From Bronco to Burb - new to me 2002 Z71 Suburban

[FW_Z71Burb]

Howdy -
Thanks for having me and I look forward to learning from you all and hopefully contribute at some point..

I’ll try to keep it short but probably fail

Daily’d a 93 Bronco for 2 years, she was a needy old Ford and our family kept on growing (now 4 boys), wife said the Bronco has got to go!

When thinking about its replacement, I remembered back to my childhood and our family adventure rig, a Black 2001 Z71 Suburban.. 230k miles, tons of towing and trips to the mountains, and simple maintenance (water pump is the only thing I know of), so I started looking…

Picked up this single owner 2002 140k miles on Father’s Day; flew out in the morning on a one way ticket and drove it home 4 hours that afternoon



L59 and 3.73 gears, original window sticker is a score!



New leather on the seats done 2 years ago by the previous owner:


Work already done
- Pathfinder A/T stock size
- AC delco fuel pump, filter, pressure regulator
- air filters
- oil change
- AC tensioner pulley / belt

She needs:
- clay bar and detail / wax to get the west Texas off of her
- brake job
- leaking oil (bout half a quart 2500 miles in)

Found out she needs above 87 octane to not trigger the knock sensor code which would come and go. Two tanks of premium and no CEL. Should I try mid grade or E85 next? $2.07 / gallon for E85

Goals:
Hoping she stays in the family a long time.. would love to powdercoat or CeraKote those snowflake wheels black at some point, like below. Anyone done that with success?

[not mine, black wheel reference]

 

[stutaeng]

Welcome to the forum!

Wow! That's an incredibly clean truck! Congratulations and looking forward to the updates

 

[4silverado]

Welcome from Kentucky. Looks good. I’ve managed to strip the clear coat off the Sierra wheels and was hoping to get them polished before winter but time is running out again

 

[FW_Z71Burb]

Welcome to the forum!

Wow! That's an incredibly clean truck! Congratulations and looking forward to the updates

Thanks Stu, I was super impressed first time I saw her in person. Front bumper is cleaner than my wife’s 18 Denali.
I washed it after my 4 hour drive home, this is her good side (drivers side has some embedded dirt down low on the door panels hope a clay bar cleans that up)

 

[FW_Z71Burb]

Welcome from Kentucky. Looks good. I’ve managed to strip the clear coat off the Sierra wheels and was hoping to get them polished before winter but time is running out again

Thank you and howdy from Texas
I got some wheel polish compound need to try, it’s not supposed to strip clear coat. Have you been sanding by hand?

 

[99Sierra2500]

That is a great looking Suburban, welcome from Indiana!

 

[FW_Z71Burb]

That is a great looking Suburban, welcome from Indiana!

Thank you! I really got lucky especially considering how rough the bronco looked, complete 180!

 

[DateNight]

Mint!

 

[FW_Z71Burb]

Mint!

Appreciate it, DateNight!

 

[ORVietVet]

Welcome to the forum from Oregon.

Good lookin' Suburban.

 

[4silverado]

Thank you and howdy from Texas
I got some wheel polish compound need to try, it’s not supposed to strip clear coat. Have you been sanding by hand?

Some. I bought the 04 Sierra wheels back around 2019 ish. I used aerosol aircraft stripper to remove the clear coat. This picture would have been just after the clear coat was removed.

Then last year started using a wire brush in a drill to remove any surface scale from one of the worst wheels (wheel corrosion started when I’d moved from North Carolina back to Kentucky where they salt the roads). Then started sanding. It is a lot of sanding. My original intent was just to get rid of the cracks / worm holes and then reclear.

 

[Tonimus]

Welcome! I love Suburbans. Nearly bought a GMT800 one myself before I got my Tahoe. I do have a '78 burb. Welcome to the club!

 

[Marky Dissod]

she needs above 87 octane to not trigger the knock sensor code which would come and go. Two tanks of premium and no CEL.
Should I try mid grade or E85 next? $2.07 / gallon for E85.

