[Diy_efi] False knock?
Grant Beaty
gbeaty at ufl.edu
Wed Nov 6 14:55:27 GMT 2002
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I re-did the repair manuals knock sensors tests and both check out ok, =
.123ms period at 4k RPMs. Timing advance still plummets when the car is =
leaned out past 10.8:1 or so, at boost levels from 14 to 19 psi. This =
has been verified by 3 different wideband O2s. The car's compression is =
perfect, 172-175 across the board, no visible blow-by anyways, and it =
burns no oil. The car actually lost power going from 10.7 to 12.0 a/f on =
the dyno, 450 rwhp to 445 (although it picked up some torque before it =
pulled ~4 degrees of timing). All other Supras I've heard of pick up =
some power when leaned out, even on pump gas, and even past 12.5:1, as =
long as its only for one dyno pull.
Does anyone have any experience with false knock associated with a/f =
ratios? Is it possible that my car simply makes more knock-noise than =
others? Unfortunately I don't have access to other Supras to experiment =
on w/ a digital scope. It doesn't seem likely that the ECU would pick up =
false knock only when the car is leaned out, but given that the =
compression is so good (59k miles of HARD driving, lots of long highway =
pulls, and quite a few road course miles too) thats the only thing I can =
think of. A plug chop on the dyno revealed no noticable cylinder =
imbalance. Coolant temps make no difference, even as low as 160F.
A few people have told me the squish area or the quality of valve seat =
installation could have a large effect on knock threashold. However, =
given that I have good compression and the plugs have never showed signs =
of det (even when it pulls 8 degrees of timing), it doesn't seem likely =
to me. I'm all out of things to try though, except for trying another =
ECU which should be coming in the mail.
Thanks for any help,
Grant Beaty
'97 T66 Supra TT 6-speed
-----Original Message-----
From: Grant Beaty <gbeaty at ufl.edu>
To: diy_efi at diy-efi.org <diy_efi at diy-efi.org>
Date: Saturday, November 02, 2002 12:01 PM
Subject: Re: [Diy_efi] Knock sensor Q
=20
=20
I just measured the 1st knock sensor's frequency with my =
ghetto-o-scope ( http://polly.phys.msu.su/~zeld/oscill.html ), and it =
appeared to have a period of about .08ms at 4k RPMs, whereas the repair =
manual states it should have a frequency of .123ms. Does anyone know if =
this is a signifant difference? (I know there is virtually no chance of =
anyone have any idea, but hey, it worth a try since sensors are $130 a =
pop).
=20
Thanks for any help?
Grant
-----Original Message-----
From: Grant Beaty <gbeaty at ufl.edu>
To: diy_efi at diy-efi.org <diy_efi at diy-efi.org>
Date: Tuesday, October 29, 2002 2:20 PM
Subject: Re: [Diy_efi] Knock sensor Q
=20
=20
It read the same as another FJO they had at the dyno, and the =
same as a friend's FJO, and the same as another friend's FJO, etc.
=20
Grant
-----Original Message-----
From: Justin Starkey @ VMP <justinv6 at bellsouth.net>
To: diy_efi at diy-efi.org <diy_efi at diy-efi.org>
Date: Monday, October 28, 2002 12:05 PM
Subject: Re: [Diy_efi] Knock sensor Q
=20
=20
I can't help you with the Knock sensor. How accurate was =
yor FJO WB? I haven't had a chance to test mine against any others.
Justin Starkey
www.VelocityMustangPerformance.com
**Quote Original E-Mail In Reply**
----- Original Message -----=20
From: Grant Beaty=20
To: diy_efi at diy-efi.org=20
Sent: Sunday, October 27, 2002 11:22 PM
Subject: [Diy_efi] Knock sensor Q
=20
=20
Has anyone ever seen a knock sensor, or even a ECU, go =
bad & trigger knock sooner than others?
=20
My car actually makes peak power with an a/f of about =
10.5:1 on pump gas. It doesn't matter if the boost is 15 or 19, it just =
pulls too much timing. Leaning out from mid-high 10s to 12.0: lost =
5rwhp, and its even worse in the 1/4 mi, where it at WOT longer (2-3 mph =
would be lost with a similar tuning change).
=20
I've done a plug chop on the dyno, and it didn't show =
any cylinder imbalance. Compression is 172-175 in all cylinders. My FJO =
WB has been verified against others. Carbon build up isn't possible with =
my driving style. So the only thing left to check is the electronics, =
and new knock sensors aren't cheap, so I'm asking here first.
