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Problem getting the black smoke to clear up with A-team. Looking for ideas.

WarWagon

WarWagon

Well it hits on 7 of 8...
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I am looking for suggestions with my current setup - nothing more and no slight made or implied to A-team or my tuner.

1995 suburban is literally a mosquito fogger. Black smoke on acceleration that clears up to a medium black. Smokes like a NA 6.2 climbing the Eisenhower tunnel. Recall the thread where this failed emissions so badly that it passed as it sooted up the smoke sensor to failure... It is like the EGR I don't have is stuck open.

I get black smoke at anything but the lightest of throttle. Runs good and pulls strong to the redline.

This is a non-standard A-Team install. I am using 6.2 heads and the higher 6.2 compression along with 6.2 military precups. 4" exhaust with straight through muffler and nothing else. K47 air filter assembly. low temp t-stat, HO water pump and Kennedy low temp fan clutch with Dmax fan. Fresh injectors. new timing chain and verified timing marks. 30K or so on the used 6.2. No exhaust or intake leaks. 6000 miles on install and A-Team. Orange tube replaced with blue silicone hoses - so no boost leak there. No fender snorkel seen.

Tuner has made some changes by cutting fuel back and timing. This dropped the EGT's and smoke some. Tune runs fine in another 6.5 w/ A-Team.

EGT's climb and stop at 1210, IAT is 256 degrees on a 100 degree day with 10 Lbs boost or more seen by the MAP. 135 IAT when not on the throttle. Timing desired appears to match actual very closely if not perfectly. PMD resistor is missing or burnt out and bypassed elsewhere in harness for now. It was 100 degrees out for the above numbers.

Can't tow with it as ECT and EGT's go through the roof.

I am looking for ideas or suggestions outside of tuning just in case I have something else going on. Perhaps the 6.2 items require different tuning or will not work with this setup?

I will try the stock chip and see if it still has trouble. What else should I double check?
 
I know you probably have already checked but how is the air filter or is there any restriction in air supply? You have 4 in exhaust, is the down pipe the same? Are you leaking exhaust on the crossover donuts or the crossover itself? Can you spin the turbo by hand?

Before swapping turbos I would remove the air filter and elbow and run it open turbo, will the turbo spin at idle?

If I understand correctly, this change happened when you installed the tuner chip? Can you reinstall the old chip? Or did this happen when you installed the ATT? Or did this just happen?

I know you have already checked these things but this is where I would start.

Good luck

Brian
 
Start by using the factory tune and then lets see if it still smokes. Aces with ten pounds of boost or more I don't think the turbo is the problem. Anything is possible but just throwing things out there is not. I am thinking that the IP has a fuel delivery issue, how new is the IP. If the fuel was turned back and it still smokes then it is either the pcm tune or IP. Could be a number of things, coolant temp reads correctly to the PCM? You can call me if you want to speak on the phone.

Also stated that the truck pulls hard to the redline, Turbo shouldn't be the issue.
 
Can't swap turbo's due to the last turbo was junk from my avatar pic engine shrapnel event. (It died a nasty death. Bearings wiped out and it ate debris through the exhaust and intake from the CDR dumping metal filled oil/coolant in it. Ewwww!) IP is unknown. It could be original with 183K on it or replaced at any time in the past. Suburban was purchased with blown engine so there is no before comparison to make. (#8 injector failed and melted the piston that seized and shattered letting the rod beat holes in the bore.) I can only compare to my 1993 and 1988 Suburban I owned long ago. Tune was put in from day 1. Never ran the original tune...

I just need a second pair of eyes if you will to make sure I don't have anything else going on before chasing down many tune changes.
 
Me too. ^

The 6.5 inj(stock or marine?) with the 6.2 heads and cups could be an issue(not enough atomization with the amount of fuel).

Could be the IP,but i doubt it
 
6.5 Stock injectors.

Resistor is a 1/4 watt Radio Shack unit back-probed in the wire harness by the IP. #3 value by the chart. OEM resistor has failed or is missing.

Stock Tune will be run tomorrow.
 
Slim Shady said:
Start by using the factory tune and then lets see if it still smokes. Aces with ten pounds of boost or more I don't think the turbo is the problem. Anything is possible but just throwing things out there is not. I am thinking that the IP has a fuel delivery issue, how new is the IP. If the fuel was turned back and it still smokes then it is either the pcm tune or IP. Could be a number of things, coolant temp reads correctly to the PCM? You can call me if you want to speak on the phone.

Also stated that the truck pulls hard to the redline, Turbo shouldn't be the issue.
Click to expand...

My point was he inquired about using it with the 6.2 mil precups. Sorry I dared..
 
I dared?

Aces nothing meant by it, (the problem with no inflections) I don;t think with ten pounds boost that the thing would be smoking if it was a turbo problem. The fact that the turbo can get ten pounds of boost means the turbo has enough drive energy. I might be WRONG but hopefully for my sake I am not. I suggested the factory tune so that if there are any anomalies or programming glitches that would eliminate that.

Buddy does a good job with custom stuff so it isn't an issue with what he has done. It may be a problem with the pmd and the resistor but we have to start somewhere.

The Gm 8 will mask a lot of fuel problems, ask Turbine Doc and I how we know. :skep: Course we would have to give you a good brain washing after that because it would be highly top secret (yeah).

So a stock factory tune would be a good place to see if it smokes, just my two well maybe five cents worth. So no insult meant if it came across as that.

OK ?

