anyone know about knock sensors and neutral switch codes?

[GT500916]

I had my engine light come on a couple of times in a period of maybe a few months, and it had stuff to dow tih spark plugs "i think" both times gave me 2 same codes, knock sensor and the neutral switch code... but my car is 5speed manual not AT!!

Sometimes when im on the freeway , lets say at like 3,000rpms cruising it sometimes start jerking, kinda like bogging a little, sometimes its hard to notice, almost like maybe a fuel injector is disty and not spitting enough fuel in the engine and lets it jerk a little, ist weird.

I again replaced the spark plugs to new ones and reset my ECU and for a while it was normal but now it started doing that again, and im not sure what the heck it can be, i replaced the fuel filter, spark plugs, might have to check on the timing.

Has anyone had this problem or similar and were able to fix it or find out what it was maybe?

[SHIFT_KA24DE]

interesting... but if you have 5mt ... you wouldn't have a neutral safety switch right? they only come with auto transmissions...

hmm..

[GT500916]

^^ exactly manual tranny doesnt have neutral switch, so what the crap !

[atamotua]

Wrong.... manual trannies also have neutral switch... i know cause i have done the auto to manual swap on my 98 240sx and that's how i found that out.... they have a REVERSE SWITCH and a NEUTRAL SWITCH as well...

[SHIFT_KA24DE]

really? never knew that....

they may have a neutral and reverse switch which acts as an indicator but we're talking about the neutral safety switch which prevents the engine from starting unless it's in N or P.

but, a 5mt 240 will start up fine no matter what gear you're in... as long as you disengage the safety switch with the clutch. I don't know i'm not really sure on that... please explain further... i guess i was wrong.

[GT500916]

thats funny, my engine light is not on but i did the diagnostic anyways and it said #34 wich is the knock sensor, but it doesnt give me the engine light , hmmm..

Earlier today i bought some chevron fuel injector cleaner from chevron gas station for $5, wich has $2 main in rebate and i put that in my almost empty gas tank, then put some supremete chevron gasoline in there 12 gallons and went for a little drive and i didnt get any hasitations or loss of power or jerking and bogging like i had before... but thats something i had once in a while not always, so i dont know if one day of driving will tell me anything, ill have to see how it goes in the next week, ill posts results when im empty again

[k3smostwanted]

Originally Posted by SHIFT_KA24DE

really? never knew that....

they may have a neutral and reverse switch which acts as an indicator but we're talking about the neutral safety switch which prevents the engine from starting unless it's in N or P.

but, a 5mt 240 will start up fine no matter what gear you're in... as long as you disengage the safety switch with the clutch. I don't know i'm not really sure on that... please explain further... i guess i was wrong.

i am pretty sure there is no "neutral safety switch which prevents the engine from starting unless in N or P." that is another switch that connects directly to the gear selector itself...not on the transmission. i think...

the neutral switch is located on the transmission which serves virtually no purpose on the manual transmission car except to let the computer know its in neutral. this is why most people that choose to do 5-speed conversion do not hook this switch up because it is not a necessity.

as for the detonation sensor...if this is fouled or shorted it will cause the computer to change the air-fuel mixture trying to correct what it thinks is detonation. so in this case, the reason why your car may be acting funny sometimes is the computer is attempting to richen the air/fuel mixture trying to keep the motor from, what the sensor is telling it, detonating.

just a thought and trying to help a little...if anyone can enlighten me on the neutral switch on the transmission, feel free. i have gotten my information from doing a 5-speed conversion on my 300zx and it seems that everyone who does this conversion never connects the neutral switch on the manual transmission so i assume it serves a minute purpose.

[SHIFT_KA24DE]

ah ic...

well, i just read about the inhibitor switch in the Chilton repair manual for the 89 240sx auto transmission ... so i just assumed it was that. I guess they can be wrong, too.

[GT500916]

Problem still there... ren engine code again and it give a 55 wich is "no problem" code i believe. Im thinking its one of 4 things... fuel pump, because its making weird noices sometimes, bad fuel injectors, bad distributor, somehow getting bad spark (any advice on this?) Knocking sensor, i dont even know where it is and i dont have a manual and does anyone know how much those are? ir how do i know if its bad and how could that be the problem of my car hesitating, jerking at cruising speeds, loosing power at certain rpm levels, and feel like i step on the gas and quickly let off while normally driving and sometimes at WOT.

[GT500916]

Problem Fixed!!

[GT500916]

well, yea it kinda just went away actually

First i went and got some chevron with techron fuel injector cleaner stuff at Chevron for $5 then i put that in my empty tank and filled up with 12 gallons of chevron 91 and drove around town for a while but the problem was still there, it would stutter and hesitate as different times and at different speeds and rpm levels.

well since im working night shift this week i have the whole freeway to myself at 3am so i tried to clean my injectors by actually pushing the car to some speeds, but then it would start to stutter and i would lay off and drive normal again, then the next morning i tried to do it again, and this time it wasnt stuttering (like i said it does it at random times) so then this was a perfect time to get those injectors blasting at their max, so i got up to 120 right the where the governer cuts off to where i cant go any faster and then i layed off the gas and drove normal since that day and it hasnt stuttered ever since!!