Thats good to know.
I thought that if there are issues with OL fueling, that should be addressed with the OL tables, not a table that could affect ALL fueling tables.
Thats good to know.
I thought that if there are issues with OL fueling, that should be addressed with the OL tables, not a table that could affect ALL fueling tables.
Yes you are correct. If it's ONLY open loop fueling "on startup" having the problem, then only open loop should be addressed, BUT odds are, it's all of the fueling as a whole or at least that's what I often find What I was mainly meaning by the open loop part, was instead PE open loop....
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
I haven't put E85 in for a long time (I assume its also problematic too).. It's E0 - E10 and it's consistent taking taking 2-3 seconds of cranking after sitting for 30+ minutes. I'm sure it does it at the 15 minute mark too, but I'm baselining 30 minutes for my testing. It also happens at the 1.5 hour mark as well.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
I have to ask, why did you spend the money to have Banish get the data vs buying something like OEM or ID? Future plans for FI?
My understanding is this.
First offset is not a good term. Offset indicates moving the injection event sooner or later (like SOI or EOI). But apparently offset is an adder to the total pulse width.
The ECM knows the air going into the engine (dynamic airflow) and then divides that by the AFR for the fuel. Then it has to calculate how long to hold the injector open to spray that amount of fuel. There are many variables: fuel pressure, manifold pressure, system voltage, etc.
However, the fuel injector is an electro mechanical device. My theory is that there are two ways that heat effects the injector.
1) heat increases the electrical impedance on the solenoid that opens the pintle valve. This means that the applied current to the solenoid will take longer to saturate the coil, thus delaying the initial opening of the valve.
2) metal expands when hot and due to the small orifices in the injector and the pintle valve itself, the effective area shrinks.
So the offset is an adder to counter act the weakened performance of a hot injector.
And it is in this context that I do not prefer to zero out the offset temp table. I'd love to hear everyone else's thoughts on this.
Last edited by Cringer; 04-27-2024 at 11:25 PM.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
It started because I got too good of a deal on a flex fuel sensor. I know adding E on an N/A motor isn't worth much, but I was chasing a community 1/4 mile list times and every ounce of torque was gold. Ran out of LS3 injector. Tried LSA injectors but the spray pattern sucked. Blindsquirrel suggested L96 injectors (slightly bigger than LSA and correct spray pattern) but they were too small. Found a deal too good to pass on these...I misread the ad in my excitement....thought I was getting ID...I'd never even heard of FID fml. Anyway you gotta piss with the cock you got.
So now this is a tuning lesson for me. Unfortunately.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
I understand the mechanics of heat and an EH/EM component lol. Hence why that table shouldnt be played with Willy Nilly to compensate for something unrelated. I also wouldn't zero it out. Getting it right is going to be the challenge. That's why I said try a known table and "bake" in around it. Best a guy could do I guess?
Last edited by ns158sl; 04-28-2024 at 09:42 AM.
the issue at 30mins is only in cranking mode as it dosnt get to the run mode when realistically it should, so injector data, cranking fuel, cranking spark, startup airflow is all that should be in play
As they should. Cylinder airmass is at maximum with the engine off. Cylinder fills with air. Once you start cranking, airflow begins. The cylinder just isn't empty before. Looks like it needs some fuel back in the OL tables.
I wouldn't bother with anything injector tip-temp related. Outside of a nice set of fine wire thermocouples, it'll just be a guess to calibrate it. Just leave it stock.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
Ok so just a follow up here. 07GTS had commented on a different thread that maybe EOIT was to blame. I had come to this same conclusion (or at least an idea to test since traditional/air/fuel/spark adjustments didn't seem to change anything), but was too lazy to try it. But at this point there was nothing left to experiment with!
So long story short, I swapped in the original LS3 injectors and went back to the OL settings from a 2012 Holden PPV flex fuel vehicle. I wanted to take the FID injectors/data out of the equation. The heat soaked restarts improved, but still were problematic.
I tested in two configurations with regard to EOIT and both worked very well:
1) Delay the spray until just before PPV (trying to straddle PPV with half the pulse width on either side) with Make Up Mode disabled.
2) Take advantage of the Make Up Mode RPM table to chop the total pulse width up into smaller chunks across the intake stroke, but still delay the spray until somewhere before PPV.
Basically, my conclusion is that big injectors make hot start ups worse. This is because since it is a much smaller pulse width due to (a) its a bigger injector and able to move more fuel and (b) the commanded EQ Ratio results in less fuel. Cold starts (with a much richer EQ Ratio) just mask the issue since IPW is longer, resulting in fuel being sprayed closer to the sweet spot.
So by moving to a smaller injector (longer overall pulse width) and spraying close to the sweet spot = much better hot starts. My next test will be to put in those larger injectors and see what happens.
As far as the sweet spot, since a big cam is going to have problems moving air at low rpms during cranking, you have to take advantage of PPV. This gives a much better chance of getting the fuel into the cylinder and less effects of transient issues (fuel sticking to the port walls and evaporation). Perhaps the sweet spot is just before or just after PPV...have to experiment more to see what each engine likes.
Here is the latest log.
LS3 injectors - EOIT Adjustments - Heat Soak 32 minutes.hpl
Last edited by Cringer; 05-02-2024 at 03:49 PM.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
As edcmat-l1 says, larger injectors are like filling a shot glass with a fire hose.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
Because there is very little connection between the air and the fuel in the early stages of cranking. The FA Mult table is a function of soak time and ECT, and the sequential enleanment is a function of injection events and ECT...none of that relates to the air. Its the final value after crank enleanment that should be relatively close to run fuel - but thats where you transition to run fuel, so it makes sense.
You're right about the large injectors being tougher to manage during cranking. Can't defeat physics...is what it is. Still think it could use some mult put back into the OL IVT table though.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
hey Cringer i have a 2014 chevy ss sedan too and also have the same issue so i will be paying attention to this post. cold starts are very crispy and impressive but after driving to normal temps pulling into a drive thru at McDonalds or Culvers and shutting off your engine so other people can hear, start up is lazy af and not the same at all cranks for at least 3 seconds and sounds like a pos.
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
cool. i will make the change and see if that works for mine.
2009.5 PBM G8 GXP M6 W/Roof-Self tune, OBX LTs, Kooks axleback, LSA blower, cam,
Monster LT1-SC clutch, flex fuel, 12 psi [email protected] 1,800 D.A
2007 TBSS-Self tune, bolt ons [email protected], 1,900 D.A
1991 GMC Syclone- Self tune/catback 12.8@104, 4,200ft D.A