Hey Vortec Guys! / Sierra pickup / Suburban / Yukon etc - Finally has Index!

[rayra]

From what I've read it seems the vent valve is just commanded closed whenever the key is on and the computer just periodically commands both purge and vent valves open while the engine is running to suck the VOCs out of the canister.


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ate: May 21, 2013 Bulletin Number: 13D-070
Subject: ACDelco Spark Plugs 41-110 and 41-962 - Application Update
Description
ACDelco announces that 2006 and older, as well as some 2007, spark plug service applications
covered by the iridium spark plug 41-110 have moved to the platinum plug 41-962. For the
older model years, GM used a double platinum spark plug in production, and these older
applications are to be serviced with the double platinum plug 41-962. 2007 and newer
applications used iridium plugs in production and service requirements will remain assigned to
the iridium plug 41-110. Both plugs meet original equipment specifications for the applications
designated. Catalog changes for the Epicor and WHI systems will be updated in the June
release 2013. ACDelco recommends you begin adjusting your stocking requirements for the
41-962 in preparation of the upcoming catalog updates. The estimated sales volume split
between the two spark plugs is 50/50 based on these application changes and vehicles in your
markets.
Effective Date
Immediately

General Information
Reference bulletin attachment for year, make and model applications for each of these
ACDelco spark plugs. Please refer to Electronic Catalog Provider for complete application
information.
These plugs fall into the family pricing matrix for double platinum and iridium plugs. The 41-
962 will be less expensive for older applications and will keep ACDelco competitive in the
IAM.
For these plug applications, there will only be one plug per application.

http://acdelcoadvantage.saepio.com/LWSe ... 3D-070.pdf

 

[rayra]

psoted the above service notice / change as I was trying to find the right gap for the new plugs I've had sitting around for a couple months. I was expecting the evap valves this morning, so I got busy doing other stuff, figuring to roll right on with the valves when they arrived.
I pulled the new plugs out (41-962, platinum) - everything says 'no adjustment required, pre-set gap, just put them in, don't mess with them might damage them' - and almost all their cathodes were bent to crap.

The individual, 4-pack, and rockauto shipping box are pristine, no sign of abuse. I only found two minor indentations on the inside surfaces of the end tabs of the individual boxes. This horrific crap was MADE that way. Going to take some more pictures of the packaging and send it all off to Delco, maybe somebody will give a damn.
Anyway, I measured their damage, only 2 of 8 were in spec, at .040" So I carefully re-gapped everything before installing them.


The missus got all her service done at the dealer during her (extended) 100,000mi warranty period. We could find no indication that the plugs were ever changed. IIRC they ought to have been as part of a 100,000mi service. So I found what I expected when I pulled her old plugs, 41-110 iridium plugs. And I have to say they were in great - even amazing - condition for 180k+ mi. They just had some light ash, which is as good as you can hope for and a testament to how well these motors do, when everything is working properly. even with the earlier oil ingestion issue, they're very clean, nor was there any built up carbon on the chamber-exposed threads. Once they were broken loose they came right out.
Don't know how I managed to break #1, other than it was awkward getting my tool combo clear of the alternator / battery cable red junction box.
The plug tips themselves were for all intents completely unworn. Miracle of heavy metals, I guess. These plugs probably would have worked fine for another 12 years / useful life of the vehicle.

Also grabbed a pic of the serpentine belt tensioner. Put a fresh belt on it not long ago. The only spec is that the alignment mark on the arm (where pulley / belt is) remain between the outermost of the three marks on the tensioner body / mount. This picture is about as tight as things get. As the belt slackens the arm indicator will migrate to the left, betwen the reference marks.

The valves showed up after 1pm, at which point I was packing it in. Too hot, plugs were done. So I'll hit it again early tomorrow morning. I did poke at them a bit, air does pass thru the vent valve when not energized / off the vehicle. Air does NOT pass thru the purge valve, when not energized / off the vehicle. So it seems the system is cut off normally then both the purge and vent are triggered to open at the same time.

