Comments on: How to Clean a Throttle Body - Update

By: craig

craig — Wed, 26 Nov 2008 07:51:05 +0000

Hi Simon,
There are a couple of possible causes for your Commodore idle problems. The most common problem we see is the Idle Air Control Valve is either ‘gunked up’ or faulty. They can be removed for cleaning by first removing the throttle body and then removing two torx screws ( which can be undone with a pair of vise grips if you don’t have access to torx bits). Throttle body cleaner is good for doing this and while the throttle body is off it is a good idea to clean out the passage that the valve operates in. If cleaning makes no difference to idle quality replacement Idle Control Valves can be bought from most aftermarket parts suppliers.

Something else to check for is a vacuum leak around the inlet manifold to cylinder head area or where the throttle body attached to the inlet manifold. The easist way to check this is with the engine running spray small amounts of throttle body cleaner around where the inlet manifold joins the cylinder heads and also where the throttle body bolts to the manifold. Use only small amounts of spray as it is very flammable!! If the idle speed increases when the throttle body cleaner is sprayed and decreases again when you stop spraying you have a leaking gasket in that area. It may be a case of simply tightening the bolts but if this doesn’t rectify the problem the gaskets will need replacing.

Hope this helps and please let us know how you get on.

By: Simon

Simon — Tue, 25 Nov 2008 10:56:09 +0000

I had a high and then low reving 1990 SS ute i decided to clean the thodle body with a pressure can but i still have problem of high revs and low when cold. This is very intermitedly. Some times when i driving an dthis happens revs go up and down and some time engine turns off. Ive had the TPS changed. What do i do now rectify the problem?

By: Eric

Eric — Mon, 14 Jan 2008 07:14:10 +0000

“I am just getting unto the world of throttle bodies having just bought a Rover MGF MY2000 with a 1.8i Rover K series engine. it has a plastic 48mm body that gives trouble with sticking throttle when hot and an unstable idle speed from the TPS I belive! I have just bought a new Alloy 48mm that is suposed to clear the above mentioned problems, but before I fit it to my car I was wondering if it could be bored out to 52mm and modified to give me more BHP and crisper respons. The casting on the 48 & 52’s appear to be the same. Any experts out there would you please advise as to what I should do Thanks Eric

By: craig

craig — Thu, 13 Sep 2007 23:47:52 +0000

Thanks again John, you’re a champ!

By: jrhook

jrhook — Thu, 13 Sep 2007 23:35:33 +0000

HI Craig, thanks for the post. I have been talking to those in the “Know” and the consensus is to Wipe the throttle body out with a clean lint free cloth (NOTE:petrol is still being used by some?). Under no circumstances use a pressure pack spray Drectly into the throttle body.
This is what the VZ-VE commodore HF6 engine workshop manual says in regard to Thottle body cleaning.

“When cleaning / inspecting the throttle body:
• Do not subject the throttle body assembly to an immersion cleaner or a strong solvent. Damage to the throttle position sensor and / or sealed throttle shaft bearings will result.
• Never use a wire brush or scraper to clean the throttle body. A wire brush or sharp tool may damage the throttle body components.
Under no circumstances should the clip (1), six places, retaining the cover plate (2) to the throttle body be removed. If the cover is removed, the vacuum seal between the cover plate and the throttle body will be broken. This will allow the ingress of foreign particles and / or moisture and render the throttle body unserviceable
The throttle body must not be subjected to any form of shock such as dropping it. If the throttle body is subjected to shock, damage may result to the fragile motor magnets within the throttle body.”
I might add a tip here for anyone planning on cleaning an engine.
Do it cold and avoid pressure washers if possible or at least don’t direct spray onto connectors.
What happens? When the air temperature inside the connector is high (Engine operating 80-90 Deg C) it will, when sprayed, cool. This contracts the air in the connector creating a partial vacuum (connectors associated with EFI are sealed) drawing moisture into the connector and thats when the problems start.
Hope this helps.
Cheers,
John