Idle/rev Problem

[boxman32]

hi,once again another problem has occured and i hoping someone has come accross this problem before and can help please.i have a 1996 20i ghia galaxy,the problem is that when i start it,either from hot or cold the revs are erratic.if i rev the car to 4000rpm it stays there for a while then slowlly drops back down to 1500rpm,rarelly going lower than that,sometimes it will stay at 4000rpm and not drop back down atall.through the gears as i push down the clutch the revs stay at whatever i take it too (3000rpm-4000rpm).i also noticed today it strugles to go over 4000rpm,it used to accelerate faster as it got to 4000rpm but thats now its limit.does anyone have any idea what could be wrong,i cannot afford to take it to a garage.hope someone can please help me.

[chewtronics]

Hi,

ive the same problem with a 2.3 petrol, ive replaced the idle control valve, new thermostat, and new bottom temperature sensor, no change still have the same problem, any ideas would be very greatful

[boxman32]

i have changed a sensor that is closest to air filter box(not sure what sensor is called),it made no difference.someone will soon be fiiting something to do with fuel management(he thinks this is the problem).

[Mirez]

When I had the 2.3 I replaced the idle speed control valve (ISCV) to fix this. Keep in mind the ECU learns the figures from the ISCV on the Ford so bolting a new one on wont immediately solve the issue, I found I needed to reset the ECU (battery off for 15 mins) after for it to then idle correctly. It seems to be a weak point on the ford engine and I ended up changing it for a 1.8 escort one later on as it went funny again. 23K later and the escort one was still working fine so possible a galaxy ISCV design issue? Not sure the percentage of people who have had issues on the 2.3?

 

Anyway, certainly I would be looking at the ISCV on the 2.0 - though I dont know much about the VW engine, the characteristics are symptomatic (two very big words lol) of a sticking ISCV. Happens a lot on mondeos where the valve gums up with carbon so try removing it and cleaning with carb cleaner first. Engine power loss shouldn't be THAT noticeable though - however with the vavle stuck in the open position air will be by-passing the throttle body (TB). Since the ECU uses the position of the TB (combined with the MAF (Mass Air Flow) sensor- the other bit you changed) to calculate the correct mix (amount of fuel vs volume of air), its possible that the volume of air in the chambers will be significatly higher then the ECU would imagine. The result could make it run lean and subsequently show a loss of power and performance. If that makes sence lol!

Edited May 27, 2008 by Mirez

[n.peckdd]

Hi,

Can anyone post a photo or give details whch way round the idle control valve goes please? Is the electrical connecter on the drivers or passanger side when viewed from the front?

 

Thanks.