O2 Sensor Removal - Help

juejaimon

juejaimon

Experienced Member
Joined
9 March 2002
Messages
1,029
Location
California
Hi All,

I am in the process of removing my manifolds from my '91. I removed the one towards the back of the car without any problems. I am currently struggling with the forward one.... I can't seem to get the O2 Sensor off so that I can drop the heat shield to access the manifold nuts... i've been sitting on my garage floor for hours looking at this sad site. Please advise if you know of any tools or tricks that can help me out.... I had a can of WD-40 sitting next to me the whole time... i remember reading a thread to not use it because it can ruin the O2 Sensor......so I refrained from using it...
 

Attachments

  • Headers-023.jpg
    Headers-023.jpg
    72.2 KB · Views: 483
I had to use different combos on the front & rear to get them out, but I can't remember which one I did what way. Sears carrys an O2 sensor socket, I used that + breaker bar on one. The other I used a 22mm open ended wrench and a hammer. Not subtle, but it worked (and quick too).

Good luck with the install!
 
P.S. to save you a little time, here are some other tricks I discovered in replacing my forward manifold:

Forward manifold removal - That heat shield won't come out without removing some other stuff (forward engine support beam, AC compressor at minimum, shift linkage cover) I've heard of some people being able to do it by just loosening some of those, but It did not work for me FWIW.

Forward engine support beam removal- I couldn't budge the center pin in the front beam, so I removed the entire bracket it attaches to (3 bolts). They are not identical, so remember which goes where.

Better access to work - I took off the entire shift linkage cover to give myself more room to move. I did not disconnect the cables. I Also undid the belt to the AC compressor, unbolted it, and then just used an upside down bucket to hold it off to the side. Make sure you have something handy that will keep it up as high as possible.

Preventative maintenance - if you are going to replace your oil pan gasket, you better do it before you install headers. You have to take them off again to replace the pan. IF you decide to do this, follow the manual VERY closely in the tightening sequence, use a torque wrench and watch how far you are pinching the gasket out (whould be uniform and to the edge).

Safety - support the engine when you take out the beam! I used a floor jack underneath the tranny, and the 2x4 trick between the forward valve covers and the firewall.

Briank's torch trick is a good one, remember that. With a little PBBlaster and a torch you can get anything loose. Remember things expand with heat, so apply where you want the expansion (i.e. on the nut vs the bolt, or in your case on the manifold)

That is all I can think of off the cuff, but PM me if you want. Have a good time!
 
White94,

Thanks for the heads up....and your time in writing a descriptive post.... i'm having second thoughts of doing the forward manifold now... :(

Do you think I would experience any problems with the car with a 97+ rear header and a 91 manifold in the front? ;)

Also, I was piecing the exhaust components together and found that my Dali Sways will interfere with the rear 97+ header/cat setup (the cat, actually). I may need to sell my Dali Sways now and find some 97+ sways...
 
juejaimon said:
White94,

Thanks for the heads up....and your time in writing a descriptive post.... i'm having second thoughts of doing the forward manifold now... :(

Do you think I would experience any problems with the car with a 97+ rear header and a 91 manifold in the front? ;)

Also, I was piecing the exhaust components together and found that my Dali Sways will interfere with the rear 97+ header/cat setup (the cat, actually). I may need to sell my Dali Sways now and find some 97+ sways...
Click to expand...

You are certainly welcome. Ask away if you need some more help, here PM, whatever.

I would certainly go ahead and finish the project. I am not familiar with the 97 headers specifically, but trust me when I say that you are at the most intimidating part of the project. Just push through it, things LOOK a lot harder than they are.

I would say this, be sure you have the proper tools for the job. To my mind, those are: Floor jack, 4 stands, torque wrench, 10,12,14,17mm 6pt sockets, I'd also get a 6pt deep sockets of the same sizes, extensions, a ratchet, (preferably ratcheting) open ended wrenches of the same sizes, a breaker bar, a wobble, and something to remove the o2 sensors(22mm wrench works). FWIW, I would also have some simple green, anti-seize, PBBlaster and the service manual.

