Ok, irregular smokin' has me puzzled......

[great white]

Truck is as in sig below.

Here's what has me puzzled:

there's a large hill here (British Columbia seems to be all hills) that I have to cross a couple times a day. It's about a 4-6% hill and roughly 450 feet high.

Sometimes, I can motor up the hill with no problems and no smoke. Other times, she lays down a WWII destroyer sized "smoke screen" that makes everything behind me disappear.

There seems to be no rhyme of reason to it.

Is this normal? If so, why does it do it sometimes and not others in pretty much the same throttle demand/conditions?

Or do I have an intermittent lift pump/breaking down IP in my future? (don't have the raptor on the truck yet).

The truck doesn't smoke that much other times, I get the "puff" when I hammer the throttle but it seems to run clean most of the time. She can be a tiniest bit hard to start and will give a "puff" when lighting off. (duraterms are sitting on the bench waiting to go in)

I also have to change out the injectors, they're on their way here as we speak. As afar as I know, the stockers with 400 000+ kms are still in there.....

:frown2:

 

[BigBlueChevy]

Seeing as the stock injectors are in there with that much mileage in there, is making me believe that one of them might be getting stuck open. Are we talking loaded or unloaded here?

Are you getting any codes when this happens? There is a chance that your wastegate solenoid is getting stuck open and preventing boost at all, which would explain the excessive black smoke.

 

[THEFERMANATOR]

What is the boost doing when this happens? I had an issue like this and it ended up being the boost sensor in the intake was bad. It thought it had boost but didn't actually have any and would open the wastegate. Only happened intermittent as well.

 

[Detroit Dan]

Is it fuel smoke or oil smoke?
I had a worn out gasser engine that would occasionally line up the piston rings due to the egg shaped cylinder bore. With the rings lined up it would blow oil smoke like crazy for a few minutes or until you shut it off and restarted it.

 

[great white]

Seeing as the stock injectors are in there with that much mileage in there, is making me believe that one of them might be getting stuck open. Are we talking loaded or unloaded here?

Are you getting any codes when this happens? There is a chance that your wastegate solenoid is getting stuck open and preventing boost at all, which would explain the excessive black smoke.

Empty.

No codes.

No boost gauge.

EGT gauge but not hooked up yet.

Stock vacuum actuated wastegate, all tests good in the driveway (vac pump also).

What is the boost doing when this happens? I had an issue like this and it ended up being the boost sensor in the intake was bad. It thought it had boost but didn't actually have any and would open the wastegate. Only happened intermittent as well.

Sounds like it might be time to buy a boost gauge...

Is it fuel smoke or oil smoke?
I had a worn out gasser engine that would occasionally line up the piston rings due to the egg shaped cylinder bore. With the rings lined up it would blow oil smoke like crazy for a few minutes or until you shut it off and restarted it.

Dunno. But it does have a bit of blowby smoke. Tailpipe smoke is black as pitch when it happens....

 

[WarWagon]

Boost gauge is a cake install over EGT. EGT can be installed on the crossover pipe to get it in. Getting it in is more important than waiting to put it in the ideal location.

 

[great white]

Boost gauge is a cake install over EGT. EGT can be installed on the crossover pipe to get it in. Getting it in is more important than waiting to put it in the ideal location.

It's all coming apart next week to do injectors, glows, crossover pipe and that's when I'll tap in the EGT gauge.

I'm going to try and get the fuel system sorted by the end of the month too (prefilter, raptor, etc)

With any luck, the injectors will address the issue. I do know that it rattles like a sum-b first start in the morning until it gets about 30 seconds worth of heat into it....and I mean "sharp rapping" kind of loud.....

 

[chrisk1500]

w/g solenoid or vac pump is flaky....

As already mentioned, a boost gauge will confirm this....

 

[Turbine Doc]

Agreed heavy black smoke on hard pull is lack of air, vac pump, or solenoid, or diaphragm in vac actuator on side of WG has a leak, you can be making enough boost to not code but just a little opening of the WG will allow it to not make any boost.

You can wire the WG fully shut for test to see if it clears up this will eliminate the wg from being suspect, if it clears then you need to investigate the why. Gauge also will help trouble shoot this, I see a TM or ATT in your future.

 

[mitchedo]

My vote is for a flaky solenoid -- what with the symptoms being intermittent and all. They don't always set a boost code when the boost is out of spec for short bursts.

Of course, the MAP sensor could also be shot.

A real time scanner is your friend. I bought Autoenginuity and can monitor everything real time. It's been most helpful.

 

[buddy]

I suspect you may have a vacuum hose crack, and at sometimes its sort of sealed but not others. I would just check those brittle plastic hoses, or connect vacuum straight to turbo wastegate actuator to troubleshoot. If you all of a sudden have a ton more power its probably had a leak for a long time. A crack can come in and out intermittently happened to me, and in the same situation, going uphill. I could get high boost if I really laid into it, because vacuum would suck crack more closed I presume and enough vacuum to suck wastegate closed. It got a lot worse the next week so I went out and popped the hood and found a crack in a bend of that hose. I think the stock system is awesome, I would stick with it if I didnt have an ATT. The TM doesnt perform as well as the vacuum system would (caveat, when it was programmed to work well)

 

[great white]

sticking with the stock stuff for now gents. -8 is only a year old.

