Black Soughty Exhaust, 05' 5.3

JRW68 · May 21, 2005

My 05' has been burning pretty rich since I got it, the tail pipe is coated with a pretty heavy black sought. I get a puff of black smoke during cold starts. But my fuel mileage is decent and I dont have a rough idle.

The truck sat on the lot for a few months before I bought it, perhaps it needs plugs and wires?

My grandfathers 04' 5.3 pipe is clean as a wistle and so is my uncles 03'. I have 5500 miles (2400 miles were from pittsburgh to dallas and back) on the truck already and it hasn't gotten any better.

It doesn't use any oil and seems to run decently, I plan to keep running it until it starts to act up.

If my tail pipe is getting this bad, the 02 sensors will surely foul in a matter of time. So far no codes or DIC indicators.

Just curious about anyone elses experiences with this?

mmmikkke · May 21, 2005

My 05' has been burning pretty rich since I got it, the tail pipe is coated with a pretty heavy black sought. I get a puff of black smoke during cold starts. But my fuel mileage is decent and I dont have a rough idle...
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Have you had this truck in to the dealer? If not, have them show you another '05 5.3 truck with equal soot build up in its tailpipe. Sounds like they'll be over a barrel if there's something that needs to be fixed, they'll have to fix it, or at least try.

Unfortunately, sometimes you have to put them over a barrel to get them to even *look* at something like this. So make sure you begin your discussion with the service manager with the "show me the soot" request.

JRW68 · May 21, 2005

I will surely take it to the dealer in due time and when I do I will surely raise hell if they act like there is nothing wrong (which they probably will do).

My main concern is that they will just reflash the ecm for lower performance. They did this with my brother, his tranny wasn't filled all the way up when he bought it and slipped pretty bad a few times. He took it back to get filled, get a record of them not filling it in the first place, and have the tranny checked out. They reflashed it to shift softer, sent him on his way, and reflashed it again when he returned for it slipping still. They never changed the fluid or anything, just kept making it shift softer to mask the problem until the warranty was up. Made me furious, he later sold the truck.

So I can see it now, my truck may need 02 sensor, plugs, wires, MAF, MAP, or whatever and because its not throwing a code, they will just reflash it for a lower output. It drive me nuts when little diagnosis is done on a vehicle. So Im gonna hold out for a bit til I figure out what exactly is wrong. My father has a snap-on scanner so I should be able to effectively diagnos it over time.

As of right now I have no adverse effects from it as far as I can tell, I get 18mpg on the interstate and as I said no rough idle or lopeing either. Thats not to say it wont start acting up or that my mpg could be better.

I just got to thinking about it, I think the county where I bought the truck has a tailpipe emission test required for inspection and the dealer I bought it off of inspected it when I bought it... Ide be interested if it would truely pass... I imagine that they just threw a sticker on it.

Maybe Ill try to get a decent picture of it to show you guys, Im pretty experienced with vehicles and high performance motors and this is clearly not normal. My 84' and 79' burn cleaner than this and neither had cats.

The dealer I bought it off of hates me with a passion, I heard they are still trying to paint that door they took off mine and replaced with one from another truck. They cant get the paint to match. No skin off my back though and I really dont care if they hate me, cant say I care for them much either.

Elwood 2000 · May 21, 2005

My 2000 has had soot in the tailpipe since day 1. Everyone else I know who has a truck with the 5.3 has soot too.

Personally, I find it strange that you know of a couple trucks that DON'T have soot in the pipes.

jwhjr · May 21, 2005

My 04 has some soot too. Runs great, no problems.

JR

mmmikkke · May 21, 2005

My 2000 has had soot in the tailpipe since day 1. Everyone else I know who has a truck with the 5.3 has soot too.

Personally, I find it strange that you know of a couple trucks that DON'T have soot in the pipes.

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That's right, kill the messenger.

That's the attitude of the dealers, too. The customer must be an idiot.

sablowme · May 21, 2005

My 04 has some soot too. Runs great, no problems.

JR

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i have a 04 seirra and it does the same i recently installed headers on it and if you think the soot is bad at the pipe you should see it inside the exaust ports in the head. if you think about it theres alot of explosion goin on in these trucks so i kinda expected it. but other than that it runs great.

but im not an expert on this i work at a dealer in the parts dept. and most of the trucks i see have this same issue.

toataly off this topic but some of you that have 99-02 new style trucks might of complaned of a tapping at idle when cold and eventuly goes away, gm said that this was because of carbon build up in the motor. and that this was normal, honestly i had an 01 silverado and used to drive about 80mph everyday, there realy shouldnt be any carbon build up...lol

Elwood 2000 · May 21, 2005

QUOTE(Elwood 2000 @ May 21 2005, 10:28 AM)

My 2000 has had soot in the tailpipe since day 1. Everyone else I know who has a truck with the 5.3 has soot too.

Personally, I find it strange that you know of a couple trucks that DON'T have soot in the pipes. confused.gif

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That's right, kill the messenger.

That's the attitude of the dealers, too. The customer must be an idiot.

I NEVER said the "customer" was an idiot! I just said that I have NEVER seen a 5.3 Silverado WITHOUT soot in the pipes! I will give you the benifit of the doubt here since you may have misread what I was saying because in type there is no tone of voice or facial expression, but ease up a bit. All I was saying is that what he describes regarding 5.3 Silverados without soot seems odd to me, that is all.

mmmikkke · May 21, 2005

I NEVER said the "customer" was an idiot! I just said that I have NEVER seen a 5.3 Silverado WITHOUT soot in the pipes! I will give you the benifit of the doubt here since you may have misread what I was saying because in type there is no tone of voice or facial expression, but ease up a bit. All I was saying is that what he describes regarding 5.3 Silverados without soot seems odd to me, that is all.

