March 18, 2012, 8:51 pm
Just wanted some advice really. My 2003 Focus Zetec 1.6 SE idles at about 650RPM which is a little low and I can notice the headlights dim a little on occasion when sitting at traffic lights.
I've done a bit of searching around and have read that cleaning the ICV and throttle body might help, but I've done both of these and it hasn't made a difference. I also read that it could be the MAF sensor but my model doesn't have one of those instead having an MAP sensor.
Could it still be that the ICV is just faulty? Is there a way to test it? What would starting the engine with the ICV unplugged do out of curiosity?
Any pointers at what else it could be would be much appreciated.
March 18, 2012, 9:29 pm
When did it last have a good service? Also would get the alternator checked as well, although it could be the drive belt. Not sure what these engines should idle at, but that dosnt sound too low. Is it trying to stall at idle?? AFAIK the idle speed is controlled by the PCM, so it could also be a faulty sensor such as a lamda sensor.
March 19, 2012, 7:21 pm
It was only serviced a bit before xmas. I think they are meant to idle around 850 ish.
Had the cam belt done in November and they checked the aux belt at the same time and said it was ok.
It doesn't try to stall no but it is still lower than it should be and I'm going to be upgrading the stock speakers in the summer so it might start struggling with the increased load.
I've gotta get a key coded soon so I might just get them to read the ECU for any errors at the same time if there isn't anything else I can check reasonably easily.
March 19, 2012, 7:44 pm
650 is a bit low 670 to 730 is the correct range 650 is the lowest rev limit this wont stop the lights dimming thats due to the load on the battery at idle though it should only be a slight dip if reving it makes the lights brighter the alt is likely okay so you need to check the vacum hose from the throttle the pcv valve then replace the icv. it could also need a pcm update but ide try the first 3
March 19, 2012, 9:15 pm
Cheers for that... Where is the PCV valve?
I'm going to do a little test I read earlier tomorrow when I drive to work:
1. Warm car up to normal temp.
2. Switch all electrics on - heated screen/window/fan/lights etc etc.
3. Rev up to 3,000 rpm and hold for a couple of secs.
4. Let go pedal and watch revs drop.
5. If they drop to about 1,000 then slowly down to around 850, the valve is ok.
6. If they drop straight to around 600 or so, then the valve is faulty.
Might not be 100% accurate but will give me an idea if the ICV is actually dead.
March 20, 2012, 1:06 pm
Well, I did that test this morning and it just went straight from 3000+ RPM straight down to 650 RPM without any slow down.
That would imply the actual valve is cattled.
March 20, 2012, 2:34 pm
9 times out of 10 its te valve and the low idling is a sure enough way to tell dont bother removing it and cleaning it as its usually a waste of time just replace it mate
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