You can do it, just take your time. The front manifold does take more time, but that is just part of the game. There is nothing terribly difficult about it. Stick with it and post pics if you get stuck.

Regarding the sways, I really can't say. The CT headers routed everything in the same place and would have worked with either stock or CT sways (I had one and installed the other). If it were me, I would see if the stock sways fit (I bet they do), and if not spend you money on a new set of swaybars. Personally, I would go aftermarket if you need to. They really do make turn in quicker. If you need some photos, shout. I'll jack mine up and shoot a pic of whatever you need.

Mark
 
juejaimon said:
PBBlaster?.... is this stuff safe to use on the O2 Sensor? or will it have the same ill effects as the WD-40?
Click to expand...

Do NOT use this on the o2 sensor! Just brute force. Try and get a sharp impact, it seems to break it loose better. 22mm wrench and a hammer worked for me. Heat can only help!
 
AutoZone sell an 02 sensor socket for about $9. Well worth it. Also if you remove the wiring connector up top, you can actually wiggle the heat shield out withthe sensor in place, once the shield is out you can gain a ton of access for a 22mm wrench or the 02 sensor wrench. NO way you can mix the manifolds, bad idea.

HTH,
LarryB
 
Larry Bastanza said:
AutoZone sell an 02 sensor socket for about $9. Well worth it.
Click to expand...

Agreed. Sears has them too. If you want to borrow mine, I'll send it to you.
 
Larry Bastanza said:
AutoZone sell an 02 sensor socket for about $9. Well worth it. Also if you remove the wiring connector up top, you can actually wiggle the heat shield out withthe sensor in place, once the shield is out you can gain a ton of access for a 22mm wrench or the 02 sensor wrench. NO way you can mix the manifolds, bad idea.

HTH,
LarryB
Click to expand...

Thanks Larry....I already tried one of those 02 sensors that has a side partially missing to allow for the wiring harness. But once I put the socket on, there is no way for me to attach the ratchet to it due to the confined space. I went to home depot and to kragen, and they don't stock the 22mm wrench...but only adjustables.. sigh. I'll try Sears after work today.
 
Get a 3/8" breaker bar, they have a small head and you should have the clearance. Remember, once it cracks loose it will just spin out without a wrench.

The other thing you can do is, from your pic (I think) you have removed the front beam, which means the front trans mount is loose. So... remove the back trans mount too(do not worry the drive train is OK supported by the two side mounts), then you can actually rock the drivetrain to get clearance with a ratchet or breaker bar(you will move the oil pan towards the rear of the car). I am sure your clearance needed is not much to get the ratchet/breaker bar in there.

EDIT: I do see now your front beam is still in place, this is causing alot of clearance issues for you. It is not difficult to remove, look it over in the service manual

Good Luck and DON'T give up, you will get it:). Also once you get this off, give the remainder of the nuts on the exhaust manifold(near the cylinder head) a good blast of PBBlaster. Will help very much. Just keep the 02 sensor away from it.

HTH,
LarryB
 
When you go about reinstalling the front beam and if you removed the engine mount bolt (rather than removing the entire mount as described above, I’ve never been successful at reinstalling that), tape the special engine mount nut in place to the beam before raising the beam in place. The advice above is good about removing the shift cable cover and the shift cable holders so that the cables are loose enough to allow you to drop the beam and carefully move it out of the way. I wouldn’t worry about supporting the engine as it is held in place by three other mounts.

DanO
 
juejaimon said:
Thanks Larry....I already tried one of those 02 sensors that has a side partially missing to allow for the wiring harness. But once I put the socket on, there is no way for me to attach the ratchet to it due to the confined space. I went to home depot and to kragen, and they don't stock the 22mm wrench...but only adjustables.. sigh. I'll try Sears after work today.
Click to expand...
Sears has the 22mm, that is where I got mine.

LarryB said:
EDIT: I do see now your front beam is still in place, this is causing alot of clearance issues for you. It is not difficult to remove, look it over in the service manual

Good Luck and DON'T give up, you will get it. Also once you get this off, give the remainder of the nuts on the exhaust manifold(near the cylinder head) a good blast of PBBlaster. Will help very much. Just keep the 02 sensor away from it.
Click to expand...
Larry's right (as always!). You gotta get the front beam out of there. Its not bad. PBBlaster is a must for the manifold nuts. Be sure to use antiseize when you put it all back together too (but not on the o2 sensor).


