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

[Electrickian]

Looks good to me. What plastic weld did you use?

I sacrificed a soldering iron tip to use only for plastic (they're almost useless for soldering metal after that) and cut my own "stitches" from scrap pieces of aluminum sheet. And it works best to use the same plastic, but not necessary. I've seen some plastic welding kits online, but I'm doing fine as is

 

[Fless]

I sacrificed a soldering iron tip to use only for plastic (they're almost useless for soldering metal after that) and cut my own "stitches" from scrap pieces of aluminum sheet. And it works best to use the same plastic, but not necessary. I've seen some plastic welding kits online, but I'm doing fine as is

I have a couple of Weller soldering guns and use one of the smoothing tips for plastic.

 

[mikez71]

Installed Amazon A-premium brand RR window regulator. $56 shipped with prime.
Ordered it wednesday, it arrived thursday night.
Easy install and bolted in perfectly.

However, a little crickling noise when window gets near bottom.
Sounds like cable rotating on itself and the individual strands rubbing against other strands.
Harder to hear with door panel on and it seems to be getting better..?

I don't see what broke in my old one, but the cable got wound funny..
Only thing I saw inside the door bottom was a few tiny pieces of white plastic.

Unplugged stereo temporarily. Sweet silence!
I ordered some stereo plugs from ebay so I can make an adapter to split the rear signals into front..

Also my rear heat works now! So hopefully a coolant bleed is why my coolant level dropped a little..

I kept worrying it might have a blown HG, because I see water in tailpipe after startup..
It makes a 6" round wet spot on concrete after I rev it, but doesn't smell like coolant when I rub it on my fingertip.
After driving around a few blocks it's all dry..Hopefully just the larger 6.0 exhaust setup.
Two large downpipes don't merge for a few feet, and also the cat's are further back, not right under the manifold? idk...

 

[mountie]

Installed Amazon A-premium brand RR window regulator. $56 shipped with prime.
Ordered it wednesday, it arrived thursday night.
Easy install and bolted in perfectly.
View attachment 482806
However, a little crickling noise when window gets near bottom.
Sounds like cable rotating on itself and the individual strands rubbing against other strands.
Harder to hear with door panel on and it seems to be getting better..?

I don't see what broke in my old one, but the cable got wound funny..
Only thing I saw inside the door bottom was a few tiny pieces of white plastic.

Unplugged stereo temporarily. Sweet silence!
I ordered some stereo plugs from ebay so I can make an adapter to split the rear signals into front..

Also my rear heat works now! So hopefully a coolant bleed is why my coolant level dropped a little..

I kept worrying it might have a blown HG, because I see water in tailpipe after startup..
It makes a 6" round wet spot on concrete after I rev it, but doesn't smell like coolant when I rub it on my fingertip.
After driving around a few blocks it's all dry..Hopefully just the larger 6.0 exhaust setup.
Two large downpipes don't merge for a few feet, and also the cat's are further back, not right under the manifold? idk...

In certain weather, my 5.3 drips a 6” puddle… due to simple condensation. But, not often.

 

[SpareParts]

They all drip a little when starting cold. One of the by products of burning gasoline is water and with a cold exhaust it can condense before reaching the end on the pipe.

 

[Electrickian]

Where's the system that takes the exhaust water condensation and circulates it back into the coolant or wiper fluid reservoir?

 

[mikez71]

I have this weird feeling GM designed the factory exhaust like they did was for sound, emissions, and so it won't do that.

Won't do what?
The downpipes look fairly large to me, I'll measure and take pics tomorrow..
It sounds a little burbly compared to my 5.3..

Drove about 10 miles today..
First the HVAC was stuck on heat! It could be I didn't plug the HVAC connector in firmly..
(the plug was 90% inserted, because I plan to take it out again.. )
After stopping somewhere, pushing on the connector (no significant movement).. the HVAC blew cold again!
No HVAC codes..

THEN, about halfway through the drive, the check engine light came on!

P0101, MAF sensor.. failed/passed.. Hopefully an easier fix...
Drives fine, idles smooth, no hesitation and power seems good.
The inspection monitors for O2 and cat completed, but evap has not completed yet.
I reset the P0101 code...Probably shouldn't have, there may have been freeze frame data.. Oh well..

Guess tomorrow I'll inspect intake boot, vacuum hoses, wiring..
Maybe buy a can of MAF cleaner.. clean throttle body..
I can datalog MAF output, some guidelines on what to look for on charm.li
Air filter seemed OK.. (backside was still white..I'll check frontside tomorrow)
Last time the fuel trims were even & low, so hopefully not an intake gasket leak..

I wonder if the amazon oil filler could be leaking.. I definitely hear it leak when pushing it sideways.. That and an oil change are the only things done to it lately..

Praying it's not a partially clogged cat, which shows up in searches as a less common fault..

Other suggestions?

 

[mikez71]

Removed the amazon 'YCUPONE' oil filler to return. I can tell you YNOTCUPONE!
Finally I compared O-rings..
Original on right.. Amazon one is a little smaller & thinner..

Couldn't find my calipers, original on left.. about 2mm smaller diameter!

I don't know if this caused my P0101 code, but I don't want it on my engine either way.
Major leak if you deflect the filler with your finger, and the O-ring material *seems* like it would harden with engine heat.
At least I got to look under one valve cover..

Spent a little time with my friend Lacquer Thinner...(gasket cleaned separately..)

Now using oil cap direct on cover as @TheAutumnWind mentioned..
I did nothing else, so I will eventually find out if the P0101 code comes back or not, and if YCUPONE was to blame.

 

[mikez71]

Exhaust pics, downtube is ~2.75". Cats are a ways from the manifold.. Left bank cat...

Right bank cat.

