powerfc knocking problems ?

[radiobar]

hi !

my powerfc always shows knock up to 120.
even when there is no load i.e. going downhill in gear with no throttle.
my afr shows 20.9% o2, so there is no fuel in the cylinders.

i have changed the sensor twice with no effect.
after a total rebuid of the engine the problem is still there.
powerfc was also exchanged

the problem started right after installing jun cams incl. uprated springs.
can the springs cause a false knock signal ?

it seams to appear in lower rpm before 3500
on full load its fine up to 8000 rpm.


any other ideas what to do ?

i cant do any setup with this knock.

thanks

 

[Shaun]

How noisy are the lifters?It has been known for noisy lifters to affect the knock sensor.Cant you calibrate the Power FC for normal engine noise like you can on the SAFC2?

 

[radiobar]

hi !

there is no calibration on powerfc.
engine has only around 700 miles and valve clearance was adjusted
few days ago.

its strange that it appeared after cam+springs installtion just when
i left the garage.(on old engine)

can springs cause a knock signal ?
are there any aftermarket knock displays ?

thanks

 

[Shaun]

I've not heard of any knock issues created just by changing the valve springs as long as the cams are shimmed correctly.What are your AFR's at the points where your getting knock?Have you tried adding/removing fuel at these points?There are a few aftermarket knock monitors.The "LINK" make a very good one that you can calibrate for normal engine noises.

 

[radiobar]

hi !

my afr is ok. there are no special points. its jumping around.
it even happens at 0 load,so it must be a wrong signal.
when going in gear with no throttle injectors are switched off,
so there cant be any real knock.

i have no idea what to do now.

what is the valve clearance for uprated cams ?
do you set it to standard 0,14-0,17 mm?

thanks

 

[campbellju]

When wqe were mapping Andy's car, a failing wheel bearing caused a dodgy knock signal. A knock sensor is just a filtered microphone so any noise that is in the right (wrong) frequency range will be detected as knock.

 

[radiobar]

hi !

here is a video of my signal(car is standing)
its interesting that the values are lower when car is cold.
at idle i got below 10 in the morning.

http://www.weidewaren.de/MOV00294.3GP
(3gp player needed)
maybe i make one with better quality...

it cant be a wheel bearing - its also there when car is standing.

 

[campbellju]

I can't open the file on this PC. The wheel bearing was just an example, anything that makes th wrong nois will cause you problems. cams, cover, parts not screwed done correctly.

 

[radiobar]

hi !

you need to save the file to your computer.
and open it with a 3gp player.
just google for 3gp player

my engine was rebuild completly with all new parts
and i also took a close look on all bolts etc.
everything seems fine. but the problem is the same
as before the rebuild.

 

[campbellju]

Its alright, I'm on the right PC now
Yes you have a lot of noise there. It could be electrical noise or it could be mechanical noise. The way it improves at higher revs makes me think mechanical but never say never.

 

[radiobar]

hi !

but how to find it out ?
i have this "doctor tool" - dont now how its called.
but i cant hear anything...

 

[radiobar]

hi !

still no success.
i will remove the jun springs now.

but what will happen if i use standard springs with jun cams(272,11.0 lift) ?
will it be fine ?

i also have the option of installing 264 hks cams which are fine with standard springs.

after the rebuild i installed a 2871R(the biggest one),so maybe i dont
need the 272 anymore.(got 3071R before).

can i reach around 400hp or little more with the hks cams ?


thanks

 

[radiobar]

hi !

started to change the springs today.
and it seems that they are installed wrong way.
there is a yellow mark on them and it should show
to the head. but all of them are on top.

so i will keep the uprated springs and install them how it should be.
its very tricky with the cams in place,but it works.
should be ready on monday.

 

[radiobar]

hi !

springs are correct now. but there is no effect.
what know ?
could it be the valves ?
some of them have clearance around .22 (should be .14 - .17)

 

[radiobar]

hi !

i reshimmed everything again and now i got clearances .14 - .16 at all valves.
engine sounds very nice.
knock is now below 40 most of the time.
only had 77 once. but there are no more values over 100
and the signal is not jumping so much as before.

i also removed the "bridge" over the chain
does it have any sense ?
and the strange metal piece between 1st/2nd cylinder is also removed.
what is this for ?

what do you think ?
are the clearances still wrong ?
i was told to adjust .10 with jun springs - but jun says .15 !