What did you do to your NNBS GMT900 Tahoe/Yukon Today?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Joined
Apr 11, 2018
Posts
7,124
Reaction score
14,365
Location
St. Louis
That's the one thing I haven't done to this rig yet. I run 89 because I get a pre det knock on the 87. And towing the boat too. Should I still try the E85 due to this?
If your rig is Flexfuel capable, won't hurt to try. E85 is like 105-110 octane.

I've heard mine ping a bit on 93 octane when punching it when getting on the highway (have a Diablo tune on it) but it doesn't do it when running E85
 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
Posts
15,323
Reaction score
42,689
Location
SE PA
If your rig is Flexfuel capable, won't hurt to try. E85 is like 105-110 octane.

I've heard mine ping a bit on 93 octane when punching it when getting on the highway (have a Diablo tune on it) but it doesn't do it when running E85
No trying to find somebody local that actually has it...
 

RooTBeeRthe1st

Full Access Member
Joined
Jul 11, 2018
Posts
1,104
Reaction score
2,533
Freeing up the oil control ring and swapping my valve cover basically stopped my oil consumption. It was consuming a quart about 2500 miles too. It had also started smoking at start up after long drives on the interstate. I just sucked some water through the intake while revving it slightly. I took a water bottle and poked a small hole in the lid so it would spray a fine mist/stream in the intake while I had someone rev it. I did that around 150k miles.
What's the reason for a valve cover change?
 

justchecking

Supporting Member
Military
Joined
Jul 18, 2021
Posts
409
Reaction score
1,151
Location
SW Ohio
If your rig is Flexfuel capable, won't hurt to try. E85 is like 105-110 octane.

I've heard mine ping a bit on 93 octane when punching it when getting on the highway (have a Diablo tune on it) but it doesn't do it when running E85
Which Diablo tune do you have on it? I have Diablo Tow tune and am running 93 Octane. My first camper tow with tune and 93 octane will be next week in prep for Ohio turkey season.
 

pwtr02ss

Full Access Member
Joined
Apr 1, 2013
Posts
11,868
Reaction score
25,557
Location
Tennessee
What's the reason for a valve cover change?
I can't remember what year yours is but mines an 08. Somewhere around 10-11, they changed the design of the valve cover to reposition the pcv system. This helps with oil consumption. The reason for the upper engine soak/clean is to free the rings up from all the previously consumed oil. I'd bet if you did those things, you'd fix your problem
 
Joined
Apr 11, 2018
Posts
7,124
Reaction score
14,365
Location
St. Louis
Which Diablo tune do you have on it? I have Diablo Tow tune and am running 93 Octane. My first camper tow with tune and 93 octane will be next week in prep for Ohio turkey season.
The Performance tune, 93 octane.

I only run 93 or E85

I think I might have an economy tune, that's supposed to sacrifice some performance for better mileage. With these higher gas prices I might install it and try it for a couple weeks and see how it does.
 

RooTBeeRthe1st

Full Access Member
Joined
Jul 11, 2018
Posts
1,104
Reaction score
2,533
I can't remember what year yours is but mines an 08. Somewhere around 10-11, they changed the design of the valve cover to reposition the pcv system. This helps with oil consumption. The reason for the upper engine soak/clean is to free the rings up from all the previously consumed oil. I'd bet if you did those things, you'd fix your problem
I have a 14 so I suppose my valve covers are good.
My catch can doesn't collect very much...hope I have sticky rings.
 

iamdub

Full Access Member
Joined
Apr 23, 2016
Posts
20,821
Reaction score
44,950
Location
Li'l Weezyana
Freeing up the oil control ring and swapping my valve cover basically stopped my oil consumption. It was consuming a quart about 2500 miles too. It had also started smoking at start up after long drives on the interstate. I just sucked some water through the intake while revving it slightly. I took a water bottle and poked a small hole in the lid so it would spray a fine mist/stream in the intake while I had someone rev it. I did that around 150k miles.

I never knew this was one of the Avy's adventures. Cool stuff!
 

Forum statistics

Threads
132,704
Posts
1,872,865
Members
97,519
Latest member
Noel74329

Latest posts

Top