Priming, Cranking, Afterstart

[rob@vems.co.uk]

I've drawn this up as an attempt to describe the states that VEMS goes through from start-up to idle.

[dnb]

Just a couple of observations about Afterstart

I presume the warmup enrichment table isn't applied at all in afterstart since it isn't mentioned.

How is the afterstart enrichment scaling applied? 
As (VE_calc + Afterstart_added)*afterstart_scale or as VE_calc + (Afterstart_added*afterstart_scale)?
(Syntactically unnecessary brackets added for clarity )

[dnb]

I've just been looking at the afterstart thing again - there's not enough information to work out the scaling.  What temperature is the afterstart_added parameter scaled to 1?  (I suspect at -40c)  If this is the case, then if the afterstart_scale parameter is too small (ie less than 22%), then it'll result in reducing the base pulsewidths from the map table.  I suspect this isn't desirable as it would be easy to get to zero pulsewidth above 77C! 

Anyone care to comment about my interpretation?

[guzior]

Can you look at this config:
http://www.sendspace.com/file/n0v2vg
I can't cope with the normal starting of the engine. Whether the engine is warm or cold I have a very long spining time and move the throttle to start the engine. Sometimes, when the engine for a long time will not catch, after start it able to show a trigger error.

Injectors are LowZ 750cc/min@3bar with series resistors.

[guzior]

Does someone have any idea?

[gunni]

Do you have a datalog to go with that?

[guzior]

No, but i try to do that.

Here it is:
http://www.sendspace.com/file/9aa1ne

[gunni]

More details about the engine?

[guzior]

Stock Audi 2.2 20vTurbo (5cyl)
Holset HX35/K26 hybride, series triggers (135 tooth on flywheel, 1 pin on flywheel and Hall on cam), Injectors, as I wrote 750cc/min LowZ with 7,8ohm series resistors, 5 coils. Flywheel is a series audi dual-mass.

[gunni]

Have you tried to lower the pulsewidth?
It looks a bit high for 750cc injectors.

[guzior]

Have you tried to lower the pulsewidth?
It looks a bit high for 750cc injectors.

I'm trying many different configs. Starting from 19ms on crank cold and 5.2ms on crank warm to 7/3 and engine still won't start. Maybe crank advance is wrong?

And what is the "cranking threshold"?

[gunni]

I don´t know what that means,

19deg advance for starting it a little high, try 10.

[rob@vems.co.uk]

You really need to check the cranking advance with a gun - then you need to look at the amount of fuel you're putting in at cranking - what PWs are you seeing?  I always start with a rule of thumb of cold cranking = 3 x Req Fuel, warm cranking of 0.75 x Req Fuel.

You may have flooded the cylinders - pull out the plugs let the cylinders breathe and give the plugs a clean.

Check that you have a good spark - I always do a visual check to see that the spark plugs are sparking - make sure that the fuel pump isnt powered.

[guzior]

what PWs are you seeing?

During the cranking, PW is about 8-8.7 (outside is -3.5 degrees).

You may have flooded the cylinders - pull out the plugs let the cylinders breathe and give the plugs a clean.

Done

I always start with a rule of thumb of cold cranking = 3 x Req Fuel, warm cranking of 0.75 x Req Fuel.

I try this tomorrow.

You really need to check the cranking advance with a gun

In this engine is 5 coils, all under one, common cover, which also attaches it to the head. Maybe I can run the gun directly from VEMS?

[mattias]

You really need to check the cranking advance with a gun

In this engine is 5 coils, all under one, common cover, which also attaches it to the head. Maybe I can run the gun directly from VEMS?

I have used a regular spark plug lead between the #1 cyl coil and spark plug, must be done on all Coil-on-Plug engines basically - unless you can trigger from something else (not likely).