Ok, good description. Presume this is a temp measure to rule out the knock sensor.
Ok, good description. Presume this is a temp measure to rule out the knock sensor.
Unless you find the wire is off before we get a resistor
would an airbag one work?
could try it highly doubt it will do any damage to anything
But i'm wondering, maybe the knock sensor fault is a clue? head has been off wiring has been moved about, now its not playing ball maybe its wiring related
Took this from a 240sx forum.
Quick question on the knock sensor bypass. I'm throwing the #34 DTC and the wiring appears ok and has continuance. The knock sensor has some small cracks in the plastic housing, but I don't know that it means it is bad. I have seen some old posts mentioning wiring a 1 Megaohm resistor in to fool the computer and stop throwing codes/retarding timing. But the link is no longer working. Does the resistor just need to go in between the sensor harness and ground? Just take the place of the knock sensor?
Doesnt say for sure but I did read a 1k ohm resistor which I imagine is 1000 ohm.
Tomorrow night is the night! I'm going to remove the intake side, check all hoses and that the knock sensor is connected.
If it is connected, should I disconnect and check on datascan for a fault, plug in again, check datascan again? If he knock sensor is connected, could this point at a faulty sensor, or rule out the sensor?
You should be able to reach it without taking the plenum off.
Cool, going to check the pipes under too, just incase.
EDIT: Didnt make it to the car tonight, will be Sunday now. You free Mark?!
Last edited by Topper; 19-08-2011 at 22:34.
ok, so i have taken off most of the intake side and can see the Knock sensor (KS), the cable that attaches to the KS only has one yellow wire, the plug on the other end of the cable has a yellow and black wire.... I presume a black wire (earth) should plug on the KS too?
Mine is also 90degrees clockwise to the one posted by Joey above.
I have taken pictures and will upload later of each end of the wire, will take off the wire and try get a replacement
EDIT: Have removed the wire, it appears there doesnt need to be a black wire coming from the KS as there is only one terminal and one wire outlet from the KS plug. Picture to follow:
Last edited by Topper; 28-08-2011 at 17:43.
Following the post above, I've finaly got round to putting up pictures:
KS plug at Intake: Two wires
Other end of wire at KS: One wire.........
Looks ok to me
Put it back on then?
Maybe put a new one on for the sake of ruling it out. Does anyone know if the standard ecu retards the timing when cold ie could the engine temp sensor cause the car to retard the timing all the time?
The black earth wire won't be needed for the knock sensor, because it's bolted to the block, which is earthed itself, and the part of the KS touching the block is metal, so just having it bolted to the block is earthing it.
You could measure the resistance across the sensor then replace it with an equivilent resistor, saves looking around and people saying it's 1KOhms, then 540 ohms, then 56KOhms, then the quote from John said 1MOhms, etc. Just measure it yourself and go from there. I could measure the 2 I have from my det-cans & KS-Pro, the Nissan one just looks like a generic BOSCH knock sensor, same ones used in Phorumla det-cans and knock analysers.
IIRC it does retard the timing to 5* on cold start and once warmed up should move to 15*. That could explain why it's constantly running 6* of timing, but doesn't explain why the car runs so badly when the timing is locked to 15*.Originally Posted by redsx94!
Obviously the ECU is constantly adjusting timing to maintain a steady idle, and the more timing it uses the more of the engines power is used (until MBT of course) to maintain that idle. Idle timing is always considerably less than MBT, but the reason for that is so the car has a bit of reserve that it can automatically adjust and use when needed. For example if any car has been mapped to run at MBT on idle with everything turned off, then once you turn on the heaters, air con, wipers, lights, etc, etc the ECU will not be able to generate more power/energy by advancing the timing to keep everything running, so it will bog down and die due to too much load on the engine.
Hence, on idle a car never runs MBT, so that the ECU can constantly adjust timing to keep idle steady, even when engine loads are changing due to the owner of the car turning things on/off.
So this is an odd issue, it idles fine at 6* timing, but when you advance the timing, which will actually give it more power if everything is setup correctly it bogs down and tries to die?? Something mechanical is not right from the sounds of things.
One of my mates had a car that had a similar symptom but may not be related,
As soon as any load was put on it died,in reverse it would rev all day long.
Turned out it it was crank sensor, it did not throw up any fault codes.
As soon as thus was replaced the car fired up and reved freely?
He also asked if the cams were put back in the right way round?
@ HermaN - How do I measure the resistance?
The car doesnt run "badly" at 15*, but is a bit lumpy. The main issue when the timing is at 15* is the heitation when the throttle is opened quickly (when stationary) and the lack of willingness to pull when driven. At 6* it rev's with no hesitation and drives like it should.....
@ Joey - Dont start this again, i'm 99% sure the cams are in as they came out, i'm only 99% as its been a while and you guys are challenging me.....
Last edited by Topper; 12-09-2011 at 11:09.
Where are the part numbers located on the cams to rule that out?
Crank sensor though?
Greetings from turkey!
Resistance is measured with a multi-meter across the pins of the knock sensor, then you can get a resistor of equal value which can fool the ECU into thinking the sensor is there and working when it's unplugged, just for testing purposes.
Johns suggestion of the crank sensor could well be spot on, and the factt you changed the head gasket could well be a red herring and causing you to look in the wrong place. The hesitation and lack of willingness to pull as you say does sounds like a timing issue, either the timing itself is out or one of the sensors is not reading correctly.
I know you guys tested Johns sensor in your car, but did you test your sensor in his car to confirm it's working properly? After that I would try the crank sensor to eliminate that as the issue. It's a pain, but these things require a process of elimination.
Oh, and off topic here, but John, when you back in the UK?
If it is the crank sensor I owe him a pint!
I'm back 9pm tonight in Manchester.
Back 5pm Aberdeen,
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