The Unexplainable, Unresolved issue an expert LS builder and Dealership can't figure out

[AZCreeker]

The repair shop tells me its most likely due the carbon build up from the direct injection.
We will see.
if not he will also inspect injectors, and check rich/lean/emission at tail pipe.
I really hope they can figure it out, I love this truck, just want to have the smell gone.
if successful, I'll have them install a catch can, can you guys recommend the most popular option?

 

[gooffeyguy]

A bad catalytic converter/s?

 

[iamdub]

The repair shop tells me its most likely due the carbon build up from the direct injection.
We will see.
if not he will also inspect injectors, and check rich/lean/emission at tail pipe.
I really hope they can figure it out, I love this truck, just want to have the smell gone.
if successful, I'll have them install a catch can, can you guys recommend the most popular option?

All you really need with a catch can is a good baffle setup. The expensive ones are functionally no better or worse than the cheap ones, for the most part. I like the $18 one on Amazon that has recently been discussed in the "Get a catch can before any other mods" thread. Add a stainless scrubber pad and you should be good to go, especially since your GenV shouldn't be passing as much oil as many GenIVs.

 

[AZCreeker]

All you really need with a catch can is a good baffle setup. The expensive ones are functionally no better or worse than the cheap ones, for the most part. I like the $18 one on Amazon that has recently been discussed in the "Get a catch can before any other mods" thread. Add a stainless scrubber pad and you should be good to go, especially since your GenV shouldn't be passing as much oil as many GenIVs.

a 18$ dollar one sure sound better than the UPD dual ones I see for 300$

 

[iamdub]

a 18$ dollar one sure sound better than the UPD dual ones I see for 300$

The only time you may need a fancier one, such as the dual valve unit from UPR, is if you're boosted. All you're doing on an LS engine is scrubbing ("filtering") a single, one-way circuit. There are crappy catch cans that basically rely on gravity to let the oil droplets fall out of suspension. The more filtration media you have (within reason- you don't wanna choke down the flow too much), the better. I have a $100 catchcans.com one on my Tahoe that works great and even better once I added more coalescing (filtering) media (stainless scrubber pad). I saw recently where a member took it a step further and modified his to hold one or two extra scrubber pads. His modifications didn't look like they'd hamper the airflow anything significant and I'll be copying his idea one day. I bought the $18 one for my brother's truck and added the stainless pad. I don't see how it would be any less effective than my $100 one or any other one of a higher price but same design. The ONLY drawback I saw to it was that it only had a 3 ounce capacity. I consistently drain 3 ounces out of mine every 5K miles. My brother drained maybe 1/2 a teaspoon out of his at a 3K mile change. His intake is dry on the inside so his motor ('05 5.3- Gen3) just isn't passing much oil at all through the PCV system. I'd expect your Gen5 to be an improvement over my Gen4 and not pass much oil. But, there's no laws against draining the catch can between oil changes (At every fill-up? Bi-weekly? Monthly?) until you get an idea of how long you can go between drainings. You can drain it and pour the oil right back into the motor.

This is the one I got off Amazon:

https://www.amazon.com/gp/product/B07JQKHW9W/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1


And this is where/how I added the scrubber pad:

 

[Tk59194]

Here is the UPR unit. I very much liked that it came with factory hose fittings. Didn't mind spending the extra cash considering how much i paid for the vehicle.

 

[Rocket Man]

Damn direct injected engines, they seem to have had their share of issues when they first came out. Hope you get it figured out and find someone worthy of the ediblearrangements.com gift basket because those things are awesome. The fruit not the injectors.

 

[GTNator]

I confess, I didn’t read all 47 posts above, only you’re first post and recent update. I know you said you think it’s coming from the tailpipe... you also said it’s a sweet smell? To me it sounds like antifreeze or a radiator leak. If it’s dripping onto you’re exhaust it may manifest itself the way you describe. It can also make its way into you’re cabin through the vents.

If I totally off base cause I didn’t read the other post, please ignore. Good luck.


