Aircooled beetle cold start CL idle valve behaviour

[OctaneDBS]

Hi guys

I have been having a odd issue with cold starting and closed loop idle, after having tuned open loop i have closed loop idle active and it works perfect except for when cold starting below 2 degrees.
The first 2 start attempts the engine catches and then dies and only after the 3rd attempt the engine start successful, when looking at the data-logs i noticed the idle valve opening the first 2 attempts and closing on the 3rd (PWM duty cl idle active)
I have to admit i have closed loop idle activating very fast but it has been working for anything above 2 degrees.

going through the code i could not find anything explaining this behaviour.
Any clues to what might cause this ? (please scroll down in the screenshot to see the pwm duty)

Screen Shot 2018-01-19 at 08.48.25.png (285 KiB) Viewed 428 times

The car is an air-cooled beetle so 160 deg is normal operating temp ;)

[gtmdriver]

I have a 1600 twin port air-cooled beetle engine running on MS2 v3 using a Jeep IACV to control fast idle. I have never been able to get it to start without at least a little throttle applied but once it's up and running the IACV works a treat to give a quicker idle that slows progressively as the motor warms up.

[turbo conversion]

After looking at you msq you may want to try increasing ase at the temps you are having trouble with.

It has been my experience if the engine fires and then dies in a few seconds it needs a little more ase.

David

[turbo conversion]

I have a 1600 twin port air-cooled beetle engine running on MS2 v3 using a Jeep IACV to control fast idle. I have never been able to get it to start without at least a little throttle applied but once it's up and running the IACV works a treat to give a quicker idle that slows progressively as the motor warms up.

I am using a 95 Jeep IACV and do not have any issues with cold (down to 0* F) or hot start.

It takes some time but when you get all cold cranking parameters and IACV position set correctly it will start with just hitting the key.

David

[gtmdriver]

I have a 1600 twin port air-cooled beetle engine running on MS2 v3 using a Jeep IACV to control fast idle. I have never been able to get it to start without at least a little throttle applied but once it's up and running the IACV works a treat to give a quicker idle that slows progressively as the motor warms up.

I am using a 95 Jeep IACV and do not have any issues with cold (down to 0* F) or hot start.

It takes some time but when you get all cold cranking parameters and IACV position set correctly it will start with just hitting the key.

David

Sorry. I wasn't suggesting the problem was with the valve, It seems to be a problem with the aircooled VW engine. There was another post a couple of months back from someone who found that the flat four needed a lot of cranking to get it to fire.

[OctaneDBS]

hi guys for the reply's

That seems to align with the experiments i been doing, i have been adding ase and been decreasing the cranking idle pwm which seems to improve it.
still it seems odd when looking at the ase, cranking and pwm curve's, they goes almost strait up ....

i am afraid when adding more ill drown it ;)

Screen Shot 2018-01-26 at 10.23.02.png (422.58 KiB) Viewed 347 times