LS6 stroked and boosted new build. Huge coughing/studdering at 0 vac on acceleration

[SiriusC1024]

Here's a thought for everyone. This coughing, sputtering is only at 0 vac. Thinking out loud here. Is this when my blow off valve closes? Maybe there is a rush of air going into the engine and causing a lean situation? I know my throttle would be open slightly because I am slowly accelerating.
Any thoughts?

The injector data is set for vacuum-referenced IFR, but Offset is non-referenced.

What is the P/N of those 800cc Deka's? Got a link to where you purchased? Those are also known as Deka 80's, but there is a short and long version. Looks like you're using the AACorvette 80lb Long Deka IV data. Is that what you have installed?

Yeah it's the AACorvette Deka 80 Long data. What you need to do is go into the Offset table and copy the 0kPa column to the rest. Engine>Fuel>Transient>Min Fuel Mg to 0.010.

I'm also assuming by 0 vacuum you mean low manifold pressure and high vacuum. 0kPa vacuum is atmospheric pressure, or WOT without boost. The more vacuum the more error due to the Offset not being setup correctly. Not sure how this made it past the tuner with 20 yrs experience, but whatever. The Min Fuel setting is probably acting as a floor and not allowing short enough injector pulses to get fueling correct. Again, need to see Injector PW for both banks.

Injection timing would be a good thing to do. What are the complete specs, including ICL, for this Stage 4 cam?

See it's like I was saying. Injector data and MAP. Get the GM sensor per previous recommendations and adjust your injector data. Things will go a lot smoother.

Set P0101-P0103 to MIL on First Error instead of Second. Even with and SD OS you still have to manually set it to fail the MAF.

After all this see if you can get a good VE table going.

[Virtue]

Thank you for everyone's help. I was away for a wedding over the weekend.

edcmat-l1 : I will change my plugs soon. I just wanted to get things a little better before I change them so I don`t fowl the new plugs. I had the NGK-BR7EF in the car originally. The Canadian distributor for the HP Tuner product, out rightly said, he will not tune the car until the NGK pieces of crap are removed and the iridium plugs are installed. Yes, they also did the compression test. $1500 later, I had to install the new plugs myself and the car was not tuned. This was my second tuner. I did have one cylinder with no compression. That was fixed by me. The original builder for the engine put washers under the rocker arms. They missed the one washer and it kept the valve open. I since have fixed and removed the washers. And installed the correct push rods.... Had to do with geometry? Also, my new Deka injectors were leaking vacuum because the o-rings were too small for my FAST intake. Fixed.

SiriusC1024 : Seriously, thank you for your help. I think I did everything you asked. The car needs more help now for a tune. When you have time, please look over changes I made to see if I did everything how you suggested to change. I thought I engaged the Injector Pulse Width ( both banks) but I didn`t get the numbers on the time graph to show...? Maybe I missed something?

My injectors are the long Deka 80`s. They have been tested here locally, and they all match almost perfectly. P/N is 110324. It matches with the Siemans' website.

I have a N/A camshaft. I was not thinking of boost until building the engine. I had a better cam before this one, it was ground for turbos, but I recently stroked my engine and I read here, on this forum, that I needed 6* more timing with duration for both intake and exhaust with a stroker. So, I bought this cam. My gauge reads 9 in Hg at idle. Not really good. I know now....
Summit 8709R1. ICL is 110* LSA 113* 3* advance, intake 238* exhaust 246*, lift .626 .605

Question: I read here in the forum that my P59 ECM can't handle a negative number for the MAP. This is why I purchased this 3 bar MAP from EFI Source because it is made for my Gen 3 engine. The GM 3 bar MAP has a negative offset. That's why I didn't purchase the GM. Is this true?
So, this EFI Source one, has a positive offset. Entered in my tune.

Not sure If I did this correctly. "The injector data is set for vacuum-referenced IFR, but Offset is non-referenced." I zeroed the Offset table?

Anyways, this is my new log after these changes. Attached.Log 13e, after initial change from forum.hpl2005 5.7 M6 CTSV 2BAR Cory Virtue 4281 basetune 13 SD (1) different MAP sensor(1).hpt

[blindsquirrel]

No, use the 0 kPa VAC column from the datasheet, then paste that into every column all the way across the whole table in the editor. There are mistakes in all the others except the flow rate table, too.

If you hover over an item in the editor a little description will show up at the bottom, and also gives the min/max allowed. Your P59 will take 0 to 1280 kPa for the Linear, and -105 to 105 kPa for Offset.

[Virtue]

Thanks blindsquirrel,
all of these issues are from the last tuner.... with 20 years of experience. If you only knew the heart ache everyone has caused me.