[Diy_efi] Re: (was: IAC counts) VE tuning issues

Sat Jan 1 13:44:50 GMT 2005

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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. When 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.

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 last 
time I reassembled after checking lifter preload?...I've done worse before!...

I will report on progress as it happens. Yesterday's forecast for today was 
50% chance of rain.

Happy New Year,
Mike

At 10:04 PM 12/31/2004, you wrote:
>that may be the problem... while tuning, plug the AIR system as it injects 
>air to the exhaust like a giant leak...
>
>
>-------Original Message-------
>
>From: <mailto:mfrels at ix.netcom.com>Mike Frels
>Date: 12/31/04 21:54:09
>To: <mailto:diy_efi at diy-efi.org>A list for Do-It-Yourself EFI
>Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues
>
>Don't you mean 'injectors are much SMALLER than #24 they are supposed to be?'
>
>Anyway as far as oxygen getting into the exhaust stream the only thing I
>have really checked is proper AIR system operation. That is working as it
>should. I have not re-checked that exhaust manifold bolts since spring when
>I put the engine in. Yes, I am still running cast iron manifolds. I will
>take a wrench to the exhaust bolts and nuts tomorrow. Thanks for that
>possible pointer.
>
>The injectors are brand new Accel 24 pounders. No, I did not have them
>flowed before installing as I believed I could trust them from the factory.
>Is experience counter to this?
>
>Mike
>
>At 05:59 PM 12/31/2004, you wrote:
> >I look at it this way:  BLM's greater than 128 means the ECM is having to
> >add fuel to keep the mixture right.  This means it's getting more air than
> >it should according to the VE tables, which means the table values need to
> >be raised by the appropriate factor.  [(BLM/128)*current VE] is a very
> >good formula for finding how much to adjust it.
> >
> >If you're getting 160 BLM's and you have 80's in the low-rpm VE table,
> >then either your injectors are much bigger than the 24# that you think
> >they are, or you have a pretty significant vacuum leak, or you're getting
> >a false lean reading from the O2.  First thing to do is check for exhaust
> >leaks before/near the O2, as that will REALLY screw with your BLMs.  Where
> >did you get the injectors?  Are they new or used, and have they been flow
> >tested?

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<html>
<body>
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.
When 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. 
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
last time I reassembled after checking lifter preload?...I've done worse
before!... 
I will report on progress as it happens. Yesterday's forecast for today
was 50% chance of rain. 
Happy New Year, 
Mike 
At 10:04 PM 12/31/2004, you wrote: 
<blockquote type=cite class=cite cite="">that may be the problem... while
tuning, plug the AIR system as it injects air to the exhaust like a giant
leak... 
&nbsp; 
&nbsp; 
-------Original Message------- 
&nbsp; 
From: <a href="mailto:mfrels at ix.netcom.com">Mike
Frels</a> 
Date: 12/31/04 21:54:09 
To: <a href="mailto:diy_efi at diy-efi.org">A list for
Do-It-Yourself EFI</a> 
Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning
issues 
&nbsp; 
Don't you mean 'injectors are much SMALLER than #24 they are supposed to
be?' 
&nbsp; 
Anyway as far as oxygen getting into the exhaust stream the only thing
I 
have really checked is proper AIR system operation. That is working as
it 
should. I have not re-checked that exhaust manifold bolts since spring
when 
I put the engine in. Yes, I am still running cast iron manifolds. I
will 
take a wrench to the exhaust bolts and nuts tomorrow. Thanks for
that 
possible pointer. 
&nbsp; 
The injectors are brand new Accel 24 pounders. No, I did not have
them 
flowed before installing as I believed I could trust them from the
factory. 
Is experience counter to this? 
&nbsp; 
Mike 
&nbsp; 
At 05:59 PM 12/31/2004, you wrote: 
&gt;I look at it this way:&nbsp; BLM's greater than 128 means the ECM is
having to 
&gt;add fuel to keep the mixture right.&nbsp; This means it's getting
more air than 
&gt;it should according to the VE tables, which means the table values
need to 
&gt;be raised by the appropriate factor.&nbsp; [(BLM/128)*current VE] is
a very 
&gt;good formula for finding how much to adjust it. 
&gt; 
&gt;If you're getting 160 BLM's and you have 80's in the low-rpm VE
table, 
&gt;then either your injectors are much bigger than the 24# that you
think 
&gt;they are, or you have a pretty significant vacuum leak, or you're
getting 
&gt;a false lean reading from the O2.&nbsp; First thing to do is check
for exhaust 
&gt;leaks before/near the O2, as that will REALLY screw with your
BLMs.&nbsp; Where 
&gt;did you get the injectors?&nbsp; Are they new or used, and have they
been flow 
&gt;tested? 
</blockquote></body>
</html>

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