EFI Cold Start Maps?

[JohnJL]

I had to abort a day at the track, towed all the way there and she wouldnt start for anything. This has been a problem before.

Today I progressively tested increasing cranking fuel settings by 10% throughout the day with no success. Temps were between 5 deg C and 10 deg C, I left 30 mintues between each attempt to let the cylinders clear and charge the battery. I logged every attempt but no joy.

Anyone running EFI willing to post their cranking fuel maps? I'm super frustrated...2 hours tow in each direction, plus 8 hours today = no joy.

If you dont have a map to post, if you know % increase in fuel from hot starts for cold starts that would be helpful too.

Thanks

John

[drmatera]

on a 50* cold start i'm around 20% more fuel. Be careful, non start when cold doesn't always mean lack of fuel..... did you try to flood clear it? ie: throttle at WOT while cranking. That typically cuts off the injectors so you can crank the engine over to clear out a flooded condition

[JohnJL]

Thanks for that, I'm surprised how low your enrichment is. I started at 100% more than the idle pulsewidth and kept increasing in 10% increments from there. I regularly did as you suggest, starting ending each attempt with a WOT floodclear for 2-3 seconds. My ECU is also set to automatically floodclear every 14th unsuccessful cranking event...

It starts OK in warm weather (70 degrees F) with 14ms pulsewidth, which is ~100% more than the cold idle pulsewidth (idle waries between 4ms and 7ms depending on temps)

[drmatera]

sorry, been a long day. my cold cranking tapers from 400% @ -40*

[proffighter]

As I am not finished with fine tuning, it will make no sense to post my setup, but I can tell you I am about 200% of the value at cold start, like this:

Value injection at 1000rpm: 60
Temp fuel value at 5°C: 65
Start value at 5°C 10

Total amount then: 135
I can post my whole map if needed... it runs well but needs still a bit fine tuning.

[Midlife930]

Hi,

Last weekend temps, my cranking is just under 300% and afterstart enrichment is about 40%.

Dave

[JohnJL]

Guys,

This is exactly what I am looking for, thanks. If you are willing to post screenshots of your posts or more datapoints like those then please so.

Thanks!

[proffighter]

What kind of EFI are you using? Megasquirt, SDS,...?

I will post my table this evening (Here in Switzerland), when I am back at home. For you it will be late afternoon

[JohnJL]

Thanks. Its Adaptronic.

My post-start enrichment seems right, the problem is getting it to catch at anything less than tropical conditions.

[proffighter]

Do you read AFR's?

[JohnJL]

Originally Posted by proffighter

Do you read AFR's?

Yes, except during cranking.

[fletcher0780]

[proffighter]

Here is my complete map, feel free to ask if you need further infos:

[JohnJL]

Awesome. Here are my current ones, I'll do some contrast and compare. Thanks guys!

Main corrections menu



Cranking corrections table...weird curve here because I was only fooling with the corrections at the ambient watertemp, which was about 7 degrees Celcius. This is towards the end of the day, I have worked up from 100% extra fuel to 210% extra fuel at the current temp. Yeah, I know it ways Water Temp but fear not, it is Oil Temps, as it should be ;=)



And finally a screenshot of a log of an unsuccessful starting try...I highlighted the rows where the starter was engaged...





Anyone else who wants to post their enrichments or tables is formally and cordially invited!

[drmatera]

Mine are high due to the E85

[JohnJL]

Fletcher, that's a very useful, thanks. I see NE CT, where? I grew up in Marlborough.

Roland, our cars have some very similar parameters. We're both aircooler 911s with ~3.4L, intercooler boosted and running 55lb injectors. I am not familiar with your tables, could you translate those to what your pulsewidths are at say 32F (0C) 60F (15C) and 77F (30C)? Are your fuel pressures ~40psi?

Dr, do I understand you right that you run 20% more fuel at 50 degrees F during cranking?

Thanks guys

[drmatera]

here is my cranking table. note the drastic drop off around 90*, that is when my warm up valve closes

[proffighter]

I don't know pulse width as I don't use them, but tabe is structured like this:

Value 0 = 0%
Value 255 = 100%

This is only for one parameter, not duty cycle of injector!

There are following parameters which end in the total amount of fuel:

rpm's
MAP (pressure)
Engine temp
Air temp (given by ECU, should not be changed)
Start temp (additional fuel when starting for choosen cycles)

Fuel pressure is 3bar=43psi

When you look at my table then, you get a total of (0°C air and engine temp):

67+46+75+33+89=310

Here table and temp chart:

[b930]

Roland, any idea how to access the air temp map in the SDS? I thought it was hard coded in for their GM sensor. Would like to change mu table as it runs lean after hot soaking.

[proffighter]

Yes, you'll find it on the SDS webpage, here:

EM-4 Tech Page

Scroll down to "How to enable access to air temperature values"

Don't know if it's valid for EM-5 too... Anyway, be careful, it's hidden for some reason!

There is also a comparison between different type of sensors