front o2 sensor multiplug access D1

[Tugela]

Recently replaced my rear oxygen sensors and want to do the same with fronts. From crawling around under the truck it's not obvious where the wires from the sensors lead. They both vanish into the darkness above the transmission. RAVE (Ch. 17, Emissions, page 200, "heated oxygen sensor") procedure calls for removing the coil pack to access the multiplug, but only for the left hand sensor.

For those who have done this swap, what's the best way to access the multiplugs? From under the truck? From above, inside the engine compartment? Seems awkward no matter what. Any tricks that would help this go smoothly? I've already checked the sensors themselves to make sure they will loosen from the y-pipe.

 

[discostew]

Recently replaced my rear oxygen sensors and want to do the same with fronts. From crawling around under the truck it's not obvious where the wires from the sensors lead. They both vanish into the darkness above the transmission. RAVE (Ch. 17, Emissions, page 200, "heated oxygen sensor") procedure calls for removing the coil pack to access the multiplug, but only for the left hand sensor.

For those who have done this swap, what's the best way to access the multiplugs? From under the truck? From above, inside the engine compartment? Seems awkward no matter what. Any tricks that would help this go smoothly? I've already checked the sensors themselves to make sure they will loosen from the y-pipe.

They end up at either side of the coil packs on little brackets bolted down by the top bell housing bolts. May be easier if you take the coils off the mounting bolts but leave all electricals attached. Be very carefull when bolting the coils back down that the harness does not get trapped under the bracket.

Make sure you note the color of the connectors and what side they go on. They can be switched and cause a great deal of trouble. The fueling adaptions get done to the wrong bank and the truck will run like shit. And nobody will be able to figure that out unless they are very smart like us.

 

[Buddy]

They end up at either side of the coil packs on little brackets bolted down by the top bell housing bolts. May be easier if you take the coils off the mounting bolts but leave all electricals attached.

x2 on unbolting or removing the coils. I've managed to unplug those front O2's a few times from below but it's not fun and you have to twist yourself into all kinds of positions to get your hands far enough up on the bell housing. If you have Popeye forearms you might as well forget about it.

With the Coil pack removed it's actually quite easy to access them.

 

[best4x4]

I laid across the top of the engine bay and got my arm back there and was able to unplug them without removing the coil packs.

 

[Tugela]

I laid across the top of the engine bay and got my arm back there and was able to unplug them without removing the coil packs.

I'll try this first. My wingspan is 6'7" so hopefully I can reach, but if not removing the coils is no big deal. I would prefer to see what I'm doing so I know which way to orient the plug going back in.

 

[best4x4]

I was able to see if I positioned a flashlight over by the AC lines and aimed it back towards the coil packs. I also had an LED headlamp on my head which helped as well. I laid a mat down, then laid across the engine bay, and gave my 4.0L the reach around and unplugged them one at a time. As long as you don't have GIANT hands you shouldn't have any problems doing it that way.

 

[discostew]

I was able to see if I positioned a flashlight over by the AC lines and aimed it back towards the coil packs. I also had an LED headlamp on my head which helped as well. I laid a mat down, then laid across the engine bay, and gave my 4.0L the reach around and unplugged them one at a time. As long as you don't have GIANT hands you shouldn't have any problems doing it that way.

What color pants did you have on? Who made the led flashlight head gear? Do you think I could unplug them both at the same time instead of one at time? If laid across the engine like you describe somebody might try to do me.

 

[best4x4]

Yeah my wife must have seen me laid out across the engine bay because late that evening I got laid.

 

[group captain mandrake]

Removing the coils is a much easier way to do this in my opinion. A few months ago I did a bunch of experimentation on my front O2s that required multiple removal/re-installs. The first time I probably had 30 to 45 minutes max into the removal of the coils, cleanup of the mouse nest and oil, and both O2 sensors R&R. And I had to heat up the O2s to get them loose. After a couple of R&Rs I had the process down to less than 10 minutes. The hardest part is releasing the little connector tab, but at least you can see the little bastard tabs from above.

 

[fishEH]

X2 on removing the coils. Much easier than contorting and scraping your arm to get the plug.

 

[best4x4]

Guess I must not have large enough hands to get all scratched up. Simply reached around, unclipped em, and swapped them out. Maybe 10min tops.

I'd try reaching around first and if that looks like a no go do as suggested above and remove the coil packs.

 

[discostew]

Ya but your from Texas. So how do we really know what you did. Your a shifty fucking bunch down there. Seems like if you guys were as big as you say you could stop these stupid Mexicans from moving to Illinois. You do that for us and we'll figure out how to get you guys some regular shoes so you can stop wearing those fucking cowboy boots and hats

 

[group captain mandrake]

I'd try reaching around first

LOL, That reminds me of this.

 

[discostew]

LOL, That reminds me of this.

I was laughing my ass off and I didn't even know what was loading.

 

[best4x4]

Yep a proud Texan here!

 

[jastutte]

i've done this both ways. much easier to remove the coil packs. two bolts if i recall.

 

[fishEH]

i've done this both ways. much easier to remove the coil packs. two bolts if i recall.

4. Actually they're studs. About half the time you get the nut off, the other half the whole stud comes out. The hardest part is getting the nut threaded on again because you definitely won't get your fingers in there.

 

[Tugela]

Project update. I tried the contortion approach and managed to reach the driver's side front O2 sensor multiplug without removing the coil. That took all of a minute.

Then I found out that I couldn't free the passenger side O2 sensor from the Y-pipe. Great. This again. I stopped there, not wanting to fuck up the hardware like I did on the driver's side downstream one a couple months back. So my truck has 3 new sensors out of 4. That will have to do for now.

 

[best4x4]

Told ya it wasn't a big deal!

 

[discostew]

Good call on not ripping that seized sensor out of that pipe.

There fixed that