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High revs when idle, no one can figure out the problem :(

63K views 53 replies 6 participants last post by  R.S.LOGAN 
#1 ·
Ford Focus 1.6 gas 2001.

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.
 
#4 ·
If I remember correctly the switch on that year was fitted on the power steering pump but could be wrong . When the power steering is under load and the engine revs drop , this lets the ECU know it has to increase revs to keep engine from stalling . Could be some other fault , but worth checking .

p.s
On some cars they have a sensor mounted in the high pressure PS line / pipe
 
#5 ·
Hmm, seems kinda wierd because it doesn't matter if i move the steering wheel, the revs go up and stay there until the car stops. Anyway, i'll give it a try.

Also, i've read somewhere that the EGR might be the problem, is that possible ? And if yes, how can i tell ?

Thank you.
 
#11 ·
Ok, so it seems that my car DOES NOT have an EGR, an engineer checked under the hood. He also couldn't find one as a spare part for my car.

The car also doesn't have a DPFE sensor or a MAF (massive air flow) sensor.

So before i check the psp switch, i thought i should change the MAP (manifold absolute pressure) sensor. From what i've read, the MAP sensor controls the air intake, somehow working with the EGR (which i don't have). Anyway could the MAP be the source of my problems ?
 
#12 ·
I'll continue posting here for the sake of other that might have my problem.

I've measured how much the alternator (i think that's what it's called in english) charges the battery, it should be 13-14, but was 15.

The electrician recommended changing my relay (?) - which is a part of the alternator (?). He said that might actually be the problem, cause the ECU gets bad input from the alternator and overwhelms the TPS / IACV.

I'll post more after i fix it, the day after tomorrow.

I also believe i'll have to change the IACV again.
 
#14 ·
Charging at 15v is a bit high and may be caused by the regulator in the alternator being faulty . Better to replace alternator if that is fault rather than strip down and overhaul .Could also indicate a battery with weak cells and alternator trying to compensate for low battery . If it is overcharging , battery will probably be knackered . Load test and check .
 
#17 ·
You have a MAP equiped 1.6, rather than MAF- this system works on air
pressure rather than volume. You will need to remove the MAP sensor, as the
small air pipe often blocks with oily crud / deposits. Do NOT use carb
cleaner / air line directly into the map sensor, if its little pipe is
blocked, blow across the top of it with your cleaner.

There is no EGR on your car.

This shows the map sensor ,

Map Sensor MS064 Ford Focus 1.6 2001 - From Livingston Autoparts Ltd cheap car parts and car accessories website
 
#21 ·
i fixed my alternator, i changed the MAP sensor and i changed the IAC valve again, nothing happened

the guys at the service say that on their laptop, they are getting bad information from the ECU, and they said the ECU is definitely the problem

i'm going to get that checked, but from what i've heard, it's really expensive :(
 
#23 ·
I had a problem with my '88 Escort several years ago, the idle speed would go extremely high and wouldn't return to normal until I turned it off and restarted. The problem was the ECU. I doubt this is your problem, but just thought I'd mention it. Have you checked for vacuum leaks?
 
#25 ·
Something else to check ,

" Check to see if there is a sensor in between plugs 2 and 3 (this is a cylinder head temp sensor) , if so check that the wiring for it is O.K .

The advice about the cylinder head temp sensor is valid as earlier models had an interference problem. The wiring to the temp sensor runs alongside the HT leads of nos 1 and 2 plugs. This wiring could pick up interference from the leads. It was recommended to ensure the wiring was as far from the leads as possible.The fault may still ultimately be the ECU .

Thanks for the advice.. I took the ecu out and took it to an auto electrician. he said it had failed the test on a small output diode so he replaced it .It seems to be running excellent!!! "
 
#26 ·
I still haven't fixed it. Here's what i've done so far:

- changed TPA (4 times)
- changed IACV (4 times)
- changed MAP sensor
- changed water temperature sensor
- changed PCV valve
- changed the whole alternator
- there is no false air intake
- the wiring is good
- no computer errors
- other checks, everything is fine

This is what happens now:
- when the car is at a complete halt, it idles at ~1200 rpm
- i looked at the IACV (a new one), and i can clearly see it's a bit open, instead of being completely shut
- if i block the IACV, the car runs and idles normal at 800-1000 rpm

It's clear that something is keeping the IACV open (just a little bit).

The guy at the car service said the ECU is showing correct readings so i don't think it's that, but he'll check it after Easter (cause the car service is closed until then).

Any other thoughts ?
 
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