Hammer Down

I recently purchased someone else's problem and seem to be finding a new problem every day. But we're in good spirits on getting her back to where she needs to be running wise. No matter how high my blood pressure gets.

2005 GMC Yukon Denali XL - AWD - 6.0l - 122k miles

Im getting zero check engine lights with zero codes stored.

Problem #1 Evap - Can not pump gas into the vehicle, wide open is never an option. Pumping pennies at a time.
So, I did some research and replaced the Vapor canister vent solenoid, that was no good. Secondly I replaced the Vapor canister, which it was clear it was bad as all the charcoal pellets were falling out of it. After a quick swap out I tried to pump gas but only with the same results. So back to the drawing board I went. Did some more research and decided to replace the Vapor canister purge valve on the intake manifold. Now when I replaced that I noticed something shaking in the line. In the old valve was charcoal pellets! I then decided to blow out the EVAP line coming from the Vapor canister to the purge valve. After spending an hour of going back and forth getting the line completely clear of pellets which it was completely clogged. After blowing out everything, I put it all back together only to get the same results at the pump. Pennies at a time! What am I missing here? Number 2 is completely clear, is it possible that the number 3 line is clogged! I just thought about that as Im posting this.



Problem #2
HVAC - (Blower Motor) Well to put it simply, the AC/Heat blower motor only wants to work when ever it chooses to do so. Its either on or off. When it is working you can adjust everything as fan speed / Temp / Fan direction and it works as it should. So I don't think its the blower motor itself but the Blower motor resistor itself. Any idea on how to check this system without having a GM computer to pull the HVAC codes?

Problem #3
Front Differential - Howling noise coming from the front drivers side. Makes the noise from 20mph (noticeably) - 60mph when accelerating. When left off of the gas the noise will disappear and come right back as soon as any torque is being applied. Upon deceleration the noise is noticeable from 30mph - 10mph. Ive been on the under side and see no visual issues with the drive shafts or axles. I have not pulled the plug on the front differential to see if there is a surplus of metal on the magnet. Im assuming it is the carrier bearing. What other known issues are there with these side effect?

Im a believer in DIY, and Ive never rebuilt a front differential before. Ive rebuilt FWD 5spd trans, rear ends, engines, and a 4l60-e that got the better of me! Knowing I would have to purchase the kit plus some tools (bearing pullers, ect) would you say that it is doable in your garage? Or just eat the remanufactured cost and throw it in?


Problem #4
Service Ride Control - Havent looked into it yet, but its telling me to everything I start this monster up. I have looked and made sure that the connections are intact from the shocks to the compressors. When I put the key in the ON position I do not hear the pumps working at all. If you could shed some insight on this issue for me to get it taken care of, that'd be great. New shocks with new pumps looks a bit pricey from a google search.

Problem #5
Service Tire Monitor - It does have brand new tires on it, and after reading it up in the owners manual, I found the way to re-program the system. Once I have turned the exterior lights on and off 4 times and get the double honk, I immediately either add or drain air from the tire for it to change pressure for 30 seconds and the computer never acknowledges it. I should be hearing that honk after atleast 15 seconds from what the book says. I have tried this many times on the front drivers tire with no success in that confirming honk. I am once again assuming that the TPMS is gone bad. And that will be a trip to the tire shop just to get all 4 new ones installed? Any way to test these?

Thats all of it so far..
John

henryt26

Problem #1: Have you attempted to clear the line that vents from the canister and runs up parallel to the filer neck? That's the usual culprit. Once the tank begins to build pressure during fill-up, it stops the pump because of backpressure. (should be a rubber hose roughly 1/4 -3/8 thick.)

Problem #2: Try a climate control calibration. (I don't remember off the top of my head if it was this model I performed it on so don't quote me on it)

Problem #3: Only thing I can suggest is double/triple checking the hub bearings.

Problem #4: Typical culprit is a failed compressor or you will get codes for failed vent valve/flap. You can purchase a re-man compressor and transfer over the drier if its still in good condition which saves you about $70 (the compressor comes with a drier service kit which is new silica balls, filters, and seals) .I've replaced many compressors on escalade, suburbans, yukons, etc but again scan it for codes if you can.

Problem #5: Continue with the re-learn procedure even though one wheel doesn't chirp. The process is learning in the tire position relative to the car so if left front doesn't chirp go on to right front and it will think that's the left front when it chirps. (This will give you a general idea of how many sensors are dead). If you are capable of popping the bead on the tire you can replace the sensors yourself. Go out to any parts store and purchase the VDO Redi-sensors. They follow the oem relearn procedure and don't require cloning.

euthorus

Just to add my .02

#1 - any chance there is something that should not be in the bottom of the tank ?

#3 - are you certain it's not one of the brake components scraping on the rotor/hub/rim ? These Yukons can backout their caliper bracket bolts if they were not zealously torqued / loctited.

#4 - put 12 Volts directly to the compressor if it doesnt turn on it is fried.

#5 - Amazon sells those sensors for around $40 last time I got them and using the radio vs the magnet to wake them up is a world of difference.