question about o2 sensors, CA spec has two, I want one Options

[6strngs]

I have a CA spec car... this means, my car has 2 o2 sensors instead of one. when I go turbo (hopefully very soon) I'm sure the downpipe will only have a slot for one o2 sensor... so, is there like a resistor or something I can do so that my car doesn't freak out from only having one o2 sensor?

[Batman722]

just get a dp with a second bung (for a wideband). Then you can use that for the 2nd 02 sensor. That's what Manny did

[6strngs]

just get a dp with a second bung (for a wideband). Then you can use that for the 2nd 02 sensor. That's what Manny did

but what if I want to go with a wideband? which one will I put it in? also, if I tune to run a little rich won't the second o2 sensor see that and take out fuel?

[playr158]

you can always have a 3rd bung installed....but isn't your 2nd O2 sensor down under your car in the midpipe after the cat? or does cali spec have 2 in the downpipe?

[6strngs]

you can always have a 3rd bung installed....but isn't your 2nd O2 sensor down under your car in the midpipe after the cat? or does cali spec have 2 in the downpipe?

on my car, the way it looks is they are only about 10-12 inches apart. both before the primary cat. unless what I'm seeing isn't my 2nd o2 sensor, but I am pretty sure that it is.

hang on a sec, so, you're saying that a wideband o2 does not replace one of the existing ones? hm, I always thought it did, but now that you mention it, I guess it makes sense. so, would I have to get some sort of flange welded in in order to add a bung for another o2 sensor, or what would I have to do?

This post has been edited by 6strngs: Mar 23, 2007 - 12:45 AM

[presure2]

heres what you do.
most (99%) of widebands also output a narrowband signal, that will replicate your normal o2 sensor.
you place the wideband in the lower bung of the DP, (like dustin suggested) and wire the extra wire to your ecu, and that gives the ecu the 2nd O2 signal it needs, and you have your wideband.
dan, the cali spec has both sensors in the DP.

[Negative]

Except STs. o0black0o's 25th anny ST has the second o2 past the cat underneath the car. It's a calispec as is all the cars in Houston.

[6strngs]

heres what you do.
most (99%) of widebands also output a narrowband signal, that will replicate your normal o2 sensor.
you place the wideband in the lower bung of the DP, (like dustin suggested) and wire the extra wire to your ecu, and that gives the ecu the 2nd O2 signal it needs, and you have your wideband.
dan, the cali spec has both sensors in the DP.

so, where did you get the berk technology downpipe with 2 o2 sensor bungs, or did you have one welded on?

[presure2]

heres what you do.
most (99%) of widebands also output a narrowband signal, that will replicate your normal o2 sensor.
you place the wideband in the lower bung of the DP, (like dustin suggested) and wire the extra wire to your ecu, and that gives the ecu the 2nd O2 signal it needs, and you have your wideband.
dan, the cali spec has both sensors in the DP.

so, where did you get the berk technology downpipe with 2 o2 sensor bungs, or did you have one welded on?

i got it from berk technology. lol
it came with both o2 sensor bungs.

[6strngs]

heres what you do.
most (99%) of widebands also output a narrowband signal, that will replicate your normal o2 sensor.
you place the wideband in the lower bung of the DP, (like dustin suggested) and wire the extra wire to your ecu, and that gives the ecu the 2nd O2 signal it needs, and you have your wideband.
dan, the cali spec has both sensors in the DP.

so, where did you get the berk technology downpipe with 2 o2 sensor bungs, or did you have one welded on?

i got it from berk technology. lol
it came with both o2 sensor bungs.

did you have to ask for it like that, or do all of them just come with 2?

[presure2]

all the V1 and V2 pipes have the lower O2 bung, as well as 99% of the 3" pipes on ebay.
the KO racing 2.5" one will have to be ordered from KO to get the lower bung.

[6strngs]

all the V1 and V2 pipes have the lower O2 bung, as well as 99% of the 3" pipes on ebay.
the KO racing 2.5" one will have to be ordered from KO to get the lower bung.

actually, at ATSracing.com they say this in their description of the KO 2.5" downpipe:

Includes all necessary hardware, support brace and second O2 sensor bung for easy wide band tuning.

but for now, I'm actually considering just getting a stock downpipe from a cali-spec mr2 or st185. (or federal spec and weld an extra bung on). then I can upgrade the downpipe later on, which should just bolt on if I already have an exhaust made to fit up to the oem 3s downpipe. right?

