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

[j91z28d1]

No, I don't have a concensous on our fuel pumps but several of us have been reporting our fuel pump trims to compare their conditions to one another. Mine used to be rock solid at 43.5 psi all the time, even at WOT. Then one day it slipped a psi while accelerating and came back up and now waffles around while driving but only 2 psi.

The trim is in the 1.5s now and there is a new one sitting on my shelf in the garage. Soon as the weather cools off it's going to get changed before we head west to Monument Valley.

Will also be changing out all of my u-joints too. Almost 190K and nothing wrong but now have the press and tools do it at home properly and don't want any issues on that 5K mile trip.

are you seeing the psi moving around on a scanner or a real. gauge? are all these the returnless type? so much stuff is different on these hybrids, I'm always left wondering what's normal and what's not haha. I should probably take a look at mine


my experience with my 96 tahoe and my old camaro days u joints is replacing never worked out 100%. I would buy new drive shafts from gm (or junkyard for the camaros) or I always had a vibration at high speeds even when a drive shaft shop took me back and showed me their balancer said it was fine.

 

[swathdiver]

are you seeing the psi moving around on a scanner or a real. gauge? are all these the returnless type? so much stuff is different on these hybrids, I'm always left wondering what's normal and what's not haha. I should probably take a look at mine


my experience with my 96 tahoe and my old camaro days u joints is replacing never worked out 100%. I would buy new drive shafts from gm (or junkyard for the camaros) or I always had a vibration at high speeds even when a drive shaft shop took me back and showed me their balancer said it was fine.

I use the data from the Torque Pro app on my phone or the Tech-2 for the fuel pressure. I have had my Tech-2 connected to two GMT900 hybrids and they also ran at 43.5 psi like mine.

Haven't changed a u-joint in decades as we'd been driving FWD minivans until I bought the truck. Never had a problem back then.

A common problem is that folks will buy a Spicer 1350 and jam the retainers into place which causes binding issues. We run AAM 1355 joints which Spicer also carries but too many get the wrong parts and have issues.

I'll try to remember to photograph or video us changing them and what to look out for when we do it.

 

[Doubeleive]

are you seeing the psi moving around on a scanner or a real. gauge? are all these the returnless type? so much stuff is different on these hybrids, I'm always left wondering what's normal and what's not haha. I should probably take a look at mine


my experience with my 96 tahoe and my old camaro days u joints is replacing never worked out 100%. I would buy new drive shafts from gm (or junkyard for the camaros) or I always had a vibration at high speeds even when a drive shaft shop took me back and showed me their balancer said it was fine.

return line systems were done away with years ago probably around 2002/2003 as far as I know

 

[Life_Of_TC]

It's white powder. Everything works better with the white powder... for a few months anyway.

Yeah then you gotta work a 12 step program after

 

[gooffeyguy]

Getting ready for a camping trip with the 2012 towing mule later this week and thought I’d change the oil. Talk about pulling a string. Noticed that my oil cooler lines have gone from a seep to a steady, slow drip. Wait… is that an orange stain below my drivers side motor mount? Fuuuuuuck.

Buttoned up after the oil change and went for a drive. Strange noises coming from my left front wheel. Got home, jacked up that side and sure enough, play in the bearing. Good lord.

So I decided to get it done. Replaced the wheel hub, swapped the motor mount with the Hummer mount I’ve had waiting for this, and installed new cooler lines. All from my new parts stash. 6 hours later and it’s time for bed!

View attachment 396563
View attachment 396564
View attachment 396565

I know it's been a couple months since you did this, but I have a couple questions.

My oil lines are seeping and I have a small leak above the oil filter. I was thinking of changing these lines out when I change out the exhaust manifold bolts and gasket. I already installed the Hummer mount a couple years ago.

Did you remove the wheel well liner and do this from the side? Did you have to unbolt the front driveshaft u-joints and lower the shaft to get to the oil cooler bolts? And finally, with me already having the smaller Hummer mount, do you think I'll have to remove it for line clearance?

 

[Geotrash]

I know it's been a couple months since you did this, but I have a couple questions.

My oil lines are seeping and I have a small leak above the oil filter. I was thinking of changing these lines out when I change out the exhaust manifold bolts and gasket. I already installed the Hummer mount a couple years ago.

Did you remove the wheel well liner and do this from the side? Did you have to unbolt the front driveshaft u-joints and lower the shaft to get to the oil cooler bolts? And finally, with me already having the smaller Hummer mount, do you think I'll have to remove it for line clearance?

Yes, I removed the liner and worked from both the top, side and bottom. Couldn't have done it with the liner in, I don't think. And yes, I think you will also need to remove the motor mount temporarily to get enough clearance to maneuver the hard lines out/in. :-(

 

[j91z28d1]

return line systems were done away with years ago probably around 2002/2003 as far as I know
View attachment 403013

noticed the hybrid has to have a different rating lol. 50-75 key on because of course they do lol. why you'd need all this extra fuel pressure and oil pressure in a system designed to run the engine as little as possible.

crazy truck.. but it keeps me interested at least so far. I'll have to see if I have a fuel pressure pid on torque next time.

 

[gooffeyguy]

Yes, I removed the liner and worked from both the top, side and bottom. Couldn't have done it with the liner in, I don't think. And yes, I think you will also need to remove the motor mount temporarily to get enough clearance to maneuver the hard lines out/in. :-(

Oh, did you use OE GM replacement oil cooler lines, and did it come with the gasket? When looking on RockAuto it doesn't show or say if it does

 

[Geotrash]

Oh, did you use OE GM replacement oil cooler lines, and did it come with the gasket? When looking on RockAuto it doesn't show or say if it does

Yes, I did, and yes it does.

 

[89Suburban]

I installed drop spindles and during the process on the first side I must have been too rough and the wheel sensor must of got damaged. So I had to pull that side back apart again to install a new one and all was fine. I did the other side this weekend and was SUPER gentle with that sensor. But it still threw the code again. So I was super pissed off. I got another new one and installed that today. Ok in the driveway so far, test drive later will confirm. So super aggravating to have to dig back into both sides again after all the spindle work.

Then Saturday night it went into limp mode and got stranded 20 miles from home 10 oclok at night. I plugged my scanner in and got the P2135 code. This happened a few months ago one night too. I scanned and got that code and messed with the the plug on the throttle body and gave a couple of good slams to the throttle pedal and it went away. Until it happened again this night. Same code, did the same hail mary techniques. Fired up fine. When I went back under the hood as soon as I touched the harness plug it shut off. Gave it another "wishful wiggle" and started and ran fine. Drove home fine.

Just to clarify it only showed that one code during the initial stranding Saturday night. And I did not clear it.

Today after installing the new speed sensor I pulled the intake snorkel off to remove and check the TB sensor plug and wiring. I can not find anything wrong that stands out. I used compressed air to blow out the connection and plugged it back in tightly. The throttle body assembly was replaced around 40K miles ago with a Pep Boys unit.

When I fired it up after checking that plug all seemed fine on the dash board. I ran the scanner to clear the code and now found I have 3:

P1516
P2101
P2135

I cleared them all and will test drive tonight. Didn't look up the other codes yet because I am getting my ass kicked by this truck and everyone else and their fkng problems. So that is where I am at right now.

This hit me again last night. Had to limp home. Had to hoof it to work this morning. Gonna borrow the F-150 work truck for the weekend while I try to attack this. Plan is to replace the pedal sensor assembly and go from there.