Get this, I got one of those "quality" 4-2-1 headers off e-bay and it only let the O2 sensor read off a couple cylinders.In addition to all the previouse add ons, I just shaved the head on it(0.28" off )Felt great!!So I thought I might move the O2 sensor down stream to the main collector that bolts up to the cat. just to see if it would help or hurt any.......

Well-it runs nice, accelerates more smoothly, and idles like it did factory

Problem: it does not accelorate as fast as it did before I move it.

Conceivable solution: Leave the one were I moved it.Remove the plug from were it was and isntall another O2 sensor.Put both on one switch that lets me choose wich one to operate with.
Is this possible? Has anyone ever tried this?Also will the feed back to my computer get all screwed up having to go through that switch?
Feed back much appreciated-GOOD-BAD-whatever....


Modified by Civiclized at 7:23 PM 10/13/2005

 

Why not just put them in the stock location ?

 

I know it suck trying to explain with out pics, but the deal is I had it wee the after market header allowed it to go(that is closest to the stock location as it gets. But the problem is it only reads off 2 cylinders verses reading all four as it does on a fastory manifold. thus why I moved it.

I guess what I should really be asking is it possible to put them on a swtich or will it do something extremly stupid like fry my comupter?

 

Putting them on a switch is stupid. Close the holes with a cap, and reweld the 02 bungs in the right spot.

 

It won't read correctly in winter as the exhaust manifold won't heat up down there. You'll need a 4-wire heated O2 sensor to work correctly down there, and for that you'll need an OBD1 computer to read it correctly. Believe me it will not run right, I've tried.

Thus, you have 3 options:
1 - put the stock manifold and 02 sensors on
2 - have the new manifold outfitted with the proper bungs
3 - convert to OBD1

 

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^
Thank you-thats exaclty what I needed to know

 

You can wire up a 4 wire O2 to run on an non-OBD set-up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sgt_Ox &raquo;</TD></TR><TR><TD CLASS="quote">You can wire up a 4 wire O2 to run on an non-OBD set-up.</TD></TR></TABLE>

No you can't. I've tried this and researched it and others have run up against the same problem I have. When decellerating or going down hill with the throttle up, it doesn't read right and you get a check engine light, and the car doesn't respond properly to the throttle. I have to reset the ECU every 20 minutes or so to keep it running right. The 4-wire doesn't give the same response as the 1 wire and the ECU I presume can't interpret it correctly.

I've got the 4-wire hooked up right now, and my next step is to convert to OBD1 as soon as I can find a cheap ECU, otherwise I can live with it until then. I would put my stock manifold back on, but I threw it away while moving combined with the fact that the stupid exhaust shop welded my header to a flex pipe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX7 &raquo;</TD></TR><TR><TD CLASS="quote">It won't read correctly in winter as the exhaust manifold won't heat up down there. You'll need a 4-wire heated O2 sensor to work correctly down there, and for that you'll need an OBD1 computer to read it correctly. Believe me it will not run right, I've tried.

Thus, you have 3 options:
1 - put the stock manifold and 02 sensors on
2 - have the new manifold outfitted with the proper bungs
3 - convert to OBD1</TD></TR></TABLE>

2 - have the new manifold outfitted with the proper bungs
I have had this done to both headers I've used. So easy and so effective.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX7 &raquo;</TD></TR><TR><TD CLASS="quote">

No you can't. I've tried this and researched it and others have run up against the same problem I have. When decellerating or going down hill with the throttle up, it doesn't read right and you get a check engine light, and the car doesn't respond properly to the throttle. I have to reset the ECU every 20 minutes or so to keep it running right. The 4-wire doesn't give the same response as the 1 wire and the ECU I presume can't interpret it correctly.

I've got the 4-wire hooked up right now, and my next step is to convert to OBD1 as soon as I can find a cheap ECU, otherwise I can live with it until then. I would put my stock manifold back on, but I threw it away while moving combined with the fact that the stupid exhaust shop welded my header to a flex pipe.</TD></TR></TABLE>let me rephrase before you think I'm wrong anymore.

You can run a 4 wire O2 in a non-OBD set-up if you're wanting to use aftermarket headers with the O2 bung down by the collector.

I've done it and had no check engine lights what's so ever. Though I was running a Spoon chipped PR3 with the disabled secondary O2 and using a CTR exhaust manifold and downpipe set-up.

Black-ground (just grounded out)

Black-12v switched (ignition ideally tapped into the dizzy's IGN wire)

White-signal wire (C8 and C16)

Green-heater ground (C12)

From my understanding the single wire can work just fine in header assembly as long as the O2 is located higher up on the manifold/tubes it's hotter up there and all it needs to do is send the signal (however I've heard of people having issues with their modified welded bungs high up on the tubes- location is key). The reason you need a 4 wire for location near the collectors is in the matter of heat (since the O2 needs to create voltage signal). Hence the need for the O2 internal heater so that it may read properly. So as long as you have it running and set-up correctly you can send signal to you non-obd ecu correctly and it'll run accordingly.

 

i just have to ask... how do you know its "not accelerating like it did"

butt dyno = teh suck

btw, the o2 sensor should have no affect on full throttle acceleration as its bypassed in open loop mode i.e. full throttle

 

thanks for the information, I was thinking of getting mine chipped but never really had a reason until now.

chipping the ECU is much easier than converting to OBD1 as I just need to get the speed governor removed.

THANKS! I'll try it out.

 

IF its obd 0 you should only need the upstream O2, and the only repurcussions for not running a downstream cat in ur car (if it comes with one) is that the check engine light willl come on, and the car will run in open loop (most likely run rich) but every engine runs in open loop at full throtle anyway, so it shouldn't change the speed at all.
as for it reading only 1/2 the cylinders, that shouldn't be a problem either unless you have a problem with the other cylinders.
the second O2 sensor is only for emissions purposes so the computer can monitor if the cat is working properly.

 

Eresuncabron: Please read the entire thread.

 

the reason they have heated O2 sensors is so that it will get up to opperating temp quicker and go into closed loop for emisisons purposes i dont see why you couldnt run the single wire down stream further it will just take longer to heat up but it shouldnt make a difference other than that. right?

 

exactly what engine are you running?

B16A1 ODB0 needs to cylinder 1&3 and 2&4 seperately.....unless you convert to ODB1


I have a 4-1 header I modified to work well tith an ODB0 system though it sees on one of the equally controlled pair it still works as it gets feedback from each pair...