Poked around underneath, the '05 Tahoe has the canister and vent valve under the cargo area, directly above the yoke on the rear differential. My attack plan is to disconnect both valves, and the lines at the canister. Then blow out both the purge line and the vent line, blow the canister out in both directions and install the new valves and close it all up. Shouldn't take more than 90mins, even at old man pace.

 

[fl0w3n]

Anyone got some ideas of what to check to help smooth out the idle? I wouldn't necessarily describe it as rough, but it'll just have the odd "shake" that kind of rocks the body. Kinda can just feel it through out the truck.

I've cleaned the MAF which looked fine to start. New plugs. Oil change. New fuel filter. Checked for vacuum leaks using some brake clean around the intake area. Only thing I haven't done is anything with injectors.

 

[Hillbilly Heaven]

I wouldn't worry too much about which plugs the dealer put in it at service time if they even did. They probably had a shelf full of those plugs and rather than deal with trying to send them back just used them till they ran out.

Looking at the ground strap as best I can with a computer screen it does look like the heat range was dead on the money with all of them but #3. Why is #3 so different as in it looks HOT!

 

[Stryder106]

Interesting on the new plugs Rayra - I purchased those same plugs and they were all gapped at .043 right out of the box. Yours must have come out of the factory on the Friday before Memorial Day at about 3:30pm.

 

[rayra]

For those still battling the vortec pcv problem.....

Moroso now makes a catch can kit for our 99-13 GM trucks.

http://www.shopmoroso.com/eb/catalo...og.productgroup.&expand=true&menuId=main.menu

I've seen a few folks online (and I think AA1PER?, here) mount and plumb an air compressor oil separator on the firewall adjacent to and above the EGR port. Seems to work.

 

[rayra]

Anyone got some ideas of what to check to help smooth out the idle? I wouldn't necessarily describe it as rough, but it'll just have the odd "shake" that kind of rocks the body. Kinda can just feel it through out the truck.

I've cleaned the MAF which looked fine to start. New plugs. Oil change. New fuel filter. Checked for vacuum leaks using some brake clean around the intake area. Only thing I haven't done is anything with injectors.

Idle Air Solenoid. Driver side of the throttle body. Spraying 'safe' throttle cleaner just pushes the sludge back into the Idle Air solenoid and binds it up. That solenoid / plunger is how the comp controls the idle. Come small bolts, take it out, clean it and the orifice really well. Check also for any air leaks between your MAF and cylinders. Intake manifold gaskets?

 

[rayra]

I wouldn't worry too much about which plugs the dealer put in it at service time if they even did. They probably had a shelf full of those plugs and rather than deal with trying to send them back just used them till they ran out.

Looking at the ground strap as best I can with a computer screen it does look like the heat range was dead on the money with all of them but #3. Why is #3 so different as in it looks HOT!

Yes, it does. I was looking at that. These motors often develop sticking lifters, typically #1 or #3. This motor has had that problem, 'solved' with some solvent flush. But very possible that lifter is still sticking or lagging, resulting in a partial lift, resulting in incomplete scavenging on the exhaust cycle. About the only thing I can think of that would make just that cylinder look like that. No codes. If it was a clogging catalytic (all original), they'd all look alike on that bank. Can't think what else it might be. I'll check the gaps on them, just out of cuirousity. If it is over that too would make it run hotter, wouldn't it?


eta taking another look at the plugs at my desk. The #3 doesn't look anywhere near as it did in that pic. Has some tan residue that still falls in the 'normal' range on all the color plates. Although it is the only one that looks like that and all the rest look the same as each other.
If I'm googling right, these 41-110 plugs have an iridium anode (fine pointy tip) and a less pronounced platinum raised pad on the cathode. The cathode pads are almost gone and there's clear sign of arcing along the edges of the cathode arm facing the anode. Don't know if they are supposed to do that or not, a la a 'split fire' plug. I don't think they are, might be a byproduct of the platinum being worn down (shrug).
More concerning is that none of them gauge at more than .028" Seems they were gapped quite close and far closer than I would expect.

