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Author Topic: Cleaning the throttle valve assembly Omega 2.0 16V  (Read 11383 times)

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Cleaning the throttle valve assembly Omega 2.0 16V
« on: 05 April 2008, 10:30:11 »

This process is described for a left hand drive Opel Omega 2.0 16V, X20XEV engine (without cruise control).

This is a translation of the same post from my native language into English. I hope I didn't make too many mistakes.

I decided to document the complete process of removing, cleaning and reinstalling the throttle valve with idle control valve and idle speed stepper motor on Opel/Vauxhall Omega-B because there is no guide as complete as this on the Internet. I believe you can only really fix this properly if you remove the part and clean it thoroughly. I hate those half-done jobs cleaning things while still mounted on the car. I was performing this process during the past two days and I documented everything. Since there's 45 pictures in this guide and I don't know if the forum will accept them all I decided to upload those on a different server. So to see the pictures just view them on this link:

By the way, "slika" means "picture" so when you see "slika_01" it means "picture_01".

The simptoms of a dirty throttle valve or idle speed stepper motor are:
- occasional jerky, erratic idle
- ocasional stalling of the engine, mostly with stepped-on clutch while the car is slowing down to a stop
- probable low power and responsivness of the engine

The assembly which needs cleaning is basically comprised of three parts:
- throttle valve (throttle body)
- idle speed stepper motor
- idle control valve

It is all located on the left side of the engine under that big air intake hose (slika_01, slika_02)

1. Disconnect the negative, minus (-) terminal of the car battery. This will cause the saved values to be lost from the computer, the time and date will be reset and probably also the car radio code will later need to be input again.

2. Remove or detach wiring harness plug from intake air temperature sensor, wiring harness plug from hot film mass air flow meter and crankcase ventilation hose from cylinder head cover. (slika_03, slika_04)

3. Release the metal clamp on the air intake hose on the side where it is mounted onto the air cleaner housing and on the side where it is mounted onto the throttle body. You can then remove the air intake hose and put it aside. (slika_05, slika_06)

4. Remove wiring harness plug from the throttle valve potentiometer and from the idle speed stepper motor. (slika_07, slika_08)

5. Detach the accelerator Bowden cable from the throttle body. First pull away the part with the rubber joint and then the part with the ball joint. I lubricated the rubber joint a bit with WD40 so it came off easier. Be careful not to lose the plastic pin behind the rubber joint. Perhaps it is worth remembering which jag it is placed on in case you take it off. I did that and later positioned it back on the same jag but I never bothered to check what exactly it's function was. Could be some sort of idle tweaker ... never mind. The ball joint on the other side of the cable has a metal splint in it. You have to remove that before you can pull the ball off. It could be wise to use a drop of oil to lubricate the joint so get it off easier. I've had major problems getting the thing off. It just wouldn't go. I had to use a screwdriver and a hammer and hit it a few times. In this case you have to be careful not to bend the metal arm on which the joint is mounted and you have to be careful not to damage or destroy the ball joint itself. I managed to leave quite a few dents on it. (slika_09, slika_10, slika_11)

6. Remove the fastening clamp for fuel distributor pipe adapter from accelerator Bowden cable bracket / throttle body. (slika_12)

7. Remove fuel supply line from fuel distributor pipe adapter. Counterhold (fixate) at fuel distributor pipe adapter with 17mm wrench and unscrew the fuel supply line with 19mm wrench. Expect a few drops of fuel from the supply line after you remove it (have a rag ready to capture it). (slika_13)

8. Detach coolant hoses from throttle body. I did not have any escaping coolant from these lines but it may be wise to be prepared anyway. (slika_14)

9. Detach vacuum hose for tank vent valve from throttle body. (slika_15)

10. Remove 4 fastening bolts with which the throttle body is attached to the intake manifold and remove the throttle valve. Be careful not to drop anything into the intake manifold hole as it can cause severe engine damage. Also remove the gasket. You will replace this with a new one later (gasket: intake manifold to throttle body, part number: 90412686, catalogue number: 8 28 466) (0.64 EURO). (slika_16, slika_17, slika_18)

11. Put the throttle valve assembly on the table and first remove the throttle valve potentiometer (black thingie) and put it aside. Then remove the right part of the assembly which is the idle control valve and the idle speed stepper motor (solenoid). There is another gasket there which you should also throw away and later replace with a new one (gasket: throttle body to idle control valve, part number: 9240103, catalogue number: 8 37 302) (2.89 EURO). Now take the valve you just removed from the throttle body and take off the idle speed stepper motor (solenoid), that's the part with the black connector on it. Be careful not to lose the black rubber gasket there. You will then have all three parts of the whole assembly on the table. I call the idle speed stepper motor a solenoid because I believe that the thing doesn't really turn or spin but rather pushes the rod inside the idle control valve up and down (in and out). If you hold the solenoid assembly and shake it along it's axis you will hear the clicking of the solenoid inside moving up and down. The throttle valve potentiometer itself does not need any cleaning.
« Last Edit: 06 April 2008, 08:15:30 by Auto_Addict »