Sent from my iPhone using Tapatalk

 

[Dooba]

I bypassed my 04 Yukon’s heater core a couple months back because ethylene glycol (antifreeze) in vapor form was leaking into the cabin. It had a sweet smell to it.

I bypassed the heater core and the smell went away instantly.

I’m not saying you have a faulty heater core or anything, but I do agree that its most likely an antifreeze leak somewhere.

 

[AZCreeker]

I figured that its for sure a raw gas smell and its coming from the tail pipe.
I originally thought it was coming from around the side of the truck but I think its just the downturn tail pipe hitting the ground then going everywhere.
the reason I am sure is because if i remote start the truck, cold or already warmed up, I smell it right away putting my nose next to tail pipe.

The shop is done with my car and telling me to come see if I can still smell it.

I will update findings. If any.

 

[AZCreeker]

Here is the UPR unit. I very much liked that it came with factory hose fittings. Didn't mind spending the extra cash considering how much i paid for the vehicle.

View attachment 228681 View attachment 228682 View attachment 228685 View attachment 228686

I do like the factory hoses fittings as well, which model/ part # did you get? I see they have a few options available. Great pictures by the way thanks.

 

[Csurp]

Actually, just yesterday I was poking around Autotrader to see what pre-99's might be out there for ***** and giggles. I so badly miss my '96 two door 4WD. I wake up every morning and punch my sack for getting rid of it. Seems that finding one up to my standards in this area for a reasonable cost is doubtful. Guess most of them are just too used and old now.

They spent a bunch of money on this one.

https://inventory.davisautosports.com/vehicles/98/1996-chevrolet-suburban-2500-4wd

 

[Tk59194]

I got the most expensive unit with the dual (clean/dirty) side valves. It was pricey, but worth every penny imho. I do not believe all catch cans are created equally. After speaking with the owner and engineer over at UPR and reading through the 40+ page thread over in the GM truck forum, I decided to go with this unit. I have an 18LT tahoe and wife has a 16LT suburban. Im anxious to compare buildup on the valves in a few years. I believe mine will be clean, and hers will require walnut blasting. Just my opinion. Time will tell.

 

[RET423]

Coolant leaking into the exhaust after you shut off the engine, when you restart it you smell the Coolant as it gets pushed through the exhaust until it burns off; probably drivers side head issue.

 

[WTSHARK]

The only time you may need a fancier one, such as the dual valve unit from UPR, is if you're boosted. All you're doing on an LS engine is scrubbing ("filtering") a single, one-way circuit. There are crappy catch cans that basically rely on gravity to let the oil droplets fall out of suspension. The more filtration media you have (within reason- you don't wanna choke down the flow too much), the better. I have a $100 catchcans.com one on my Tahoe that works great and even better once I added more coalescing (filtering) media (stainless scrubber pad). I saw recently where a member took it a step further and modified his to hold one or two extra scrubber pads. His modifications didn't look like they'd hamper the airflow anything significant and I'll be copying his idea one day. I bought the $18 one for my brother's truck and added the stainless pad. I don't see how it would be any less effective than my $100 one or any other one of a higher price but same design. The ONLY drawback I saw to it was that it only had a 3 ounce capacity. I consistently drain 3 ounces out of mine every 5K miles. My brother drained maybe 1/2 a teaspoon out of his at a 3K mile change. His intake is dry on the inside so his motor ('05 5.3- Gen3) just isn't passing much oil at all through the PCV system. I'd expect your Gen5 to be an improvement over my Gen4 and not pass much oil. But, there's no laws against draining the catch can between oil changes (At every fill-up? Bi-weekly? Monthly?) until you get an idea of how long you can go between drainings. You can drain it and pour the oil right back into the motor.

