Help!?
 

Hey peeps hope someone can help me .
If I disconnected my battery my 940 turbo will idle with good afrs for a few minutes then start to lean out to around 20 on my afr gauge.
Driving the car is fine and afrs seem normal . Car idles fine too apart from the lean afr reading .?
It is a modded 940 turbo with to blue injectors and 16t turbo etc etc
Also noticed that a ballast resistor thing is getting very hot is this normal ?
I think its a pre injection ballast or something?
I've already done the resistor mod for the injectors
But this is another one ?
Any help be much appreciated

The ECU needs time to relearn the fuel trims which you erased by disconnecting the battery.

The second resistor is probably for your dim-dip so will get hot, that's why it's aluminium clad to disperse the heat.

Leaning
 

Cheers for reply . I know it needs to re learn .
When I Google the part number it says its a fuel injection pre resistor?
Should idle around 14.7 on afr gauge which it does for a bit if I disconnect battery . Just seems like once car becomes to get warm ot messes up and leans out .
If I leave battery connected it just idles lean all the time .??
Only when I discon Its fine for few mins and you can see the afr gauge lean right out in instant and stay there ?

You need to monitor the lambda sensor and see what it is doing

What is it leaning out to on your AFR gauge?

That begs the question, when you did the resistor mod (i'm guessing you bypassed it to use high resistance injectors?) did you bypass the correct one? As far as i'm aware, you only have one injection resistor.

Yes, 14.7:1 is stoichiometric, lower is rich, higher is lean but as Dai pointed out, you need to monitor the Lambda sensor. The output of that should swing from a smidge over 0.00V to a smidge under 0.99V with stoichiometric equating to ~0.45V. Where is your wideband sensor for the AFR meter located?

Also, just to be clear, you're not disconnecting the battery with the engine running are you? Also is it a known good battery?
Is the engine cold, warm or hot during these tests you're carrying out?

Leaning
 

Hi it seems to always idle around 20 on afr gauge.
Will cruise at 14.7 and 10/11 ish at wot.
So driving it seems fine its why its leaning on idle.?
Just to be clear if I disconnected the battery so it resets itself when I reconnect and start the car it will have good idle afrs until it warms up a bit then goes straight to 19/20. And from that point there after will always have chappy idle afrs. Just can't work out why .
The resistor/ ballast thing I'm talking about sits on the passenger wing with the rsr and power stage thing.
And when I Google the part number it says its a pre injection ballast resistor?
But that part gets really hot after 5 mins of ignition on or engine running and my mates identical car with same mods doesn't?
Any help be appreciated. Also has a brand new bosch lambda sensor with genuine plug .

Check your fuel pressure at idle. Also if the resistor mod is what i think it was, bypassing the resistor so you can run high resistance injectors then there shouldn't be any current flowing in it and therefore no heat.

Leaning
 

Yeah thanks I will check the fuel pressure.
In the same position on the wing there are 2
Ballast resistor things 1 which had 4 in it which I've removed for the injector mod and another with 2 in it which is the one getting hot and don't know what its for?

Some pics would help identify things. I'm wondering if that is the injection resistor and you've modded another resistor or perhaps there are two injection resistors on yours.

What is the Bosch part number on your injectors?

Pictures
 

At your service....
7/46: Dim/dip resistor
20/15: Injector ballast resistors