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Ok, maybe I wrongly construed a group of posts, including yours, as dismissing JRW68's question and impugning his observation skills. If that was not your intent, then all is well.

If you reread his post, what he seems to be saying is that he has a lot more soot than the other similarly equipped trucks that he has seen. He speaks intelligently about whether he has a rough idle or other indications of a rich fuel condition. He sounds like he is fairly knowledgeable and he's asking for the help of other knowledgeable members of the forum.

I'm inclined to accept his observations as realistic and move on toward helping him solve his problem.

hihosilverado · May 22, 2005

Ok a few things........

1. I would not worry about whether or not the dealer likes you....sometimes if they think you will throw a fit if they dont fix your vehicle correctly they work that much harder to get it right.

2. I would be more worried about the puff of smoke on startup than anything else...I dont know how you could measure the amount of soot in the pipe......how much is too much? It is normal to have some soot in the pipe.

3. I dont think the dealer can "detune" your engine.......and if it is running rich than obvioulsy it will actually be better running if you get it balanced correctly.

4. Don't be ashamed to bring your complaint up........the service writers and service managers may look at you like you are crazy but for the most part they are chosen to deal with people, not to diagnose problems or even know anything about them..

JRW68 · May 22, 2005

I appreciate everyones replys and yes i do have a fair amount of expereince with EFI and various EFI systems. My experience ranges from rebuilding several 70's style engines, working on go-karts, racing my crf (district 5 MX), helping my father diagnos vehicles (25yr old self employed mech.), several FI convesions, senior desigin dealing with combustion rig designs, PSU mechanical engineering degree... and now designing helicoptors for the military. up until now, my newest vehicles was an 84' s10 converted to FI 4.3 v-6.

I appreciated the support even the replys that are seemingly obvious, as an engineer, simple things can be overseen.

I have three 5.3L v-8s in the family... all newer than 03's... none have as much soot as mine its pretty bad... .today I started to notice some adverse affects... definitely runin too rich (lack of power (VERY inconsistent) on the hills)... the cause is unknown yet. Im leaning towards a slight sensor malfunction, MAF or MAP... possibly even as simple as a fouled 02

I could care less what the dealer thinks but its pretty common for dealers to just reflash rather than diagnos. I know several guys who work at dealerships and I really dont have much faith in their diagnostic abilities. No offense, im sure there are some good dealer mechs out there but not around here.

My father gets alot of dealer work, I had to diagnos my girlfriends father's taillights (her brother is a dealer trained mech and couldn't figure out that the harness was copletly shortted at the gas tank), and every time I have had a family member take a vehicle in for a mechanical issue... its always been "solved" by reflashing... especially with all three new 5.3L in the family... I think its lazy, and show how much they lack in diagnostic understanding of these vehicles.

Im gonna throw it on the scanner here in another week and see what all the sensors are reading... hopefully find one out of wack. Then take it to the dealer and see what the find. Like I said, I prefer to know the solution before I goto the dealership... so I can dictact how I want it fixed.

Im just open to your thoughts and experiences....

Thanks Again guys

PS, pardon anything that doesn't make sense or is miss spelled... its 5am here... and I have a bit of a buzz going after my buddies bacheleor party.

Elwood 2000 · May 22, 2005

PS, pardon anything that doesn't make sense or is miss spelled... its 5am here... and I have a bit of a buzz going after my buddies bacheleor party.

It is is 5am and you are just getting home, it must have been a good party!

While I am not a mechanic, woundn't a failed O2 sensor set off the "Service Engine Soon" light? You are right, finding a dealer who can diagnose problems is getting harder to do.

Good Luck with your issue, I hope it works out well. Keep us posted!

mmmikkke: No worries, I was not dismissing anything, I just found it odd that he knew of trucks without soot. My Silverado and Suburban both have a ton of soot in the pipes, but they both run great.

mmmikkke · May 22, 2005

mmmikkke: No worries, I was not dismissing anything, I just found it odd that he knew of trucks without soot. My Silverado and Suburban both have a ton of soot in the pipes, but they both run great.

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JRW68 · May 22, 2005

It is is 5am and you are just getting home, it must have been a good party!

While I am not a mechanic, woundn't a failed O2 sensor set off the "Service Engine Soon" light? You are right, finding a dealer who can diagnose problems is getting harder to do.

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Yes, good party haha...

Sometimes sensors are bad but not bad enough to trip a code... they can actually be a nightmare to diagnos because they cause faint intermittent problems that are nearly impossible to isolate until they completely fail or get worse. Im actually suprised I haven't tripped a 02 code yet because they have to be getting pretty fouled out for as soughty as the tail pipe is. I had it on a scanner the other day and the 02 sensors were pretty active so they arn't fouled yet. With my luck, what ever is causing it will go bad all at once and Ill have to baby the truck home in limp mode or some crap.

Anyways... I hope to have it all straightened out this week, Ill keep everyone posted.

Matt99Z71 · May 24, 2005

Theres obviously something slightly amiss, it shouldn't be black and sooty. Mines clean as a whistle too, it should be with properly working efi at 14:7:1. Just have the dealer check it and let them know that you have a pretty good idea of what your talking about. One O2 might be faulty or something, should not be black though, mine aren't.