[Diy_efi] Re: (was: IAC counts) VE tuning issues
David Cooley
n5xmt at bellsouth.net
Sun Jan 2 21:58:52 GMT 2005
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you can avoid the O2 cooldown problem by installing a heated O2... run th=
e
heater from Switched 12V and ground=0D
=0D
=0D
-------Original Message-------=0D
=0D
From: Charles McDowell=0D
Date: 01/02/05 16:33:49=0D
To: 'A list for Do-It-Yourself EFI'=0D
Subject: RE: [Diy_efi] Re: (was: IAC counts) VE tuning issues=0D
=0D
Let us know if you figure out the idle. I also have what seems to be
excessively high BLM right at idle. I have close to 128 all over but whe=
n I
stop I can watch the idle cell BLM just creep up to 140 or more. It seem=
s
that the other cells within the same BLM grouping are fairly happy, but w=
hen
it goes all the way down to idle it gets messed up. I haven't had time t=
o
mess with it for a while but I was guessing maybe the O2 sensor just cool=
ed
off or something (I have headers). Or possibly it just needs more VE. I
have to work on it to see, but I'd be curious what you figure out.=0D
=0D
I know my 7747 can be set up to go to open loop at idle, but I don't have=
it
set up that way. Is this why they have it, because closed loop is flakey=
at
idle? I'm not sure how you'd tune your idle though without O2, unless ju=
st
by feel.=0D
-----Original Message-----=0D
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Mike Frels=0D
Sent: Sunday, January 02, 2005 3:08 PM=0D
To: A list for Do-It-Yourself EFI=0D
Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues=0D
=0D
=0D
AIR valve is working as it should. I checked the diverter valve with vacu=
um
on the manifold side and it doesn't bleed air into the exhaust. Before
warming up the engine I checked the exhaust manifold bolts and nuts. All
were tight, except for two. Guess which two? The two that hold the manifo=
ld
tight against the #7 exhaust port. They were completely loose. Oxygen was
coming into the exhaust just inches from the O2 sensor. Murphy's law agai=
n I
guess. After tightening I took it for a quick drive. The butt scan said i=
t
was running much better. I took it for a quick second drive with proper s=
can
tool attached. Much better! Idle is still at 160 but all the surrounding
rpm/kPa ranges are yielding 130-145 BLMs.=0D
=0D
I feel like I am now getting somewhere. Thanks for the exhaust leak tip..=
=2E=0D
=0D
Mike=0D
=0D
At 05:50 PM 1/1/2005, you wrote:=0D
=0D
I have had trouble with the AIR system bleeding air into the exhaust even
with the valve "off". Had to plug off the air line whlie tuning. Once I =
had
the idle set, and re-connected everything, it would creep to ritch. Had =
to
replace the valve in the end. Also had problems with the exhaust manifo=
ld
not sealing at the head on another vehicle and giving lean readings on th=
e
o2 sensor. Idle blocks are hard to tune, in my opinion, since they have =
to
be lean to pass smog.=0D
=0D
--Karl =0D
=0D
----- Original Message ----- =0D
=0D
From: Mike Frels =0D
=0D
To: A list for Do-It-Yourself EFI =0D
=0D
Sent: Saturday, January 01, 2005 5:42 AM=0D
=0D
Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues=0D
=0D
=0D
I was reading HELMS this morning(couldn't keep the eyelids open past 11:0=
0
last night) AIR should only inject into the exhaust manifolds when cold a=
nd
in open loop to help burn converter destroying unburned fuel. When it war=
ms
and goes closed the AIR should then divert to the converter. I interpret
this to mean the AIR system should have no influence on my 02 readings.=0D
=0D
=0D
Just the same I am going to double check for proper operation today. Hmmm=
=2E.
could I have switched the two connectors to the diverter valve last time =
I
reassembled after checking lifter preload?...I've done worse before!...=0D
=0D
=0D
I will report on progress as it happens. Yesterday's forecast for today w=
as
50% chance of rain.=0D
=0D
=0D
Happy New Year,=0D
=0D
Mike=0D
=0D
=0D
At 10:04 PM 12/31/2004, you wrote:=0D
=0D
that may be the problem... while tuning, plug the AIR system as it inject=
s
air to the exhaust like a giant leak...=0D
=0D
=0D
=0D
=0D
=0D
-------Original Message-------=0D
=0D
=0D
=0D
From: Mike Frels=0D
=0D
Date: 12/31/04 21:54:09=0D
=0D
To: A list for Do-It-Yourself EFI=0D
=0D
Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues=0D
=0D
=0D
=0D
Don't you mean 'injectors are much SMALLER than #24 they are supposed to =
be?
