IAC clean without Throttle body removal

[Blake200]

Sorry if this has been covered but I can't see it anywhere in great detail.

I would like to clean my IAC due to the revs hanging up high and a high idle. It's been sat for sometime so feel this would be a good job to do either way.

Is it possible to clean it without removing the complete throttle body, i know some have said you can just remove the intake pipe is it then just a case of flushing it with some carb cleaner?

Any photos or someone to point me in the right direction on how to gain access that would be great.

Thanks in advance

[Carolyn]

Sometimes you can get a result that way.  If you have a straw on the nozzle of your spray can, there's a little hole in the inside of the throttle body that is the idle air duct.  Try and spray directly in there.

If that doesn't do the trick, try some WD.  Then give it a bit more carb cleaner.  

If that doesn't work, get yer spanners out.

[Ardent]

Blake
Just for clarity, the revs hanging high, we are talking when properly warmed up and not just from a cold start.

[shnazzle]

It isn't that much of a pain removing the assembly to be honest.  Granted I've done it a fair few times now, sadly.
Bonus is that you can make sure you give it a proper clean.

It's fiddly for sure, but not difficult. As long as you clamp the water hoses to the IACV.

For one of mine it took a fair bit of carb cleaner and jiggling to get it to move. The other one freed up quite easily.

Also, make sure you stay on top of your air filter and also ensure your PCV valve is sealing properly. One of mine had quite a bit of thick oily gunk with grit. Can only be caused by a sub-par filter and oily gasses.

[Blake200]

Blake
Just for clarity, the revs hanging high, we are talking when properly warmed up and not just from a cold start.

Thanks for all the replies, I may initially give an inspection with just removing the intake and possibly try and view it with the camera probe if possible, I have a brake cleaner bottle with a good adjustable spray so this may do the trick.

As for the above it first fires up around 2500-3000rpm before dropping to 1500rpm. It never cuts out or fails to start.

If I leave it to warm so the needle gets up to running tempreture the revs then drop from 1500rpm and when the throttle is increased it sits up around 2500+ before dropping 3-4 seconds later.

The cars been in the family for a fair few years and I know this job hasn't been done why it's one I wanted to carry out.

[jonbill]

That doesn't sound like IAC to me - More like an air leak or a sticky cable.
Fwiw, you can take the IAC off the throttle body in situ.

[m1tch]

Have you tried anything like resetting the ECU to get the engine to relearn things?

[Carolyn]

Taking the throttle body off looks a lot more intimidating than it actually is.  If it hasn't been cleaned in a long time, it's worth doing.  If you don't feel up to tackling it, fair enough.  Dirt around the butterfly can cause enough of an air-leak to cause problems.
Once the inlet duct is off, there are two small hoses to clamp off, two bolts and two nuts to get it loose, two electrical connectors (easier when it's loose) and the throttle cable.  It is fiddly, but a patient attitude will get you through!
I've been through my files and can't find any close-ups of the throttle body, but I'm sure you'll find some with a bit of Googling.
Here you go:  m http://www.mr2roc.org/phpBB3/viewtopic.php?f=11&t=30163 m

[Bossworld]

Are there any security/torx bolts involved? Feel this is another task I should probably do

[shnazzle]

Only if you want to do it properly and remove the IAC actuator from the body.

That way you can spin the valve while freeing it up.

You do have to screw it back in in the EXACT same position or it will affect your idle

Knowing how disgusting they get now having done 3, I'd take it apart completely and do a thorough job.

[shnazzle]

I'll get the spare one out today for some pics

[Carolyn]

Are there any security/torx bolts involved? Feel this is another task I should probably do

Yes.  5 pointers.

[Blake200]

Success wasn't a bad job atall and like others have said is fiddly but is a doable job.

IAC was very dirty as was the TB so cleaned both out and re assembled.

