You guys better listen to Sam he knows what he is talking about. Tuned and i think now owns a lsx record holding 5th gen car. He's helped me a couple of times with the tune on my lsx swapped mustang coupe and has been spot on every time. i have also noticed some cranking issues on this recent ls3 headed 408 in my coupe and its also rich on start up.
1993 reef blue Mustang coupe
Ls1 conversion
1 7/8 cooks headers
AFR 205 heads
Fast 92/92 intake
PAT G./ EPS Custom cam 230/234 .600”/.602” 112LSA +2 advance
century Built 4l60e with Circle D 3500 converter
4.11 gears
1993 reef blue Mustang coupe
Ls1 conversion
1 7/8 cooks headers
AFR 205 heads
Fast 92/92 intake
PAT G./ EPS Custom cam 230/234 .600”/.602” 112LSA +2 advance
century Built 4l60e with Circle D 3500 converter
4.11 gears
Will try the -5% from cranking tables Monday and report back.
2007 Suburban - Slammed, Cammed, Geared and Stalled.
I have had my cranking ve table way below my regular ve table and the problem is still persistant. I will continue to subtract and see what happens.
2003 Chevy Silverado Daily Driver, 408 Iron Block,
LS3 Heads/Intake, 231/239 114, 4L80e, Yank SST 3200.
Ok got one of the problem childs squared away... Ended up being overly rich during cranking. Ended up redoing the lower end of thecranking VE, VE and MAF table to fix that one up. It would false start previously and was in the 10's for afr during cranking. Now its in the mid 12s during cranking and through the first moment of start up and never started so good.
This 03 silverado ss though is a perplexing one... one in every 3 times it will false start. Watching it on the wide band it will be in the high 11's on startup when its working right and quickly scoot up to the high 13's during warmup. When it messes up it will be lean as shit, crank and start and run for a half second then die and you gotta keep messing with it 2-3 different cranking cycles to get it to light off again. Its deff lean during cranking, 22.0. The tach signal comes up to almost 200 rpm, the inj pulse width goes to 3.0ms.
The only thing that hasnt been addressed with this one yet is the fuel PSI consistency at the rail. A check valve is getting installed today.
Ive been up and down with the cranking VE and the stage 1 FA mult and going richer has helped the normal starts even more, but this random false start still happens. Makes one wonder is it really is NOT the tune and a fuel delivery issue across the rails like people are saying. We shall hopefully find out shortly.
Last edited by BAD LS1; 08-22-2012 at 08:38 AM.
2007 Suburban - Slammed, Cammed, Geared and Stalled.
OK i think the above mentioned 03 silvy SS is figured out. The addition of a check valve to keep rail pressure maintained, helped some as it extended the no start cycle out to about every 6 key starts but didnt solve it. So i ended up adjusting the afterstart enrichment numbers up almost 20% and seemed to 100% solve it so far!
2007 Suburban - Slammed, Cammed, Geared and Stalled.
my car did that forever! i belive it lies in the injector data. once i switched to new injectors it disappeared
00' WS6 370/PT4788/TH400
99' T/A N20
If you have a hot starting problem, try relocating the IAT.
High ECT and sitting, means the IAT will be hot too and
push your "perceived" air mass down, making cranking too
lean.
Cranking VE table is important, and you'll have to fake it
because there's no way to get good data. Extrapolate
based on what the main VE trend looks like, 800-400.
Does it have any cam position sensor codes?
Sounds like a crank reluctor or cam position sensor issue to me.
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
Still cant get mine to start up normally. I richened up the afterstart enrichment table like you said BAD LS1 but still the same. I tried leaning that table out some and still the same response. Not trying to thread jack, just trying to keep this thread going.
Is this still the case, or is it still hard to start?seemed to 100% solve it so far!
2003 Chevy Silverado Daily Driver, 408 Iron Block,
LS3 Heads/Intake, 231/239 114, 4L80e, Yank SST 3200.
Got a copy of the tune you can post? And no its still working good! I havent tackled the stock fuel system 2001 416 truck head on yet. But got 2 of the 4 working correctly so far.
For purely shits and grins, have you tried shutting off the VATS as a test yet? i had the idea for that above mentioned truck because it false starts too like a vats prob once in a while.
2007 Suburban - Slammed, Cammed, Geared and Stalled.
Here is my tune as it sits right now. Most of it is back to stock except the cranking VE since I could'nt find anyhting in the tune to help false starts.
2003 Chevy Silverado Daily Driver, 408 Iron Block,
LS3 Heads/Intake, 231/239 114, 4L80e, Yank SST 3200.
Well I think I got it close. Leaning out the VE didn't help at all. So I figured the tune must be lean already. That would make sense because it usually takes two-three cranks to start it. It must need the 2-3 prime pulses to get enough fuel to fire. So I added .200 to the entire prime pulse table. That caused a rich condition where it would fire first piston up and then die immediatley. So basically I zeroed out the prime pusle table and almost trippled the first pulse table in the hotter regions. From about 90 degrees to 220, it tapers from .250 to .150. The addition of fuel seems to be what this combo needed.
I now can tell when cranking is rich or lean. If it continuously cranks without fire, its lean. And when it fires but dies real fast, it is rich. I figured I would post up my findings for someone who can use it down the road. Thanks guys for your help
2003 Chevy Silverado Daily Driver, 408 Iron Block,
LS3 Heads/Intake, 231/239 114, 4L80e, Yank SST 3200.