high revs

[Chillidoggy]

14 minutes ago, Escape said:

You are of course right Ian that the vacuum is used for the throttle jack and EBPV. 😳 But most have been removed and a leak in the system is unlikely to lead to high idle as it uses vacuum to open the throttle.

 

Agreed, however I was thinking more of a possible vacuum leak in the associated EBPV/throttle jack pipework, an easy box to tick, but we need to know if those systems have been removed/blocked off.

[Dan Andrews]

18 hours ago, Chillidoggy said:

It does have something to do with engine management in respect of the EBPV and throttle jack, so perhaps it's worth a check.

Dan - has your car still got it's EBPV and throttle jack? I know a lot of them have been binned, mine included.

I will have a look thanks

[scottytwo]

I managed to get my old Dell XP to fire up to record settings at idle. Seems to confirm an IAC setting issue.

I'm still confused about why when coasting the idle is fine but as soon as the car stops moving, it starts hunting and increasing the idle to 1200ish.

160824 idle.csv

[sailorbob]

Your IAC valve counts are going to zero which means the ECU cannot control the idle speed. As said above, you probably have an air leak or your throttle plates need closing.

[scottytwo]

Thanks. I suspect the adjustment on the IAC as a previous garage had to "make an adjustment" to get it through the MOT emissions. 

Do I need to remove the chargecooler to adjust the IAC and will I be winding the screw in or out?

Edited August 16 by scottytwo

[sailorbob]

The IAC valve is not adjustable.  You need to determine if you have an air leak or if your throttle plates need closing.

[scottytwo]

Ah, it will be the throttle plate adjustment I will need to do. I'll re-read the section in the manual...

[scottytwo]

I've had a look at the adjustment, but on my car the adjustment screw isn't sitting on the "stop" on the manifold. This looks like I could only turn the screw "in" which would open the plates further but would reduce the counts (according to the manual). That seems to be the opposite of what I need to achieve?

I couldn't physically push the adjustment screw against the manifold. And it is a right pain to get to!

[Escape]

That indicates someone has already tried to adjust the idle, but didn't succeed. So you need to look for another path for the air to reach the intake, like a split pipe from the manifold.

There is also the possibility the 4 throttles are no longer synchronised and one or more are staying open even with the throttle lever against the stop. Normally, they come set from the factory and should never be adjusted, but you never know.

[Dan Andrews]

Hi all just done another freescan high revs cut in and stayed at about 1800 looked at IAC reading, and it was reading 138 engine was up to temp. Im going to take a stab and change TPS as well as only reading 89 - 90 when fully depressed. I have found the TPS sensor but cant find location of the IAC in manual. Can someone help me out with location and is it difficult to change.

Thanks

[Sparky]

TPS may just need adjusting; I wouldn't change it until you've done that as it's entirely possible you could buy a lemon.  IAC - did you reset it with the Freescan software first?  It can be found just forrward of the chargecooler, pretty much beside the oil filler cap.  Normally two very small Torx screws; take care!