knock sensor, ton of other problems.

[all stock]

ok, i've spent a lot of time reading about poor idles, bad idles, slight loss of power, bad mpg, etc.

i've done a ton of things to try to fix the problem, but i'm at a standstill and wits end.

here's my story:
91 ka24de. 94k mi. car ran alright.(i didn't say great) felt like slight power loss at low rpms. slight hesistation before 3k, fuel cut occured sometimes at 6krpm instead of 7k, poor gas mileage (15ish). throwing code 34. idle sometimes bogged between 700-500 randomly at idle. feels like it's misfiring at idle. did the double exhaust cam trick a week ago, now it's very apparent it misfires at idle. shakes.

replaced ects, knock sensor, ks wiring subharness, engine harness, did 1M resister trick...no luck. still throws the code motor mounts are good, replaced ecu. still same code. swapped mafs, no luck. even tried running 91.

the cabin wiring is kinda screwy on the car. when i brake, the rear defrost light comes on, dr front side speaker doesn't work, yet i get continuity. sometimes the seatbelt light comes on randomly.

if i can't fix it, i'm gunna think about either selling it or making it into an ITA spec car and run se-r cup.

[all stock]

i have stumped everyone?

[HalveBlue]

The only thing I can think of is improper wiring.

[MELLO*SOS]

Are you sure you used a 1M-Ohm resistor? Also double check your resistor splice with a DMM -- make sure the other end has a GOOD GROUND. If you leave it open you'll get the code 34 still! I only say this because you say you've used two ECUs with the resistor trick and got a code 34 on both of them. If the resistor is spliced in properly it should get rid of the code 34. Just to be sure; you cut the incoming KS wire (white on my 92), then soldered a resistor to the ECU-side of the wire, then grounded the resistor against the chassis? You basically want to ground the KS pin on the ECU through your 1MOhm resistor...

After you get the code 34 taken care of I'd suggest you reset your idle rpm and timing.

GL... code 34 FTL

[PS13SILVIA]

If you keep throwing the knock sensor code immediatelt after clearing codes your problem is a short to ground in the signal wire I personally fixed 4 240sx and all had the same short to ground within inches of eachother, located in the plastic case just over the fuel rail, look for a bubble in a thicker black wire, this will be your short to ground.....

[PS13SILVIA]

Well I fixed my knock sensor error code problem.

After spending many hours actually days on this shit I finally fixed the problem and the ECU now gives me a code 55 ......

Heres are the diagnosis steps I performed:

1. Disconnect ECM harness connector from ECM.
2. Disconnect KS subharness connector from KS.
3. Check harness continuity between terminal (B) and ECM terminal (27).

Im my case continuity did exist (so good to go right? NOPE) im still getting a code 34 and my knock sesnor is good to go.

Next I pluged everything back together like it should be then:

Step:
1) With a DMM, one probe to ground other back probing pin 27 (Knock Sensor) with KOER and KOEO.

Results = 0.013v (no good) FSM states you should see aprox. 2.5v at idle and or KOEO.

2) I disconnect ECM harness connector from ECM and de-pin, pin 27 from harness connector alltogether.
3) I re-attach the ECM harness connector to the ECM with pin 27 detached from connector.
4) With my DMM I ground one probe and the other to pin 27 and I get 5v, so the ECU is good to go.

So next step:
1) Taking a jumper wire to pin 27 and reconnecting the original (white) KS wire to the jumper wire I instantly lose the 5v (so im thinking why what is causing this to happen (a short to ground etc etc)
2) I take the same jumper wire and disconnect the original (white) KS wire from it and get about 3ft of regular 16 gauge wire and run it directly to the knock sensor subharness terminal (B).
3) I take measurements back at the ECM with my DMM one probe to ground other to pin 27 and I get 2.5v (good to go finally
4) So now I clear the codes and start the car run it for a few seconds and shut it off.
5) Check codes for any errors and all is good (code 55 finally)

If some of you are wondering why I didn't get 5volts when I rewired, its becasue the KS itself is a 0.560M-Ohm resistor and it reduces the voltage down to approx. ~2.5v.

My code 34 was instantanious means I could clear the codes and get code 55, start the car for 1 second then turn it off and check teh codes and I have a code 34, thats becasue it basically had no voltage present of pin 27.

Some other things that still stump me is I still got continuity between pin 27 and the KS sub harness but why or where was the voltage going to im by no means an electrical expert but I wanna know where it was going, is that what a short to ground would do???

http://www.zilvia.net/f/showthread.p...highlight=code

[all stock]

thank you all for your input. it is greatly appreciated.

i'm going to play with the dmm some more today. so far, my ground is good. batt neg to ground reads 0 resistance. i cut and rewire pin 27 with 1M ohm to ground. measured voltage...it read 1.45V. weird. so I calculated how much more resistance i'd need to run 2.5...i came to 1.67M ohm. weird this was, as i added 670k resistance, the voltage only read 1.89V...i'm a little stumped. this is KOEO. i'm going to try what PS13 said, KOER and try to figure out what the problem could be...

[all stock]

ok...this is weird. KOEO directly from pin 27 to ground reads 2.25V, KOER reads the same. however, when i place probe to ground koer or remove it, idle changes...shouldn't the dmm not have much of an impact on it?

[all stock]

tried to put it in diagnostic mode ii, flashed more than 5 times in 10 seconds...so it's ok

[all stock]

i am at a loss...don't understand why i'm getting 1.45volts with pin 27----1Mohm---ground. what should i be aiming for? 2.15v?

[all stock]

ok, i'm an idiot. i cut pin 20. i rewired it back up and ran a 1M ohm resistor. code 55. lol

there's a lot of white wires around that area...heh.