 

[Hillbilly Heaven]

Usually what will cause a hotter cylinder would be a lean fuel system or ignition timing. We can throw ignition timing out as it is not going to change more than a couple of degrees cylinder to cylinder. My bet is a sticky real dirty injector or the tiny screen in the injector.
Going to pass your plug pic on to some LS tuners and see if they agree. I believe mixture is trimmed bank to bank. I don't think the GM ECU is powerful enough to detect a lean or rich cylinder based on crank, cam, and O2 sensor.

 

[rayra]

Interesting on the new plugs Rayra - I purchased those same plugs and they were all gapped at .043 right out of the box. Yours must have come out of the factory on the Friday before Memorial Day at about 3:30pm.

yep. I'm guessing these are stuffed by hand and somebody wasn't happy in their work that day. 6 of 8, two separate 4-packs affected. And likely packed in the same case.
The individual plug and 4-pack end flaps have the plug code 41-962. The 4-pack also has the 8-digit GM inventory number 19299585. The side tabs of each box have different 7-digit numbers. That might just be stock numbers of the boxes themselves. There no 'inspected by' or QC codes I can see. Just an anonymous factory worker.

 

[Hillbilly Heaven]

Ok this is weird two totally unrelated post get answered with the same answer. My LS expert tells me he doubts it is a dirty injector but could be. 9 out of 10 times it is intake gasket. It will not leak enough to show DTC misfire but get this it will show a slight ROUGH IDLE.

 

[rayra]

Usually what will cause a hotter cylinder would be a lean fuel system or ignition timing. We can throw ignition timing out as it is not going to change more than a couple of degrees cylinder to cylinder. My bet is a sticky real dirty injector or the tiny screen in the injector.
Going to pass your plug pic on to some LS tuners and see if they agree. I believe mixture is trimmed bank to bank. I don't think the GM ECU is powerful enough to detect a lean or rich cylinder based on crank, cam, and O2 sensor.

Thanks, be interested to hear what they think. Did an intake manifold gasket and knock sensors on this vehicle not long ago. Cleaned the business end of the injectors then, didn't see anything obvious in the 'cleaned' spray patterns in the filthy ports. Don't recall running any injector cleaner additives in the Tahoe, but did in my Sub.
The 'coincidence' with the lifter issue still has me favoring that idea.

/there are no coincidences in internal combustion engines

All in all I still have express my favorable impression of these engines. I don't even consider this string of stuff as 'problems'. Not measured against old-school SBC motors of the 70s and 80s. For my Vortecs, I'd just call this 'middle aged'. Niggling stuff, in their second hundred thousand miles. I'm just happy they hold up so well, compared to earlier generation motors.

 

[Stryder106]

Will spraying carb cleaner around the intake detect a leak by the idle increasing or will the computer instantly detect that and adjust it down?

 

[Stryder106]

I just had to have a new (January) knock sensor replaced as it was defective. The good thing is it was under warranty because I paid to have them replaced before as I didn't have the time to do it myself.

 

[rayra]

Ok this is weird two totally unrelated post get answered with the same answer. My LS expert tells me he doubts it is a dirty injector but could be. 9 out of 10 times it is intake gasket. It will not leak enough to show DTC misfire but get this it will show a slight ROUGH IDLE.

It's possible. Got a little bit of a shudder at idle, but RPMs seem steady. OR are changing too rapidly to be reflected in the dash needle. Best I can figure it's been ~~18k mi since I did the intake manifold work at the start of this topic. I'll check torque on the manifold bolts tomorrow morning while I'm farting around with the purge valve. Shudder could also be a degraded balancer. At 180,000 mi I'm well outside my personal experience with these motors. Starting to worry about wheel bearings and CV joints, too.

That's in no small part why I started this topic, to both relay info and possibly learn some. Good community of folks wheelin' these vehicles, wtih high mileage. If there are any faults, they'll show up here.


Delco OEM harmonic balancer is $68 via rockauto