Garage19

Any ideas on how to get a stronger idle?

Problem is i think i have found the limits of Megasquirt.

Setting up col's car (2ltrZT) at the mo which has 680cc injectors and I'm struggling to get a decent idle.

I think the problem is MS only has 0.1ms resolution. I am getting pulse widths of say 1.6ms at idle and 1.2ms of that is injector opening, so this leaves a true open time of say 0.4ms.

This means i the minimum adjustment the ecu can make is 25% either way of the existing fuel delivery.

Needless to say it does not love running closed loop at idle.

At the mo i have set the idle higher (1100 rpm) where i can get a good strong idle. As it is mainly a track car this isn't the end of the world i suppose.

I guess the only proper solutuon is to swap on to MSII that doesnt have all the features developed yet, but does have 0.01ms resolution.

reality

The other alternative is to go to 8 smaller injectors and use staged injection in ms+extra code 8)

ECU Monitor Enthusiast

iTrader: (1)

Megaquirt isnt sequential injection so that is a big disadvantage with
large injectors.

Dont know if its possible if megasquirt has the feature, but try
advancing/retarding the injector fire point (with respect to crank position).

Stu @ M Developments

iTrader: (12)

What exactly is teh problem? High HC's? Too rich? Too lean?

Exactly what i was about to suggest.

If that fails, try swinging the cams to obtain a more stable air velocity at low speed.

reality

Unfortunately it doesn't.. it's pretty crude!

ECU Monitor Enthusiast

iTrader: (1)

You could try lowering the fuel pressure slightly but you would need to
remap the whole thing again and obviously, you reduce the ultimate
BHP of the injectors.

JesseT

MS2 is the obvious answer, but there is also the new HiRes version of the firmware that improves on the old 0.1 ms resolution limit. Also make sure that you have the number of injections per cycle at a minimum and alternating.