=0D
=0D
=0D
=0D
Anyway as far as oxygen getting into the exhaust stream the only thing I=0D
=0D
have really checked is proper AIR system operation. That is working as it=
=0D
=0D
should. I have not re-checked that exhaust manifold bolts since spring wh=
en=0D
=0D
I put the engine in. Yes, I am still running cast iron manifolds. I will=0D
=0D
take a wrench to the exhaust bolts and nuts tomorrow. Thanks for that=0D
=0D
possible pointer.=0D
=0D
=0D
=0D
The injectors are brand new Accel 24 pounders. No, I did not have them=0D
=0D
flowed before installing as I believed I could trust them from the factor=
y.=0D
=0D
Is experience counter to this?=0D
=0D
=0D
=0D
Mike=0D
=0D
=0D
=0D
At 05:59 PM 12/31/2004, you wrote:=0D
=0D
>I look at it this way: BLM's greater than 128 means the ECM is having t=
o=0D
=0D
>add fuel to keep the mixture right. This means it's getting more air th=
an=0D
=0D
>it should according to the VE tables, which means the table values need =
to=0D
=0D
>be raised by the appropriate factor. [(BLM/128)*current VE] is a very=0D
=0D
>good formula for finding how much to adjust it.=0D
=0D
>=0D
=0D
>If you're getting 160 BLM's and you have 80's in the low-rpm VE table,=0D
=0D
>then either your injectors are much bigger than the 24# that you think=0D
=0D
>they are, or you have a pretty significant vacuum leak, or you're gettin=
g=0D
=0D
>a false lean reading from the O2. First thing to do is check for exhaus=
t=0D
=0D
>leaks before/near the O2, as that will REALLY screw with your BLMs. Whe=
re=0D
=0D
>did you get the injectors? Are they new or used, and have they been flo=
w=0D
=0D
>tested?=0D
=0D
=0D
=0D
=0D
=20
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<DIV>you can avoid the O2 cooldown problem by installing a heated O2... r=
un the heater from Switched 12V and ground</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV id=3DIncrediOriginalMessage><I>-------Original Message-------</I></D=
IV>
<DIV> </DIV>
<DIV id=3Dreceivestrings>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>From:</B></I> <A href=3D"m=
ailto:charles at taildragger.info">Charles McDowell</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>Date:</B></I> 01/02/05 16:=
33:49</DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>To:</B></I> <A href=3D"mai=
lto:diy_efi at diy-efi.org">'A list for Do-It-Yourself EFI'</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt"><I><B>Subject:</B></I> RE: [Diy_=
efi] Re: (was: IAC counts) VE tuning issues</DIV></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D901542621-02012005><FONT face=3DArial color=3D#0000ff =
size=3D2>Let us know if you figure out the idle. I also have what s=
eems to be excessively high BLM right at idle. I have close to 128 =
all over but when I stop I can watch the idle cell BLM just creep up to 1=
40 or more. It seems that the other cells within the same BLM group=
ing are fairly happy, but when it goes all the way down to idle it gets m=
essed up. I haven't had time to mess with it for a while but I was =
guessing maybe the O2 sensor just cooled off or something (I have headers=
). Or possibly it just needs more VE. I have to work on it to=
see, but I'd be curious what you figure out.</FONT></SPAN></DIV>
<DIV><SPAN class=3D901542621-02012005><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D901542621-02012005><FONT face=3DArial color=3D#0000ff =
size=3D2>I know my 7747 can be set up to go to open loop at idle, but I d=
on't have it set up that way. Is this why they have it, because clo=
sed loop is flakey at idle? I'm not sure how you'd tune your idle t=
hough without O2, unless just by feel.</FONT></SPAN></DIV>
<DIV dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft><FO=
NT face=3DTahoma size=3D2>-----Original Message-----<BR><B>From:</B> diy_=
efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] <B>On Behalf=
Of </B>Mike Frels<BR><B>Sent:</B> Sunday, January 02, 2005 3:08 PM<BR><B=
>To:</B> A list for Do-It-Yourself EFI<BR><B>Subject:</B> Re: [Diy_efi] R=
e: (was: IAC counts) VE tuning issues<BR><BR></FONT></DIV>AIR valve is wo=
rking as it should. I checked the diverter valve with vacuum on the manif=
old side and it doesn't bleed air into the exhaust. Before warming up the=
engine I checked the exhaust manifold bolts and nuts. All were tight, ex=
cept for two. Guess which two? The two that hold the manifold tight again=
st the #7 exhaust port. They were completely loose. Oxygen was coming int=
o the exhaust just inches from the O2 sensor. Murphy's law again I guess.=
After tightening I took it for a quick drive. The butt scan said it was =
