V50 1.8 petrol high idle issue

[theRsole]

cheers, definitely not normal, seems like something is sticky - was worse this morning again - better get it cleaned before the wife smashes through a wall!

[StatusRed]

Originally Posted by domhart10

Yeh on start up the car will rev and hold itself above the line for a bit and then drop down after a bit. (I never pull of until its dropped down)

How long is "a bit"?

[domhart10]

Originally Posted by StatusRed

How long is "a bit"?

its not long, maybe around 30 seconds I think. There are quite a few Volvo s40 T5 video's on idle start ups.

[StatusRed]

Originally Posted by domhart10

its not long, maybe around 30 seconds I think. There are quite a few Volvo s40 T5 video's on idle start ups.

Interesting.. Mine seems to stay at higher revs for longer but it definitely does go under 1K RPM (more like 800) once the engine has got to temperature. Checked the manual too and it mentions how the engine does this on cold starts - explains why I've noticed it happening more recently rather than when I got the car in the summer! Thought something might have been wrong at first.

[domhart10]

Originally Posted by StatusRed

Interesting.. Mine seems to stay at higher revs for longer but it definitely does go under 1K RPM (more like 800) once the engine has got to temperature. Checked the manual too and it mentions how the engine does this on cold starts - explains why I've noticed it happening more recently rather than when I got the car in the summer! Thought something might have been wrong at first.

thats pretty good, mine does it regardless everytime I start up for about the same length each time on first start.

(Bit frustrating whenever I want to do a silent start to not wake everyone up)

[nboy]

I found that if I put in Shell V-power nitro (and continue to do so) it solves the problem. When I have reverted back to supermarket fuel (95RON) it starts to have the problem again, especially when the engine is cold.

[theRsole]

just an update on here - leaky vacuum pipe was the cause

[mmalbon]

Originally Posted by domhart10

Check your Idle Air Control Valve. They get a little gunky, and if it is stuck so that it cannot close all the way, the engine will always get extra air just like a vacuum leak, and the fuel injection will compensate by adding more fuel. Actually, don't check it: just remove the IAC, spray it out with IAC cleaner, and remount it, and see if that fixes it.

Where is the idle air control valve on a V50 petrol 1.8?
Also, how does the plastic engine cover come off, do you just pull it?

[volvopilot]

Originally Posted by mmalbon

Where is the idle air control valve on a V50 petrol 1.8?
Also, how does the plastic engine cover come off, do you just pull it?

you can pull the engine cover off, no need to unclip anything.

not sure if the 1.8 has an idle air control valve. I always thought that drive by wire (electronic throttle bodies) don't have one and they simply regulate the idle by adjusting the throttle plate accordingly.

If you experience these problems I would start with checking the intake system for leaks in hoses. It might get un metered air between the throttle body and TMAP sensor. In that case I would suspect the green throttle body gasket. You can easily replace this by unbolting the throttle body. While you are at it, clean the throttle body itself too. Get a new Air filter and make sure everything is tightly connected together.