This post has been edited by 6strngs: Mar 27, 2007 - 10:50 PM

[Negative]

I have 3 stock Turbo downpipes. I will check to see if they have 2 o2 bungs and I can get one to you. Also the second half of the stock 5s downpipe is the same design but I think the bolt pattern makes the exit come out to the pass side for some reason. I now I have one bolted up this way in my garage.

[6strngs]

I have 3 stock Turbo downpipes. I will check to see if they have 2 o2 bungs and I can get one to you. Also the second half of the stock 5s downpipe is the same design but I think the bolt pattern makes the exit come out to the pass side for some reason. I now I have one bolted up this way in my garage.

thank you! if any of them do have 2 O2 sensors, let me know.

and, nothing of the exhaust will be original. I'm talking about using a 3sgte downpipe and mating it to a custom exhaust, then, later on taking an aftermarket 3sgte downpipe and mating it to the same custom exhaust, nothing will be from the 5s at all.

[Negative]

Good plan but the second half of the 5s downpipe is the same so no need to buy that. Trust me - I have a ton of downpipes from GT's, Al-tracs, and MR2's both turbo and non. The only ones that seem to be slightly different are the MR2's.
Need anything else for the turbo setup? Need a rebuildable CT-26 or the manifold? Intercooler?

This post has been edited by Negative: Mar 28, 2007 - 4:20 PM

[6strngs]

Good plan but the second half of the 5s downpipe is the same so no need to buy that. Trust me - I have a ton of downpipes from GT's, Al-tracs, and MR2's both turbo and non. The only ones that seem to be slightly different are the MR2's.
Need anything else for the turbo setup? Need a rebuildable CT-26 or the manifold? Intercooler?

I have a manifold. I do need a CT-26, but I was hoping to find one already rebuilt or low milage that wouldn't need a rebuild since I don't know how to rebuild a turbo. basically, I have most of the 3sgte stuff, here's what I still need:

intercooler + piping + couplers + clamps
turbo
downpipe
walbro 255lph fuel pump
Apexi SAFCII
1 step colder spark plugs
BOV (looking for a Greddy type RS)
oil filter relocater
boost controller (can't afford electronic, so just a cheap MBC)
the custom oil feed line
gauges (boost, oil pressure, AEM UEGO wideband O2)

here's what I have so far:

3sgte manifold
3sgte 2bar map sensor
3sgte Oil pan (modified for use on 5sfe)
3sgte oil and coolant lines
set of 460cc injectors

the only thing really holding me back right now is money. But I've got a bit more to spend right now, so if you have anything I need, let me know.

[Negative]

Got the downpipe and FMIC [Approx 30" x 10" x 3"] or MKII MR2 which would work nicely just a little small but made for CT-26 plus the inlet and outlet are on the same side so it makes it very easy for 5S-FTE. I have one Turbo [Don't they all] that just leaks oil but shaft play is ok. Got a homemade 2s-r-us style MBC. And you don't actually have to relocate the oil filter if you don't want to - I'm not going to.
I just need:
2 Bar Map Sensor
Walbro Fuel Pump and bracket
RX7 Injectors [trying to get that group buy going but need 5 people]

What did you modify on the oil pan? You mean just closing the hole on the oil level sensor?

[6strngs]

Got the downpipe and FMIC [Approx 30" x 10" x 3"] or MKII MR2 which would work nicely just a little small but made for CT-26 plus the inlet and outlet are on the same side so it makes it very easy for 5S-FTE. I have one Turbo [Don't they all] that just leaks oil but shaft play is ok. Got a homemade 2s-r-us style MBC. And you don't actually have to relocate the oil filter if you don't want to - I'm not going to.
I just need:
2 Bar Map Sensor
Walbro Fuel Pump and bracket
RX7 Injectors [trying to get that group buy going but need 5 people]

What did you modify on the oil pan? You mean just closing the hole on the oil level sensor?

for the oil pan, yeah I do mean just closing the hole. I didn't actually do it myself, I bought the oil pan like this from someone over at celicatech.com who was using it on his 5sfte.

