Welp, I got the Blazer fired up tonight and promptly downloaded another burn to the prominator.

Here’s the problem that I’m having. I recalculated the BPW according to a long lost thread that I found for the larger Holley injectors, OK, so good so far .Now here’s the irritating part.

I’ve leaned the O/L AFR to almost 14:1 from cold to 26 degrees C, BUT I”M STILL GETTING BLACK SMOKE OUT THE PIPES! Along with that blasted popping as the cat comes up to temp! After some datalogging, I used the ALDL to Bin utility to recalculate the VE tables, which I will download to the prominator tomorrow; if that doesn’t work, I’m gonna pull out what’s left of my hair! Does anybody have any suggestions as to what I’m missing? TIA

 

Hey man!

What are the specs on the cam you've got in your K5? If you're getting a lot of valve overlap due to a low lope separation angle (less than 112 LSA) or tons of duration, your 02 sensor may be sending the ECM a false lean condition signal, when the truth is that the mixture is extremely rich. Unfortunately, the 02 sensor detects 02, and not fuel, so you could literally have fuel pouring out of the exhaust, and still have the 02 sensor informing the ECM of an extreme lean condition.

I don't have a ton of understanding when it comes to hammering proms out yet, but I do believe that a common fix for a large cam with a rich idle is to modify the target A/F ratio in the idle cells to something far leaner than 14:1. Again unfortunately, its impossible to really know what you need to be setting the A/F ratio to without a wide-band 02 sensor, so the best you have to go on is smell, and when the cat stops popping.

However, this all isn't to say that there isn't possibly something else that is wrong with your truck, but it is a possibility

Russ

 

I wish I had a larger cam in it, but to tell the truth, except for that Holley TBI and a freeer flowing exhaust, she's all stock. I had another tranny leak (dipstick tube seal, which I'm in the middle of fixing) and as soon as I finish, I'll download a new burn. I used that little aldl to bin utility program to recalculate the VE tables, so we'll see what happens.

 

Or it could be you still need to take more fuel out, since you say (from cold to 26c). It could be that your going into C/L at 26c. Does the smoke quit after 26c and run better?
If so you need to raise the numbers in the O/L vs Cool table. Just raise the the numbers for the START UP TEMP upto 26c. Raise the numbers a full point at a time (1.0) till it clears up when you get close it will start and stall out eg not enough fuel. Then you can go back and add fuel to "give it what it needs"

 

Is it a Holley 4 barrel, or 2? How are they wired?

I'd try a 100% stock table once.

Then try JUST changing the Injector constant or BPW or what have you.

It can't be THAT far off.

 

Is it a turbo 350 tranny, vaccum shifted ? You mentioned the leak at the dipstick tube ... did you notice the fluid or just that it was low ?
I'm only mentioning this because I've heard of this happening. Remove the hose going from the vaccum regulator on the tranny up to the intake, make sure it's not wet (If the regulator is bad, it's possible your leaking tranny fluid into the intake causing the smoke out the pipes).