|08-15-2014 04:45 AM|
Humphrey - hope you meant MPG not MPH.
High idle shouldn't hurt the clutch much, you only slip it moving from a stop & the rest of the shifts should match pretty close so you don't have to slip it then.
High idle would affect MPG as the engine is using fuel when not needed.
That throttle plate needs to get centered & adjusted for sure. Easiest off the car though you wouldn't even have to unhook the cables to do it - just pull it off & lay a towel underneath to cover the engine, maybe a board for a work surface.
Loosen the adjustment screw & the throttle plate screws & wiggle the plate position to let it close completely to the bore. THEN tighten the plate screws & recheck - it needs to close fully & evenly then without binding. AFTER that's done, you can use the adjustment screw to give it a slight crack open for a starting point. Recheck again for smooth operation & no binding.
Once that's done you can reinstall it completely for engine start & final adjustment.
Get the engine running & warmed up, then get your adjustment screwdriver handy to tweak the adjustment. You'll be disconnecting the IAC & using your hand on the throttle to keep it running as needed while you adjust the stop screw to get about 525 rpm steady from that adjustment. Basically getting it to run at a low idle without you holding it, then checking the dash display & readjusting it 'till you get that speed.
The idea here is to get a mechanical idle rpm adjustment BELOW that controlled by the IAC, so the IAC is slightly open & able to control idle speed at normal warmed up condition.
IF the mechanical idle is too high, the IAC can never drop it to a target speed since with that fully closed it still idles too high.
Should you find it idles high even with the throttle plate closed & IAC disconnected, you can be sure either the IAC is stuck partially open or there's a vacuum leak that hasn't been found.
Hope that explains both practice & theory enough to be of help.
|08-15-2014 03:44 AM|
I still have this issue. Mine is probably going to be that I've not yet fixed the placement of the flap in my TB as I had removed the screw holding it in and took out the flap and when installing it I had it upside down or backwards but Ive since put it back but still is a little out of place.. I also had a vacuum leak which I took care of right after getting the car. Another problem I found while trying to solve this was that the throttle cable was fraying inside its casing causing it to stick- dished out 150$ something for that. Ive yet to replace my IAC as I've cleaned it twice but not sure if that did any good. Once with carb cleaner and another with diesel and a airgun.
As for what mine is doing, the RPM holds at a high rate upon decelerating but once I arrive at full stop, it will lower to an acceptable RPM and that is pretty much it. Again, probably due to the small gab in my TB.
@Sailor, my MPG has also dropped since this issue with high idle. I've already replaced the clutch (and components) with a clutch kit from RockAuto. I am wondering if that high idle is what caused the clutch disk to turn to dust.. Honestly, it wasn't that hard to do being as it was my first time performing such a repair- my and my dad had it down in an hour or so. I am sure the next time we'd cut down on that time as we've got the experience.
|08-14-2014 08:32 PM|
OK, sounds like yours is "stuck" at 1,000 rpm for an idle speed (I assume it doesn't change when warm).
Items to check include:
First - check throttle cable & throttle plate at the throttle body to make sure there isn't a mechanical hangup keeping the throttle slightly open.
Second - check for vacuum leaks from any hoses attached to the intake. PCV from engine to intake is a particularly common on for problems.
Third - Check IAC If it's sticky/stuck you may be able to clean & get it working again without replacement.
|08-14-2014 12:57 PM|
|charliebrownboy||My symtoms are as follows: On start and in neutral revs are just over 1000. When clutch is depressed without putting into first gear revs go high to 1300, on selecting first revs come down to just 1000 or just below. On changing up to 2nd when putting in clutch, revs climb again. On releasing clutch and engaging gear revs come down. This happens when depressing clutch to change gear. Sorry if I have not explained myself more clearly|
|08-11-2014 10:24 PM|
"30 in Fifth with the revs high" is part of what had me guessing in that direction, hard to interpret everything that is intended by some comments.
Disconnecting the negative for a while will do a reset, and idle will be high after that until it settles down. Letting it idle until it drops when first started after such a reset speeds up the relearning process.
Small vacuum leak is a possibility for higher than normal idle speed, the confusing factor right now is the comment that it "comes down to normal in neutral".
I'm afraid that I'm a bit lost as to just what symptoms you're experiencing, rather than guessing & to get more looks than this addendum to an old thread receives I'd suggest starting your own new thread - stating the exact symptoms afresh for more eyes to get a look.
|08-11-2014 06:42 AM|
thanks again for reply, however and with all due respect I do not think the clutch is slipping. I have taken advice from various experienced sources and all agree the clutch is ok. The car does accelerate very well, its just the high revs, I have had experienced a slipping clutch before and it is not that. My thoughts are leaking vacuum hose. I have been told that with a car of this age it may be possible to delete all the info recorded in the ECU by disconnecting the battery earth strap and touching the positive lead which will put the ECU back to its factory settings. I do appreciate your opinion and would not for one moment totally disregard a failing clutch.
|08-10-2014 11:54 PM|
High RPM when started cold is normal, as you mentioned it's fine later when warmed up ("normal in neutral").
High RPM in gear means the clutch is slipping, you likely see rpm changing without the speed changing proportionately.
Not surprised the mpg is low, engine is just burning up the clutch more instead of moving the car.
Needs a new clutch, no easy fix.
|08-10-2014 04:54 PM|
Thank you for replying. The car is 1999 focus petrol 1.8 with zetec engine When I first start the car in the morning, the revs go up without me doing anything to about 1200. When I select first the revs go up when I put the clutch in then come down again. the revs are higher than norm in all gears. I can cruise at 30mph in 5th gear with the revs high. The revs come down to normal when in neutral. Overall when in gear the revs are higher than normal and noticeably higher when the clutch is depressed. When clutch released revs decrease but still high after gear is selected.
|08-09-2014 07:36 AM|
Higher than normal for a while after changing a battery is normal, since the computer is reset & needs to "learn" a bit again - shouldn't last too long though.
Giving it a chance to idle down to normal revs after start up when changing the battery helps speed up the learning process (takes a few minutes or more depending if it was warm already).
Description is hard to figure out though, "high in gear" can only happen if the clutch is slipping - rpm in gear is determined by which gear & what road speed.
OK in neutral but high with clutch depressed is a bit confusing as well - does it STAY high with the clutch depressed or does it just jump up when the clutch is first depressed.
We don't have your exact model here, so I can only help with general guesses/info. To help others, could you mention the year of the car as well?
|08-09-2014 07:11 AM|
High Revs on depressing clutch
I am a newbie from England and not very experienced with Ford Focus. My car a Focus 1.8 zetec petrol saloon developed high engine revs after I changed the battery. The revs are high on first start up and in general are high in gear but particularly so when depressing the clutch. in neutral the revs come down to normal. the engine itself runs smoothly but the mpg is horrendous. Any help would be greatly appreciated. Thank youj
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