DIY: Throttle Body Cleaning
Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!
Comment:
Possible problems experienced due to excess Carbon and oil buildup:
* The engine stalls when idling, especially when using A/C.
* The Idle revs sit below the standard idle rev level.
* Intermittent Rev hunting during idle.
* Small loss of overall engine power and smoothness.
NB: If the engine is revving too high (for instance 2000RPM+ when cold, 1500RPM+ when warm) or experience other eratic idling problems, you may need to clean out the carbon deposits in the IACV screen, and/or screw back in the FITV plug (D-Series engines).
[Search OzHonda for more info]
Engine pictured is a D16A8 (ZC) non-VTEC.
Aim:
To remove contaminants in the throttle body.
Required:
Plyers
Phillips-head screwdriver
A Can of Carby/Throttle Body Cleaner
Spark Plug Remover (optional)
An old shoelace/rope of about 1 meter
A Throttle cleaning Kit which should include a long Snake-like cleaner.
(You can use an old Toothbrush and a clean rag, if you done have a snake).
Park the car outside when doing this.
:!: CAUTION: When you are spraying in the Throttle Body, be careful that the plastic nozzle extension on the Can does not fall off and down into the Intake Manifold! Same with the toothbrush or any other loose object!
Step 1 - Air duct removal
Turn off the engine, apply the handbrake, put the gear in Neutral.
(1) Loosen the Ring around the Air Duct using a Phillips-head ScrewDriver.
(2) Disconnect the Sensor Electrical Plug. Its probably a good idea to unscrew and remove the sensors, as they can be damaged by the Carby/Throttle cleaner. But on my engine, the sensors didnt pass all the way through into the throttle body.
(3) Unclip and remove the Idle Bypass Pipe - Air Duct Side.
(4) Unclip and remove the Idle Bypass Pipe - Engine Side. Move this pipe out of the way if needed.
Note: The location of the FITV is shown in blue incase you need to work on that another time. Leave it be for now.
http://img380.imageshack.us/img380/3387/throt19ck.jpg
Unscrew and remove the Air Filter Cover to properly remove the duct:
http://img211.imageshack.us/img211/8643/throt26vb.jpg
Now pull out the Air Ducting and put it aside. While it's out, you should check it for dirt and cracks, and clear out the small tube. If the small tube has a dirt buildup, you may have a damaged Air Duct or your Filter needs replacing/cleaning.
http://img211.imageshack.us/img211/7061/throt34ev.jpg
Step 2 - Cleaning the Throttle Body using Carby/Throttle Body Cleaner
There are a few ways of doing this, its a matter of personal preference.
If you are a n00b at DIY work, then simply follow choice A.
Choice (A) = Car OFF -> Clean -> Car ON (Quick and easy but dirty)
- This involves cleaning the throttle body while the engine is off, re-assembling everything, then running the car for 15-30 minutes while all the crud passes through the engine. The car will be hard to start and will bog alot because all the crud has flooded the Intake Manifold.
Bogging the engine wont necessarily harm the engine, and this technique is actually the "normal" way according to some sources (i.e. manufacturers of Carby/Throttle body cleaners).
Choice (B) = Car ON -> Clean while ON (Quick but can be tricky and risky)
- This involves cleaning the Throttle Body WHILE the engine is ON.
The problem with this is its hard to clean the inside of the throttle body properly because the engine will RedLine if you open the Throttle Plate too far. But its good because the engine wont bog as much, since the crud will be passed through the engine gradually instead of all at once. If you want to do a major clean then this choice is not really suitable. Another downside to this is that dirt flying in the air may be sucked into the engine and possibly cause damage!
Choice (C) = Car OFF -> Clean while turning the engine (More work, but can be cleaner)
- Recommended by user 'iamhappy46' :-)
This involves removing the spark plugs, disconnecting the ignition coil wire/plug and prevent the motor from hydrolocking when flooding the motor with carby/throttle body cleaner. Doing it this way will also clean sludge off your piston crowns. Your can turn the starter motor over (it won't fire) while spraying the TB out as well.
Choice (A)
While the engine is off, rig open the Throttle Plate so it stays wide open (see pic below). You can do this by tying a Shoelace or rope around the Throttle Spring/Lever, pulling it so the Throttle Plate opens completely, then tying the other end to a strong metal object opposite the throttle body. I used the drivers side suspention bolt.
Spray and clean the inside of the Throttle Body using the Carby/Throttle cleaner and a Toothbrush + Rag, or use a Throttle Body Snake Cleaner designed specifically for this job.
Let it dry for a minute, then give it one last spray to release the residue.
Alot of contaminated Carby Cleaner liquid will go into the Intake Manifold, but dont worry.
http://img211.imageshack.us/img211/5889/throt47qc.jpg
Reconnect everything (reconnect the hoses, air intake, and sensor plug) and get into the car.
Now here is the fun part.
Due to the dirty carby liquid flooding the intake manifold, the car will be quite hard to start and will complain and chug alot for a minute. Dont worry, ignore that sinking feeling in your gut lol! It will start eventually.
You may need to hold the revs at around 2000RPM+ for the first few minutes while all the crap passes through, otherwise the engine will bog and stall alot. Ignore the huge white cloud of smoke coming out of the exhaust :D
Once the engine can idle by itself, leave it idling until the white smoke stops.
Choice (B)
Turn on the engine. While the engine is ON, slowly spray and clean the inside of the Throttle Body using the Carby/Throttle cleaner. You will need to partially open the Throttle Plate by turning the Throttle wire spring with your fingers. But beware that the engine will rev very high if you open the plate too much, which is not a good thing to do for long periods, and revving high while carby cleaner is entering the engine may be a concern. If you want to just do a major cleanout and use the Snake or Toothbrush, then it may be easier using Choice A or C.
Some contaminated Carby Cleaner liquid will go into the Intake Manifold, and the engine may choke a bit, or even stall if too much Carby cleaner goes down at once. If the engine begins to stall, open the Plate to increase the revs a bit.
Once done cleaning, turn off the car and reconnect everything (reconnect the hoses, air intake, and sensor plug). Then turn the car on and idle the car until the white smoke stops (if it is smoking).
Choice (C)
NB: I have not tried this personally so I can't go into much detail with pics etc. If you would like to add more detail, let me know and i'll update it.
While the engine is OFF, remove the spark plugs (or simply disconnect the Spark Plug Cables?), and disconnect the ignition coil wire/plug.
Clean the Throttle Body as like in Choice A. Once you have done cleaning, get in the car and turn the engine over for maybe 30 seconds. If you wish, you can turn the engine occasionally while cleaning the Throttle Body.
Note that cranking the engine uses alot of battery power so you should ensure your battery is in good condition.
Reconnect everything (reconnect the hoses, air intake, sensor plug, spark plugs, ignition coil/wire) and get into the car. Start the car (it may stall or complain a bit attempting to start, but not as much as Choice A) and idle it until the white smoke stops.
