Fast idle problem
QCan you shed some light on a fastidle problem I’m having with my 2009 Fiat Panda 1.1 with a cablecontrolled throttle body? It has 45,000 miles on the clock. From a cold start the engine reaches normal working temperature quickly, but the idle speed is excessive when the engine is hot. If I switch off the engine and wait a couple of minutes before restarting, it idles correctly.
I ran the engine with the air filter housing off and sprayed catalyst-safe carb cleaner down the idle speed control valve aperture to clear any blockage, to no avail. The throttle butterfly closes properly and if I block the idle speed valve aperture the engine stalls, so there do not appear to be any air leaks. The vehicle is well serviced and fully-synthetic oil is used. The EML is not illuminated and there are no stored fault codes. Connections appear to be good. The engine starts promptly hot, warm or cold.
The fact that switching off and leaving the engine seems to rectify the fast idle seems to suggest that rising heat could be affecting the temperature sender unit. Is this a possibility or do you think it may be a throttle body or ECU fault? If you think it’s the throttle body, is this a dealer-only part or can you recommend a quality make? Colin Rider
AAs you have said, there are three likely possibilities. The temperature sender could be reading incorrectly and, if you have suitable equipment, I would advise checking the actual reading of the sender using live data when the engine is hot. The other two possibilities are that either the ECU has a problem or the throttle body itself is faulty.
Autodata advises that there was a common problem with your Panda regarding the ECU causing poor idling from cold, which would also cause the engine idle speed to drop during gearchanges. However, this is not the problem you’re suffering from.
I would first check the temperature sender reading, then consider talking to the dealer to see if the ECU software requires updating. If neither of these steps rectifies the problem, I would send the throttle body off to be tested at either ecutesting.com or bba-reman. com. If a new throttle body is needed, actronics.eu can supply a replacement for approximately £205.