How does my Car run without an O2 sensor??
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Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
How does my Car run without an O2 sensor??
Just discovered my 92Z with a 350 TPI has no O2 sensor in the exhaust..The car runs low 14's at almost 100 MPH, gets decent mileage, runs fine around town...Just took it on a hi-way trip, and was getting about 20 MPG..The car starts fine, and goes into Closed loop..A fellow worked on my exhaust, and I gave him a new O2 sensor to put in while he had it up on the rack..There is no bung in the pipe, nor can I find the pigtail to plug it in..It has Headman shorty's, and a really crappy home made Y pipe...What are some of the things the previous owner could have done to trick the computer..It does pop a O2 sensor code sometimes, but not always..Strange...Thanks for any help on this, Tom
#3
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Re: How does my Car run without an O2 sensor??
A custom tune for full time open-loop mode would do it. I have done this to several vehicles, but not these specific ones mentioned here. I'm not the only one out there doing it though.
I don't trick the ECM to go closed-loop without the O2, but it is possible in many codes to do so with custom patches to the adaptive learning code.
If your car and EPROM are all stock, but with no O2, then I'm not sure what to tell you. It shouldn't be able to go closed-loop, and very unlikely to run well at part throttle.
I don't trick the ECM to go closed-loop without the O2, but it is possible in many codes to do so with custom patches to the adaptive learning code.
If your car and EPROM are all stock, but with no O2, then I'm not sure what to tell you. It shouldn't be able to go closed-loop, and very unlikely to run well at part throttle.
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Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Re: How does my Car run without an O2 sensor??
Runs fine at any throttle, like i said, I never knew it did not have one....Thanks for the answers, this has really got me bugged..
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: How does my Car run without an O2 sensor??
what is connected to the o2 wire? it should be on the drivers side down by the steering shaft.
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Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Re: How does my Car run without an O2 sensor??
I know where it should be, but I cant find it..I just replaced the one in my 89...It may be pulled up somewhere..I will have to look closer..Thanks
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Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Re: How does my Car run without an O2 sensor??
Well I say it goes into closed loop, the reason after about 5 minutes it idles down, and runs better just like my 89 does..Im not sure if that means it is tho, but it does get good mileage..Man, I don't know what to think...I have code scanned it, and it pops an O2 sensor code, but it only does it part of the time..Strange..
#9
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Re: How does my Car run without an O2 sensor??
Well I say it goes into closed loop, the reason after about 5 minutes it idles down, and runs better just like my 89 does..Im not sure if that means it is tho, but it does get good mileage..Man, I don't know what to think...I have code scanned it, and it pops an O2 sensor code, but it only does it part of the time..Strange..
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Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Re: How does my Car run without an O2 sensor??
exhaust....Thanks all...
#11
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Re: How does my Car run without an O2 sensor??
If you look at the ECM, pull the cover and look at the chip, you may beable to tell if someone has put a custom chip in there or not.
Not 100% sure how this works, but I thought if the ECM didnt get an o2-ready signal, it would remain open loop. Factory Open Loop tunes are close enough to run right, even handle some mods. They have to be right since you are in open loop every time you start up and it stays like that for a few minutes if a cold start, or few seconds if a hot restart. I think your car is likely sticking in open loop
Not 100% sure how this works, but I thought if the ECM didnt get an o2-ready signal, it would remain open loop. Factory Open Loop tunes are close enough to run right, even handle some mods. They have to be right since you are in open loop every time you start up and it stays like that for a few minutes if a cold start, or few seconds if a hot restart. I think your car is likely sticking in open loop
#12
Re: How does my Car run without an O2 sensor??
If you look at the ECM, pull the cover and look at the chip, you may beable to tell if someone has put a custom chip in there or not.
Not 100% sure how this works, but I thought if the ECM didnt get an o2-ready signal, it would remain open loop. Factory Open Loop tunes are close enough to run right, even handle some mods. They have to be right since you are in open loop every time you start up and it stays like that for a few minutes if a cold start, or few seconds if a hot restart. I think your car is likely sticking in open loop
Not 100% sure how this works, but I thought if the ECM didnt get an o2-ready signal, it would remain open loop. Factory Open Loop tunes are close enough to run right, even handle some mods. They have to be right since you are in open loop every time you start up and it stays like that for a few minutes if a cold start, or few seconds if a hot restart. I think your car is likely sticking in open loop
hello
i have orginal chip in ECM and i have O2 sensor in exhaust manifold but i dont have wire(s) for O2 sensor(pos. D6 & D7) in ECM and i dont get any error messages . what you think about this?? and it is true that you wont go closed loop without o2 sensor
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: How does my Car run without an O2 sensor??
Yeah, but in open loop you are getting gas like twice a day. It just wastes too much gas. Closed loop is the ticket IMO.
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