.