running much better. I took it for a quick second drive with proper scan =
tool attached. Much better! Idle is still at 160 but all the surrounding =
rpm/kPa ranges are yielding 130-145 BLMs.<BR><BR>I feel like I am now get=
ting somewhere. Thanks for the exhaust leak tip...<BR><BR>Mike<BR><BR>At =
05:50 PM 1/1/2005, you wrote:<BR>
<DIV class=3Dcite type=3D"cite" cite=3D""><FONT face=3Darial size=3D2>I h=
ave had trouble with the AIR system bleeding air into the exhaust even wi=
th the valve "off". Had to plug off the air line whlie tuning. Once=
I had the idle set, and re-connected everything, it would creep to ritch=
=2E Had to replace the valve in the end. Also had probl=
ems with the exhaust manifold not sealing at the head on another vehicle =
and giving lean readings on the o2 sensor. Idle blocks are hard to =
tune, in my opinion, since they have to be lean to pass smog.<BR></FONT>&=
nbsp;<BR><FONT face=3Darial size=3D2>--Karl</FONT> <BR>
<DL>
<DD>----- Original Message ----- <BR>
<DD>From:</B> <A href=3D"mailto:mfrels at ix.netcom.com">Mike Frels</A> <BR>
<DD>To:</B> <A href=3D"mailto:diy_efi at diy-efi.org">A list for Do-It-Yours=
elf EFI</A> <BR>
<DD>Sent:</B> Saturday, January 01, 2005 5:42 AM<BR>
<DD>Subject:</B> Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues<BR>=
<BR>
<DD>I was reading HELMS this morning(couldn't keep the eyelids open past =
11:00 last night) AIR should only inject into the exhaust manifolds when =
cold and in open loop to help burn converter destroying unburned fuel. Wh=
en it warms and goes closed the AIR should then divert to the converter. =
I interpret this to mean the AIR system should have no influence on my 02=
readings.<BR><BR>
<DD>Just the same I am going to double check for proper operation today. =
Hmmm...could I have switched the two connectors to the diverter valve las=
t time I reassembled after checking lifter preload?...I've done worse bef=
ore!...<BR><BR>
<DD>I will report on progress as it happens. Yesterday's forecast for tod=
ay was 50% chance of rain.<BR><BR>
<DD>Happy New Year,<BR>
<DD>Mike<BR><BR>
<DD>At 10:04 PM 12/31/2004, you wrote:<BR>
<DIV class=3Dcite type=3D"cite" cite=3D""></DIV>
<DD>that may be the problem... while tuning, plug the AIR system as it in=
jects air to the exhaust like a giant leak...<BR>
<DD><BR> =20
<DD><BR> =20
<DD>-------Original Message-------<BR></I>
<DD><BR> =20
<DD>From:</I></B> <A href=3D"mailto:mfrels at ix.netcom.com">Mike Frels</A><=
BR>
<DD>Date:</I></B> 12/31/04 21:54:09<BR>
<DD>To:</I></B> <A href=3D"mailto:diy_efi at diy-efi.org">A list for Do-It-Y=
ourself EFI</A><BR>
<DD>Subject:</I></B> Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues=
<BR>
<DD><BR> =20
<DD>Don't you mean 'injectors are much SMALLER than #24 they are supposed=
to be?'<BR>
<DD><BR> =20
<DD>Anyway as far as oxygen getting into the exhaust stream the only thin=
g I<BR>
<DD>have really checked is proper AIR system operation. That is working a=
s it<BR>
<DD>should. I have not re-checked that exhaust manifold bolts since sprin=
g when<BR>
<DD>I put the engine in. Yes, I am still running cast iron manifolds. I w=
ill<BR>
<DD>take a wrench to the exhaust bolts and nuts tomorrow. Thanks for that=
<BR>
<DD>possible pointer.<BR>
<DD><BR> =20
<DD>The injectors are brand new Accel 24 pounders. No, I did not have the=
m<BR>
<DD>flowed before installing as I believed I could trust them from the fa=
ctory.<BR>
<DD>Is experience counter to this?<BR>
<DD><BR> =20
<DD>Mike<BR>
<DD><BR> =20
<DD>At 05:59 PM 12/31/2004, you wrote:<BR>
<DD>>I look at it this way: BLM's greater than 128 means the ECM=
is having to<BR>
<DD>>add fuel to keep the mixture right. This means it's getting=
more air than<BR>
<DD>>it should according to the VE tables, which means the table value=
s need to<BR>
<DD>>be raised by the appropriate factor. [(BLM/128)*current VE]=
is a very<BR>
<DD>>good formula for finding how much to adjust it.<BR>
<DD>><BR>
<DD>>If you're getting 160 BLM's and you have 80's in the low-rpm VE t=
able,<BR>
<DD>>then either your injectors are much bigger than the 24# that you =
think<BR>
<DD>>they are, or you have a pretty significant vacuum leak, or you're=
getting<BR>
<DD>>a false lean reading from the O2. First thing to do is chec=
k for exhaust<BR>
<DD>>leaks before/near the O2, as that will REALLY screw with your BLM=
s. Where<BR>
<DD>>did you get the injectors? Are they new or used, and have t=
hey been flow<BR>
<DD>>tested?</DD></DL></DIV><BR>
<HR>
<DL></DL></DIV>
<DIV></DIV>
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