Engine management system

[PogoBitten]

The engine idle revs on my Peugeot 306 can vary from 700 rpm to 2400 rpm without any driver intervention. The idle regulator has been replaced but this was to stop the engine cutting out when dipping the clutch. The local Peugeot agents are unable to solve the problem, having had the car back half a dozen times. The engine management warning light comes on for prolongued periods when traveling more than a mile. Any one want to buy a pup? Or any suggestions how to cure. Thanks in advance

It now transpires that there are a multitude of people with ECU problems in 206's, and 307's as well as my own experience in a 306. It appears to be a universal ECU problem in cars less than 5 years old and Peugeot are continuing to deny responsibility or to fix with a re-call. Be warned.

[Mr Vegas]

A large variant in idle like your car's sounds like an uneven fuel/air mixture,usually this is caused by an air leak into the engine which is unmetered by the airmass/flow meter,or the engine management recieving incorrect signals from sensors around the engine e.g o2 sensor.Or lastly the ECU is at fault.

You'll have to do some checks which the mechanics should have done-check around the engine for hissing noises(air leaking from vacuum hoses) and any hoses that are disconnected or perished etc.

The fact that your engine light is on is a good thing for problems like yours-this CAN direct you into the right area if you can read what faults are stored in the memory of the ecu(which according to the year and type of engine,the mechanics would be able to see).This is where engine size/model etc would come in handy..What have the mechanics actually done?

it could be a few things depending on what you have had checked and when the problem occurs when cold/hot etc..but really need more information to help..

As for your comment about ecu's,i suppose it depends on what you have heard but ecu's aren't always to blame a lot of times it comes down to the people that's working on the car's lack of knowledge of electronics and correct diagnostics.It's very easy to assume the ECU is at fault because of it's capabilities to control most of the engine,an ecu is an amazing thing which is becoming more and more advanced there is no need to be warned of them as something that is problematic you would generally replace one in a car's life if that at all!
Now that there are software updates via the net or cd/rom,your engine is constantly upgraded via software upgardes,this is not a problem!-that may sound scary to some but the benefits far outway the occasional glitches that you will get with any software......and this is across most brands especially european vehicles.If the vehicle is new this should be covered under warranty anyway.Good luck!