TUNING and initial Testing


The car starts(cold) on the second attempt and idles very well. I have not connected the auxiliary airvalve to the VEMS yet and if the car starts and idles like this I don't see why I should.

I based my config and tables basicly on Mattias Sandgren's volvo Btwenty.

I made a lambdatable and let the egocorrection do its work. The car runs good but still needs some finetuning especially in low kpa and low rpm.


Q:When i go off the throttle the fuelcut acts brutal. I seem not to be able to save the Map-based values in the acceleration wizard. I have a tps with only three positions(0%, 50%, 100%) so I want to increase the rate of acceleration enrichement Map-based. But everytime I restart megatune with the saved msqfile those values are gone??

Q: What do the following values mean in the Basics Settings menu in megatune?

My A

MAP based Acceleration enrichment wont work for me either,looks like there is a bug with it.First try to upgrade your TPS to a fully working one (0-100%%,with your 3 position sensor its a real pain to tune the car.There is a variable called

Extras/Idle Settings General/TPS value for idle treshold.

When this is set (to say 5%),and above it (5% and on) your configured overrun fuelcut value appears to be valid (the engine revs 1650RPM for example in your situation)(it may,but not for sure,check it) the ECU will cut fuel,avoiding "overrun" condition,and give back fuel when 1500RPM is reached.

Fuelcut under is used for "deacceleration fuelcut",but it looks like reasonable (we use 18kPa,which is much more,so thats may not be the problem).

Hope This Helps //Peter

Jörgens A

Overrun fuelcut will not work well with a TPS like that, when you release the throttle to the idle position the ecu will cut all fuel until you reach the fuelresume rpm. I suggest that you set the overrun_fuelcut and overrun_fuelresume to 25500rpm. You can also choose to keep the fuelcut and make sure that the idle switch is only activated at idle, it must disengage as soon as you even think about touching the throttle. I have been through this a lot as the old CIS Audis have a switch like this that control the overrun fuelcut. The car get very jerky as soon as the switch was not perfectly tuned.