Idle / Rev Problem On S-reg Galaxy

[AbeMaca]

hi there, 1st time on the forums here and i hope you can help me out.

 

 

first of all i just got a 2.3 Petrol galaxy and while driving it would decide to Rev it self up to about 2500rpm and slowly work its way back to a good idle speed.

 

this done it ALOT of the time not just every now and then, We had a look around the engine and can noticeably here a air sucking/blowing sound from around the inlet manifold / TB.

 

when i turn the engine off you can here the air suck/Blowing sound for a further 3 or 4 seconds after the engine is off.

 

Now we have had a look around the brake pedal has gone very stiff and brakes are hard to use (they do work, but uncomfortably)

 

 

I hope you can help me out with my problem, Thanks for taking the time to read this.

 

any Help would be greatly appreciated.

[chrispb123456]

Hi there

And welcome to the site

Sounds like classic case of knackered brake servo diapragm, but also double check vacuum pipes for leaks/splits

[AbeMaca]

hi, thanks for the welcome,

 

would this just effect the revving ? the brakes have been fine (just the revving problem until today)

 

what i mean is the brakes going funny today could this be a separate problem or could it all be tied in within each other

 

 

also is the brake servo diaphragm a easy job to do?

Edited July 18, 2010 by AbeMaca

[chrispb123456]

Hi again

A bad vacuum leak will cause the engine tick over speed to rise it will also mean the engine CO levels will be affected, rises in idle speed or unstable idling is usually vacuum leaks ie, split or perished vacuum hoses.

You need to replace the servo first it's a sealed unit you cannot do any thing to it.

 

The servo removal requires working inside the car by the pedals and under the bonnet as you will need to remove the brake master cylinder,

 

The confident DIY mechanic should have no problem albeit a bit fiddly working in the car, the brakes will also need to be bled upon completion.

 

PS. don't buy a secondhand servo it's not worth the hassle of taking it all out again when you have same problem again

[AbeMaca]

ok solved the leak issue (almost) found a split vacuum hose going from manifold to master cylinder , once reconnected (bodged back on) the brakes are back.

 

ordering the new part asap , will post if this solves revving issue also.

[AbeMaca]

new part now installed and brakes work fine.

 

the car STILL rev's up on its own BUT once over 20,000 rpm i can hit the clutch and it drops down to around 15. then rises again.

 

ive changed 2 vacuum hoses that were damaged , any ideas ???

[AbeMaca]

'bump'

[sparky Paul]

If the vacuum noises have now gone, another possibility for the erratic idle could be the Idle Control Valve sticking.

 

It is located on the top of the plastic inlet manifold, fixed with two bolts. Unbolt, remove the wiring connector, then remove the valve and clean out with a bit of petrol. If that doesn't fix it completely, the only other option is to replace it. However, if cleaning makes no difference, the problem probably lies elsewhere.

[AbeMaca]

thanks for the reply Paul , i had ran out of ideas. ill check that asap and post results here

[chrispb123456]

Hi there

If cleaning the idle valve doesn't improve the problem check out the throttle position sensor,also check throttle cable and butterfly housing, also check engine wiring harness to the various components as there have been reports of bare and crumbling wiring insulation which may cause your symptoms

[AbeMaca]

ok ive now removed the idle valve and gave it a little clean up and re installed , still same issue.

 

i will check the throttle bits you listed chris ASAP and post results up here. thanks all for the assistance.