Conference terri::cars_uk

    
    Is it the management unit - or is the accellerator pedal sticking? - if
    you put your foot under the pedal and lift, does it reduce the revs?
    
    I had a car once which had this problem, and it was the cable -
    (couldn't have been the engine management unit - they hadn't been
    invented then! :-)  ) 

Sounds like the throttle damper.  This is a vacuum-plunger connected to the
throttle which prevents it shutting immediately if you suddenly lift your foot.
It's supposed to ensure complete combustion of the fuel-air mixture under all
conditions.

If yours is faulty or mis-adjusted, then it could be keeping the throttle open
too much.

As a rough guide, the throttle should be free to close, unimpeded by the damper,
to the point where it would be held partially open by the choke.  To test this,
press the pedal with the engine off and cold to prime the choke, then release
it.  The throttle is now sitting at the right position.  At that point, the
cam on the throttle spindle should just contact the vacuum plunger if you push
the plunger into the vacuum diaphragm.  If you can open the throttle further
by pushing the plunger, then it needs adjustment.  If the plunger doesn't reach
the cam, then you just don't get the "benefit" of the damper.

Note the vacuum supply to the damper is controlled by a solenoid valve powered
by the EMU.  Maybe the valve is faulty, keeping the vacuum permanently "on" so
preventing the throttle closing.

Or maybe it's something totally different.

Scott

NB The description of the throttle damper given here is based on that found on
Sierras.  It may be (and probably is) totally different on other cars!

    RE:.1
    
    It is definately not mechanical in as much as the pedal returns
    to the correct position... 
    
    RE.2
    
    You could be right... but having had no experience of "injected"
    engines prior to this I couldn't say for sure!
    
    One thing that annoys me is the garage saying that this is normal
    for this type of engine/management system... surely this is cannot
    be the case as I feel this to be dangerous, (as i have said before)
    and also means that driving the car is not a smooth operation. 
    When this "wide open throttle" situation occurs, I have to use engine
    breaking to pull the revs down.
    
    I still feel that there is a fault with the car and would like to
    speak to Vauxhall, but do not have any contact numbers!
    
    Help Please...
    
    Bob
    p.s. The car salesman at the garage concerned recommended a different
    driving style!  I *could* be wrong but have had no problems with
    any other mid-high performance cars... Audi's, 309 gti, golf, etc!

I think you mean engine braking; engine breaking is rather a drastic solution!

I always thought engine braking was using the drop in revs when you lift your
foot to slow the car down.  This is the exact opposite of the problem you have,
so is my understanding of engine braking wrong?

Go back to the garage, speak to the service manager and explain your
dissatisfaction with their diagnosis.  If he won't do anything, ask him for
Vauxhall's address / phone number, and then get on to them about it.

If the car's still under warranty, kick up a fuss to get it put right for free!

Scott

PS I was talking about throttle dampers on a carb engine; maybe it's different
on injection ones.

PPS Just because the (spring-loaded) pedal returns to its normal position
doesn't mean the throttle itself is closing!  Could be a faulty cable, or
lots of other things in the linkage...

    I had a similar annoying problem like this driving other people's Astra
    GTE 16V's.  If you apply the brakes just before putting the clutch in,
    when the engine is just turning over, the engine revs. The engine does
    seem to rev more under strain to stop the engine stalling. Maybe the
    engine mgt system decides not to do this over 2000rpm, and maybe your
    engine management system is doing it at all revs. Wherever it happens,
    it is really annoying. I don't like a car doing the driving for me!
    
    Mark.

    My 8V Astra didn't do this.  However my 16V Astra is a bit more
    severe in trying to stop the engine stalling.  It will rev to about
    2000 rpm if you do nasty things to it (like trying to pull away
    with not enough revs).
    
    The number for the Vauxhall Customer Service people is in the manual
    (and is probably elsewhere in this notesfile).
    
    Trev

    The throttle close damper sounds like a really good idea.  Shame it
    doesn't seem to work!

    
    	"Dir/tit=astra"?   I'm not too hot on notes syntax,  but shouldn't
    that be "Dir/tit=astra_owner" ?    
    
     	(Only joking,  I used to have an Astra,  well a Opel Kadett Astra
    lookalike,  honest,  didn't mean it,  oh dear)                   

     
    Derek,
    
    What's the prize for 1st place?

    
    	Vauxhall Customer Care number :
    
    			0582 - 691400
    
    

Re: .8

Probably an Astra driver who thinks all Vauxhalls are Astras :-)