I don't really know how the FMIC would work, would it really be easier to route the piping the other way so that they both go to the same end of the intercooler?

so, you're saying you DO have a downpipe with 2 O2 sensor bungs? if so, PM details so I can buy it off you!

[Negative]

Got the downpipe and FMIC [Approx 30" x 10" x 3"] or MKII MR2 which would work nicely just a little small but made for CT-26 plus the inlet and outlet are on the same side so it makes it very easy for 5S-FTE. I have one Turbo [Don't they all] that just leaks oil but shaft play is ok. Got a homemade 2s-r-us style MBC. And you don't actually have to relocate the oil filter if you don't want to - I'm not going to.
I just need:
2 Bar Map Sensor
Walbro Fuel Pump and bracket
RX7 Injectors [trying to get that group buy going but need 5 people]

What did you modify on the oil pan? You mean just closing the hole on the oil level sensor?

for the oil pan, yeah I do mean just closing the hole. I didn't actually do it myself, I bought the oil pan like this from someone over at celicatech.com who was using it on his 5sfte.

I don't really know how the FMIC would work, would it really be easier to route the piping the other way so that they both go to the same end of the intercooler?

so, you're saying you DO have a downpipe with 2 O2 sensor bungs? if so, PM details so I can buy it off you!

FMIC would be way easier that way with the 5S's intake setup. check 2slow's progress thread by the doc - they modified his IC for just that reason.
IDK about the two bungs. I think so - and if so it's already gutted and cleaned. I'll go to the garage and take pics tonight. I'll give you a retarded good deal if it is. If it's not you can send me a bung and I'll weld it up for free. I got mad MIG skills.
I also made some plates to close the hole on the 3S oil pan for mine and a couple extra for incase anyone needed one. Not trying to make money - I like helping you guys out. I wanna see more Turbo 6th gens in the states.

[presure2]

Got the downpipe and FMIC [Approx 30" x 10" x 3"] or MKII MR2 which would work nicely just a little small but made for CT-26 plus the inlet and outlet are on the same side so it makes it very easy for 5S-FTE. I have one Turbo [Don't they all] that just leaks oil but shaft play is ok. Got a homemade 2s-r-us style MBC. And you don't actually have to relocate the oil filter if you don't want to - I'm not going to.
I just need:
2 Bar Map Sensor
Walbro Fuel Pump and bracket
RX7 Injectors [trying to get that group buy going but need 5 people]

What did you modify on the oil pan? You mean just closing the hole on the oil level sensor?

for the oil pan, yeah I do mean just closing the hole. I didn't actually do it myself, I bought the oil pan like this from someone over at celicatech.com who was using it on his 5sfte.

I don't really know how the FMIC would work, would it really be easier to route the piping the other way so that they both go to the same end of the intercooler?

so, you're saying you DO have a downpipe with 2 O2 sensor bungs? if so, PM details so I can buy it off you!

FMIC would be way easier that way with the 5S's intake setup. check 2slow's progress thread by the doc - they modified his IC for just that reason.
IDK about the two bungs. I think so - and if so it's already gutted and cleaned. I'll go to the garage and take pics tonight. I'll give you a retarded good deal if it is. If it's not you can send me a bung and I'll weld it up for free. I got mad MIG skills.
I also made some plates to close the hole on the 3S oil pan for mine and a couple extra for incase anyone needed one. Not trying to make money - I like helping you guys out. I wanna see more Turbo 6th gens in the states.

none of the stock 3s downpipes have the lower o2 sensor bung. (unless someone welded one on there.) some of the JDM ones have a egt sensor bung. the o2 sensor will not fit in the smaller hole.

[Negative]

OK well that saves me some time. I can still weld one on for you if you want. W/E.

On second thought - I think there is plenty of meat there to drill and tap. What is the thread size? Hopefully it's an NPT or and amerrican straight thread but somehow I doubt it [most def not NPT]. If I have the tap I can do it for you really easy.

