Felicia 1.6 idle problem

[cesarbogota]

Hello all,

I bougth a Felicia with 1.6 engine, but the engine not remains in idle, some time after ignition the engine stops.

Any suggestion?. Also the previous owner adapted a ckp using 3 cables in the original harness (green, white, black, brown).

Any idea to help me?

Best regards,

C

Edited 23 October, 2016 by cesarbogota

[RicardoM]

From your description It is not clear if the engine stops a few seconds after start or the engine runs but can't keep the idle speed. In the former case it is an immobilizer problem. In the latter case, read below.

 

The only efficient diagnose in your case is to use a VAG-COM  scanner and look for any errors stored in the memory of ECU. Look also at live data if possible. Coolant temperature, intake air temperature and pressure, rpm.

 

In the absence of any evidence using a scanner, I can guess that either the intake air temperature/pressure is dirty/faulty or the coolant temperature sensor is bad.

 

Also the previous owner adapted a ckp using 3 cables in the original harness (green, white, black, brown).

You should ask him what is that about or restore the original wiring using an original sensor. If there are other improvisations on the car, restore the original wiring too, otherwise you'll have a hard time finding the fault(s).

[cesarbogota]

Hello, 

 

Those are the images form the scanner software:

 

 

 

[RicardoM]

Since I don't see any screen capture with stored error codes, I will assume there aren't any.

 

Note: the absence of error codes could be due to battery having been disconnected recently. In that case, I recommend driving the car a while (or at least start the engine a couple of times) to see if the ECU writes any error(s).

 

Now, looking only at those 3 screen captures, I don't have enough evidence to give you a definitive cause of malfunction (ECU not keeping idle speed). Therefore, I will make a list of hypotheses. You will have to collect more data accordingly using VCDS-Lite.

 

Preconditions:

- no vacuum leaks, no dirty/clogged vacuum hose from valve cover (see video below)

- wiring between ECU, throttle body (TB), and sensors in good order

- no error codes stored

- TB reset performed successfully

- combined sensor (intake manifold pressure + air temperature) clean (no oily residues)

 

Possible faults

• idle switch (inside TB) faulty
• throttle valve potentiometer faulty
• oxygen sensor faulty

Perform necessary tests described in detail in Skoda Felicia Workshop manual (1AV Fuel Injection and Ignition System)

 

Edited 26 October, 2016 by RicardoM