How to Clean a Throttle Body - Update

13th September 2007

How to Clean a Throttle Body - Update

posted in DIY Tutorials, EFI |

If you're new here, you may want to subscribe to my RSS feed. Thanks for visiting!

After reading my post on how to clean throttle bodies, John Rhook, e.f.i. expert and all round nice bloke had a few things to say regarding the cleaning of throttle bodies on late model vehicles. This is what he had to say;

Hi Craig, just discovered the blog. well done on getting involved in ICT. I find most in the motor trade are reluctant to adopt technology. I would like to add to you post a word of caution. Late model throttle body’s are coated and cleaning with solvent based cleaners is not recommended. There are some detergent based cleaners now finding there way into auto parts suppliers. Also some sensor failures have been linked to the use of Propelant type solvent cleaners.
Regards,
John

As I have been off the tools since 2005 and have only seen a handful of vehicles where throttle body cleaning is not recommended, I asked John to clarify this information further.

HI Craig, yes, throttle body coating is pretty much the norm now, especially since drive by wire has been adopted. Some dealers have been caught out (Ford,Mitsubishi) cleaning throttle bodies and then upsetting base idle functions (by removing laquer), which then requires back to the factory bench calibration. I am still happy to see throttle bodies cleaned, It just needs to be done with caution. I like you have been off the tools now for 5 years, after 23 on the body has had enough so I have moved into education. Look forward to more postings.
Regards,
John

If you own a late model vehicle and are considering cleaning the throttle body please check with the manufacturer before carrying out this operation. I have successfully cleaned throttle bodies on cars ranging up to the late 1990’s and early 2000’s however I would recommend checking first before doing the job on any vehicle younger than this.

I would like to take the time to thank John Rhook for his input on this subject and with any luck we will be hearing more from John in the future. He ran a successful repair business before his body gave up on him (sounds familiar!) and is well educated on automotive subjects. Good on ya John!

Craig

This entry was posted on Thursday, September 13th, 2007 at 10:04 pm and is filed under DIY Tutorials, EFI. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

1 On September 14th, 2007, jrhook said:

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

2 On September 14th, 2007, craig said:

Thanks again John, you’re a champ!

3 On January 14th, 2008, Eric said:

“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