A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto makers » Mazda
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

How to adjust the Fuel/Air Mixture



 
 
Thread Tools Display Modes
  #1  
Old October 24th 04, 02:05 AM
L Bader
external usenet poster
 
Posts: n/a
Default How to adjust the Fuel/Air Mixture


Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?

TIA...

- L

'97 STO, "Chouki"

// Change TEJAS to TX to reply via eMail //
Ads
  #2  
Old October 26th 04, 04:30 AM
chuckk
external usenet poster
 
Posts: n/a
Default

What for?
There are seveal "tricks" for specific purposes.
Alter air temperature readings
Change air flow readings.
"Clamp" the O2 sensor reading
These really only work for/during open loop, or for a very short time in
closed loop, since the O2 sensor is going to cause the ECU to adjust the
mixture in closed loop. The O2 clamp has some longer term possibilities, if
the "rich lean" change is enough to fool the ECU. It may also be necessary
to alter the second O2 sensor signal.

The usual thing is to fool the ECU and add more fuel with a timing retard as
well.

It's likely that springing for an aftermarket ECU is in your future.
..
"L Bader" > wrote in message
...
>
> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>
> TIA...
>
> - L
>
> '97 STO, "Chouki"
>
> // Change TEJAS to TX to reply via eMail //



---
Outgoing mail is AVG certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.782 / Virus Database: 528 - Release Date: 10/22/2004


  #3  
Old October 28th 04, 02:51 AM
L Bader
external usenet poster
 
Posts: n/a
Default

On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> wrote:

>What for?


After replacing the intake, building a cold air box for said intake,
and a high-flow exhaust from manifold back, I seem to be running a bit
lean...

>It's likely that springing for an aftermarket ECU is in your future.


I figured as much, but thought I would ask...

Original question below:
>>
>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>


'97 STO, "Chouki"

// Change TEJAS to TX to reply via eMail //
  #4  
Old October 28th 04, 11:02 PM
chuckk
external usenet poster
 
Posts: n/a
Default

In your case, I'd be thinking about the placement of the air flow sensor. It
may be that it's not reading quite what you need. The timing retard is
usually only needed if you add forced air (turbo/supercharger)
I'd also replace the fuel filter if you haven't already done so. Another
thing to do is to see if the fuel pressure drops below normal at higher
throttle settings.

"L Bader" > wrote in message
...
> On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> > wrote:
>
>>What for?

>
> After replacing the intake, building a cold air box for said intake,
> and a high-flow exhaust from manifold back, I seem to be running a bit
> lean...
>
>>It's likely that springing for an aftermarket ECU is in your future.

>
> I figured as much, but thought I would ask...
>
> Original question below:
>>>
>>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>>

>
> '97 STO, "Chouki"
>
> // Change TEJAS to TX to reply via eMail //



---
Outgoing mail is AVG certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.782 / Virus Database: 528 - Release Date: 10/22/2004


  #5  
Old October 29th 04, 12:59 AM
Leon van Dommelen
external usenet poster
 
Posts: n/a
Default

L Bader > wrote:

>On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> wrote:
>
>>What for?

>
>After replacing the intake, building a cold air box for said intake,
>and a high-flow exhaust from manifold back, I seem to be running a bit
>lean...


Why do you say so? You should be putting only a small percentage more
air through the system as usual.

Apparently, the JR uses a resistor in the air temperature circuit to
trick the ECU in adding more fuel. You could try the same with a much
smaller resistor. I do not remember what the resistance of the JR kit
one is, (if I ever knew,) but you could try the power forum on
miataforum.com.

Following chuck's advice in insuring the proper operation of the
OEM system first seems like a good idea, though. You hate to
have to take out the resistor later again after you replace the
fuel filter or fuel pump, say.

Leon

>>It's likely that springing for an aftermarket ECU is in your future.

>
>I figured as much, but thought I would ask...
>
>Original question below:
>>>
>>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>>

>
>'97 STO, "Chouki"
>
>// Change TEJAS to TX to reply via eMail //


--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)
  #6  
Old October 29th 04, 03:01 AM
L Bader
external usenet poster
 
Posts: n/a
Default

Chuck -

Thanks for the lead. The car has ~43K miles on it. Having owned it
for only 6 months, I've not changed the fuel filter.


Leon -

My reasoning for the "running lean" assessment is due to the blueing
verse s bronzing of the RB 4-1 stainless header.

I agree that changing the filter is a first option over adding a
resistor of unknown size...

- L



On Thu, 28 Oct 2004 23:59:05 GMT,
(Leon van Dommelen) wrote:

>L Bader > wrote:
>
>>On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> wrote:
>>
>>>What for?

>>
>>After replacing the intake, building a cold air box for said intake,
>>and a high-flow exhaust from manifold back, I seem to be running a bit
>>lean...

>
>Why do you say so? You should be putting only a small percentage more
>air through the system as usual.
>
>Apparently, the JR uses a resistor in the air temperature circuit to
>trick the ECU in adding more fuel. You could try the same with a much
>smaller resistor. I do not remember what the resistance of the JR kit
>one is, (if I ever knew,) but you could try the power forum on
>miataforum.com.
>
>Following chuck's advice in insuring the proper operation of the
>OEM system first seems like a good idea, though. You hate to
>have to take out the resistor later again after you replace the
>fuel filter or fuel pump, say.
>
>Leon
>
>>>It's likely that springing for an aftermarket ECU is in your future.

