Cold Start
Hey all,
Been fighting a long cold start crank for a while. Finally decided to figure it out. Have been adjusting the crank and after crack fuel and seem to have gotten lucky and it’s better but not where it should be, now it seems to flood out and have to keep the pedal depressed some. . But I guess my question is this.. are the positive number increasing or decreasing fuel to the throttle body.. pretty sure it’s increasing but I started to second guess myself.Its SBC Chevy 396 with
- .544 Intake / .555 Exhaust
230 Intake / 236 Exhaust duration
@ .050, 110° lobe separation angle
When I did my initial start years ago it fired right up but ever since take 20 30 seconds to start.
current settings are
prime fuel multi 87
crank fuel 20 14.8
crank fuel 65 13.3
crank fuel 170 8.6
afrer start are the same
Warmup 20 4.0
warmup 70 7.0
Any other setting are out of the box
live in Fl so i really can’t test the 20a till like Jan/Feb.
any suggestions would be welcomed..
TIA
Positive increase does increase fuel. Every combination is different. My 350 has been a bear to get cranking correct. My prime shot is maxed and all my cranking is maxed. Starts rich sometimes, but it starts. Working to fine tune.
yea feel the pain here... been battling some "cold" start issues myself..
Initial start up is not too bad but then would roll way fat..
The first couple minutes indicates lean at 14.7ish requesting 13.2 give or take..
First thing I did was take away "prime fuel Mult" (-100) from some positive number, well initial start up was no longer dead rich.. ended up at -75 to alleviate a lean pop up intake on crank..
all the choke fuel and crank mult are at 0 with exception of the Crank Mult 20 being at 9.4%
I still have some overly rich condition in the first couple minutes of start up then am fine..
I really need to find where to crank the AF (requested) number up a bit in the first couple minutes to lean it out about half a point..
Some of the parameters seem apparent but FiTech has some relationships inside their system they do not explain very well..
And this:
This value will control how quickly the fuel learning adjusts itself at IDLE to get the fuel closed loop to be near to 100%. Too quickly will cause problems for several reasons, so don't do it.
Would be far more helpful if they took a couple minutes to explain the statement lol
I am still fighting with it... I think I am going to reset the crank numbers to default and go from there. Not sure why this should be so hard...
Looks like your a little high on some of those numbers. I have a chev BB 427/550 HP and most of my numbers are in the negatives.
Try setting your prime fuel multiplier to 100. Lower all the other values a little at a time. For example Crank fuel at 20*- 14.8, bring it down by 5 to 9.8. What's the average temperature you start the car in. If you live in a cold climate this is the important one. For myself I changed the temp. breakpoint from 20* to 32* in the pro-tuning section. Anyway as the breakpoints are closer to each the changes the ECU makes allow the differences in temp. to be closer so the fuel is metered slightly different hoping to give you a better cold start.
Crank fuel at 65* bring down by 5-6.
Crank fuel 170* does it start good here I'm guessing it's too high as well.
I'll check my handheld tomorrow and post my values. My car starts without fail in any temp as long as the battery can deliver a full 12 volts or better at time of ignition. There's more but I have to check my handheld.
65-StingRay/Wayne
Hi Wayne,
thanks.. I reset everything to 0 and brought prime fuel down -40 or so. Made a huge difference. I am in North Florida so won’t get too cold... mostly 40/50s a few days of 20/30s. Right now it pops right over but still a little rich. Going to keep bring the multi down until it stops making a difference and see how rich/lean it is then head back to the crank fuel..
Thanks!
I snapped a couple of pics of my crank and warm-up. Use these only as a reference not as an exact standard. Again it comes down to HP, cam, vacuum etc. Good Luck.
65-StingRay/Wayne
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hey guys, Im new here and new to fitech.
Just reading up on a few things so I can get my system running properly.
My issue is cold start. I have to prime the system 5+ times before it will "catch" and fire. Once running, it runs strong.
In reading what you are talking about in this particular forum, regarding ambient temp upon start up and setting your crank fuel settings....I live in Canada. It gets cold here, haha...am I to understand that my settings in the crank fuel should be set rather high to ensure that I'm getting enough fuel on cranking so it will fire?
you guys all seem to be missing the crank iac setting, you need to balance the air fuel ratio when cranking and starting, add some air to it, reduce some fuel, reduce some air, add some fuel, every motor is different, after you get it to start fine tune with crank fuel AND crank iac, balance it