=20
Thanks for any help,
Grant Beaty
'97 Toyota Supra T66 6-speed
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<DIV><FONT size=3D2>I re-did the repair manuals knock sensors tests and =
both check=20
out ok, .123ms period at 4k RPMs. Timing advance still plummets when the =
car is=20
leaned out past 10.8:1 or so, at boost levels from 14 to 19 psi. This =
has been=20
verified by 3 different wideband O2s. The car's compression is perfect, =
172-175=20
across the board, no visible blow-by anyways, and it burns no oil. The =
car=20
actually lost power going from 10.7 to 12.0 a/f on the dyno, 450 rwhp to =
445=20
(although it picked up some torque before it pulled ~4 degrees of =
timing). All=20
other Supras I've heard of pick up some power when leaned out, even on =
pump gas,=20
and even past 12.5:1, as long as its only for one dyno =
pull.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Does anyone have any experience with false knock =
associated=20
with a/f ratios? Is it possible that my car simply makes more =
knock-noise than=20
others? Unfortunately I don't have access to other Supras to experiment =
on w/ a=20
digital scope. It doesn't seem likely that the ECU would pick up false =
knock=20
only when the car is leaned out, but given that the compression is so =
good (59k=20
miles of HARD driving, lots of long highway pulls, and quite a few road =
course=20
miles too) thats the only thing I can think of. A plug chop on the dyno =
revealed=20
no noticable cylinder imbalance. Coolant temps make no difference, even =
as low=20
as 160F.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>A few people have told me the squish area or the =
quality of=20
valve seat installation could have a large effect on knock threashold. =
However,=20
given that I have good compression and the plugs <FONT =
color=3D#000000>have never=20
</FONT>showed signs of det (even when it pulls 8 degrees of timing), it =
doesn't=20
seem likely to me. I'm all out of things to try though, except for =
trying=20
another ECU which should be coming in the mail.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT><FONT color=3D#000000 size=3D2>Thanks for any =
help,</FONT></DIV>
<DIV><FONT size=3D2>Grant Beaty</FONT></DIV>
<DIV><FONT size=3D2>'97 T66 Supra TT 6-speed</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: =
5px">
<DIV><FONT face=3DArial size=3D2><B>-----Original =
Message-----</B><BR><B>From:=20
</B>Grant Beaty <<A=20
href=3D"mailto:gbeaty at ufl.edu">gbeaty at ufl.edu</A>><BR><B>To: =
</B><A=20
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A> <<A=20
=
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A>><BR><B>Dat=
e:=20
</B>Saturday, November 02, 2002 12:01 PM<BR><B>Subject: </B>Re: =
[Diy_efi]=20
Knock sensor Q<BR><BR></DIV></FONT>
<DIV><FONT color=3D#000000 size=3D2>I just measured the 1st knock =
sensor's=20
frequency with my ghetto-o-scope ( <A=20
=
href=3D"http://polly.phys.msu.su/~zeld/oscill.html">http://polly.phys.msu=
.su/~zeld/oscill.html</A>=20
), and it appeared to have a period of about .08ms at 4k RPMs, =
whereas the=20
repair manual states it should have a frequency of .123ms. Does =
anyone know=20
if this is a signifant difference? (I know there is virtually no =
chance of=20
anyone have any idea, but hey, it worth a try since sensors are $130 =
a=20
pop).</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Thanks for any help?</FONT></DIV>
<DIV><FONT size=3D2>Grant</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; =
PADDING-LEFT: 5px">
<DIV><FONT face=3DArial size=3D2><B>-----Original=20
Message-----</B><BR><B>From: </B>Grant Beaty <<A=20
href=3D"mailto:gbeaty at ufl.edu">gbeaty at ufl.edu</A>><BR><B>To: =
</B><A=20
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A> =
<<A=20
=
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A>><BR><B>Dat=
e:=20
</B>Tuesday, October 29, 2002 2:20 PM<BR><B>Subject: </B>Re: =
[Diy_efi]=20
Knock sensor Q<BR><BR></DIV></FONT>
<DIV><FONT color=3D#000000 size=3D2>It read the same as another =
FJO they had=20
at the dyno, and the same as a friend's FJO, and the same as =
another=20
friend's FJO, etc.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Grant</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; =
PADDING-LEFT: 5px">
<DIV><FONT face=3DArial size=3D2><B>-----Original=20
Message-----</B><BR><B>From: </B>Justin Starkey @ VMP <<A =
=
href=3D"mailto:justinv6 at bellsouth.net">justinv6 at bellsouth.net</A>><BR>=
<B>To:=20
</B><A =
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A>=20
<<A=20
=
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A>><BR><B>Dat=
e:=20
</B>Monday, October 28, 2002 12:05 PM<BR><B>Subject: </B>Re: =
[Diy_efi] Knock sensor Q<BR><BR></DIV></FONT>
<DIV><FONT face=3DArial size=3D2>I can't help you with the =
Knock=20
sensor. How accurate was yor FJO WB? I haven't had a =
chance to=20
test mine against any others.</FONT></DIV>
<DIV>Justin Starkey<BR><A=20
=
href=3D"http://www.VelocityMustangPerformance.com">www.VelocityMustangPer=
formance.com</A><BR>**Quote=20
Original E-Mail In Reply**</DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; =
MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px"=20
dir =3D ltr>
<DIV style=3D"FONT: 10pt arial">----- Original Message =
-----=20
</DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; =
font-color: black"><B>From:</B>=20
<A href=3D"mailto:gbeaty at ufl.edu" =
title=3Dgbeaty at ufl.edu>Grant=20
Beaty</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:diy_efi at diy-efi.org"=20
title=3Ddiy_efi at diy-efi.org>diy_efi at diy-efi.org</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Sunday, =
October 27,=20
2002 11:22 PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> =
[Diy_efi] Knock=20
sensor Q</DIV>
<DIV><BR></DIV>
<DIV><FONT color=3D#000000 size=3D2>Has anyone ever seen =
a knock=20
sensor, or even a ECU, go bad & trigger knock sooner =
than=20
others?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>My car actually =
makes peak power=20
with an a/f of about 10.5:1 on pump gas. It doesn't =
matter if=20
the boost is 15 or 19, it just pulls too much timing. =
Leaning=20
out from mid-high 10s to 12.0: lost 5rwhp, and its even =
worse in=20
the 1/4 mi, where it at WOT longer (2-3 mph would be =
lost with a=20
similar tuning change).</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>I've done a plug =
chop on the=20
dyno, and it didn't show any cylinder imbalance. =
Compression is=20
172-175 in all cylinders. My FJO WB has been verified =
against=20
others. Carbon build up isn't possible with my driving =
style. So=20
the only thing left to check is the electronics, and new =
knock=20
sensors aren't cheap, so I'm asking here =
first.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks for any=20
help,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Grant =
Beaty</FONT></DIV>
<DIV><FONT size=3D2>'97 Toyota Supra T66=20
=
6-speed</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE><=
/BODY></HTML>
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