Just had a DB2 pump that accelerated by itself at 1500 rpm then would take a long time to coast down. LOTS of black smoke (GM 8 turbo) and towed poorly high egt and coolant temp (latent heat). long story short :the advance piston had worn in the bore and was letting the fuel by pass the advance mechanism and the truck did not have the proper advance and it had unusably high fuel rates for what the IP was calling for (just like an optic bump). New IP and the truck runs fine. So I rest, this is the first I have ever had a DB2 do this, (glad it wasn't my turbo). There may be some issues here that are not real apparent now.
 
Slim Shady said:
I suggested the factory tune so that if there are any anomalies or programming glitches that would eliminate that.

So a stock factory tune would be a good place to see if it smokes, just my two well maybe five cents worth.
Click to expand...

I agree..... put a stock chip back in it and see what happens to the smoke. If it fixes the problem, you know something went wacky with the perf chip. If it still smokes crazy, we can go a different direction.

Easy and quick thing to change and you won't even get dirty in the process.
 
I put the stock tune in and ran it today. I'll ignore the initial puff as things wind up. However I could not get the visible smoke to clear. The smoke was fairly light flat out at upper RPM but I could still see it in the driver's side mirror with a little wind that direction. Not smoking as much as with the tune.

Looking at the logs with the tune the turbo had 17 PSI of boost in the upper range.
 
What kind of advance were you running at the upper rpm with the stock tune?
 
I am thinking the 6.2 precups would reduce smoke. Aren't they sized to run without turbo (less air) so they swirl more air. Isn't the draw back is they will run hotter??? Not that they will smoke if you over fuel them again that is just my thinking.

I would guess IP or injector problem not atomizing fuel not lack of air or swirl from precup but not sure how to test easily. It just puffs on accel right and with light throttle seems ok if you roll into it slowly. I think the resistor only corrects for max fuel too so that in and of itself shouldn't be it unless other wiring issue with FSD.

You could always check fuel filter / LP to rule out starving the IP for fuel. IF timing is running ok doesn't sound like its totally starving for fuel but might be a little and with old age? of IP its just not crisp atomization of fuel = smoke.

Spike the fuel with cetane 8 plus and stanadyne performance formula or redline additive. Those reduce smoke best for me. That might point to poor fuel atomization/burn. I would guess you have plenty of air/swirl.
 
In partial note to the above I get slightly less smoke on B99 with the different viscosity, cetane, and oxygen in the fuel from leftover methanol the refiner uses. Still painted a smoke ring on the driveway with B99 before the restrictive Banks exhaust came off...

Resistor is not a factor with the larger fuel changes in the tune.

The smaller ports would move less air and become restrictive to more air. However I have the military cups that are larger than the standard 6.2 precups. They are smaller than 6.5 NA ports.

I am not sure if the higher 6.2 stock compression makes any difference to the problem at hand.

posted elsewhere. On the left is a head with Military precups on a 1986 6.2, 3 bars. The cups sitting on the head are 1995 turbo precups, round dot. The head on the left is 1995 NA 6.5 precups, square mark.

precups.jpg
 
Compression on the 6.2 was ~21.5:1. give or take .1-.2 of a point. Compression on early 6.5s was the same. Later on in it's life the compression dropped about a point to ~20.5:1, again give or take .1-.2 of a point. That's not a huge difference. 21.5 to 18 is a huge difference.

At least that's what my GM book says for the 93 6.5.

With the Banks turbo on my K-5, which is a lot more air than the 6.2 "C" code civilian engine was designed for, i get no smoke unless i either lug the engine, or whack the throttle(until the boost comes up). the boost coming up does lag a bit due to the banks intake hat being so large, but i have no where near the smoke you describe.
 
I figure at light throttle the precup size really wouldn't matter ?.?. Its only at heavier fuel rates that should cause an issue ???? I guess it can have an affect on timing.

The size of the precup isnt it a trade off of velocity and mass. And without turbo (less heat and air in cylinder) you want higher velocity swirl to burn all the fuel so you have a smaller precup. With turbo and more air and effective compression (boost and compression) you don't need as much swirl? I think the smaller precup's get better milage but run hotter. I would think if its a precup issue it would follow foot ie smoke with heavy throttle and be clean at light throttle. Since it smoked at light throttle with stock tune too I am guessing you are not overfueling for air I would guess its fuel not atomizing???? But I am more or less reasoning it out I haven't really tried different combination.

Again just trying to reason in my mind with your combo & stock tune you should get a real clean idle and clean light throttle increase then smoke with heavier fuel rates if it was a precup issue and the precup was starving for air with higher fuel rates ????
 
Changing the timing is not too hard and between stock and custom there is quite a difference. So trying something inbetween is not a bad idea. The custom program is capable of outputting so much more fuel it would smoke more at a good amount of throttle

Ultimately, there may be a fueling issue on the IP, that did happen on my first IP, couple of different theories
Poor atomization from low pressure, plungers could be leaking and when its supposed to jump from 2200 to 7000psi really quick, it just keeps pushing at 2200psi or even drops after injector pops. Maybe this also led to engine failure, in concert with poor injector.
OR
Timing being reported correctly because electronics are all in the right place, but poor pressure or something is causing delayed pop/injection.

Precups, smaller cups may not allow as fast of a burn at turbo fueling levels. Larger cups seems to yield better power at peak torque angles, so its plausible to suggest that smaller cups sustain a longer burn. Also a little less displacement in the engine for a little less air.

Hot fuel should atomize better, but with the smaller precups maybe you could try unplugging your fuel heater.

I think the most likely culprit has something to do with the IP.
 
Finally got time to work on this issue. With the stock tune I made changes to the IP Dennis recommended. I now have the smoke completely clear up after ~2000 RPM.

Some more changes should get me to where I want to be with this Suburban project.
 
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