O2 sensor function in L98 with weird headers
Thread Starter
Drifting
Joined: Sep 2002
Posts: 1,642
Likes: 0
From: Suwanee,Ga
O2 sensor function in L98 with weird headers
I have an interesting question that may require a tad of experience to answer. The car is an '89 L98.
I have the O2 in a well that is serves two of the four tubes of the headers. Not in the collector area. [ see the Tri-Y thread saga for picts of the exact location].
Antonio, my Exhaust Guru says the O2 sensor is calibrated to sense a mix of a bank of 4 cylinders [ as in bank firing F.I.] and predicts the end of the world if I don’t move it to the collector.
There is some logic [ and a lot of experience] on Antonio’s side...
BUT!!! That seems like more Magic Mojo than a little bitty sensor can deliver? I say sensor sees 14:1 gas mix ratio or the Computer makes a changes?
Who looses the bet?
TJM
[ I have a bad feeling about this, after reading what I just wrote? I think I’m out $25.00].
I have the O2 in a well that is serves two of the four tubes of the headers. Not in the collector area. [ see the Tri-Y thread saga for picts of the exact location].
Antonio, my Exhaust Guru says the O2 sensor is calibrated to sense a mix of a bank of 4 cylinders [ as in bank firing F.I.] and predicts the end of the world if I don’t move it to the collector.
There is some logic [ and a lot of experience] on Antonio’s side...
BUT!!! That seems like more Magic Mojo than a little bitty sensor can deliver? I say sensor sees 14:1 gas mix ratio or the Computer makes a changes?
Who looses the bet?
TJM
[ I have a bad feeling about this, after reading what I just wrote? I think I’m out $25.00].
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
I agree with you, it doesn't matter the sensor will read 2 cylinders perfectly. Although I would prefere it to be a bit more "general" myself incase of an issue somewhere else other than the 2 its monitoring.
Team Owner
Joined: Sep 2001
Posts: 62,183
Likes: 1,740
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Hooker headers have it in only one tube, not the collector, and they dont have problem after problem with it.
It would be sensitive to any problem occuring in that cylinder though.
So in my opinion, if you keep the engine tuned and checked up properly, having it read only 2 cylinders directly isnt a big issue.
It would be sensitive to any problem occuring in that cylinder though.
So in my opinion, if you keep the engine tuned and checked up properly, having it read only 2 cylinders directly isnt a big issue.
Team Owner
Joined: Oct 2006
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17
NCM Member '09
Now that I've figured out that the shop that installed my headers re-used my OE o2, and it promptly
croaked...
The Hooker 02149's run on a single tube vs. the collector (where it SHOULD be), but it runs fine...
croaked...
The Hooker 02149's run on a single tube vs. the collector (where it SHOULD be), but it runs fine...
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
I have an interesting question that may require a tad of experience to answer. The car is an '89 L98.
I have the O2 in a well that is serves two of the four tubes of the headers. Not in the collector area. [ see the Tri-Y thread saga for picts of the exact location].
Antonio, my Exhaust Guru says the O2 sensor is calibrated to sense a mix of a bank of 4 cylinders [ as in bank firing F.I.] and predicts the end of the world if I don’t move it to the collector.
There is some logic [ and a lot of experience] on Antonio’s side...
BUT!!! That seems like more Magic Mojo than a little bitty sensor can deliver? I say sensor sees 14:1 gas mix ratio or the Computer makes a changes?
Who looses the bet?
TJM
[ I have a bad feeling about this, after reading what I just wrote? I think I’m out $25.00].
I have the O2 in a well that is serves two of the four tubes of the headers. Not in the collector area. [ see the Tri-Y thread saga for picts of the exact location].
Antonio, my Exhaust Guru says the O2 sensor is calibrated to sense a mix of a bank of 4 cylinders [ as in bank firing F.I.] and predicts the end of the world if I don’t move it to the collector.
There is some logic [ and a lot of experience] on Antonio’s side...
BUT!!! That seems like more Magic Mojo than a little bitty sensor can deliver? I say sensor sees 14:1 gas mix ratio or the Computer makes a changes?
Who looses the bet?
TJM
[ I have a bad feeling about this, after reading what I just wrote? I think I’m out $25.00].
Melting Slicks
Joined: Apr 2004
Posts: 2,778
Likes: 139
From: cyberspace NY
I'm curious if you can read your BLM's for cell 0. I have seen when the 02 sensor cools off too much at idle, and the o2 sensor sees a false lean mixture. This is because the headers don't hold the heat like a true exhaust manifold.
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Race Director
Joined: Nov 2003
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Vader86 has a great website that explains O2 sensors, installation recommendations for headers, info on all sorts of mods, etc... (He responded above). Click on his website (under his sig) and read the great links he provided and you'll know tons more.
Considering the design of the Tri-Y's, the location for the O2 bung is one of the things Vette Tech did right.
BTW Vader... A year or so ago, I complained about the lack of explanation on one of your links. After spending a LOT of time on the net during the past year, I found many of the posts/sources you've referenced. As a result, I really appreciate what you've compiled. And, I should apologize. You have just about the best (non-forum) websites for C4's I found. I refer back to it often.
Team Owner
Joined: Sep 2001
Posts: 62,183
Likes: 1,740
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Having it in a primary tube would actually help prevent reaching an open loop condition at idle in comparison.
Safety Car
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From: :45 minutes from everywhere / E-I-E-I-O
Le Mans Master
Joined: Feb 2005
Posts: 5,146
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From: The Motor City
This is not as condensed as you make it sound, the proportional and integral fuel correction logic is complex. The proportional starts with the O2 sensor reading, and ends with a correction to the final calculated bpw. The proportional term always works in the opposite direction of the immediate rich/lean O2 sensor reading. The purpose of the proportional controller term is twofold. It is used to attain the desired AFR quickly. Second, it is used to maintain the switching of the O2 sensor about the desired AFR point.
Regardless of how "good the burn" (as you put it) is, based on the extent of the "look up" tables, there will always be some corrections being made.
Thread Starter
Drifting
Joined: Sep 2002
Posts: 1,642
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From: Suwanee,Ga
[QUOTE=GREGGPENN;1566226440]It's time to stop listening to Antonio. He's wrong.
Gregg I did just as you suggested .
The car is back at the house at 8:00Am this morning, with ZERO work done
It is not logical to have to spend that much.
I need more patience and a little more looking for the right solution that satisfies me.
TJM
PS: The two cops that passed me gave me a pretty sour looks, but no tickets [ on a 1.5 mile drive, what luck, both ways!! ]
Gregg I did just as you suggested .
The car is back at the house at 8:00Am this morning, with ZERO work done
It is not logical to have to spend that much.
I need more patience and a little more looking for the right solution that satisfies me.
TJM
PS: The two cops that passed me gave me a pretty sour looks, but no tickets [ on a 1.5 mile drive, what luck, both ways!! ]
Race Director
Joined: Nov 2003
Posts: 12,222
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I think you posted $500ish elsewhere? If he was going to install really nice hi-flow bullet cats and piping, it wasn't really too much. If it was just piping, then yeah.
Last edited by GREGGPENN; Jul 9, 2008 at 07:10 PM.
