I have an lsx engine that is turbocharged and supercharged and it has a hard time restarting after warm up. If I shut it off and start it real quick it starts up and runs fine. But if it sits for a few minutes then it won't idle and acts like its misfiring and if I give it some gas it'll idle rough and runs like crap until I drive it. Any help would be appreciated
Can anyone help?
You might have leaking injectors. Also, you have to check if ECT sensor reads accurate temperaturem
Got a log of it happening?
Post a log and tune if you want help
VCM Suite V3+ GETTING STARTED THREADS / HOW TO's
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2005 Corvette, M6
ECS 1500 Supercharger
AlkyControl Meth, Monster LT1-S Twin, NT05R's
ID1000's, 220/240, .598/.598, 118 from Cam Motion
2007 Escalade, A6
Stock
heres the log and tune. and I have thought about leaking injectors but it fires right up and runs rough under 1200rpm but If I driv it or give it gas and hold it at 2000 rpm it will idle but still is a rough idle and dies easy
BRAF appears to be way too low... Have you tried raising it?
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Gen 3 tune, gen 4 section. Might try posting it in the gen 3 section also.
Put MAF Airflow back to stock and since you are running SD tune, then go to Engine Diagnostics and change PO101 to 2-No Mil Light.
What's BRAF? And I have posted in the gen 3 also and on ls1 forums trying to get this figured out.Still haven't been able to get it to hot start and idle good. And what will that do for me by putting the MAF back to stock and changing the code?
Last edited by Raddtadd; 03-02-2016 at 12:07 AM.
Base Running Airflow - Same as the min airflow table... As long as MAF is all 0's and your setting the dtc's, you should be fine... Only other thing - and I haven't checked it's settings - right off the bat is that you could increase your startup airflow, but this won't fix the after start running.......
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
So how much of an increase do you think I should add to my base airflow? I've added about 10 to it and it does start a lot better. And it idles a lot better with a commanded 12.2 A/F ratio compared to a 14.7. Does that make any sense?
Increase 5% a time until it gets close to having your idle adapts just in the negative. Might want to lean out your commanded hot restart a touch... Having to open throttle more due to it "choking"....
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Where do I lean out the commanded hot restart? And what do you mean by having to open throttle more due to it chocking?
Last edited by Raddtadd; 03-02-2016 at 03:18 PM.
Too richly commanded during hot restart - from my experience with gen 3's they don't like to be too rich - can cause stumbles, spit and sputters and even start and die scenarios..... Rechecked the tune, it shouldn't be commanding richer than 14.7 or whatever stoic is set to during hot restarts. SO keep increasing BRAF until it gets right. Go off of your learned values. You may have to kill learning to dial in right....Originally Posted by Raddtadd
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Okay well it's still rich at an idle. I've just about doubled my BRAF. Do I need to add to my VE table too?
??? From the looks of the above log, it looks lean when your starting it? Looks like it needs about 12 % added in the idle area. Would have to see a current log to tell for sure. Honestly haven't looked through the entire tune either. Sounds like your heading in a decent direction though.
You'll need to 0 out your adaptive idle airflow tables in the tune and go by st idle adapt or something like that to accurately tune in the Braf... RusselK did a pretty decent write up about it if you can find it. I don't entirely remember everything about tuning these... Been about a year since the last one I worked on? I do remember the idle on them is a pita to get just right
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Yeah sorry it's readying 17 AFR at start up and after 10 seconds or so it starts cleaning up to 14-15 AFR. How do I make it run 14 AFR at start up?
This could be a few things... VE, MAF, the way your setup was scaled - using stoic or actual airflow scaling, injection timing, IVT gains (this will probably benefit you the most after MAF and VE re-tuning)... Can't look at the tune again right now, so can't tell for sure... I would focus on the IVT gain though after redoing the MAF and VE idle areas, unless something here jumps out at you.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
The log that is posted doesn't log commanded AFR and there's no wideband reading, so not a lot to go on..
Post a log and tune if you want help
VCM Suite V3+ GETTING STARTED THREADS / HOW TO's
Tuner by night
CPX Tuning
2005 Corvette, M6
ECS 1500 Supercharger
AlkyControl Meth, Monster LT1-S Twin, NT05R's
ID1000's, 220/240, .598/.598, 118 from Cam Motion
2007 Escalade, A6
Stock
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