 

[mikez71]

Datalogged some issues.. So far the MAF readings look ok, P0101 hasn't popped up, yet?
BUT my long term fuel trims max out (25%!) when I get on the gas.!!
Idle looks fine, but just driving around LTFT goes to 20%.. STFT can vary..
At WOT (88% TPS) my LTFT is 25% and STFT 15%!!

Guessing low fuel pressure and/or vacuum leak?
O2 sensors output seems to keep oscillating..
ALSO getting upto 7+ degrees of knock retard in 2nd gear at least...

Will try to slap a fuel guage on tomorrow, tired of working on this thing..
New problems EVERY day!! My head hurts...

 

[strutaeng]

I helped my nephew diagnose this overheating once o. His 4.3 S10.

At idle everything "seemed" okay on the live data. So went for a spin and literally 2 blocks over, gas pedal to the floor, was going like 15 mph, temperature rising and IDK what else.

Somehow we figured out it was catalytic converters clogged. He cut them off and truck ran great. I think he's still driving it like that, about 7 years later. Lol

 

[mikez71]

That would be a big headache for me if it's the cats!
So far my ECT has gotten upto 210, driving about 5 miles in town..
I've hit 60mph and power doesn't feel bad despite nearly 8 deg of knock retard.. so fingers crossed... again..

Ordered a cheap Amazon fuel pressure tester.. will be here by the AM..
Will test it's accuracy against my '12 Tahoe since that can read fuel pressure..

 

[Scottydoggs]

Datalogged some issues.. So far the MAF readings look ok, P0101 hasn't popped up, yet?
BUT my long term fuel trims max out (25%!) when I get on the gas.!!
Idle looks fine, but just driving around LTFT goes to 20%.. STFT can vary..
At WOT (88% TPS) my LTFT is 25% and STFT 15%!!

Guessing low fuel pressure and/or vacuum leak?
O2 sensors output seems to keep oscillating..
ALSO getting upto 7+ degrees of knock retard in 2nd gear at least...

View attachment 482917

Will try to slap a fuel guage on tomorrow, tired of working on this thing..
New problems EVERY day!! My head hurts...

has this been tuned? you got 7.9 degrees of knock retard (KR) every degree of KR, pulls 2 degrees of timing, so your down 16 degrees of timing, plus 18 is 34 degrees, and likely way to much timing, ( to much timing can cause kr)

 

[mikez71]

No tune that I know of, and truck looks completely stock so highly doubt it...Truck was possibly sitting for a year, but I've added a little fresh gas also.

Had a P0101 MAF code popup yesterday.. Will look a little closer at my log later, but there is a little squiggle you can see in the graph above..

 

[Scottydoggs]

No tune that I know of, and truck looks completely stock so highly doubt it...Truck was possibly sitting for a year, but I've added a little fresh gas also.

Had a P0101 MAF code popup yesterday.. Will look a little closer at my log later, but there is a little squiggle you can see in the graph above..

for that code you can try cleaning the maf, and inspect the pig tail wires for damage. kr maybe shift related, it looks to come on just before and after the 1-2 shift.

being you got a hpt, do a crank learn. dont think you need credits or anything to do one, iirc its in the scanner. that gets the cam and crank sensors in sync and can really clean up how a engine runs.

 

[mikez71]

Thanks for the suggestions!
The MAF wiring *looks* solid..
I don't know how this drives when running properly, but don't notice any idle issues or bad hesitation etc.

Tomorow I will check fuel pressure, do a crank relearn, spray the MAF cleaner, inspect intake boot, and maybe unplug the battery to clear fuel trims.
A new MAF looks reasonably priced, but hoping I can spot some clues before firing the parts cannon...

 

[mikez71]

Amazon pressure guage varies depending on guage angle. Seemed to be 52psi key on. Spec calls for 55-62psi. Idling engine, fuel pressure seemed to hit 55psi..
Did not test while driving because hose is short and guage varies too much.

No intake boot cracks, cleaned MAF.
Battery terminal corrosion, disassembled and cleaned.

Tried crank relearn, but the HPTuners software isn't clear if I should be revving it while the message is up, or after you hit 'OK'. Tried it both ways, but forgot to get engine upto temp! Might try again later with Tech2...

So far, no noticeable change. LTFT increases instantly to 5.5 once you rev it any amount. Driving I got it up to 22.7.. and that's after unplugging battery, so it may increase over time..

Still drives decent, still get 7.1 degrees of knock retard in 2nd and gear..
MAF log looks a little jaggy(below), but seems smooth at lower RPMs...

There are 3 total missing exhaust manfold bolts, but I don't feel like it's huge leak.
I don't hear loud exhaust ticking anyhow... What am I missing?

 

[Fless]

If I'm reading this right, the MAF is way over-reporting. It should nearly match the engine displacement (6.0?) in g/sec at hot idle. From the table and the graph, it's reporting 10.1 on the table at 635 rpm, and 12.15 at 657 rpm in the graph.

 

[SpareParts]

Idle is a little high i think so a higher reading would be normal but how much i don't know.
I usually look for a MAF to read around the same as engine displacement at 550 rpm.
Engine is not up to temp either and that will cause it to not read what you want to see either.

 

[mikez71]

Thanks Fless and Spare! I was going by this..

Warmed up idle I am reading 8g/sec. (within 3-10)
WOT at end of 1st gear I hit 213-226g/sec..(above 170)
My 5.3 is around 6.5g/sec warm idle in Drive, but is 4.8g/sec in Park...

Looking at my logs, it seems to show me in 1st or 2nd gear when I'm in Park..
And it shows 2nd gear on startup and shutdown..(But 2nd gear still shows 2nd) Hmm.
My crank relearn log shows me in 2nd gear, whole time I was in Park!