Cleaning the ICV in Situ or tips for removing?

scam75 · Apr 23, 2014

Hello All

I think my ICV my be in need of a clean out. Has anybody devised any methods that are effective for cleaning in situ? I have sprayed cleaner down the hose a few times and it has helped a little bit.

Alternatively is there a trick way of removing it for a proper clean without removing the manifold?

Thanks in advance

Stuart

Mike_Pollock · Apr 23, 2014

No trick, just VERY tight.

I did it on a N/A in situ.

scam75 · Apr 23, 2014

ORIGINAL: A9XXC

No trick, just VERY tight.

I did it on a N/A in situ.

How did you do it?

I can clearly see, and get to, one of the clamp retaining nuts and the nut on top of the clamp, nothing else! Does the clamp separate in two?

Stuart

robwright · Apr 23, 2014

Mate I would just invest in some gaskets and take the inlet manifold off. Job will probably get done quicker, better and a whole lot less knuckle rash.

Mike_Pollock · Apr 23, 2014

Rob is probably right!

I skinned knuckles used every elbow, extension, mirror, bit and ratchet I have and I would guess a turbo has more stuff in the way.

George Elliott · Apr 24, 2014

Mike is right above

I read that Fen on here did a replace w/o removing the inlet, but it is hard work

Cleaning did not fix mine

George
944t

scam75 · Apr 24, 2014

Thanks for the advice guys. I have my idle back up near 13 now with repeated spraying of carb cleaner. I think I would like to have a known good ICV at the ready before removing the manifold. I'll persist with the cleaning just now and see if I can pick one up. Does anybody have a known good one kicking about?

Also does anybody know the function of the adjuster screw on the throttle body? It seemed to act like an idle speed adjuster when I played with it last night.

Cheers

Stuart

TTM · Apr 24, 2014

Even if a standard engine bay looks worryingly full of things, removing the intake manifold really isn't that much work. I can't remember how many times I did it.

The adjuster screw is to adjust the idle speed when the ICV is disabled, which is done by bridging some pins from the round "rubber plug" of the engine harness.

scam75 · Apr 24, 2014

ORIGINAL: TTM

Even if a standard engine bay looks worryingly full of things, removing the intake manifold really isn't that much work. I can't remember how many times I did it.

The adjuster screw is to adjust the idle speed when the ICV is disabled, which is done by bridging some pins from the round "rubber plug" of the engine harness.

Cheers Thom. My idle speed seemed to adjust with the screw with the ICV connected. I assume it just alters air flow at the TB so would still affect idle speed even with ICV connected?

Stuart

TTM · Apr 24, 2014

Yes you will still alter idle speed by turning the screw with the ICV connected, but the points of disabling the ICV when adjusting idle speed with the screw are :
1) to calibrate the ICV to make sure it runs within the idle parameters programmed in the DME
2) to diagnose a possibly faulty ICV, as if there is no change in idle speed when turning off the ICV through the plug, then obviously it's not working as it should.

Check the idle adjustment procedure here :
http://www.clarks-garage.com/shop-manual/fuel-08.htm

scam75 · Apr 24, 2014

ORIGINAL: TTM

Yes you will still alter idle speed by turning the screw with the ICV connected, but the points of disabling the ICV when adjusting idle speed with the screw are :
1) to calibrate the ICV to make sure it runs within the idle parameters programmed in the DME
2) to diagnose a possibly faulty ICV, as if there is no change in idle speed when turning off the ICV through the plug, then obviously it's not working as it should.

Check the idle adjustment procedure here :
http://www.clarks-garage.com/shop-manual/fuel-08.htm

Cheers Thom, interesting. I will try this procedure tonight and see if I have a working ICV or not. To be fair I would not be chasing an issue if I didn't have an AFR gauge as my idle is pretty stable and within range. It just seems a bit richer than it used to be. Could the ICV be the culprit?

Edit to add inlet manifold gaskets are very new and I don't seem to have any vac leaks. The car used to idle around 13 on gauge but has dropped down to mid 11's of late. some carb cleaner into ICV has seen it rise back into 12's again, sometimes high, sometimes low 12's. AFR's on throttle all good. I also cleaned the throttle body last night.

Cheers

Stuart

TTM · Apr 24, 2014

Are you sure you haven't touched the FQS lately?

http://members.rennlist.org/951_racerx/FQS-adjust.html

scam75 · Apr 24, 2014

Yes I am sure I have not touched it! It's set to 0 currently. I've just had a steady richening over the last 6 months or so and to be honest hadn't paid too much attention as car wasn't used much in the winter. I had hoped a few good thrashings and regular use would sort it and since I've started cleaning things and spraying carb cleaner into the ICV, through the hose you can easily access, it has improved a bit, just not quite back to the 13's where it used to sit. Hence the reason I think the ICV may be gummed up a bit.

Stuart

robwright · Apr 24, 2014

Just one thought Stuart. Have you calibrated your AFM recently?

scam75 · Apr 24, 2014

ORIGINAL: robwright

Just one thought Stuart. Have you calibrated your AFM recently?

I don't have one Rob, I run a SciVision MAF, which means I don't have an idle mixture screw to fix my issue! But clearly I have an issue of some description as the AFR's at idle show. Currently suspect ICV, don't know what else it could be, engine is fresh and rebuilt and all gaskets are new. Vac lines are leak free and all is good on throttle, just this rich idle issue, and as it's somewhat improved by attacking the ICV with carb cleaner I am inclined to point the finger at that.

Stuart

robwright · Apr 24, 2014

My bad mate I meant your AFR. It should he periodically calibrated in fresh preferably or ehen the car hasn't ran for about a week.

scam75 · Apr 24, 2014

ORIGINAL: robwright

My bad mate I meant your AFR. It should he periodically calibrated in fresh preferably or ehen the car hasn't ran for about a week.

It's self calibrating buddy. It's an AEM gauge, it calibrates automatically each time it's switched on. I will check tonight with the engine off. It usually settles at 14.7 if I do that.

Cheers

Stuart

scam75 · Apr 24, 2014

ORIGINAL: TTM

Yes you will still alter idle speed by turning the screw with the ICV connected, but the points of disabling the ICV when adjusting idle speed with the screw are :
1) to calibrate the ICV to make sure it runs within the idle parameters programmed in the DME
2) to diagnose a possibly faulty ICV, as if there is no change in idle speed when turning off the ICV through the plug, then obviously it's not working as it should.

Check the idle adjustment procedure here :
http://www.clarks-garage.com/shop-manual/fuel-08.htm

Ok done this. It was idling spot on proper RPM with ICV connected. Disabled ICV and it was idling about 1100 rpm. No change in AFR reading. I adjusted it into spec with ICV disconnected. Reconnected ICV and still idling spot on but still no change in idle AFR! So ICV must be working to some extent. What is making it idle rich? Still spot on across the Rev range and checked calibration of AFR gauge which was in spec.

Confused

Stuart

TTM · Apr 24, 2014

Idle will be richer than 14.7 when cold obviously... has your lambda sensor ever been replaced? Could an injector or two have developed a leak during winter?
Fuel pressure ok?

I don't think the ICV will affect AFR at all (unless leaking in atmosphere) since the air flowing through it or through the TB was measured by the MAF.