Need help/ideas as to the cause of this No start on first try issue

[98Camarod]

Its funny that the vehicles we have problems with are all rectangle port heads.

But I am suffering from the same crap everyday. It is frustrating and it seems like there is no end in site.

I've got cathedral port heads, I think the problem has more to do with the regulators.

[Sam88gta1]

I've got cathedral port heads, I think the problem has more to do with the tuners .

Fixed for you.
Its in the tune. It is not a mechanical problem.

[oakley6575]

Fixed for you.
Its in the tune. It is not a mechanical problem.

How much to fix it if you know what is wrong with it?

[bigfatls6]

How much to fix it if you know what is wrong with it?

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.

[bigfatls6]

How much to fix it if you know what is wrong with it?

Subtract 5% from the cranking fuel table until the problem goes away.
Have you tried this?

[BAD LS1]

Will try the -5% from cranking tables Monday and report back.

[oakley6575]

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.

[BAD LS1]

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.

[BAD LS1]

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!

[PAT WS6]

my car did that forever! i belive it lies in the injector data. once i switched to new injectors it disappeared

[BAD LS1]

my car did that forever! i belive it lies in the injector data. once i switched to new injectors it disappeared

I believe in that too, this one has the SD 60 #'s in it with data pulled right from the GB spreadsheet and the time spent to put it all in right. Idk this one was a freak that it was so inconsistent too.

[jimmyblue]

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.

[BAD LS1]

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.

Good point! this one has a LS3 cartridge style maf with IAT, but not to say it cant be split out of the harness and a traditinal IAT installed in the end of the filter for example.

[LSxpwrdZ]

Does it have any cam position sensor codes?

Sounds like a crank reluctor or cam position sensor issue to me.

[oakley6575]

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.

seemed to 100% solve it so far!

Is this still the case, or is it still hard to start?

[BAD LS1]

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?

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.

[miker2]

Try a charger on the battery when cranking.
That may eliminate the scanner disconnecting during the crank.

that's what fried my interface.there's a warning to use no external power to computer or car while scanning.

[planethax]

that's what fried my interface.there's a warning to use no external power to computer or car while scanning.

Sorry, I have a special smart charger (similar to stacked PC Power supplies) for use in this case.
Cheapo Chargers (especially on Boost setting) can send a voltage spike.

Sometimes when Cranking it is just necessary, or use another good fully charge battery with cables.

[oakley6575]

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.

[oakley6575]

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