siemens deka 80lb/s idle problem

[wpp]

Hello,

The engine is a bmw m3 3.2 liter. The engine runs very well with 200cmc injectors with a pw of 2.2ms at idle
I have problems at idle, the pw needs to be ~1ms but the engine afr is very jumpy, it reads from 9 to 35..., id i drive it after ~2000rpm it works ok.
Today i tried siemens deka 60lb/s and they have sa same problem.
The 60lb/s injectors i tried work well on two engines i built, s50b30 and m50b25, they have less capacity and they are runing with stock ecu remaped.

If you have any advice...

Thanks

[MWfire]

flyback is good connected?

[wpp]

flyback is good connected?

yes

[MWfire]

i made cars with siemes 660cc and 900cc and no problems at idle.
660cc need 1.4ms and 900cc 1.7ms(slower open time).

[[email protected]]

Are you batch firing or sequential firing?
have you tried changing the order when the injectors fire?

[GintsK]

Double check your flyback and injections per cycle.
Bad idling could be from low flyback voltage. It is better with not connected flyback (60V internal FET diode), but then it is risky to fried some MOSFET at higher rpms.
I note with 620cc Dekas - usual 30V above Ubatt (~43V) is bit too low. If it is street car and idling quality important it is possible to rise flyback voltage by changing FETs and TVS diode...

Gints

[wpp]

I think i solve the problem, the friend who give me the vems told me that the flyback diode is indside the case, i tried puting a diode on the flyback wire and is working. It idles at 1.2 PW and the idle is stady at ~1200rpm and ~13:1 afr.
How can i check if i already have a diode inside the case?

Thanks

[GintsK]

By opening unit or by checking voltage spike value.

[lost]

Diode to the left ( in yellow sleeve) is connected  to the flyback.
Open VEMS and simply check is it there  ;D

[lost]

[MWfire]

or with DVM messure voltage drop beetween one injector and flyback. If you don't have flyback, voltage drop will be 1-1.4V