This post has been edited by Negative: Mar 29, 2007 - 5:06 PM

[6strngs]

Got the downpipe and FMIC [Approx 30" x 10" x 3"] or MKII MR2 which would work nicely just a little small but made for CT-26 plus the inlet and outlet are on the same side so it makes it very easy for 5S-FTE. I have one Turbo [Don't they all] that just leaks oil but shaft play is ok. Got a homemade 2s-r-us style MBC. And you don't actually have to relocate the oil filter if you don't want to - I'm not going to.
I just need:
2 Bar Map Sensor
Walbro Fuel Pump and bracket
RX7 Injectors [trying to get that group buy going but need 5 people]

What did you modify on the oil pan? You mean just closing the hole on the oil level sensor?

for the oil pan, yeah I do mean just closing the hole. I didn't actually do it myself, I bought the oil pan like this from someone over at celicatech.com who was using it on his 5sfte.

I don't really know how the FMIC would work, would it really be easier to route the piping the other way so that they both go to the same end of the intercooler?

so, you're saying you DO have a downpipe with 2 O2 sensor bungs? if so, PM details so I can buy it off you!

FMIC would be way easier that way with the 5S's intake setup. check 2slow's progress thread by the doc - they modified his IC for just that reason.
IDK about the two bungs. I think so - and if so it's already gutted and cleaned. I'll go to the garage and take pics tonight. I'll give you a retarded good deal if it is. If it's not you can send me a bung and I'll weld it up for free. I got mad MIG skills.
I also made some plates to close the hole on the 3S oil pan for mine and a couple extra for incase anyone needed one. Not trying to make money - I like helping you guys out. I wanna see more Turbo 6th gens in the states.

none of the stock 3s downpipes have the lower o2 sensor bung. (unless someone welded one on there.) some of the JDM ones have a egt sensor bung. the o2 sensor will not fit in the smaller hole.

what about the california specs? don't they legally need to have 2 O2 sensors?

anyway, I suppose all you need is one of these: http://store.summitracing.com/partdetail.a...mp;autoview=sku and just weld it in place. yeah dude, I'll definately buy a downpipe off you and buy a bung for you to weld in for me. As long as you're offering you're welding services, could I send you the stock 3s oil drain line for you to weld in the NPT fitting needed for the 5sfte?

I'm interested in the intercooler too. could you send me a pic, and tell me how much you want for it and the downpipe?

[alltracman78]

I have a question, out of curiosity.

I'm not telling anyone they're wrong, because I've never looked at a 94 GT in person, and I know sometimes things are how they are, they just don't make sense.

But

From everything I know the second O2 sensor [if you have one] is always AFTER the cat [or cats]. It is used to monitor how well the cat is changing the exhaust.
So, I don't understand why there would be 2 O2 sensors in the DP before the cat.

Can anyone explain?
Or does anyone have pics of a STOCK setup?

[6strngs]

yes, after closer inspection, the 2nd o2 sensor IS after the first cat. but the first cat is part of the downpipe. the second cat is under the car. I didn't realize that this was the first cat because practically the entire downpipe is covered in heat sheilds.

[hurley97]

this is of my 97 ST but it sounds like they are in the same places you are describing

you can see the first O2 in the DP at the top of the pic and the wire going to the pipe between the cat and resonator (I'm not really sure what that is but thats what I'm calling it) is the second O2


first O2 in the DP


second after the cat

[6strngs]

that's definately not where they are on a cali-spec GT. I can see both in the engine bay, looking down. maybe I'll take a pic tomorrow when it's daylight.

[alltracman78]

She has a different engine.
I don't believe it has a cat in the DP.
Her only cat is under the middle of the car.
Which is kind of weird too... :shrug:
Usually the cat is close to the engine so it heats up faster.

yes, after closer inspection, the 2nd o2 sensor IS after the first cat. but the first cat is part of the downpipe. the second cat is under the car. I didn't realize that this was the first cat because practically the entire downpipe is covered in heat sheilds.

Ah

This makes sense.
You need to keep that second O2 sensor after the cat or you will have a CEL.
Same goes if you don't uses a cat at all.

