V50 1.8 petrol idle issues

[StatusRed]

Originally Posted by volvopilot

What is the best way to clean this? I've seen some videos where they put the key to position II and press the accelerator to open the valve. Or is it easier to disconnect the battery, wait 15 minutes, remove air intake hose, unplug and unbolt the throttle body and after that clean it when it is off the car? And can I then open the butterfly valve when the throttle body is off the car (overriding the electric motor)

any help is appreciated

I've cleaned the throttle body recently and wrote a guide here with photos.

In my opinion you'll be able to clean it much better if you take it out of the engine, it's not difficult to do and doesn't take long.

[volvopilot]

thank you, that is very useful.

did you disconnect the negative battery terminal before you started unbolting?

And did you move the butterfly valve during the cleaning? I was wondering if this could be harmful to the potentiometer for the throttle position sensor.

[T5R92011]

Originally Posted by volvopilot

thank you, that is very useful.

did you disconnect the negative battery terminal before you started unbolting?

And did you move the butterfly valve during the cleaning? I was wondering if this could be harmful to the potentiometer for the throttle position sensor.

When I did this same job, I just unbolted the throttle body and cleaned up. Pushed the butterfly valve open with my finger.

Didnt disconnect any batteries etc and the car was fine.

If you're unsure, disconnect your battery anyway. Better to be safe that sorry.

[volvopilot]

Thank you very much! I will try to clean the throttle body today.

In case of erratic idle after the cleaning, is there a way to do a relearn procedure without going to the dealership? It's a 2006 S40 1.8. Is this still a car you can reset by disconnecting the battery for 15 minutes? I believe newer cars still save the ECU values even after disconnecting the battery.

[volvopilot]

I just cleaned the throttle body, off car. The guide was super useful, thank you very much for the detailed description. helped a lot.

I found that the throttle body itself wasn't too bad in terms of carbon deposit. However, the intake manifold, directly after the throttle body is completely covered in carbon. Is this a problem? It's a thin layer of carbon all over the inlet manifold, no blockages however. Only about 1mm thin.

[StatusRed]

Originally Posted by volvopilot

I just cleaned the throttle body, off car. The guide was super useful, thank you very much for the detailed description. helped a lot.

I found that the throttle body itself wasn't too bad in terms of carbon deposit. However, the intake manifold, directly after the throttle body is completely covered in carbon. Is this a problem? It's a thin layer of carbon all over the inlet manifold, no blockages however. Only about 1mm thin.

Just to answer your earlier question, no I didn't disconnect the battery, maybe I should have? But there was only 1 electrical connection which simply unplugged so I thought it was pretty safe.

Interesting that on your engine the intake manifold is metal, mine was plastic. I wiped inside it but not much came out and there was hardly any build up.

I have seen guides where they spray cleaner down into the intake manifold and agitate it, but if you do that you may find the engine cuts out a few times as it burns off unevaporated cleaner. It should start after a few goes though. Your choice if you want to try it or not.

[volvopilot]

I did a test drive yesterday night and this morning and it looks like the RPM fluctuation problem has been resolved by cleaning the throttle body! even though there was very little carbon built up in the throttle body. It makes a huge difference.

Not just the rpm fluctuations are solved, but it feels like the car has way more power too. It is accelerating way faster and smoother. It picks up way better at lower rpm and has a very fast throttle response now.

so a very recommended maintenance item! A huge improvement. So I think this problem is solved for me now.

thanks again for the guide, very useful!

[StatusRed]

Originally Posted by volvopilot

I did a test drive yesterday night and this morning and it looks like the RPM fluctuation problem has been resolved by cleaning the throttle body! even though there was very little carbon built up in the throttle body. It makes a huge difference.

Not just the rpm fluctuations are solved, but it feels like the car has way more power too. It is accelerating way faster and smoother. It picks up way better at lower rpm and has a very fast throttle response now.

so a very recommended maintenance item! A huge improvement. So I think this problem is solved for me now.

thanks again for the guide, very useful!

No problem and I'm glad to hear your issue has been resolved! How many miles are on your car btw?

I also cleaned the throttle body on mine and my sister's old car (2001 1.3l Ford Fiesta) and it made a huge difference to the throttle response and the car felt much nippier (as nippy as a 60bhp engine could feel :P). I'm planning to clean the throttle body on her new car too (Mazda MX-5).

[volvopilot]

it has 130k miles now (210k kms).

[StatusRed]

Originally Posted by volvopilot

it has 130k miles now (210k kms).

I'm on 135K miles, didn't have any issues with my throttle though, I did the clean as a preventative measure so hopefully it's saved me some aggro in the future!