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New gaskets for ICV and throttle body.
Carb cleaner or de-greasant.


Adjustable Spanner.
Flat and cross head screwdrivers.
Allen keys.
Hose compressor/clamp.

1) First of all, using the adjustable spanner, remove the breather hoses from the intake pipe and then unscrew the jubilee clip securing the intake pipe to the throttle body.

2) You should now be able to disconnect the pipe from the throttle body and move it to one side. Where possible clean out the inside of this pipe before re-assembly.

3) Next disconnect the five hoses attached to the TB. Hoses 2 and 3 are attached with clips so you'll need the adjustable spanner for them. Pipe 2 (the bottom of the two with clips) requires a hose clamp before disconnecting it as it has coolant running through it, pipe 3 is the outlet for the coolant but will only release a small amount if pipe 2 is clamped. Ensure pipe 2 is clamped before removing pipe 2 or 3.

4) To remove the accellerator cable it is easiest to pull the cable out from the grommet before removing the grommet from the metal plate. Becareful not to lose the little C-clip pushed onto the cable just below my thumb.

5) The clip holding the knuckle on to the throttle is a "C" shape with the ends bent in towards the centre. To remove the knuckle attaching the cable to the throtltle, slide a small flat blade screwdriver behind the clip where the back of the knuckle is flat (1) and carefully slide it to one side of the clip. This should release the leg from the groove in the knuckle (2). When the first one comes out do the same again but slide the scewdriver to the other side of the clip to release the second leg. Be careful not to lose the clip when it pops off.

6) Remove the fournuts holding the TB in place and be careful not to drop them. While the internals of the TB are exposed be careful not to drop any dirt, tools or parts into the engine beyond the TB.

7) To release the TB unplug the two remaining cables. One is attaced to the ICV at the front and the other is at the back of the TB housing and can be tricky to get your fingers around. With a bit of manouvering and gentle coaxing the throttle body will come away leaving you with something like this:

8) Everything brown on there is removeable with some carb cleaner and elbow grease but before you get to that bit the ICV needs to be unbolted using an allen key on the two bolts.

9) The ICV can then be stripped down further into three pieces by unscrewing the two cross head screws.

This will release the solenoid that controls the ICV and remember to keep the rubber O ring safe for later.

10) Remove any dirt from in and around the TB using the cleaner and scrubbing brush until the point where the cleaner coming away is still clear. With the ICV spray cleaner into the two holes on the side and in the top, cover the holes and shake well. You can also use a piece of cloth to rub the dirt off the sides of the holes or even the edge of a flatblade screwdriver if you are careful. Press the nib at the top of the valve to open it and spray the cleaner through. When the cleaner comes away clear then it has been cleaned and both should come away looking something like this.

11) Assembly is the reversal of removal but ensure that you use new gaskets when putting it all back together. With these cleaned you should have a smoother idle and slightly more throttle response. How much depends on the condition before and after cleaning. With the pic's above my Astra had covered 103K, most of which are motorway miles.

Here's a before and after for comparrison:


This "How to" is intended to be used as a guide to give you an idea as to how to carry out the same work on your own cars. The instructions above detail how I carried out the work on my own car and as each persons car, tools, level of experience and circumstances are different then the steps required to carry out the work will vary from person to person and therefore myself and this website cannot be held responsible for any loss, damages or injuries caused while carrying out the work. If you are unsure in anyway as to how to carry out any of the work detailed above then consult a professional for advise or consider paying them to do the work. So take care while carring out the work because YOU HAVE BEEN WARNED!!
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