>>
>>I figured as much, but thought I would ask...
>>
>>Original question below:
>>>>
>>>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>>>

>>
>>'97 STO, "Chouki"
>>
>>// Change TEJAS to TX to reply via eMail //


'97 STO, "Chouki"

// Change TEJAS to TX to reply via eMail //
  #7  
Old November 3rd 04, 04:30 AM
chuckk
external usenet poster
 
Posts: n/a
Default

I don't know if that's a good indication these days. The feds insist that
the engine run leaner than they did in the old days when we used pipe
discoloration to judge rich/lean.

"L Bader" > wrote in message
...
> Chuck -
>
> Thanks for the lead. The car has ~43K miles on it. Having owned it
> for only 6 months, I've not changed the fuel filter.
>
>
> Leon -
>
> My reasoning for the "running lean" assessment is due to the blueing
> verse s bronzing of the RB 4-1 stainless header.
>
> I agree that changing the filter is a first option over adding a
> resistor of unknown size...
>
> - L
>
>
>
> On Thu, 28 Oct 2004 23:59:05 GMT,
> (Leon van Dommelen) wrote:
>
>>L Bader > wrote:
>>
>>>On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> wrote:
>>>
>>>>What for?
>>>
>>>After replacing the intake, building a cold air box for said intake,
>>>and a high-flow exhaust from manifold back, I seem to be running a bit
>>>lean...

>>
>>Why do you say so? You should be putting only a small percentage more
>>air through the system as usual.
>>
>>Apparently, the JR uses a resistor in the air temperature circuit to
>>trick the ECU in adding more fuel. You could try the same with a much
>>smaller resistor. I do not remember what the resistance of the JR kit
>>one is, (if I ever knew,) but you could try the power forum on
>>miataforum.com.
>>
>>Following chuck's advice in insuring the proper operation of the
>>OEM system first seems like a good idea, though. You hate to
>>have to take out the resistor later again after you replace the
>>fuel filter or fuel pump, say.
>>
>>Leon
>>
>>>>It's likely that springing for an aftermarket ECU is in your future.
>>>
>>>I figured as much, but thought I would ask...
>>>
>>>Original question below:
>>>>>
>>>>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>>>>
>>>
>>>'97 STO, "Chouki"
>>>
>>>// Change TEJAS to TX to reply via eMail //

>
> '97 STO, "Chouki"
>
> // Change TEJAS to TX to reply via eMail //



---
Outgoing mail is AVG certified Virus Free.
Checked by AVG anti-virus system (
http://www.grisoft.com).
Version: 6.0.788 / Virus Database: 533 - Release Date: 11/1/2004


  #8  
Old November 5th 04, 02:19 AM
L Bader
external usenet poster
 
Posts: n/a
Default

Chuck -

I've talked with a few other gear-heads and have come to the same
conclusion. -- Based upon the lack of CEL and the relatively
unchanged fuel consumption post exhaust upgrade, I am guessing things
are OK...

Thanks to those that chimed in...

- L



On Tue, 2 Nov 2004 22:30:39 -0500, "chuckk"
> wrote:

>I don't know if that's a good indication these days. The feds insist that
>the engine run leaner than they did in the old days when we used pipe
>discoloration to judge rich/lean.
>
>"L Bader" > wrote in message
.. .
>> Chuck -
>>
>> Thanks for the lead. The car has ~43K miles on it. Having owned it
>> for only 6 months, I've not changed the fuel filter.
>>
>>
>> Leon -
>>
>> My reasoning for the "running lean" assessment is due to the blueing
>> verse s bronzing of the RB 4-1 stainless header.
>>
>> I agree that changing the filter is a first option over adding a
>> resistor of unknown size...
>>
>> - L
>>
>>
>>
>> On Thu, 28 Oct 2004 23:59:05 GMT,
>> (Leon van Dommelen) wrote:
>>
>>>L Bader > wrote:
>>>
>>>>On Mon, 25 Oct 2004 23:30:33 -0400, "chuckk"
> wrote:
>>>>
>>>>>What for?
>>>>
>>>>After replacing the intake, building a cold air box for said intake,
>>>>and a high-flow exhaust from manifold back, I seem to be running a bit
>>>>lean...
>>>
>>>Why do you say so? You should be putting only a small percentage more
>>>air through the system as usual.
>>>
>>>Apparently, the JR uses a resistor in the air temperature circuit to
>>>trick the ECU in adding more fuel. You could try the same with a much
>>>smaller resistor. I do not remember what the resistance of the JR kit
>>>one is, (if I ever knew,) but you could try the power forum on
>>>miataforum.com.
>>>
>>>Following chuck's advice in insuring the proper operation of the
>>>OEM system first seems like a good idea, though. You hate to
>>>have to take out the resistor later again after you replace the
>>>fuel filter or fuel pump, say.
>>>
>>>Leon
>>>
>>>>>It's likely that springing for an aftermarket ECU is in your future.
>>>>
>>>>I figured as much, but thought I would ask...
>>>>
>>>>Original question below:
>>>>>>
>>>>>> Does anyone have a reasonable fix, aside from purchasing the FM-ECU ?
>>>>>>
>>>>
>>>>'97 STO, "Chouki"
>>>>
>>>>// Change TEJAS to TX to reply via eMail //

>>
>> '97 STO, "Chouki"
>>
>> // Change TEJAS to TX to reply via eMail //

>
>
>---
>Outgoing mail is AVG certified Virus Free.
>Checked by AVG anti-virus system (
http://www.grisoft.com).
>Version: 6.0.788 / Virus Database: 533 - Release Date: 11/1/2004
>


'97 STO, "Chouki"

// Change TEJAS to TX to reply via eMail //
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 7 February 1st 05 02:43 PM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 10 January 2nd 05 06:15 AM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 10 December 2nd 04 06:19 AM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 10 November 16th 04 06:28 AM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 10 November 1st 04 06:24 AM


All times are GMT +1. The time now is 11:04 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.