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 Post subject: knock sensor
PostPosted: Tue Jan 21, 2014 8:48 am 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
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Location: Weymouth southwest dorset
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morning, think the knock sensor on my 185 is playing up as im getting readings of knock while cruising and quite high knocks on boost but cant hear or feel detonation from car.

Going to replace it so i can tick it off the list, but unsure as to where it is and where to purchase new one from?

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1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 9:30 am 
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Joined: Wed Jul 13, 2005 12:06 am
Posts: 4743
Location: Perth, Western Australia
Car Model: ST205
The knock sensor is located on the back of the engine block. Trained ferret is useful if you need to replace with the engine in-situ :lol:

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 9:45 am 
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Joined: Wed Jul 13, 2005 12:14 am
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Location: Camberley, Surrey
Car Model: ST205
TCB is probably the best place for a new one.

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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 10:02 am 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
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Location: Bournemouth
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Access from drivers wheelarch via steering arm hole.

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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 2:52 pm 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
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Location: Weymouth southwest dorset
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ah i know where it is now youve said. Remember putting the earth strap via whelarch with arm wedged up in there.

Anyhow thanks guys.

_________________
1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 7:51 pm 
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Group N
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Joined: Fri Mar 30, 2012 8:31 am
Posts: 332
Location: Wiltshire
Car Model: ST205
I have read that the wiring /connectors has been the cause of some problems as well so probably worth a check?

I think it is a screened cable?
Anyone actually confirm this?

Sent from my C6833 using Tapatalk

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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 7:56 pm 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
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Location: Weymouth southwest dorset
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i will check connections before purchasing new sensor as they not cheap!

If i remember right i dont think i unclipped any sheided wire plugs when i took head off last.

_________________
1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Tue Jan 21, 2014 10:13 pm 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
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It is a screened wire, but only the centre core goes into the connector. The screen is grounded at the ECU end.

The wire comes through the inlet manifold from above with the earths and the TVIS/TVSV wires.

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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 9:09 am 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
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Location: Weymouth southwest dorset
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had a mapping sesh in car last night and listening to engine with a detscope we were able to pick up on detonation and when hearing, it the knock light flashed on dash at a steady rate up the revs on a 3rd gear pull: 1.....1.......1 suggesting that my sensor is not faulty??

adjusted ignition timing by 8 degrees to eventually reduce knock an now 3rd gear pull runs through fully with maybe a flash once from light.

In 4th high revs light comes on at a rate i.e: 1......1..111111..1......1!

Apexi commander reads peak knock at 64 and has varied between runs, but i dont actually know what the number indicates?? Counts of knock??

Anyways computer ran out of battery after few hours so didnt have time to finish.

Another thing is that even though there is plenty of fuel and even a 50:50 mix of water and meth being squirted in, my egts are raising considerably quick up to the region of 920 and its measured on manifold where all ports flow to one before turbo

Does anyone else measure egts and what readings do you get?

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1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 9:38 am 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
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Location: Bournemouth
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If you've had to retard timing 8 degrees to avoid knock then egt will be higher. You may be better off running a bit richer to stop the det rather than so much retard. I would also be wanting to investigate why so much det. Maybe try some higher number plugs as a start.

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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 11:21 am 
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Joined: Wed Jul 13, 2005 12:14 am
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Location: Camberley, Surrey
Car Model: ST205
On the knock number from the pfc I have heard that it is just an arbitrary figure in that 0 = no knock, 100 = lots of knock. I have no idea if that is true however.

920 deg C sounds very high to me, I used to see 800's on my car I recall but never into 900's.

Good luck with it.

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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 3:34 pm 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
Posts: 406
Location: Weymouth southwest dorset
Car Model: None
have grade 8 plugs in at the moment, will let you know how we get on.

_________________
1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 7:04 pm 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
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Have you had the head off lately to check how coked up the engine is ?

The number on the PFC relates to the noise level the sensor is detecting. The standard sensor is very highly tuned to the frequency of detonation so the numbers usually stay fairly low until you really do get detonation. The noise level does increase with both RPM and load when no detonation is present so you need to get used to what readings you get when there's no detonation.
If you're running a GM sensor - a popular swap to 'desensitise' the standard knock control system, then you will find the background noise levels much higher but much less increase when you do actually start getting detonation.

When you retarded 8 degrees, were you listening with proper det. cans or relying on a machine showing a level ? i.e. was it definately det. or some other noise such as big end rattle which can confuse machines. Retarding ignition does quieten down big ends that have a bit much clearance.

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If at first you don't suck seed, try drier grain.

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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 9:59 pm 
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Group N

Joined: Fri Apr 06, 2012 6:13 pm
Posts: 406
Location: Weymouth southwest dorset
Car Model: None
the head wasnt to bad, had few hot spots which were all removed, valvs were cleaned and whole head dipped along with plenum. Since its been back on ive ran 50% water and methanol mix which should technicly steam clean combustion chamber.

Before battery ran out on laptop, we had managed to level out map and stop knock by listening via microphone sensor clipped onto rocker cover, but the engine light still flashes now and again so guess its just picking up excess noise?

_________________
1998 ford st24, 186hp 2.5 v6- sold
1997 bmw e36 318ti, mint hellrot red- sold
1992 celica gt4 st185- td04 340hp/330lbs
1998 mercedes E280- sold
1998 pug 1.9 td- mile muncher!
1993 rx7 542hp savage monster!!
2007 BMW 335i- in the shop gettin built!! :-)


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 Post subject: Re: knock sensor
PostPosted: Thu Jan 23, 2014 11:54 pm 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
Car Model: None
Could be you have the threshold set too low in the PFC. From memory on my brief encounter with PFC's I think there was just a single setting so should be set just above maximum noise (full chat at high RPM probably). From my experience, det. of any significance will exceed this at any RPM.

Use the det. cans and experienced ears to determine whether there is real det. and advance timing back up to a couple of degrees short of hearing det.

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If at first you don't suck seed, try drier grain.

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