Buck-Strickland

Slow start issue. Engine cranks for 3-5 seconds before it starts. Any suggestions on how to speed this up?

I’ve read suggestions to change the Ignition parameters to custom, select 24X 1X and change the coil dwell to 5ms. I’m afraid to try this; will it hurt my stock truck coils?

Other issue, randomly the idle will swing about 500 rpm up and down, seems to happen a lot after long decal, like coming off the freeway off ramp. Also, does it randomly. Happens at some point every time I drive it, but I could sit idling for 10 minutes and never have an issue. Does this have something to do with the Decal fuel? Or is the Learn feature getting into a loop of over correcting? Perhaps I should turn down the gain on the learn feature, currently at 5.

Back ground info:

Holley HP efi, 2004 5.3 from a truck, Stock truck coils, stock cam, heads etc. Only upgrades, headers, 30lbs injectors, and 160 thermostat. I’m using the LS1 tune from the Holley global folder.

Otherwise great setup!

bmf5150

Have you tried transfer learn to base,then going into fuel map and smooth out area in idle area ?

Buck-Strickland

Not yet. I can try that, but I wanted to wait a little longer, I've only driven it about 100 miles. Would that cause the idle to bounce? The idle is set at 750, but it will bounce from 500 to 1100, back and forth. If I bring the rpm up to 2500 and hold it for a moment it seems to calm down again. Otherwise it drives great.

bmf5150

The Holley tech guys told me to drive it then transfer learn to base,then go back in fuel map,and bring down and spikes !i was told to repeat process multiple times till learn table has very little correction!!

Gray86hatch

iTrader: (83)

With the set up you have I would guess your correction is very little. With in 2% I would not trans the correction to the base. It will put some holes in the map that you will have to go back and fix.

THere are some changes you can make with the IAC Hold time that may correct your decel idle issues

Tim

Buck-Strickland

Tim,

What changes to the IAC hold time do you suggest?

soundengineer

iTrader: (16)

raise your IAC hold % and raise the hold time and the decay times...

heres what I'm using that works quite well for a lot of cars
IAC Hold 40%
Ramp Decay 2.0 sec
RPM Above Idle to start ramp 1000
RPM above Idle to re-enable Idle Control 100

Startup IAC Hold 3 sec
Decay time 4 sec

usually good enough to get you started...
if it hangs too long at startup for your liking or if it flares real high, try decreasing the Hold time a little at a time till it works for your setup.

also, getting it to fire right away is also a function of the right amount of cranking fuel...
try adding to your cranking fuel 5% at a time and see if it improves, if it gets worse, try going the other way.

bmf5150

Sound engineer is the man when it comes to tuning!he helped me alot!

soundengineer

iTrader: (16)

also, your idle swing, may be as simple as the timing being too high or too low...
try a static timing to start with... you can pull it up in the menu of the software to command static timing... find where it produces the most manifold vacuum, and then back it off 4 degrees..then set your idle areas of the timing tables to be that value

Make sure Idle spark is enabled after you find what it likes for vacuum, and try increasing the 2 values a little bit

if using the LSx IAC, then see if its really jumpy or not moving much at all...
you really dont want it jumping around too much...it needs to move, just not drastic swings..if you need to, change it from LSx IAC to FAST, or to SLOW...you can even pay with the custom settings... but thats really for guys like me that understand what each value really does..

Make sure your IAC position is 5%-10% when you are at idle at full operating temperature....if it isnt, then you need to open up your TB blade and do a TPS reset.


if you have a big cam, then you may need to use Alpha-N at idle...basically below a certain RPM and TPS of your choice, you set the fuel with a mini 6x6 table...
you could just be seeing big fuel swings due to a Camshaft, alpha-N is great for making it a set fueling at idle, and still learn like normal everwhere else... its still going to compensate at idle, it just wont learn at idle.

Gray86hatch

iTrader: (83)

My timing at idle is about 40 with both engines. Really smooths them out

Tim

Buck-Strickland

I'll check all those settings and try them out. I attached my Base Timing table let me know if it looks wrong in the idle area. I know its low in the WOT section, but I'll bump that area up to 27-28 degrees later.

The car idles at 750 rpm with about 32 kPa. Also, camshaft is bone stock truck cam.

Thanks guys!

73metalman

Good reading. I'm getting ready to take the Holley Dominator plunge.

Gray86hatch

iTrader: (83)

Get it up in the mid to high 30's it should idle much better

22 is low. Hook up a vac. Gauge and raise the timing to max vac. And best idle

Tim

soundengineer

iTrader: (16)

Leave it at 22-26 for a stock cam....
26 is probably about where it makes the best vacuum... then -4 gets you to 22



you dont want your timing at Max value at idle, you want it a little below so that it can correct up or down as necessary for stable idle

soundengineer

iTrader: (16)

I wass Just playing around tonight...my starts are fast enough, but I wanted to see if I could get them faster...

so as a wild guess...
I set my "RPM to Run" to 0
then as soon as it sync'd, it started...

Just make sure your wideband is warmed up first before turning the key...and as soon as it sync's it will autocorrect fuel instantly and you will get an instant start..