I've had this problem for 2 years now, every winter it's the same thing, whenever the car is running and i press the clutch, the revs go up to 2000 and stay there until the car comes to a complete halt, at which point, it drops down to normal 1000.
Oh, but it gets better, if the engine is warm enough and i turn off the engine and then turn it back on, the revs go up to 3000. It's awful.
I've been to 3 car services, one of them being a Ford house. They all say it's because of the idle air control valve (IACV) or throttle position sensor (TPS).
I've already changed 3 TPS's and 4 IACV's all of them original Ford parts and although the problem WAS fixed, it always came back after 2-3 weeks.
The guys at the Ford told me they don't know what else to do, can you believe that ?
Tests show nothing, i don't know what else to do... it just seems unreal.
Sounds like the IACV being open a little is the problem, but what is telling it to stay open, is also the problem.
This sounds like it sucks man, and from what I read here, you have been given almost every possible link to the problem, and mechanics just keep telling you nothing is wrong.
Maybe go make a big stink at a Ford dealer about this situation, sometimes the workers don't work until someone up top yells at them.
1200RPM for a idle is high if warmed up? I know this is a UK 1.6, but our Zetec's over here idle at 800-825RPM.
Have you replaced the TPS yet?
TPS = Throttle position sensor.
Here is some info on it from a friend of mine on another forum.
Quote:
TPS= throttle position sensor, and it's on the throttle body. It's not hard to replace, but it is difficult to diagnose when it hasn't failed completely. Basically it's a potentiometer similar to a volume control on a stereo. It feeds the computer voltage through a resistor that decreases resistance as the throttle plate opens. Over time, positions which are commonly used- like right around your usual driving throttle position- get worn out. This can cause the TPS to respond "sluggishly".
The only thing you need to be aware of when replacing a TPS is to pay attention to the position of the TPS when removing the screws. Unplug the connector, then remove the two screws that hold the TPS in place. The TPS should turn slightly misaligning the screw holes. Note this alignment, the new TPS must be inserted the same way. When you insert the TPS make sure that it is flush with the mounting plate without using force. The TPS must fit onto the throttle plate's shaft before you turn it and tighten down the screws. The biggest mistake people make when installing a new TPS is to push it straight on, and force it flush with the screws. When this is done, the TPS does not line up on the shaft and the insides are sometimes damaged giving false readings.
Reflashing is not the same as clearing the ECU via removing the neg terminal. Really you should not need a reflash unless there is an update to your ECU. When you install a new electronic part- it is not a bad idea to clear the ECU. I warm up the engine- drive around the block, then disconnect the negative terminal. Once it's reconnected, I start the engine without touching the accelerator, and allow it to idle for 6-7 minutes. The ECU tests the proper air/fuel mixture in the first 5 minutes of idle after the ECU drops out of start up. If you have a tach, you might notice slight fluctuations in the idle- that is normal, and after the test is done it will stop fluctuating and the idle will drop slightly.
No problem re . your " stalling " , just trying to get all info possible and wasn't sure if I had misread .
" 4 services, each worker showed real interest in the problem, they didn't even charge me anything. They even asked me to tell them the solution if i ever find it "
Good they didn't charge you for checking over . In my experience most mechanics would try their utmost and consider it a challenge to find a solution , myself included , rather than having to be yelled at for results . Any mechanics / staff that need yelled at to do their jobs would be booted out the door in any of the garages I've been in , had or ran .Without reading all the posts again , have you cleaned the throttle body or checked if it's sticking when revs are high ? All on forum will be glad also to hear the solution when you get it fixed , keep us informed ?
Yes i have cleaned the throttle body, i even changed it (with a used one). It looks like it's working perfect. To me it seems that the problem is more than just mechanical.
Thank you both for your help, and yes, if i (ever) get it fixed, i will post the solution.
The IACV remains open and i have ~1200 revs when idling. After a few weeks, the idle increases to ~1800, and after a few more weeks it increases to 3-4000.
Each time i changed the IACV, i repeated the cycle, starting at 1200.
Have you ever checked air intake leaks / gaskets ???
Have you ever reseted ecu after changing tps or some other
parts ... ???
I`am not sure but is there 1 extra fuel injector to give cold boost ??
If there is should check that also engine temperature sensor reading
is correct... =)
Have you ever checked air intake leaks / gaskets ???
Have you ever reseted ecu after changing tps or some other
parts ... ???
I`am not sure but is there 1 extra fuel injector to give cold boost ??
If there is should check that also engine temperature sensor reading
is correct... =)
...
What about checking for air leaks where the intake manifold meets the head?
I know you said you checked all vac lines, but did you check the rubber egr lines? Sometimes they get old and crack ever so slightly, and can be missed.
My IACV is blocked (no air is getting in) but i still have high revs when idling: ~1300 rpm when the car is moving, sometimes goes up to ~1500 rpm tho. When the car comes at a complete halt, the revs drop to normal ~900 rpm.
From my knowledge, if the IACV is blocked/unplugged, that means neither the IACV nor the TPS is the problem.
i blocked it so i could use the car, if i didn't, the revs would start going up to 3-4000 rpm, i even have a brand new IACV, but i don't fit it cause i don't want it to break
I fixed it, the problem was that my camshaft was chipped in one of the corners. I'm guessing this happened because of the timing belt being incorrectly installed.
All the other parts (IACV, TPS, etc.) had nothing to do with my problem.
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