If your engine NEEDS 89 or 91 to avoid knocking, that's a sign of some kind of issue inside the combustion chamber that needs a fixing.
I'd start by removing plugs and sticking some kind of scope in the plug hole to get a look at the combustion chamber.
5.3L V8s should be able to tow ≈ 8,000 on 87 uphill on hot desert days without any knocking at all (although I always recommend 91 for hard work / play).

Before you examine the combustion chamber (maybe it just needs new plugs / wires / coil, but LOOK to see if there's more going on), here's some chemical advice:
if you use AT LEAST one-third E85 to at most two-thirds 87 octane, the effective octane is at least 91 if not higher.
Suburbans w/ 31 gal tanks need to add 10.21 gallons of 'E85' to 20.79 gallons of 87 octane gasoline, for a 91.0 octane tank.

if you use AT LEAST one-fifth E85 to at most four-fifths 87 octane, the effective octane is at least 89 if not higher.
Suburbans w/ 31 gal tanks need to add 6.21 gallons of 'E85' to 24.79 gallons of 87 octane gasoline, for a 89.0 octane tank.

If you run E10 petrol (or better), add a high-PEA (poly ether amines) fuel system cleaner like Chevron w/ Techron fuel system cleaner at 2x dosage strength.
If you run up to 1/3rd E85, you can use a high-PEA fuel system cleaner at 1x dosage strength or less.
If you run more than 1/3rd E85, only use fuel system cleaner at 1/2 dosage strength.

Previous paragraph is purely about chemical concentrations.

Only you can compare price of 87 vs price of E85 for yourself. That said, here's the cheat sheet:
If E85 is over 70% the price of 87, E85 is not worth it at that pump.
If E85 is NO MORE THAN 70% the price of E85, BUY IT NOW ALREADY.

 

[FW_Z71Burb]

Welcome! I love Suburbans. Nearly bought a GMT800 one myself before I got my Tahoe. I do have a '78 burb. Welcome to the club!

Thanks for letting me join this forum, seems like the best one after viewing a few GM forums and initial engagement. I had a great experience on the bronco forum (fullsizebronco.com) and excited to be a part of this one. I see you have an 06 Tahoe, I was second guessing my decision to buy an early model GMT800 seeing the later models have some interior updates and other updates but what's the general consensus between early and late model GMT800?? (knowing they're all great overall!)

 

[FW_Z71Burb]

If your engine NEEDS 89 or 91 to avoid knocking, that's a sign of some kind of issue inside the combustion chamber that needs a fixing.
I'd start by removing plugs and sticking some kind of scope in the plug hole to get a look at the combustion chamber.
5.3L V8s should be able to tow ≈ 8,000 on 87 uphill on hot desert days without any knocking at all (although I always recommend 91 for hard work / play).

Before you examine the combustion chamber (maybe it just needs new plugs / wires / coil, but LOOK to see if there's more going on), here's some chemical advice:
if you use AT LEAST one-third E85 to at most two-thirds 87 octane, the effective octane is at least 91 if not higher.
Suburbans w/ 31 gal tanks need to add 10.21 gallons of 'E85' to 20.79 gallons of 87 octane gasoline, for a 91.0 octane tank.

if you use AT LEAST one-fifth E85 to at most four-fifths 87 octane, the effective octane is at least 89 if not higher.
Suburbans w/ 31 gal tanks need to add 6.21 gallons of 'E85' to 24.79 gallons of 87 octane gasoline, for a 89.0 octane tank.

If you run E10 petrol (or better), add a high-PEA (poly ether amines) fuel system cleaner like Chevron w/ Techron fuel system cleaner at 2x dosage strength.
If you run up to 1/3rd E85, you can use a high-PEA fuel system cleaner at 1x dosage strength or less.
If you run more than 1/3rd E85, only use fuel system cleaner at 1/2 dosage strength.

