Actuator rattle

[outatime]

Those in the know,

I know Paul L had this problem - did you ever sort it out? Its getting worse on mine...

My EGCV actuator rattles very loudly in sequential mode. I have ETTC and have to keep it in parallel around town, or it sounds like I have a nest of rattlesnakes under my bonnet when I lift off the throttle.

I ran the hose TTC mod before the ETTC mod was done, and the actuator started to rattle on tickover after a couple of months of hose TTC - have a buggered it up by leaving it doing redundant for a while?

Now, with ETTC, it doesn't rattle in parallel but is unbearable in sequential... if I hit boost, the rattle goes only to reappear soon after.

Questions:

1) Seems to me I have a boost leak somewhere that is causing the rattle, is this possible? Could it be the pressure tank?

2) Can I stop the rattle by lashing up the bars going into the actuator?

3) If the actuator is knackered, is it worth replacing it?

Thanks.

[Martin F]

Are you still aiming to be able to run both sequential and parallel as and when you choose ?

[outatime]

Yep, I have ETTC for that reason...

Do you ask this because bracing the actuator bar will cause it to get hot in sequential? Any pressure on it towards the turbo housing and the rattle goes.

Ideally, I would like to swap between the two. My main query was whether it could be a boost leak or pressure tank problem that is causing the EGCV actuator to rattle?

[Martin F]

No i was more asking in case you were trying to run permanent TTC then you could just remove the EGCV actuator and wire the valve open.

Can't help with the rattle i'm afraid.

[outatime]

Oh well, thanks anyway.

I like the best of both worlds, also my car is still boosting too high in parallel so I use sequential when i'm giving it some and can't watch the boost gauge like a hawk...

[Chris Wilson]

This rattling seems to be common on cars with vac or pressure leaks, the spring pressure in the actuator nearly matches the pressure applied through the port and it vibrates. Check for leaks... thoroughly. Had 3 cars in recently, every one the owner swore blind there were no leaks, but found 3 to 5 leaks on each car. A leak can be, and often is caused by a lose fitting hose. IMO the blue silicone stuff is normally total rubbish as it splits and is too slippery. Replace wit quality (Gates?) black rubber or nitrile hoses, of the right ID and wall thickness. Expect to spend half a day tracking leaks and fixing. Be glad you don't have a Mazda FD, tracking vac, solenoid and turbo control probs on those is a test of a Saints patience.

[Martin F]

Based on Chris's comments\experiences then a procedure that may help is to pressurise the intake system using a compressor at say 5 - 10psi and listen\look for any leaks.

[outatime]

Thought as much, thats my saturday afternoon sorted... http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

Is it possible the leak is on part of the system only used in sequential? Boost in sequential is ~1.0bar whereas it will hit 1.3bar in parallel.

I suspected a leak, but couldn't find it when I had a poke around recently. I still have the standard hoses on btw...

[outatime]

Quote[/b] (Martin F @ Sep. 09 2004,11:29)]Based on Chris's comments\experiences then a procedure that may help is to pressurise the intake system using a compressor at say 5 - 10psi and listen\look for any leaks.
http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/rock.gif

How would one do that then? I was just going to tug at hoses and try to spot a loose one.

[Martin F]

Find an old soup can (or similar) drill a hole in the bottom and fit and schraeder (sp?) valve. Remove one of the intake hoses either the one that goes into the inner wing or the one that goes onto the throttle body and clamp the soup can into the open end and attach compressor to valve.

Turn on the air supply and try to regulate it at about 5 - 10psi, open the throttle butterfly and let the system pressurise and turn off the air supply, then listen for any leaks. You will possibly have some of the air moving from the intake to the exhaust if one set of valves are overlapping but you can close this down by turning the crank a little until one set close off.

If the leak is big enough you should be able to hear it, if not then you may need to use some soapy water on the various hoses to see where air is escaping.

As a side note i think this is one procedure where i would defenitely disconnect the battery just to save any silly accidents.

[outatime]

Cheers, soup for lunch then. Just need an old bike tyre and a compressor now... http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

[Chris Wilson]

Quote[/b] (Martin F @ Sep. 09 2004,11:41)]Find an old soup can (or similar) drill a hole in the bottom and fit and schraeder (sp?) valve. Remove one of the intake hoses either the one that goes into the inner wing or the one that goes onto the throttle body and clamp the soup can into the open end and attach compressor to valve.

Turn on the air supply and try to regulate it at about 5 - 10psi, open the throttle butterfly and let the system pressurise and turn off the air supply, then listen for any leaks. You will possibly have some of the air moving from the intake to the exhaust if one set of valves are overlapping but you can close this down by turning the crank a little until one set close off.

If the leak is big enough you should be able to hear it, if not then you may need to use some soapy water on the various hoses to see where air is escaping.

As a side note i think this is one procedure where i would defenitely disconnect the battery just to save any silly accidents.
Nice idea, and does work, but you are forgetting the need to loosen both sets of cam bearing caps off so all valves are shut. Not for the feint hearted.... http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/rock.gif

[Martin F]

Is there not a place on the cam rotation where all intake valves would be closed ?

[Chris Wilson]

Quote[/b] (Martin F @ Sep. 09 2004,13:50)]Is there not a place on the cam rotation where all intake valves would be closed ?
Very unlikely on a 6 cylinder, but can't say I have tried.

[Martin F]

Me neither, but i thought there might be a slim chance. Mind you if one set of intake valves are open as long as the exhaust ones are closed you should still have a sealed system (Discounting ducked piston rings)

[outatime]

Hmmmm, getting a little scared of this now. It sounds complicated http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/biggrin.gif

Would a leak on the intake side cause the actuator to rattle? My idle is sitting a bit high at the moment...

Where would be the first places to look?

[Nathan]

Problems like this are where a Mityvac hand pump is worth it's weight in gold.....

Never tried pressurizing the whole intake system while static.....I wouldn't have thought it would work as there will always be small leakages somewhere. Just work your way through the system pipe by pipe. Thats how we do it here anyway. Never had one we couldn't sort yet http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

[outatime]

I think i've found the problem, there are no hoses going into the EGCV VSV! The pressure line from above is still going straight into the EGCV actuator...

[Martin F]

Think that could be an issue.

http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/biggrin.gif

[outatime]

I'm surprised it even works in sequential like that, it might explain the turbos coming on at funny times http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/laugh.gif

[Nathan]

True, I find it amazing how well the cars run with all sorts of vac hoses split/leaking or disconnected! They still pull like a train in most situations so many people don't even know theres a problem!

[outatime]

I've put all my hoses back where they should be and its doing all kinds of odd things:

Boost is sequential goes no higher than .9 bar, there is no kick; it goes to .5 then builds gradually. If you put your foot down, the boost sometimes builds to around .2 then drops off before shooting up to .5 then building from there?!?

On top of that, its stuttering (no bangs) badly as it hits positive boost...

In parallel, only the first turbo is working. The exhaust note isn't changing like it usually does.

Any ideas? What would the symptoms of the EGCV VSV failing be?