How-To: Warm/Hot Starts (and cold ones) with E85

[mplspilot]

Hot starts. My car never wanted to start without a tap on the gas pedal when it was hot/warm. Number one idea was that something is wrong with fueling — leaky injectors, FPR not holding pressure, too much cranking fuel, not enough cranking fuel. Or air, not enough ISC steps, etc.

I've played with cranking fuel tables for hours, all to no avail. I've changed the "Desired ISCV initial position" tables, nothing. And then one day i decided to log ISC and figure out where the values come from. It looks like when the car is shut off the ISC is looked up from the right column, middle row (110 row in my definition) of the "Idle Stepper Look-Up" table. After the car is started, the ISC rapidly reduces using rows that go up to the very top. When the car sits longer after shut-off, initial ISC is looked up from further down the table, therefore it increases (rows marked as 140, 150, etc.).
It looks like when the warm start is an issue there is not enough ISC steps. They need to be increased. In my case increasing the value by ~20 steps in that area and toward the top of the map solved the problem.

I have no idea what the vertical definition/scaling should be. It looks as though when driving it is scaled in TPS as ISC Steps follow that exactly. When decelerating it looks to become RPM and when the car shuts off it may be time.. I dunno. It neither here nor there i guess im not a coder..

When it comes to cold starts, I've never had the issue as I live in MN where the winter E85 blend has 30% gasoline. Starts fine at as low as -20F. But if you ever experience cold start problems it is because ethanol doesn't vaporize when it's cold. It's flash point is about +12C AFAIK. So when you start the car in cold weather what ignites is gasoline. So if you have issues with cold starts you need to add fuel, to make sure there is enough gasoline in the mix when the car is cranking, with cranking enrichment tables as described here, courtesy of smart folks on here discovering new tables : cold start enrichment table


On to the pic:
2 tables on the left — cranking adjustment. Add if the problem is cold start.
2 tables in the middle — adjusted ISCV tables. To keep the car running at stop lights (up the "Desired ISCV Initial Position" at hot temp rows) and to have nice warm starts (up the values on the right side of "Idle Stepper" look-up table)

1 table on the right — stock ISCV look-up table for comparison.



Hope this helps someone.



Edit:

If you have the Temp X axis with values from -32 to 41, use this as a start:

[travman]

Are you running an open air filter?

[fixem2]

Thanks

[mplspilot]

Travman,

Yep, i run an open filter and switch between stock rubber pipe and Injen metal one. Rubber one gives the smoothest idle (and FWIW the loudest Forge RS DV whistle ) and metal one seems to give a tad more boost up top. Idle is tuned with Injen too, so it's smooth, just sometimes AFR swing up for a little bit and it gets a lope. I don't like that too much.

BTW i should have maybe mentioned that i run TTP 1000cc injectors and 280 HKS cams among other things.

And now it starts like a champ all the time, no more gas blips.
Let us know if this helps your warm starts, hope it does

[fixem2]

Look at my 96530006 ROM, my stepper table is based on COolant temp. Also what Desired ISCV table did you adjust or all of them?

I have attached a pic of what I am looking at.

[gunhaha]

Mplspilot,
On the warm start fix, did you noticed the car rpm stays up high (2000 rpm) for a few seconds after the car starts?

Also, for the my IX the Idle Stepper Lookup Table looks different from what you shown.
It goes from 8 to 81 on the "throttle position (unit)" x-axis and 0-1016 on the "rpm (rpm)" y-axis.

Thanks.

[mplspilot]

Originally Posted by fixem2

Look at my 96530006 ROM, my stepper table is based on COolant temp. Also what Desired ISCV table did you adjust or all of them?

I have attached a pic of what I am looking at.

Mine is based on coolant temp as well. (it says throttle position, but dont pay attention to that) Different ROM's have different engine temp scales, yours is from -32 to +41 C, mine is from -32 to +82. It doesnt matter. What matters is where the ISCV value is picked from when you try to start the car and have issues. Im my case it was in a 110 row, 2 right most columns. So once you figure out where it is, my guess is just like mine it's somewhere in the middle right part of that table, increase those values by 20-30 and smooth them out with the rest of the map.

For "ISCV desired" i changed the one "in neutral". One "with AC on" already has big values in it (that's why btw ppl that have issues with their car stalling at stops can remedy that by moving their HVAC control to the windshield).

[mplspilot]

Originally Posted by gunhaha

Mplspilot,
On the warm start fix, did you noticed the car rpm stays up high (2000 rpm) for a few seconds after the car starts?

Also, for the my IX the Idle Stepper Lookup Table looks different from what you shown.
It goes from 8 to 81 on the "throttle position (unit)" x-axis and 0-1016 on the "rpm (rpm)" y-axis.

Thanks.

Mine doesn't but you can try using smaller numbers in the upper portion of the map and see if that resolves it. Reduce the upper 6-7 rows by 10-15 steps maybe (put them closer to stock).
I'm assuming it started when you altered the ISCV table? Because it could also be cause by high timing if you changed any of your warm-up timing tables.

And don't worry about what the axis' say.. It may be using a scaling other than "Temp". You can click "edit" on the table and change the scaling to "Temp" for X axis if it isnt.

[LV///R]

I'm going to try this when I have some extra time. I did finally get tuned on E85, however "hot starts" require a bit of throttle at start up for me still.

Thanks for the info!

[gunhaha]

Originally Posted by mplspilot

Mine doesn't but you can try using smaller numbers in the upper portion of the map and see if that resolves it. Reduce the upper 6-7 rows by 10-15 steps maybe (put them closer to stock).
I'm assuming it started when you altered the ISCV table? Because it could also be cause by high timing if you changed any of your warm-up timing tables.
And don't worry about what the axis' say.. It may be using a scaling other than "Temp". You can click "edit" on the table and change the scaling to "Temp" for X axis if it isnt.

I did not changed the ISCV table as I don't have any issue on stop light. I did not change any warming up timing.

I only changed the Idle Stepper Lookup Table to try fix the warm start hesitation.
It jumps up to 2000 rpm only for about 3-5 seconds after it starts then goes down to normal idle rpm.

[mplspilot]

Originally Posted by gunhaha

I did not changed the ISCV table as I don't have any issue on stop light. I did not change any warming up timing.

I only changed the Idle Stepper Lookup Table to try fix the warm start hesitation.
It jumps up to 2000 rpm only for about 3-5 seconds after it starts then goes down to normal idle rpm.

I got ya. Try something similar to this:

[fatgc8]

good writeup man..

[lan_evo_mr9]

On my car during cold starts (anything below 60 degrees ambient) it wants to stall after the first 10 seconds or so unless I give it a little throttle. Would altering the idle table help this situation. I can stop giving the blips of throttle after about a minute or so.

[RAbishi]

Thanks for the writeup.

[mplspilot]

Originally Posted by lan_evo_mr9

On my car during cold starts (anything below 60 degrees ambient) it wants to stall after the first 10 seconds or so unless I give it a little throttle. Would altering the idle table help this situation. I can stop giving the blips of throttle after about a minute or so.

Try altering the big table, but first add 5-10 steps to the ISCV initial position tables and see if that makes a difference. It's better if you can log the steps with Evoscan just to see where they are at when they car tries to die and then alter the table and verify with Evoscan that it's actually using more steps and see if it helps the problem.