Checking the IRIS.

[oab_au]

I see a number of requests on how to check the IRIS.

The electrical side can be checked at the ECU plug B62( the largest plug at the ECU), wire 20 ( the middle wire of the bottom row). This is a on 13-14 volt, or 0 volts off.

To check it mechanicaly, you would have to use a mirror and a light, to look under the inlet manifold to see the rod and lever that links the vacuum diaphragm unit to the butterfly valve. This unit is under the middle of the manifold, behind the alternator.

Start the engine and watch the lever, raise the engine speed to see the lever move. I believe that it is open at idle, closing at about 1000 RPM, to open again at 4000 RPM.

If the valve is stuck open, where will be a lack of torque till 4000RPM, if stuck closed it will lack top end over 4000RPM.

The mechanical side can get stuck with goo, or something may be jamming the lever like a rats nest, ect.

There must be a picture of the under side of the inlet manifold on the forum somewhere, my connection is too slow to check pics.

Harvey.

[immortal_suby]

Not the clearest picture, but here it is.

[oab_au]

Knew it would be somewhere
That is the valve there in the middle with the lever pointing up and the link connecting it to the diaphragm, on the right side.

You may be able to see it with the belt guard removed, looking between the alt and air con.

Harvey.

[lee]

thanks guys - I've been one of "them" wondering how to do this

[oab_au]

Originally posted by lee
thanks guys - I've been one of "them" wondering how to do this

Sorry Lee didn't mean to brand you " one of them ". But coming from a Ducatiphile to a Norton lover,,,,,,,,, that is saying something.

I haven't been able to look, so if you can give us some feedback.?

Harvey.

[lee]

Hi Harvey,

I can't say I've had a good look as it's night here. I can see part of it plainly using a flashlight (belt cover off)....but just part of it, can't make out the rod/lever, daylight might be enough.

Also, I have fat hands, but someone with thin hands might be able to reach in between the PS pump & the alternator...I can almost get there...may get my daughter to try this weekend if she's around.

Ducati huh? I've always wanted one, but I didn't think I could keep up with the maintenance

that's a joke from a Norton lover to a Ducatiphile - for those reading but not familiar with the two brand's reputations in days gone by

[SVX-FF]

Hey Harvey I am wounderin gif there is any way that there can be oil leaking out of the IRIS or the diaphragm? I have oil on the top left of my motor and think I have traced it to the IRIS. The bolts are wet with oil?
Any input would help.

Thanks Steve

[mbtoloczko]

Hi Harvey,

Thanks for the how-to. I've been wondering this. I'm hoping to check it as part of a preventative maintenance project this winter. :-)

Hi,
What's the black box next to it ???

[oab_au]

Originally posted by RobSVX
Hi,
What's the black box next to it ???

The black box is a vacuum tank.

The way it operates is, manifold vacuum is used to open the valve. As the valve is opened at 4000 rpm, regardless of the throttle position, there may be no manifold vaccum advailable in the manifold, to do it. That is the job of the tank, it is charged with manifold vaccum through a check valve, to hold enough vacuum to operate the valve, even at full throttle.

That brings up another point, that Beav touched on in another thread. If the check valve is jamed open by some object, the IRIS valve will operate when you check it, with the car stopped. But when it is called to open under full throttle conditions, there is no reserve of vacuum it the tank, so the valve won't open at full throttle.

Harvey.

[TomsSVX]

good thing i put my check valve back together right, anyway i need to buy a new one for my 94 fwd

[oab_au]

Originally posted by SVX-FF
Hey Harvey I am wounderin gif there is any way that there can be oil leaking out of the IRIS or the diaphragm? I have oil on the top left of my motor and think I have traced it to the IRIS. The bolts are wet with oil?
Any input would help.

Thanks Steve

No Steve, if the manifold had enough oil in it to leak out the butterfly spindel, it would be sucked into the cylinders to blow smoke. Must be from somewhere else.

Harvey.

[SVX-FF]

Thanks Harvey,

I will keep looking. Your the man.
I mean mate

Steve

The black box is a vacuum tank.

Anyway to check it, without pulling it off ? Seems like you'd have to pull the intake for that...

I think I can see my 'Rod', but not sure. (now that I have your attention...!) I can use a light and mirror under the intake and catch a good view of it. One end appears to be the riveted to the diaphram, but don't see how it moves any ? The other end I can't really tell but is hooked up- It does appear to look like the picture in this thread.

Is this 'Rod' flat ? (Mine is and the flat surfaces faces forward).

Does it turn or does it push/pull ? Can't tell by what I'm observing that it could move anyway. Just doesn't appear to be on a moving surface.

I have good, even power at 4,000... but no surge. I was watching the rod, while my GF rev'ed the motor (it was warm) past 4,000 and didn't see any movement. I can't see any loose or bad hoses either.