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O2 Sensor Placement

zdriver123

zdriver123

New member
Joined
Sep 27, 2010
Location
Sequim Washington
So, I have to replace the entire exhaust on my 90 244. I'ts got a cracked manifold, cracked header pipe and junk exhaust. I found a manifold, header pipe and built my own 2.25 inch exhaust. The only difference is that the new exhaust has the O2 sensor in the manifold, not the header pipe down by the catalytic converter. would economy or performance be affected by installing my sensor up in the manifold instead of the header pipe. I could care less about performance, i'm looking for economy.
 
zdriver123 said:
So, I have to replace the entire exhaust on my 90 244. I'ts got a cracked manifold, cracked header pipe and junk exhaust. I found a manifold, header pipe and built my own 2.25 inch exhaust. The only difference is that the new exhaust has the O2 sensor in the manifold, not the header pipe down by the catalytic converter. would economy or performance be affected by installing my sensor up in the manifold instead of the header pipe. I could care less about performance, i'm looking for economy.
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The sensor is most sensitive when it is hottest, which is in the catalytic converter, even hotter than the ex manifold.
I would suggest getting the Magneflow 2.25 freeflow cat with the O2 bung in it, I and many others run this one and cheap. IIRC the p/n is 94135
http://www.magnaflow.com/02catalytic_converters/02product/displayuniversal.asp?universal=94135
The O2 sensor was in the cat in '91-up, and my LH 3.1 has it there, the best mpg 240 I've had.
 
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*shrug* when I ordered the downpipe, I had to pay extra to have a shop weld a bung into it since it didn't come with one, and my cat doesn't either.
 
I just checked my '88 and the sensor is in the exhaust manifold just above the connection to the down pipes. I can't get at the '89 right now, but I'm pretty sure that when I replaced the cat a few years back we re-installed the O2 sensor in to it.
 
Hi all,

My 81 242 turbo is getting rehabbed. I replaced the in-tank fuel pump with the larger later pump from ipd and a new sending unit as well. The sending unit was reverse polarity at manufacture, so i cross-wired. Now the main fuel pump is whining, so I'm planning on replacing it. But I'm wondering if the problem is the 02 sensor. I had a custom shop install a 2.25 turbo back stainless exhaust and they didn't bother to weld in a bung nut but just used sealant instead. Thoughts?
 
The stock location of the o2 sensor is under the manifold behind the turbo. So if there is a sensor in there with stock kjet. Then it's time to make sure it's working. The exhaust shop probably didn't have a stainless steel hole saw. If you do move the sensor to the downpipe. Change to a heated sensor so it won't cool off while cruising or idling.
 
Thanks Dave,

I'll put it up on stands and take a closer look, have to replace disks and pads anyway. By the way, how did you get 3-inch exhaust on your 82? I'm putting a ton of time in on my 81 and need all the advice i can get. i did all the suspension upgrades, chassis braces, sways, bilsteins, etc but am hoping to push the boost safely as well. Tips are much appreciated.

Best,
Eric
 
ok i'm in trouble. Upgrading 1981 242t, replaced the in-tank sending unit and pre-pump with the larger version.
Fires up but fuel leaks galore. Fuel running down one or more hoses to the ground. In-line pump and hoses not leaking. Leaking fuel accumulating on top of in-tank fuel bung. All hose clamps there are secure. Also, turbo dash light is on. help? Maybe the old girl wants to move on?
 
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