What did you do to your NBS GMT800 Tahoe/Yukon Today?

[Walchit]

I have noticed my OP @ about 30 at idle and just over 45 psi when rolling. My rig over 260k but the pump and timing set were done before I took ownership of it about 3 years ago

When it gets to 10psi at idle you should probably quit driving it and get it figured out. Had a guy tell me mine was probably some seal at the front of the cam or something. But I haven't noticed any leaks.
I found a motor, tranny, and transfer case out of a wrecked truck that supposedly has 90k on it for 500 bucks. Thinking about going to check it out

 

[Tonyrodz]

When it gets to 10psi at idle you should probably quit driving it and get it figured out. Had a guy tell me mine was probably some seal at the front of the cam or something. But I haven't noticed any leaks.
I found a motor, tranny, and transfer case out of a wrecked truck that supposedly has 90k on it for 500 bucks. Thinking about going to check it out

Super cheap. Have you heard it running? Can you confirm the mileage? Maybe try to run a carfax with the vin number.

 

[blueinkd]

When it gets to 10psi at idle you should probably quit driving it and get it figured out. Had a guy tell me mine was probably some seal at the front of the cam or something. But I haven't noticed any leaks.
I found a motor, tranny, and transfer case out of a wrecked truck that supposedly has 90k on it for 500 bucks. Thinking about going to check it out

Will keep that in mind.

 

[mountie]

Super cheap. Have you heard it running? Can you confirm the mileage? Maybe try to run a carfax with the vin number.

Good idea, along with taking the vin # to a dealer. ( Carfax only reports what is submitted to the website) To me, carfax is only a reference.

 

[Doubeleive]

That's cutting into my non-existent budget!

you can get a 5.3l engine with free shipping for $700 on ebay all day long, your mechanic source has lost there dam mind, most yards sell these for $600-800
all you have to do is look at the 8th digit in the vin and find a matching letter engine, most common is vin T plug-n-pray.

 

[Doubeleive]

I'm pretty sure it's the other(ds) o2 sensor that's causing its current issue. Tried a few hours to remove it with no luck.View attachment 358923

did you try heat? either a torch or take it for a good fast run and a torch, drive like I do and it should come out lol

 

[Tonyrodz]

did you try heat? either a torch or take it for a good fast run and a torch, drive like I do and it should come out lol

I went to use my map gas--bought a brand new tank--and the brass nozzle was no good. I couldn't get it to stay lit. FML. That should've been my clue right there. I also had my special o2 sockets out. Didn't work either.

 

[Z-56 Hoe]

I cleaned them all up, changed cabin air filters, checked fluids, Sunday Maintenance day.

 

[Z-56 Hoe]

 

[Z-56 Hoe]

 

[Z-56 Hoe]

Oh and I test fit the new grill for the Lifted 2002 today before paint.

 

[Sam Harris]

Here’s a good book on building an LS. It has lots of info. Not sure if it’s what you need but it’s a good start. View attachment 358677

I have this book! (Haven’t read much.. )

 

[MassHoe04]

I went to use my map gas--bought a brand new tank--and the brass nozzle was no good. I couldn't get it to stay lit. FML. That should've been my clue right there. I also had my special o2 sockets out. Didn't work either.

Tips on getting old O2 sensors out...

Heat is your friend, if you have a torch. Soaking with a good penetrant, like Kroil, will also help a lot. I used old-fashioned Liquid Wrench and tapped the bung and sensor a little to try breaking the rust bond before I started wrenching...

Since the old sensor is already getting replaced... No fancy O2 sensor sockets required. Cut the wire. Get a good, proper fitting box wrench on there with a piece of pipe on there for leverage. I didn't have a pipe, so I prayed and gave the wrench a few love taps with a 3 lb. mallet. It broke loose. I use an open end wrench to tighten the new one (just the wrench...no pipe leverage/breaker bar) to "good-n-tight" or "tight enough" torque specifications.

New sensors come with anti-seize in the box, to make it easy for the next guy.

 

[NoReverseYukon]

I went to use my map gas--bought a brand new tank--and the brass nozzle was no good. I couldn't get it to stay lit. FML. That should've been my clue right there. I also had my special o2 sockets out. Didn't work either.

Those O2 sensors sure don't like you, do they Tony. Maybe a few penetrating oil/drive/cool cycles will help in loosening it up.

 

[Tonyrodz]

Tips on getting old O2 sensors out...

Heat is your friend, if you have a torch. Soaking with a good penetrant, like Kroil, will also help a lot. I used old-fashioned Liquid Wrench and tapped the bung and sensor a little to try breaking the rust bond before I started wrenching...

Since the old sensor is already getting replaced... No fancy O2 sensor sockets required. Cut the wire. Get a good, proper fitting box wrench on there with a piece of pipe on there for leverage. I didn't have a pipe, so I prayed and gave the wrench a few love taps with a 3 lb. mallet. It broke loose. I use an open end wrench to tighten the new one (just the wrench...no pipe leverage/breaker bar) to "good-n-tight" or "tight enough" torque specifications.

New sensors come with anti-seize in the box, to make it easy for the next guy.

I tried an air hammer a few times, soaked it a few times too. Trying to get it off with a socket it started to look like the bung(metal)was bending some, so that's where I just left it alone. There's also not a good angle to attack it either. So awkward. BTW--It's in the collector on a long tube header.

 

[MassHoe04]

I tried an air hammer a few times, soaked it a few times too. Trying to get it off with a socket it started to look like the bung(metal)was bending some, so that's where I just left it alone. There's also not a good angle to attack it either. So awkward. BTW--It's in the collector on a long tube header.

Understand completely. It is not unusual for even the pros in a shop to cut out the old sensor and weld in new bungs. Maybe it will break free before you get to that extreme... Fingers crossed!

 

[mountie]

I tried an air hammer a few times, soaked it a few times too. Trying to get it off with a socket it started to look like the bung(metal)was bending some, so that's where I just left it alone. There's also not a good angle to attack it either. So awkward. BTW--It's in the collector on a long tube header.

Tony....... PATIENTS ..... then take a sit on a stool..... respond to a silly forum post......

Then try again......

 

[Tonyrodz]

Those O2 sensors sure don't like you, do they Tony. Maybe a few penetrating oil/drive/cool cycles will help in loosening it up.

They hate me and the feelings are mutual!

 

[mountie]

They hate me and the feelings are mutual!

I don't remember what the stuff was, but my brother brought home from a Navy yard machine shop, a spray can of something that really loosened up a stuck bolt/ sensor.

You might try a West Marine store,,, they have some products , auto stores don't sell.

 

[Walchit]

Super cheap. Have you heard it running? Can you confirm the mileage? Maybe try to run a carfax with the vin number

I figured it probably has 300k and he's lying to me also. He takes forever to respond and it's hasn't been with a phone number or address yet so I'm not too optimistic. There is another guy with the same combo from a truck with a rusted out frame about an hour from me.

I might try this guys trick to put a red o-ring and maybe a new pump in, but I'm afraid I already drove too far on it. I really just want to know what the problem was at this point.