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Re: Cleaning the throttle valve assembly, complete
« Reply #1 on: 05 April 2008, 10:30:57 »

12. First spray some carbo cleaner into the opening on the solenoid and shake it. Repeat this a few times and wipe clean the dirt that comes out as you go. Do the same with the idle control valve. Spray in some carbo cleaner, use your fingers to plug the holes and shake well so that all the dirt dissolves and runs out. Repeat that until you get clean spray come out of the valve and you don't see any more dirt inside, then wipe it dry. Now do a thorough job on the throttle valve / throttle body itself. Clean the whole mechanism and all the holes leading inside it (like for example that vaccum hose for the tank vent valve). Throttle body itself is not that critical but the throttle valve does need to be thoroughly cleaned. I used an old tooth brush, cotton sticks and anything I could use to do a really good cleaning. You can lubricate the springs on the throttle body with WD40. By the way, please DO use the carburator cleaner spray for the cleaning job and not WD40. I did a test and tried both and I can tell you straight that carbo cleaner is about 4 times as effective as WD40 is. WD40 is good for lubrication but nothing beats carbo cleaner at dissolving and removing that oily dirt in the throttle valve assembly. I only used WD40 to lubricate the solenoid and idle control valve after I already cleaned them good with the carburator cleaner spray. (slika_25, slika_26.jpg, slika_27.jpg, slika_28.jpg, slika_29.jpg, slika_30.jpg, slika_31.jpg, slika_32.jpg, slika_33.jpg, slika_34.jpg)

13. After you clean all the parts let them dry or wipe them and then assemble them back together. The surfaces where two parts meet need to be very clean. Don't forget the rubber seal when you put the solenoid back onto the idle control valve and the new gasket when you put the idle control valve back onto the throttle body. (slika_35.jpg)

14. Now do the air intake hose. It is put together from three parts. The first part which comes connected to the air filter housing in the car is the part with the intake air temperature sensor. The middle part of the hose is actually the hot film mass air flow meter. I didn't have to clean those two parts as they were very clean already. The third part of the hose is the one which comes mounted onto the throttle valve. Is is also the part onto which the crankcase ventilation hose from the cylinder head cover is connected. Therefore you will find this part to be quite dirty and will need cleaning. Take this part of the air vent hose away from the other two parts by releasing the metal clamp and then clean it good. I again used carbo cleaner here since it works good on this type of dirt. Do a good job on the joint where the crankcase ventilation hose is connected and also clean that hose itself. (slika_36.jpg)

15. Now you need to do some cleaning on the car. First clean the hole into the intake manifold and it's sealing surface where the gasket will later come. Clean the inner wall of the intake manifold about 4 cm deep so that you expose all the holes where three aditional hoses are connected. Clean these holes good. I didn't actually remove any of these small hoses from the intake manifold throat but I did spray the holes good with carbo cleaner and used a small wire brush on them. If you have enough motivation you can take those hoses off and do an even better job. (slika_37, slika_38, slika_39)

16. Remove the smaller hose from the cylinder head cover and clean both holes on the cylinder head cover as well as the opening on the smaller hose itself. Then attach the smaller hose back to the cylinder head cover. You will attach the bigger (crankcase ventilation) hose to the larger hole later. (slika_40, slika_41)

17. When you thoroughly clean the sealing surface on the intake manifold and on the throttle body you can install the new gasket and put on the throttle body. Fasten it back onto the intake manifold with it's 4 bolts (tightening torque 9 Nm /6.5 lbf. ft.). Then attach all the hoses and wire connectors back in reverse order as before:
- attach the vacuum hose for tank vent valve to throttle body
- attach the two coolant hoses to throttle body
- fasten the fuel supply line to the fuel distributor pipe adapter (counterhold on fuel distributor pipe adapter)
- attach fastening clamp for fuel distributor pipe adapter to Bowden cable bracket / throttle body
- mount the accelerator Bowden cable ball to ball joint and re-insert the metal splint in it
- insert the plastic pin behind the rubber joint on the accelerator cable and attach the joint to the throttle body
- connect wiring harness plug to idle speed stepper motor
- attach wiring harness plug to throttle valve potentiometer
- attach air intake hose to throttle body and to air cleaver housing and tighten the metal clamps
- attach wiring harness plug to intake air remperature sensor and hot film mass air flow meter
- attach crankcase ventilation hose to cylinder cover and to air intake hose
(slika_42, slika_43, slika_44, slika_45)

18. Connect the negative, minus (-) terminal of the car battery and set the time, date and input the car radio code if needed.
« Last Edit: 05 April 2008, 15:12:07 by Perplexer »

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Re: Cleaning the throttle valve assembly Omega 2.0 16V
« Reply #2 on: 06 April 2008, 07:58:32 »













































« Last Edit: 27 October 2009, 10:34:55 by jimbob »
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