This is the one I got off Amazon:

https://www.amazon.com/gp/product/B07JQKHW9W/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1


And this is where/how I added the scrubber pad:

View attachment 228670

View attachment 228671

Wow, in all my years as a cop (28+), that's the first (and only) time I've ever seen any steel/copper wool used for any "other" purpose than stuffing a crack pipe. I actually had to take a couple of screenshots and send it to a couple of my colleagues, captioning; "Look, it's NOT just for smoking rock!". Thank you for that- More importantly, the density of the ss wool, is it tightly compacted? Or would you say (as you mentioned) not so tight so as to be more restrictive. I'm fascinated by this and confess never hearing of anything like this, but then again my days of custom truck/vehicle mods are pretty much behind me and I pay to have my oil changed. Thanks for the info!

 

[iamdub]

Wow, in all my years as a cop (28+), that's the first (and only) time I've ever seen any steel/copper wool used for any "other" purpose than stuffing a crack pipe. I actually had to take a couple of screenshots and send it to a couple of my colleagues, captioning; "Look, it's NOT just for smoking rock!". Thank you for that- More importantly, the density of the ss wool, is it tightly compacted? Or would you say (as you mentioned) not so tight so as to be more restrictive. I'm fascinated by this and confess never hearing of anything like this, but then again my days of custom truck/vehicle mods are pretty much behind me and I pay to have my oil changed. Thanks for the info!

LOL

I can't believe I never thought about this! I actually lost a great job due to the owner relapsing (I never knew he had a history) and the company that him and I built and grew like a wildfire went under in a few quick months. Opened my work van one morning to find a torn up Chore Boy, spilled box of baking soda and a burnt glass pipe on the driver's seat. We found crack rocks, paraphernalia, clothing and used condoms all around the shop, warehouse and his office.

Anyway, the density of the scrubber pad (use stainless, not copper) isn't an issue. Apparently, plenty of air flows through it to keep the system happy. I've opened the drain valve with the engine running and the vacuum there feels every bit as strong as what's in the brake booster hose.

 

[Tonyrodz]

LOL

I can't believe I never thought about this! I actually lost a great job due to the owner relapsing (I never knew he had a history) and the company that him and I built and grew like a wildfire went under in a few quick months. Opened my work van one morning to find a torn up Chore Boy, spilled box of baking soda and a burnt glass pipe on the driver's seat. We found crack rocks, paraphernalia, clothing and used condoms all around the shop, warehouse and his office.

Anyway, the density of the scrubber pad (use stainless, not copper) isn't an issue. Apparently, plenty of air flows through it to keep the system happy. I've opened the drain valve with the engine running and the vacuum there feels every bit as strong as what's in the brake booster hose.

I was following you up til the used condoms lol!

 

[iamdub]

I was following you up til the used condoms lol!

Ugh. Hookers and blow... In the office, on the fab table, probably over the cold saw... Dude was a pimp and a dealer in a past life. I only knew him as a Bible-thumping family man until some narcs showed up three weeks after he went missing.

 

[91RS]

I didn't read the whole thread but is it a 4x4? If so, change the front differential fluid. Seen that cause an odd odor a few times since the vent tube is under the hood.

 

[AZCreeker]

So to revive this old Thread, here is an update for anyone interested.
I took my suburban to the GM expert independent shop.
The did not address my concern, they sold me a Direct Injection cleaning and Injectors cleaning.
Not that I mind, as I wanted to do the direct injection cleaning anyways.
This did not change any of the smell.

To recap if some of you don't want to go back to all the different pages and bogus info I was given or thought it could be, this is where I stand on this of of right now:

At every start upt, cold or fully warmed up engine: the truck rear tailpipe smells super rich.
as in raw gas strong smell.

I am taking the truck to an actual emission place who is going to hook up HP tuner or some diagnostic to look at the tables while starting it tomorrow morning

Recently, I had a 19 loaner with the 5.3 and I could have sworn that that brand new unti also does the same thing, smells really rich at startup and idling.

My particular smell stop once I get going and then stop.


Maybe its something GM designed (poorly) into the truck, my truck is all stock with no lights on the dash, everything indicate that I am running in good condition.

I will update with that shop finding.