S40 V40: Poor idle after battery change

[Richierich73]

Hi, I have searched and read a few posts on this, but they are mostly related to diesel engines.

Car: 2002 V40 1.8i Petrol 122bhp

My problem: After returning from a 2 week holiday, someone had tried to break into my V40, and as a result, the alarm flattened the battery. The battery completely died and would not re-charge, so I have replaced it, but now the engine will not idle very well. It stalls after revving, and during idling it raises and drops engine speed.

I have seen posts relating to Idle control valves and others about the ECU resetting due to the battery change, but I am not sure which is applicable to my engine.

Any help will be gratefully received.

Thanks, Richard

[aldred309uk]

It's not something as simple as dirty or loose battery terminals?

[Richierich73]

Possibly, they were very dirty. Can you explain how this would affect idle speed? I'll check this tomorrow.

Thanks,

Richard

[druid]

You have a GDi and would benefit greatly from using the re-learn.
Here you go

Learning function if GDI engine.
On GDI equipped cars, when the ECu is replaced or the battery is reset (disconnected), an idle
learning function for the ECU will be required

Idle Learning Procedure

1. Start the engine and warm the engine until the coolant temperature reaches 85c or higher.
When the coolant temperature is 85c or higher, you only have to switch the ignition to the
ON position.

2. Turn the Ignition to the LOCK position to stop the engine.

3. After 10 or more seconds, restart the engine.

4. Run the engine at idle for 10 minutes with Transmission in nuetral (P for Auto), air con
and heater off.

5. Stop the engine.

6. Restart the engine and run it at idle for 10 minutes with Transmission in neutral
(P for Auto), air con on at
max cool, fan high speed and windows open.

7. Repeat steps 5 and 6.

Note:
1. When ambient temp is 20c or higher and the air con has been continually operated, step 7
may be omitted.

2. During idle in steps 4 & 6, when engine operation switches from lean operation to
stoichiometric operation,
engine stall can occur. In this case, clean the throttle body (throttle valve) thoroughly
and repeat step 1 and
the subsequent steps.

[Richierich73]

Thanks,

Could someone post a guide to clean the throttle body? I have seen one on a previous post by gatos, but the link has been removed.

I am sure the car will stall when idling

[druid]

It probably will but stick to the system and it will work, as for a guide i cant really help but its not that hard. Take of the corrugated air hose and you will see if you need it or not. Like i say, if it stalls just start it again and carry on.