My crossover also has a leak at the drivers manifold (flange rotted out). Could this be contributing factor? I've already got a warpspeed crossover sitting in the garage waiting to go on...

I think I'll wait until I get injectors and the crossover pipe done before I go any further. I'll check out the vacuum line as buddy suggested though...

 

[Turbine Doc]

IMO the Vac system sucks :laughing:

It has a propensity to give out when you really need it, and unless you plan on rebuilding it in it's entirety, or carrying all spares you need you need to keep it alive I don't see the reason for keeping it, especially in a early model unit where the entire system has been cycling an infinite number of cycles. even the late model 6.5 year 2000 is now 10 years old , ATT or TM is where I'd spend the $$$..

Do what you will, I ran both vac and the TM I did not see any appreciable difference between the two in what I used the truck for daily driving or towing that made a good case for keeping the sucky system ):h going; especially once it started shedding vac parts with age. For best reliability go with the TM, for best overall, shed the GM turbo and go ATT as all the GM turbos are getting long in the tooth 10+ years if original.

 

[NVW]

sticking with the stock stuff for now gents. -8 is only a year old.

My crossover also has a leak at the drivers manifold (flange rotted out). Could this be contributing factor? I've already got a warpspeed crossover sitting in the garage waiting to go on...

I think I'll wait until I get injectors and the crossover pipe done before I go any further. I'll check out the vacuum line as buddy suggested though...

When my crossover rotted out in the same spot I lost 1/2 my boost or more, in my case it was sudden and didn't change. It ran rough.

 

[Turbine Doc]

s

My crossover also has a leak at the drivers manifold (flange rotted out). Could this be contributing factor? I've already got a warpspeed crossover sitting in the garage waiting to go on...

..

Ah yeah.... it has a little to do with it, that leak is lost drive gas to the turbo, ergo lowered boost & black smoke :nono: probably not enough of a loss in normal course of events daily driving there is enuff oomph in the turbo to make up for the loss, but when putting the load to it, your turbo isn't keeping up with the demand.

 

[great white]

A real time scanner is your friend. I bought Autoenginuity and can monitor everything real time. It's been most helpful.

Got a couple, been a while since I've run a log though. Good suggestion, I'll give 'er a go soon and see what's goin' down...

IMO the Vac system sucks :laughing:

It has a propensity to give out when you really need it, and unless you plan on rebuilding it in it's entirety, or carrying all spares you need you need to keep it alive I don't see the reason for keeping it, especially in a early model unit where the entire system has been cycling an infinite number of cycles. even the late model 6.5 year 2000 is now 10 years old , ATT or TM is where I'd spend the $$$..

Do what you will, I ran both vac and the TM I did not see any appreciable difference between the two in what I used the truck for daily driving or towing that made a good case for keeping the sucky system ):h going; especially once it started shedding vac parts with age. For best reliability go with the TM, for best overall, shed the GM turbo and go ATT as all the GM turbos are getting long in the tooth 10+ years if original.

My -8 is a year old, just doesn't make sense to rip it off yet. Financially at least. PO replaced it and had the receipt. Maybe once I get the rest of the truck sorted out it'll be time for the stocker to go...

The vac pump is working fine, but I'll probably just replace it when it's done. That's about all that's left of the original 12 year old stuff, unless it's already been replaced...

The vac lines are all going stainless eventually. Do it with every vehicle I own to do away with rotting rubber/plastic lines...I prefer hard lines and proper standoff's over flexible crap wherever they can be used. "Occupational hazard" I guess....

What I really need to do is get an "in" with Westers and get a hold of one of their tuner programs. Not a retuned PCM, the software/hardware they sell to shops...

I miss being able to tweak and tune....

 

[buddy]

You have an in with Westers, an $1800 in ):h

 

[great white]

You have an in with Westers, an $1800 in ):h

Yup, but it stings a little bit.

I wish EFILive supported these trucks.

At least that's "only" 800 bucks........:rolleyes5:

 

[Crankme69]

GMDT Scan for my OBD1 was the best $200 bucs I spent. Can not change the tune with it, but it sure helps out tremendously when trouble shooting an issue.

GMDT has nothing available for OBD2 iirc correctly, hint hint...!

I had an intermittent failure with my EGR solenoid (now deleted) that would have been near impossible to track down without it.

 

[Turbine Doc]

Yup, but it stings a little bit.

I wish EFILive supported these trucks.

At least that's "only" 800 bucks........:rolleyes5:

EFI was contacted about possibly supporting these, they apparently deemed it to not be a viable business venture for them, IMO big mistake on their part.