Previous paragraph is purely about chemical concentrations.

Only you can compare price of 87 vs price of E85 for yourself. That said, here's the cheat sheet:
If E85 is over 70% the price of 87, E85 is not worth it at that pump.
If E85 is NO MORE THAN 70% the price of E85, BUY IT NOW ALREADY.

WOW, thank you for this response on my engine knock / fuel octane topic and all the helpful information.. it's been the biggest source of heartburn since purchasing it.
to expand on it, the code it threw was P0332. CEL light would come and go.
on cold start, it will knock for about 4-5 seconds and go away. I havent located the source of the knock. no other pinging or knocking once she's warm and drives great. I was hoping to have the plugs and cylinders checked on the next oil change to see if there's anything that can be found. I have no real maintenance history so don't know how old the plugs are, but judging by how the owner cared I have to assume they were changed at around 100k miles according to the maintenance schedule.

 

[FW_Z71Burb]

Some. I bought the 04 Sierra wheels back around 2019 ish. I used aerosol aircraft stripper to remove the clear coat. This picture would have been just after the clear coat was removed.
View attachment 4342
Then last year started using a wire brush in a drill to remove any surface scale from one of the worst wheels (wheel corrosion started when I’d moved from North Carolina back to Kentucky where they salt the roads). Then started sanding. It is a lot of sanding. My original intent was just to get rid of the cracks / worm holes and then reclear.

thanks for the info, they look great! good luck with the rest of the project... can't imagine how much sanding it takes to get them looking good!

 

[ORVietVet]

Thanks for letting me join this forum, seems like the best one after viewing a few GM forums and initial engagement. I had a great experience on the bronco forum (fullsizebronco.com) and excited to be a part of this one. I see you have an 06 Tahoe, I was second guessing my decision to buy an early model GMT800 seeing the later models have some interior updates and other updates but what's the general consensus between early and late model GMT800?? (knowing they're all great overall!)

I have a 2005 Tahoe Z71 and at one time owned a 2002 Tahoe LS. IMO, after being in shops for 40+ years and seeing a lot of different models and gens of the Tahoe/Yukon/Suburbans, the GMT800 wins hands down as far as reliability. I don't need much other than the most comfortable seats of any GM vehicle, GMT800, and the reliability of the rest. I just want heat/a-c/radio/air bags/power/control and great viewing. I get that with the GMT800. I have also owned pickup trucks that were GMT800's.

One weak point, that I am dealing with this morning, is the ignition switch. I have not changed one on my 2005 Z71 YET but have on the 2002 Tahoe and my girls 2002 TrailBlazer.
Easy to swap out but wish it would last longer. The original GM switch was all black and then an upgrade had a grey cover on one side. Now, GM no longer makes it. Lots of aftermarket. OE #15242754 fits my Tahoe and is a US331 in Standard. Luckily, I saw this coming and bought a Genuine GM one about a year ago.

The other electrical component that can cause problems, is the electrical junction box/connector plate at the passenger side rear, that is exposed. I have one of those too.

 

[DateNight]

The knock sensors could be getting old and giving false knock

 

[Tonimus]

As far as early and late GMT800 SUVs, I prefer the later ones because of the L59. It's the flexfuel model, but doesn't have a flex fuel sensor. Bigger injectors, steel fuel rails, doesn't care what gas you put in it. The SUVs are also non-CAN. I like the lower level of tech. Everything else is just styling. There's a decent amount of aftermarket support, so you can do a lot.

Knock sensors are a common issue. Seems to be more prevalent with guys who wash their engine bays. That's just anecdotal, though. Other stuff can also cause false knock readings. Loose heat shields, large exhaust manifold leaks, bad motor mounts. I wouldn't be surprised if a loose top cover could cause the occasional knock reading.

 

[FW_Z71Burb]

The knock sensors could be getting old and giving false knock

I also thought the same... but i do find it interesting the CEL went away during 350 miles of premium fuel and hasn't come back