More Data
Printed From: West Coast Fieros
Category: Technical Topics Forum
Forum Name: Technical Questions and Discussions
Forum Description: Got a technical question about your fiero? ask it here.
URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=2975
Printed Date: 22 November 2024 at 8:02pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: More Data
Posted By: mxracer208
Subject: More Data
Date Posted: 02 July 2012 at 4:16pm
I got the USB ALDL cable from Red Devil River the other day and I tried it out
this afternoon. My car runs very rich and it smells terrible. I put a new O2
sensor in last year. The car is an 86 GT with the 2.8 and a 4 speed.
key on, warm
Coolant Temp: 89 and 192.2
MAT: 28.33 and 83
MAP: 4.69 and 98.55
BLM: 128
INT: 128
O2: 350.76 (it varied a lot)
BPW: 6.99
IAC position: 131
If needed I can also post idle and driving data too. I am not sure what all
these numbers mean so any assistance would be awesome. Thanks
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Replies:
Posted By: bcampbell
Date Posted: 03 July 2012 at 1:45am
If BLM and INT are always at 128 even when driving then
it sounds like it's not leaving closed loop. If BLM/INTs
are below 128 that means that the engine is running rich
and the computer is leaning the fuel mixture to
compensate. If it is above 128 then it means the engine
is running lean and adding fuel to compensate. IIRC it
can swing between 108 and 140 or something like that.
BLM is the long-term multiplier and INT is the short
term. INT will usually change constantly but BLM doesn't
change as quickly. These only change once in closed loop
(engine fully warmed up).
If you're running rich all the time it can foul the O2
sensor quickly so the computer might think it's lean when
it's not, adding fuel and running rich. Also some say
that different brands of O2 sensors have slightly
different signals so it's best to buy a Delphi sensor.
If you were to unplug the O2 sensor and it didn't run as
rich (although it would throw a code); that would
probably indicate an issue with the O2 sensor.
If it's not leaving open-loop that's another issue
because the computer won't use the O2 sensor to
compensate for undesired air/fuels until it enters
closed-loop. To enter closed loop it usually needs to
reach a certain temperature and needs to be running for a
set amount of time (unsure of the specifics).
Hope that's helpful.
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'86 2m6 F23 5-speed, LSD, 3.5L LX9
'89 Firebird 3500T, T56
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Posted By: mxracer208
Date Posted: 03 July 2012 at 12:54pm
I watched the readings that I recorded while driving. The BLM and INT varied
between 120 and 129. Mostly at 128. It was always running closed loop. O2
varied between 110 and 950. INT and BLM changed at the same times
always. The car was up to temperature, (185 F or 85 C)
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Posted By: bcampbell
Date Posted: 03 July 2012 at 7:23pm
Sounds like it might be running slightly rich but the
computer is able to compensate. Does it still run rich
once fully warmed up? Try seeing how it runs with the O2
unplugged.
O2 voltage varies so quickly on my engine I only use the
BLMs to get an idea of what the air/fuels are actually
like.
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'86 2m6 F23 5-speed, LSD, 3.5L LX9
'89 Firebird 3500T, T56
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Posted By: bcampbell
Date Posted: 06 July 2012 at 8:26pm
I would also check for exhaust leaks as that could affect
the O2 sensor reading.
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'86 2m6 F23 5-speed, LSD, 3.5L LX9
'89 Firebird 3500T, T56
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