DanO said:
When you go about reinstalling the front beam and if you removed the engine mount bolt (rather than removing the entire mount as described above, I’ve never been successful at reinstalling that), tape the special engine mount nut in place to the beam before raising the beam in place. The advice above is good about removing the shift cable cover and the shift cable holders so that the cables are loose enough to allow you to drop the beam and carefully move it out of the way. I wouldn’t worry about supporting the engine as it is held in place by three other mounts.
Click to expand...

I couldn't get the special nut to budge, so I took off the whole front support bracket. It works either way. I used the floor jack under the tranny to get everything to just the right spot for easy reassembly. IF the special bolt comes loose, that is probably easier.
 
Great!! Glad you got it. I have to say you do not like getting things out of the way though:):). You must have had a heck of a time with the manifold, with that A/C compressor in place! My rule is if it is a PITA to get around, get it out of the way:):).

Sounds like you project is all down hill now. Congrats.

HTH,
LarryB
 
Larry Bastanza said:
Great!! Glad you got it. I have to say you do not like getting things out of the way though:):). You must have had a heck of a time with the manifold, with that A/C compressor in place! My rule is if it is a PITA to get around, get it out of the way:):).

Sounds like you project is all down hill now. Congrats.

HTH,
LarryB
Click to expand...

Larry...it's certainly a good feeling... i can't wait to take the car out for a drive... unfortunately, i'm waiting for the arrival of the new header gaskets...
Actually, the A/C compressor did not interfere at all, I had a wobbly attachment and it worked like a charm.


btw.... does anyone know if the two O2 Sensors (front and rear) are interchangeable?

thanks,
Steve
 
Yep, the o2 sensors are interchageable. Be careful as they have different length wiring harnesses though (might not reach to the connector).

Congrats on the install!
 
Thanks Mark... I can't believe I almost gave up. I'm glad I posted on Prime. :D

Regarding the O2 Sensors, i was thinking they were interchangeable but I began my doubt when I saw different prices for each of the front and rear. Maybe it had to deal with the different lenght of wires attached? :rolleyes:
 
Hi Steve,

Yes I have the swivel extensions too. Putting it back together and getting that last bolt on is quite a pain with the A/C compressor in the way though:).

Enjoy the Drive!

Later,
LarryB
 
juejaimon said:
Regarding the O2 Sensors, i was thinking they were interchangeable but I began my doubt when I saw different prices for each of the front and rear. Maybe it had to deal with the different lenght of wires attached? :rolleyes:
Click to expand...

That is correct. I have swapped mine before and the wire reached in both cases. If I remember correctly, going front to back wasn’t too much of a problem in terms of wire length but going back to front, the wire was a little short but still made it. The real problem with swapping the sensors is how the two rubber grommets on the O2 wire line up on the wire holders on the head—they don’t real well when swapped. I’d be concerned with the long-term integrity of the wire, especially swapping back to front.

DanO
 
Larry Bastanza said:
Hi Steve,

Yes I have the swivel extensions too. Putting it back together and getting that last bolt on is quite a pain with the A/C compressor in the way though:).

Enjoy the Drive!

Later,
LarryB
Click to expand...


Larry, i had to move the A/C compressor to put that last nut in ;)
 

Similar threads

jsullyboy
Low Engine Power before 4k RPM
2
Replies
29
Views
783
NSX78__
NSX78__
nsxspdfreak
O2 Sensor CEL and TCS Light
Replies
0
Views
373
nsxspdfreak
nsxspdfreak
fusionrace
O2 sensor harness wiring - help
Replies
14
Views
948
MotorMouth93
MotorMouth93
W
NEED HELP: Dropped wrench in engine bay
Replies
11
Views
439
Driver's Therapy
D
AdventureNSX
Looking for Fuel Tank Removal Procedure within Service Manual
Replies
12
Views
779
Honcho
Honcho
Back
Top