Won't come off idle

[fastslvblkcar]

I will give you the build first. This is a new built 408ci stroker. It has a BTR stage 4 400ci+ camshaft in it with some LS3 heads. I am running a drive by wire setup with the adapter for 8 to 6 pin Tbody. It has a 2008 suburban Tbody. My system is from a 2005 Escalade DBW. My tune is setup to tune SD. I am using an AEM wideband. I am having 2 problems. 1 I am lean on start up until the engine gets through the startup enrichment period. I Believe I can tune this out with the startup tables. My bigger issue is that I can idle the car all day long but when I touch the throttle, it wants to or it will stall immediately. I did not change any throttle body tables and do not know what to change and how much. I did change the injector size and engine size before firing it up the first time. I have also modified the base idle air flow. I am mostly concerned with the throttle response. If my data log needs more info, let me know what you need to see to help me out.

[tana99ss]

What injectors are you running? and have you attempted to see if you have the correct injector data

[blindsquirrel]

What the hell happened here?

screenshot.15-03-2023 06.18.32.png

And why is Short Pulse Adder unchanged from a stock LQ9 file?

[fastslvblkcar]

I used GM PN 12609749. I looked up what vehicle they would have came on and copied the injector data from a stock file I got from the repository.

[blindsquirrel]

The only stock file from something that used 12609749 would've been a Gen 4. It's not a straight copy/paste since the formats are so different. And the data in your file is not done right.

[fastslvblkcar]

It has been a year since I added the data that I found. I was just looking back through it and I couldn't have gotten the data from a stock vehicle file. I don't know where I got that data. What do I replace it with since it must be incorrect.

[blindsquirrel]

Fuel system? Regulator type? Fuel pressure?

[blindsquirrel]

This will only be correct if I guessed right about your fuel system stuff.
base tune 3 sd - 12609749 58psi non-referenced.hpt

[fastslvblkcar]

Fuel pump - Walbro 450lph
fuel filter - 58psi corvette style internal regulator

[fastslvblkcar]

If this is correct for my fuel system, I will program it tonight and see what happens. Thanks for the help.

[blindsquirrel]

Have you put a real gauge on the rail to check the pressure? Those Corvette filters can be... suboptimal with large pumps.

[fastslvblkcar]

I added an inline gauge.

[blindsquirrel]

And? The Corvette filter/regs are advertised to do 58psi, but they often don't. Did you confirm with your gauge that it really is at 58?

C'mon, this is not like buying a classified ad in the newspaper back in the olden days, you aren't being charged per word.

[fastslvblkcar]

yes, it is running at 58psi. That is why I added the inline was to verify that it was otherwise why add a gauge? This isn't a civic where you add gauges because it is "cool". I am at work for another 9 hours and have limited time to respond. I guess I figured that by me telling you that I added the gauge that you would understand that the fuel pressure was at 58.

[blindsquirrel]

Said it before, but you'd be amazed how many guys come on here with a cranks-no-start or other problem and say 'yea I cheked fuel pressure its fine' and then get asked 'yeah, but are you sure it's fine? what was the number?' and they say 'its good it pegs the gauge straight to 90psi as soon as I hit the key'.

It's frustrating to feel like you're fighting to get actual data.

[fastslvblkcar]

I understand completely. I am constantly arguing with our service writers because they get suck poor information from customers. I will get this data put in and programmed tonight and run a log and repost the results tomorrow. Thank again for the help.

[blindsquirrel]

If you've been making changes for a while with the bad injector data like it was, likely you'll have to un-do a lot of stuff.

[fastslvblkcar]

Yeah, I was thinking that but I mostly have just made changes to base air flow, based off of other people that have the 408 setup and had been running it. That stuff helped me get it running and stay running but it didn't help off idle. I will give this a try and see how it goes from there. Hopefully the other changes I have made won't have to be changed back.

[fastslvblkcar]

Well, I inputted the injector data and put the tune in and now it is so lean cranking that I could only get it to start and stay running 1 time. This time again I could not get the engine to rev with the throttle pedal. I went back into the tune and set everything that I had changed before, back to where it was except the base running idle air flow. I left these alone as they are mostly inline with what the MAF is reading. I will try this and hopefully it will stay running. I guess with the correct injector data I have a good starting point but the throttle pedal acted exactly the same as before I put the new data in. I added a log for you to look at if you would like. I also added the new tune so you can see what I had to change back.

[jsf55]

Have you checked too see if any dtc codes are set ? i had an issue with my throttle body where the wiper had worn out and would go "dead pedal" but a reset of the dtc's would make it run fine