Digifant injection problem

[VEEDUBBED 0]

I've ironed out quite a few problems concerning my corrado's G-charged 16valve 9A mill,1 problem i can't seem to rectifiy concerns the idle speed.

If i start the engine cold it starts first time and has an exellent idle,fast idle is fine during warm-up,the engine accelerates like a motorbike engine,the problem starts when the lamda probe starts cycling,which is normal during idle and cruising,what i can't understand is as soon as the display on my narrow band AFR starts to sweep the engine's idle is totally shot,stumbling,missing etc,if i turn the engine off and start after a couple of seconds the engine's idle is perfect,900 rpm regardless of load,headlights,steering,hrw etc,however,as soon as the small LEDs on the meter start to cycle away from stoich-crap idle,no amount of tuning the co-pot,ign.timing etc has any effect,faulty lamda probe?,then why does the meter show that the 02 sensor works,cycling,fuel cuts when decelerating,full throttle shows rich(after digi-lag)....

Any ideas would be most welcom by yours truly.

Any ideas would be appriciated by yours truly,

[VEEDUBBED 0]

TTT

[sciroccotune 0]

the idle is controled by the idle control valve which is controled by the ecu, have you checked for 12v etc at this valve?

[stevemac 0]

I've altered the thread title slightly to attract more attention.

 

I would imagine that the ISV is, at least in part, functioning correctly. If the engine idles properly when cold, I would expect the ISV to be okay.

 

It sounds as though the ECU is receiving some kind of a signal from the lambda probe but for some reason is not adjusting either the timing or fuelling correctly. I would check the wiring from the ECU to lambda probe, ensuring all earths & other wiring connections are secure.

 

I assume you've already tried a new blue temp sensor & tested the wiring to/from it ?

[sciroccotune 0]

sorry not ke jet then....silly me...

[VEEDUBBED 0]

Thanks guys,yeah, i've done all there is to do,new blue temp sender,timing at ~6/8 BTDC,1 meter hose on the correct nipple,cam timing is ok(KR inlet),changed the idle valve 'cos i've got so many spares i don't have to worry,exhaust is OE with a hollowed out CAT,fuel press is 3 bar at idle and ~4 when under load,plugs are Ngk7es and are a brown/tan colour,even after pushing the engine on motorway,air filter is OE G60,boost pressure is 0.5bar absolute,remember that the static comp. ratio is the original 10.8/1 but doesn't pink at all,huge front mount intercooler,O/E injectors and eeprom(G60),regardless of the comp.ratio,the digifant ecu SHOULD fuel enough for 0.5 boost.

[stevemac 0]

Try unplugging the Lambda sensor wiring & running the car - does it still display the same faults ?

 

Car will run a little rich but should be okay for testing purposes.

 

Could be a faulty probe. Cutting fuel on decelleration & richening on full throttle will be controlled by the ECU from pin-switches on the throttle housing, not the lambda signal.