Help me get this 4.8L running!
08-13-2013, 04:19 PM
#1
Help me get this 4.8L running!
So the truck fires up every time no problem. It runs for a sec and then the idle desired airflow starts to skyrocket (.545 increasing to 4.5). Obviously the idle air trims go to 150+ when this happens and the rpm shoots up to 2500 or so then drops to 300-400 rpm and stumbles until it dies. I can't tell if the truck is rich or lean. The wideband will read for a sec and then it shows ---
I put a ls3 maf on this truck so I know it isn't tuned or it yet. When I try putting it in SD, it will fire and immediately die just like sprayedenali's truck was doing. Check out my normal tune and the SD tune and let me know what you see.
I copied a stock 4.8L MAF and VE table to these tunes so it shouldn't be too far off.
I put a ls3 maf on this truck so I know it isn't tuned or it yet. When I try putting it in SD, it will fire and immediately die just like sprayedenali's truck was doing. Check out my normal tune and the SD tune and let me know what you see.
I copied a stock 4.8L MAF and VE table to these tunes so it shouldn't be too far off.
Last edited by oakley6575; 08-13-2013 at 04:37 PM.
08-13-2013, 05:14 PM
#3
Okay thanks Jake. That kept it running in SD. So now the problem is it just falls on its face after initial start up. So it will start and go almost immediately down to 400-500rpm and hang there till it dies or I shut it off. You can see the idle desired airflow is F'ed.
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08-14-2013, 05:15 PM
#9
The difference between MAF and VE could be part of it. I've also noticed that not all injectors scale the same, which is almost to be expected. So you'd have to make up for the difference in the VE be it higher or lower. Not really an issue. It does change your calculated air mass flow rate though, so that will make your transmission shift differently. Just something to keep in mind.