I am yet to fire it up as noticed a loose pipe that was already like this prior to me working on the car. It looks like it's part of some kind of secondary air? Have tried uploading a photo bellow




Thanks again for all the help so far

[shnazzle]

First pic is the view when it's mounted. Looking at throttle position sensor

2nd shows intake, the hole to the IACV is on the left
3rd is the hole to IACV
4th shows the 5 point security torx bolts on the IACV actuator
5th is manifold side of tb

[Bossworld]

Thanks both

[shnazzle]

If you look at the 4th pic, looking at the security bolts...

Before you loosen the bolts, put Tippex around where the bolts are along th plastic, so that you can put it back exactly where it was

Oh and the 3 bolts that hold the IACV onto the TB are very very tight and also very soft so be very sure to use the right size screwdriver bit.

I ended up having to dremel one

[Carolyn]

Success wasn't a bad job atall and like others have said is fiddly but is a doable job.

IAC was very dirty as was the TB so cleaned both out and re assembled.

I am yet to fire it up as noticed a loose pipe that was already like this prior to me working on the car. It looks like it's part of some kind of secondary air? Have tried uploading a photo bellow




Thanks again for all the help so far

That goes to a spiggot on the top of the inlet manifold, not far along from the throttle body.  Car will not be happy until that's back in place.

[ChrisGB]

That pipe being off could well have been the cause of the fast idle.

[Bossworld]

upload photograph

Another set of tools soon to be confined to the single purpose cupboard, along with the o2 sensor socket  s:) s:)

-


Blake200 - how did you get on after the clean/fixing that loose hose?

[shnazzle]

Until you need to remove the ECU... for some reason  s:) s:)

[Bossworld]

So mines currently off the car, fully cleaned up and the valve was indeed sticking before.

Quick question about said valve. It seems to take up about a quarter of the circular opening. I didn't note the orientation when I took it out, but it seems it's magnetic and only seats home when it's positioned upwards.

Just want to check that sounds correct? I did try gently reinserting at various angles and it wouldn't seat home so I'm relatively confident I'm on the right track?

Edit: yes there's a cavity  m https://youtu.be/Yy2xqS1lfz8 m

Ps Patrick you were right about those bolts, had to dremel a groove into the front most one

[shnazzle]

The magnet part does sit one way. What you need to make sure of is that the valve itself sits in the metal body exactly the same way

[Bossworld]

Aye thanks used a marker pen on all screws as you advised so should be back to where it all started albeit with cleaner parts.

Unfortunately won't know how much difference it's made until the car is back on the road, it's idling in the garage (door open obvs) at the moment. Suppose this will also have affected an ECU reset.

Edit: idling perfectly at 900 once warmed up. Thumbs up and thanks all for the help  s:) s:)

I did read that a sticking TB can induce overrun popping, wonder if that has much effect on our cars. Presumably some popping is due to TTE/ precat removal?

[shnazzle]

Aye thanks used a marker pen on all screws as you advised so should be back to where it all started albeit with cleaner parts.

Unfortunately won't know how much difference it's made until the car is back on the road, it's idling in the garage (door open obvs) at the moment. Suppose this will also have affected an ECU reset.

Edit: idling perfectly at 900 once warmed up. Thumbs up and thanks all for the help  s:) s:)

I did read that a sticking TB can induce overrun popping, wonder if that has much effect on our cars. Presumably some popping is due to TTE/ precat removal?

Just been pointed at this again to see if there's anything to move into the "how to clean IACV" how to.
Never did get to the last part of this.

The popping on overrun is perfectly ok. It's a little more pronounced with the TTE and de-pre-cat due to less baffling and material getting in the way of the shockwaves. A stuck valve introduces an unexpected lean condition in open loop (overrun is open loop) so the stock ECU never compensates for it.

Bangs on the other hand need to be kept to a minimum. That's a big explosion of unburnt fuel in a blazing hot exhaust.
Helen's does this after a hard drive. You shift down with heel toe and BANG!