Engine start very very difficult when cold.
I can start the engine only using ether.
Once started during warmup I can maintain only using the accelerator.
To summaryse a lot of sympthomes makes me suspecting srongly the IAC valve not working properly.
This valve was used on my previous engine and mecanically checked.
But data in VEMS play an important role and I am now investigating on the VEMS parameters to control well this valve.
I recorded log and did initial analysis.
I saw that the IAC duty cycle is always 100%
I saw a frequency of 200hz and PID of 255, 25, 10.
I saw in other config that some are using lower frequency and different values for PID, warmup etc...
How to set or get good reference parameters for a quick start of the engine and warmup available for Audi 5 cylinders ?
Many thanks in advance.
Laurent.
Is it a Bosch 3-pin IAC ? If so, 100hz seems to be the correct freq http://www.vemssupport.com/forum/index.php/topic,1900.0.html
Chech that Dual Solenoid is Enabled Check wiring and that Higher DC% == More air into engine, not viceversa (forget this in case of a 2-pin IAC)
PID values of 50/25/50 seems OK.
You have to set the IAC Reference curve vs CLT to reasonable values.
Under "Start/Idle -> Idle Crankning, PWM" you can set DC% at crankning. 85% is probably OK at cold engine, same or lower at warm engine.
Remember the fueling at cranking must be set correctly also. First set Crank VE% when warm and laborate with "Start/Idle -> Crankning Enrichment Curve"
/Erikk