[Diy_efi] Re: (was: IAC counts) VE tuning issues
Mike Frels
mfrels at ix.netcom.com
Sun Jan 2 21:11:45 GMT 2005
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AIR valve is working as it should. I checked the diverter valve with vacuum
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 manifold
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 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.
I feel like I am now getting somewhere. Thanks for the exhaust leak tip...
Mike
At 05:50 PM 1/1/2005, you wrote:
>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 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.
>
>--Karl
>----- Original Message -----
>From: <mailto:mfrels at ix.netcom.com>Mike Frels
>To: <mailto:diy_efi at diy-efi.org>A list for Do-It-Yourself EFI
>Sent: Saturday, January 01, 2005 5:42 AM
>Subject: Re: [Diy_efi] Re: (was: IAC counts) VE tuning issues
>
>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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<body>
AIR valve is working as it should. I checked the diverter valve with
vacuum 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 manifold 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 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 getting somewhere. Thanks for the exhaust leak
tip...<br><br>
Mike<br><br>
At 05:50 PM 1/1/2005, you wrote:<br>
<blockquote type=cite class=cite cite=""><font face="arial" size=2>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 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> <br>
<font face="arial" size=2>--Karl</font> <br>
<dl>
<dd>----- Original Message ----- <br>
<dd>From:</b> <a href="mailto:mfrels at ix.netcom.com">Mike Frels</a> <br>
<dd>To:</b> <a href="mailto:diy_efi at diy-efi.org">A list for
Do-It-Yourself 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.
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.<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
last time I reassembled after checking lifter preload?...I've done worse
before!...<br><br>
<dd>I will report on progress as it happens. Yesterday's forecast for
today 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>
<blockquote type=cite class=cite cite="">
<dd>that may be the problem... while tuning, plug the AIR system as it
injects air to the exhaust like a giant leak...<br>
<dd> <br>
<dd> <br>
<dd>-------Original Message-------<br>
</i>
<dd> <br>
<dd>From:</i></b> <a href="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="mailto:diy_efi at diy-efi.org">A list for
Do-It-Yourself EFI</a><br>
<dd>Subject:</i></b> Re: [Diy_efi] Re: (was: IAC counts) VE tuning
issues<br>
<dd> <br>
<dd>Don't you mean 'injectors are much SMALLER than #24 they are supposed
to be?'<br>
<dd> <br>
<dd>Anyway as far as oxygen getting into the exhaust stream the only
thing I<br>
<dd>have really checked is proper AIR system operation. That is working
as it<br>
<dd>should. I have not re-checked that exhaust manifold bolts since
spring when<br>
<dd>I put the engine in. Yes, I am still running cast iron manifolds. I
will<br>
<dd>take a wrench to the exhaust bolts and nuts tomorrow. Thanks for
that<br>
<dd>possible pointer.<br>
<dd> <br>
<dd>The injectors are brand new Accel 24 pounders. No, I did not have
them<br>
<dd>flowed before installing as I believed I could trust them from the
factory.<br>
<dd>Is experience counter to this?<br>
<dd> <br>
<dd>Mike<br>
<dd> <br>
<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
values 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
table,<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
check for exhaust<br>
<dd>>leaks before/near the O2, as that will REALLY screw with your
BLMs. Where<br>
<dd>>did you get the injectors? Are they new or used, and have
they been flow<br>
<dd>>tested?</blockquote><br>
<hr>
</dl></blockquote></body>
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