304 Knock Sensor

[whiskeytango]

Yesterday I changed my intake manifold gaskets. While removing the wiring loom I broke the plug on the knock sensor (It still plugs in just loosely).

Started it this morning and went for a drive. It all seemed fine until I got to about 3500rpm. It feels like the fuel is been restricted or the timing is not been advanced properly. Did some googling and figured it might be the knock sensor.

I went for a couple of quick drives trying to jam the plug in more with no success. Then I decided to unplug it totally and give it a crack. Worked perfectly!

Now I'm not sure how this works cause I really know stuff all about them so if anyone has an any ideas I'm all ears...

On a side note. I have a Memcal from Ace. Is it possible the tune he sent has the knock sensor disabled? But then it shouldn't effect it at all if it's broken or not... Anyway just thinking out loud.

 

[Deuce]

Are you sure it was the knock sensor?
I didn't think you would have one (only on hsv motors), and it you did you wouldn't go near it for intake manifold gasket swap.

 

[whiskeytango]

Yes it's a VS SIII with a VT roller cam. Looks exactly like a knock sensor in the same spot everyone has described so I assume they come with it.
The wire goes through the injector loom, down the front of the block and along the sump gasket.

 

[woteva]

Yep, that's the knock sensor.
Can you see any error codes when disconnected ?

 

[whiskeytango]

Yep, that's the knock sensor.
Can you see any error codes when disconnected ?

Just had to search how to check codes cause I've never bothered before lol.
Figured it out I think.
I got 12, 35, 43 and 49.
So if I'm right I got

IDLE SPEED ERROR (Idles perfect)
KNOCK SENSOR CIRCUIT FAULT
CAM/CRANK SIGNAL INTERMITTENT (What can cause this?)

Tried resetting it by disconnecting the battery so they were fresh. Had the same codes straight away.

Took it for a quick blocky to make sure I wasn't imagining things. Definitely running 100% normal with the sensor disconnected. Its actually 25 degrease outside tonight so its the coolest I've driven it in months. Went like farrkk.

Shouldn't it straight away try to pull the timing when it has any issue like it been disconnected?

 

[BlackVXGTS]

The knock sensor is only there to protect your engine from detonation (pinging). What fuel are you running? If it's 98 then your engine is unlikely to suffer from detonation, so you probably won't need the knock sensor at all. If you are running standard unleaded you probably should replace the sensor. If the sensor is faulty (damaged in your case) then total advance can be retarded by as much as 12 degrees by the knock sensor input.
Refer to the attached files re your error codes:

 

[whiskeytango]

The knock sensor is only there to protect your engine from detonation (pinging). What fuel are you running? If it's 98 then your engine is unlikely to suffer from detonation, so you probably won't need the knock sensor at all. If you are running standard unleaded you probably should replace the sensor. If the sensor is faulty (damaged in your case) then total advance can be retarded by as much as 12 degrees by the knock sensor input.
Refer to the attached files re your error codes:

Always ran on 98 and tuned for it.

Cheers for them I'll have a proper look tonight.

 

[gtrboyy]

Most tunes I'd expect knock sensor disabled or not turn on untill certain rev range...depends on the tuner & engine I suppose.

Ask tuner if it's disabled or sensitivity turned down if that's possible or not.

Main reason is when modified mechanical noise can set it off.

On a stocker you disconnect the knock sensor or melt/crush the loom wire it will set off the cel light & get intermittent faults iirc


Idle speed error could be anything caused by other things that made it misfire or stumble.

Knock sensor circuit -broken plug or sensor or loom wire...if it's disabled shouldn't be an issue might just need disconnect battery let it sit & reset 10mins(?)

Cam/crank signal to me is seq dissy...could be wiring or plug issue or even old fault when set timing in limp mode.

Keep messing with it...usually it's something simple & fluke it haha

 

[whiskeytango]

I just went for a couple of km drive with it disconnected while it was cold to rule out any operating temp discrepancies and it ran normal.

How long do the errors stay logged?

When I first turned it over on Saturday arvo I realized immediately that I forgot to plug the coil in. Possibly got the crank sensor error from then if it's linked.

5-6 weeks ago when I had the manifold off to clean it the IAC got full of **** and ran like crap when I first started it. Cleaned it up and fixed it. Could be from then...

I'll shoot ACE a message now and ask while the battery is disconnected for an hour or so.

 

[gtrboyy]

Suppose to clear after certain amount of starts 20 or so not sure unless faults reoccur.

Some claim to turn lightswitch on just make sure power is totally drained when battery disconnected *shrugs*

Seemed like urban myths but disconnecting power for 5-10 mins or so sounds more plausible.