Fiesta idle

Caerdyddblue · 19-09-2019, 11:40 AM

Hi everyone,

Posting this as hoping to get some advice/tips on what people may think the problem is with my Fiesta, not sure if they are linked together or could easily be standalone. Tried to find out as best as I can online but haven't found anything.

First of all on start up my Fiesta holds a high idle (about 1200-1300rpm), stays flat in that range until the engine warms, then it drops down to the normal 800-900 range, if the engine is turned off and restarted then it goes straight to the normal range if the engine is still hot. Once the engine is hot, the range is normal however the idle will hiccup, drop a few hundred rpm then pick straight back up, sometimes it can have a few together or a single hiccup.

Secondly when the AC is turned on, it kind of feels like the wheels are sort of slipping, goes away when its been on for a little while, is this just the system starting to pressurise or symptoms of a larger problem?

Finally a more simple one, what km range should I be looking to have the timing belt changed?

Thanks,

Ben

GTLEGEND · 20-09-2019, 09:22 PM

Year or model and engine/trans configuration will help identify any potential issues for one to assist.

**russellw** · 21-09-2019, 04:58 AM

The high idle at startup is almost certainly a sensor failure but you'd need to scan for codes to know which one as several could cause the symptoms.

When the AC starts there are sensors that raise the idle speed to compensate but unless you have a slipping AC compressor belt there shouldn't be anything else related.

As noted above, timing belt will depend on which engine you have.

Caerdyddblue · 21-09-2019, 05:42 PM

Quote:

Originally Posted by GTLEGEND

Year or model and engine/trans configuration will help identify any potential issues for one to assist.

2007, 1.6l petrol, manual. Thanks!

**Luke Plaizier** · 27-09-2019, 01:15 PM

Re: the high idle or idle hunting....

Do some research on the PCV valve for your car - like in UK forums for example (Mk6 or Mk6.5 Fiesta). On some motors a cracked hose between the PCV valve and the Intake runner can leak extra air into the intake and cause idle problems. It is a thing on many cars. It definitely affects the XR4 and is a right ***** to access on that motor, but it has also happened on my BA XR8, which was much easier to get to.

Luke

**Luke Plaizier** · 27-09-2019, 01:52 PM

An example of how much of a dirtball it is to get to on the XR4/ST150:

Luke

**Luke Plaizier** · 27-09-2019, 02:02 PM

Whilst it doesn't specifically help you here, this is how much easier it is to change on a BA XR8.....

Luke