Excess Black Smoke Still Has Me Stumped

[GWS]

I pulled the IAT sensor yesterday. It wasn't even dirty. I cleaned it anyway and re-installed it but it did not help my excess black smoke at low boost. I also cleaned and re-oiled the K&N with no positive results. Changed the fuel filter a few days ago. Nothing. Tanked up with fresh fuel. Still smokes. Checked the turbo for oil and it's clean. I think the over-fueling is occurring across the powerband since the truck seems to pull stronger. Its just that the smoke is more evident at boosts under 10 lbs. I guess I should have the pump pressures tested, check the fuel pump return valve and test the IAT and MAP sensors. Any ideas?

 

[Evan A. Beck]

Any boost leaks? Even little ones can cause black smoke under light to medium acceleration.

 

[GWS]

Thanks Evan. I will double check all the intercooler connections.

 

[Alan Reagan]

Unplug the VA and see if it reduces/eliminates most of your smoke. I think you will find that the VA and summertime driving tends to produce quite a bit of black smoke on starts, shifts, and when the engine is under load. Probably has to do with the IAT fine tuning the timing at the same time the box is doing the same thing.

 

[Steve St.Laurent]

Looking at your mods I'd definately say it's the VA box. The VA box fuels all the time so it will make a lot of smoke down low. On one of the GLTDR trips I was following Doc Tinker and he had put a VA box on his truck with 275 injectors and he smoked WAY more than I do with 275's and a powermax3 on level 9. Difference is his smoke cleared up when he made boost, mines keeps smoking lightly (because I'm fueling way more). In your case with the PE box as well you'd get it on both ends. JMHO

 

[Diesel Freak]

your VA/275 combo will make smoke. That is where it is comming from

 

[Sky]

I have herd the VA tends to over fuel. Im willing to bet if you unhook it it will stop.

 

[Alan Reagan]

You'll see and feel and immediate difference. Usually the VA just provides the low end. Once the turbo spools up it disappears.

 

[GWS]

Guys, yanking the VA was one of the first things I tried when I initially discovered the smoke. While I do get less smoke with the VA pulled and the Edge turned off, its still far too much for basically a stock engine with 275's. I'm going to try testing the pressure release valve on the fuel return from the pump. If this valve is sticking and not popping off until a higer pressure is reaced, it could (according to the manual) cause black smoke.

If the valve is ok, then I may start throwing new sensors into it, starting with the IAT, and if needed, a new MAP sensor. I could also just live with it, since the performance is not suffering.