Hi Everyone,

I've spent a lot of time looking for answers on briskoda and the information has been very helpful but I'm still having problems.. Please help!!

The car is a 1997 Skoda Felicia 1.3 Spi. 58,000 miles. It starts fine when cold, but after 15 minutes or so starts to run terribly and stalls at idle. If I let it cool for a bit it will start fine until it warms back up then same problem.

So far I have:

• Replaced: ignition coil, plugs, rotor, spark plug wires, coolant temperature sensor, fan switch sensor, hall (crank position) sensor, battery, new tank of fuel, fuel filter.
  
• Adjusted: Tappets (no change)
  
• Attempted ECU reset via battery disconnect and earth to body
  

Notes:

• Vag Com reads with ignition in on position engine code: hall sensor no signal (due to not being running?)
  
• Upper radiator hose is cold until thermostat opens and then is hot. Coolant was low before but filled up with no air pockets and still same problem.
  
• Throttle cable is taught.
  
• Wiped down the throttle body but it was clean as a whistle anyway
  
• When running without air intake there is even fuel spray from the injector into throttle
  

So, I have no idea what to do. One thing I have noticed is that at idle, the butterfly in the throttle is not moving at all on its own... Is it supposed to???

Please help, love this little car!

Edited 11 November, 201015 yr by sky

Hi Everyone,

I've spent a lot of time looking for answers on briskoda and the information has been very helpful but I'm still having problems.. Please help!!

The car is a 1997 Skoda Felicia 1.3 Spi. 58,000 miles. It starts fine when cold, but after 15 minutes or so starts to run terribly and stalls at idle. If I let it cool for a bit it will start fine until it warms back up then same problem.

So far I have:

• Replaced: ignition coil, plugs, rotor, spark plug wires, coolant temperature sensor, fan switch sensor, hall (crank position) sensor, battery, new tank of fuel, fuel filter.
  
• Adjusted: Tappets (no change)
  
• Attempted ECU reset via battery disconnect and earth to body
  

Notes:

• Vag Com reads with ignition in on position engine code: hall sensor no signal (due to not being running?)
  
• Upper radiator hose is cold until thermostat opens and then is hot. Coolant was low before but filled up with no air pockets and still same problem.
  
• Throttle cable is taught.
  
• Wiped down the throttle body but it was clean as a whistle anyway
  
• When running without air intake there is even fuel spray from the injector into throttle
  

So, I have no idea what to do. One thing I have noticed is that at idle, the butterfly in the throttle is not moving at all on its own... Is it supposed to???

Please help, love this little car!

sounds like a possible throttle position sensor issue to me! unfortunatly its a "sealed" part for the throttle body. but thats not entirely true. If you remove the throttle body you will see on the right hand side of it (when oriented same way as it would be fitted to engine) a end cap with metal flaps bent over holding it on. prise open these flaps and eventually the cap will pop off. go mental with the carb/brake/switch cleaner in there.

when your hapy its been throoughly cleaned check that the little wires going to the idle microswitch are intact, and that the switch has continuity when the butterfly is fully closed, and no continuity when you open the butterfly.

put it all back togther, refit to car. remove battery power for a bit to help clear the ECU and then give it a whirl. Redoing the basic settings in VAG COM may be necessary as well

hope this helps,

Gavin

Does it have a MAP sensor? Poor running and stalling when at idle was caused by that on my wife's Fabia 1.4 MPi...

HTH

Do you know what the "hot idle" speed actually is? This sounds like the hot idle may be too low, particularly if the engine runs fine as soon as you open the throttle.

Autodata says 800 +/- 50 rpm, adjusted using 'A'

So set it to 850rpm and see how you go...

Notes:

• Vag Com reads with ignition in on position engine code: hall sensor no signal (due to not being running?)
  
• Upper radiator hose is cold until thermostat opens and then is hot. Coolant was low before but filled up with no air pockets and still same problem.
  
• Throttle cable is taught.
  
• Wiped down the throttle body but it was clean as a whistle anyway
  
• When running without air intake there is even fuel spray from the injector into throttle
  

1, it's normal for vag-com to only work with ignition on

2, radiator hose normal to only get warm when thermostat is open

3. throttle cable should not be tight, there needs to be a little bit of slack, try and post a pic up if possible

4, cleaning the throttle is always a good place to start

5, fuel mist at the intake is normal

1, it's normal for vag-com to only work with ignition on

2, radiator hose normal to only get warm when thermostat is open

3. throttle cable should not be tight, there needs to be a little bit of slack, try and post a pic up if possible

4, cleaning the throttle is always a good place to start

5, fuel mist at the intake is normal

is it normal for vag-com to read hall sensor no signal when only the ignition is on, with the car not running?

i'll slacken up the throttle cable a notch or two.. it was very loose but at the advice of another post made it taught, which made no difference to the problem.

the throttle doesn't move at all on its own when idling no matter how loose or tight it is though...

i'm thinking maybe the iac or stepper motor, that is, if the throttle should be adjusting itself to compensate at idle. the idle speed does feel very low.

any ideas what could be wrong?

yes that's right the hall effect switch does nothing when the engine isn't running, the way it works is a magnetic field is created by the lug on the flywheel passing the sensor whiich is amplified by the ecu, and obvisouly if the flywheel is not spinning you dont get the signal.

my initial guess is the stepper motor in the throttle housing is bust, it's very common for them to fail... i'm on my 4th throttle body now and that started playing up yesterday.. in fact whenever i see them in breakers i always buy it to keep ready as a spare (the 16v ones are a bit rarer)

I see where the throttle cable argument is coming from, but I'd think that it's more likely to cause problems with cold running if it's too tight.

Also, I've a nasty feeling that Tom's right about the stepper motor, but checking the base idle speed first is cheaper!