[6strngs]

She has a different engine.
I don't believe it has a cat in the DP.
Her only cat is under the middle of the car.
Which is kind of weird too... :shrug:
Usually the cat is close to the engine so it heats up faster.

yes, after closer inspection, the 2nd o2 sensor IS after the first cat. but the first cat is part of the downpipe. the second cat is under the car. I didn't realize that this was the first cat because practically the entire downpipe is covered in heat sheilds.

Ah

This makes sense.
You need to keep that second O2 sensor after the cat or you will have a CEL.
Same goes if you don't uses a cat at all.

well, for the time being I'll still have a cat after I go 5sfte. but, I was planning on gutting it... is there anything I can do about that CEL?

[presure2]

I have a question, out of curiosity.

I'm not telling anyone they're wrong, because I've never looked at a 94 GT in person, and I know sometimes things are how they are, they just don't make sense.

But

From everything I know the second O2 sensor [if you have one] is always AFTER the cat [or cats]. It is used to monitor how well the cat is changing the exhaust.
So, I don't understand why there would be 2 O2 sensors in the DP before the cat.

Can anyone explain?
Or does anyone have pics of a STOCK setup?

jeremey, your right.
the primary is right up top, with the 2nd being directly after the main cat that is attached to the exhaust manifold.

[alltracman78]

well, for the time being I'll still have a cat after I go 5sfte. but, I was planning on gutting it... is there anything I can do about that CEL?

Why, why, why gut it?
You are going to add 3 hp. Roughly.

Are you planning on using the stock cat on a stock CT26 DP?

Get a good high flow cat, such as a 3" Catco.
Put it in your nice 3" exhaust.
Put the 2nd sensor after it.
This SHOULD ensure you don't get a CEL from it.

[6strngs]

yes, for the time being I want to use the stock CT-26 DP w/ stock cat. Eventually moving to either a 2.5" downpipe mated to a 2.5" exhaust. or a 3" downpipe mated to a 3" exhaust. (I haven't decided which yet.) And I was probably going to with something like a magnaflow high-flow cat under the car. but, since on the aftermarket DP it will already have 2 O2 sensor bungs I would probably just use those two.

so, you're saying I should wire the second o2 sensor way down like where hurley's 2nd one is?

[alltracman78]

Personally, I would recommend a 3".
Especially with FWD.

Yes, if you mount it in the DP before the cat it will set a code.

Your cat changes [catalyzes] the stuff in your exhaust to different amounts, and creates some new ones.
One of the effects is it smooths out the rich/lean.
That is what your ECU is looking for to ensure the cat is working right.
If it sees rich/lean on the 2nd sensor it will set a code.
For OBDII it's PO420. I don't know off the top of my head if you will only get an O2 sensor code, or if you will get a specific code for the 2nd sensor.

You will probably have to extend your wiring to do this.
I suggest you solder it well. This will help prevent that code in the future [less chance of the connection becoming bad].
Also, protect the wires well. Keep them away from the exhaust pipe and cover with some type of tubing.

[presure2]

just FYI, ive had my 2nd O2 sensor installed in the lower part of my DP (no cat) for almost 2 years now.
ive never had a problem with it throwing codes.
i think i MAY have gotten one, maybe once..lol
(i've had a problem with the wiring for my wideband, which sends a signal to the ecu to replicate the 2nd o2 sensor, but that is a seperate issue that has to do with the plug on my wideband controller, not the ecu or o2 sensor working)
imo the OBDI setup is not as strict on what it requires as far as values from the 2nd o2 as say a OBDII or newer ecu that REQUIRES that thing be placed just so and working PERFECTLY for it not to set a hard code.
also, on our cars, with the cali setup, the 2nd o2 sensor code works on what toyota calls a "two trip detection logic"
basicly, the problem happens, the ecu stores it in memory, but dont throw a code, untill you shut the car off, and start it again, and it sees the same problem again.
also, it will only throw the code when your @ WOT for 2 seconds or more.

[alltracman78]

I stand corrected.
Apparently the 94/95 O2 sensors are monitored differently than the 96^.

FYI, there are a couple of sensors that use 2TDL. Same goes for OBDII.
And if it doesn't see the problem for 3 consecutive trips, the light goes off.
It will still hold the code in memory though.