Well I am gonna tackle the EGR valve and O2 sensor tomorrow. I have two questions if somone can help.

1. What do I torque the plenum bolts to when I put it back
together?

2. Does my '87 Trans Am have one O2 sensor or two? It is a
305 TPI (LB9).

Thanks if you can help.

Bill

 

AZ,

The LB9 has a single O² sensor on the left (driver's) side:



I can reach them from the top. If you're removing it tomorrow, go out right now and apply some penetrating oil to get it loose. Overnight it will have a chance to penetrate and might make all the difference in getting it off in one piece. Apply extra anti sieze compound when replacing the sensor. The replacements never come with enough. Unplug the sensor lead and thread it through a box-end wrench to break the sensor loose. There is just enough swing to get them loose that way with no damage to the hex.

As for the plenum fasteners, the runner-intake bolts are specified at 18-20 ft/lb, and upper runner-plenum bolts are 15-18 ft/lb. If you set your wrench for 18 ft/lb for everything (including the throttle body) you'll be just right. Again, clean the threads of the fasteners and apply anti sieze compound. Steel fasteners tend to sieze and heat-fuse in aluminum, as you are probably about to find out. I'd strongly suggest applying penetrating oil to all those fasteners as well, ASAP!

Another thing - Don't use a cheapo Torx bit, or you'll be starting another one of those "Oh, SHOOT! I stripped my plenum bolts..." kind of threads. Get a domestic bit instead of some Pacific rim product. Proto, Apex, Snap On, Mac, etc. all offer good quality bits. Apex is by far the best, but they are hard to find.

Clean the bolt head recesses with a small screwdriver, awl, or whatever is necessary to allow full engagement of the driver bit. I don't want to be reading another one of those posts when I return from vacation...

Good luck. It's really not that difficult. It's also a really good time to remove and clean the EGR valve base, just to prevent future problems.

 

Thanks Vader. Gonna get my hands dirty tomorrow. I'll let you know how it goes.

Bill

 

BTW - The fuel rail hold-down bolts are 18 ft/lb, too.

 

Does anybody know what size the torque bolts are on the plenum? I want to make sure I get right socket.

 

T-40. The plenum extension (trim cover) used T-15 screws. You'll also need a regular 10mm hex socket for a few of the bracket bolts, fuel rails, and throttle body.