DaveK

Hi,
Not managed to find and DIY info on replacing the oxygen sensors (pre cat).

I assume I will need to take the rear bumper and intercoolers off - or can it be done just by jacking the car up?

"02996ttx50

jack the car up and bumper off once exhuast is off should be it. no need to mess with i/c's??

DaveK

Thanks.

I assume you mean "once bumper is off"? I wasn't expecting to remove the exhaust!

dprantl

It's possible to remove the O2 sensors without removing anything, just jacking the car up. It's not easy though, and you will probably need just the right size stubby 22mm wrench.

Dan

Macster

Be sure you get the right sensors. Wideband.

Handle the new sensors with care.

Avoid touching the tips.

Do not use any anti-seize on the threads.

Do not use any contact cleaner on the electrical connectors.

PelicanParts.com

Just get under the car and take a look. Shouldn't be too technical besides having the correct tool to remove the sensors.

-Luccia

"02996ttx50

i just did mine tonight. i shouldnt say "I" lol.. but it's an hour job, ( coulda been less we mess around with stuff ). both. i was having cels ( 0132 0152 02 sensor ...hi output bank one and two ) from running decatted in the last week and hopefully this has cured it. if it's even possible, the car is even faster now than it was an hour ago with the bad o2's gummed up 02' sensors. they get this white residue on them?

either way i needed to do em, and.. ask and ye shall receive. man i got a good buddy..who brought both the 02's ( n/c ) and switched em out for 75 bucks and a cpl beers

it was easy with the car jacked a foot or so std floor jack engine center

edit: my earlier mention of exhaust was when i believed i had to get into the bungs that screwed into the decat pipes... lol. never mind. no need to remove exhaust or bumper

DaveK

Well, I tried but gave up.

There is very little space - even if I could get a spanner in there (which I couldn't), I still can't reach some of the clips for the cables. I tried taking the bumper off but without removing intercooler and heat shield that doesn't help.

One for the mechanic I think - wanted the alignment done anyway so it can be done at the same time.

"02996ttx50

although I ( again ) mostly stood there and opened beer? it was an hour job with other stuff involved/fixed, and my buddy, ( admittedly a "pro" ) got it done in that little time with the car floor jacked and a cresent wrench. for real. there is NO bumper removal or ic's removal. theyre not even that near ( or very near ) the ics's! they're not even remotely "in the way" is my point. nor is the bumper a hindrance.

leave it to a tech.

DaveK

The sensor is on top of the exhaust. From underneath the car the only access is from the inside - I.e from towards the centre of the car. But access is very limited - post cat sensor looked slightly easier to get to and removing that might have given more space for the pre-cat I guess. But the heat shield is next to the exhaust (obviously) and if the intercooler and heat shield was removed there would be totally free access to the sensor.

It may not be necessary with experience and the right tool, but not sure how you think they are nowhere near.

dprantl

Yes, that is what I was saying earlier. Most 22mm wrenches are quite long and there is not enough clearance in there to fit them and be able to get any significant turning force on them. You need a special short 22mm wrench and get just enough force on it to loosen the O2 sensor. After that, you can usually just unscrew it by hand. Another option is to get a flexible crow's foot wrench on which you can set the angle of the wrench head with respect to the shaft. The clips should be accessible from inside the engine bay if you extend your arm down in there, but you will have to do it by feel. Something like this may make the job easy:



Dan

Dock

Do you own a set of those (or even one or two)? If so, where did you buy them?

rmc1148

Snap on has them but pricey. I have some but not a whole set. Premier I believe its a UK company so could buy online?

993GT

bumper off, intercooler assemblies out, 02 wiring disconnect in engine bay and drop the exhaust.
Use some heat around the o2 bungs and they should come out well(use an o2 wrench), consider using an o2 thread chaser on the exhaust before re-installing the o2's. Don't forget new turbo-to-catalyst flange O-rings.

rmc1148

Good info 993GT last 02 sensor I replaced left the threads in the exhaust manifold= you talk about some tough tapping lol but got it done.