Has anyone successfully cleaned their ICV?

[markmalin]

Wondering if anyone has done this and actually fixed it...like for good?
And if so, how did you clean it? What did you use and how?

Thanks
Mark

[Joe Bob]

Cleaning the ICV, idle control valve.

[Pedro '84 Coupe]

I've done it twice since I bought the car in 2017. Last time was just last week. Used brake cleaner both times with good results. Brake cleaner leaves little to no residue unlike carb cleaner or similar products. Be sure you let it dry completely before hooking it back up. You want to clean so that the valve moves freely. If yours is really gunked up, try using a small brush to help with the cleaning.

[markmalin]

Originally Posted by Joe Bob

Cleaning the ICV, idle control valve.

Thanks for the link. Have you done this then, and it worked for you? I'm wondering if anyone else actually did this and it worked long term? This thread and others I've read seem to have a smattering of some people who say it fixed things, others who say it just was temporary. I'm curious to hear of someone's actual experience, or if there is anything definitive. Other than buying a new one.

Mark

[markmalin]

Originally Posted by Pedro '84 Coupe

I've done it twice since I bought the car in 2017. Last time was just last week. Used brake cleaner both times with good results. Brake cleaner leaves little to no residue unlike carb cleaner or similar products. Be sure you let it dry completely before hooking it back up. You want to clean so that the valve moves freely. If yours is really gunked up, try using a small brush to help with the cleaning.

Thanks, Pedro. I appreciate the input!

Mark

[Joe Bob]

Cleaning it is one thing, finding the cause is another.

[boyt911sc]

Mark,

Cleaning alone will not fix your ICV problem unless you test and verify the operation of the valve. There is a specified procedure to energize the solenoid valve and confirm its operation.

Tony

[markmalin]

Originally Posted by boyt911sc

Mark,

Cleaning alone will not fix your ICV problem unless you test and verify the operation of the valve. There is a specified procedure to energize the solenoid valve and confirm its operation.

Tony

Thanks for the info, Tony. I understand. I'll also do the procedure for testing when I get to that point. I've had a number of 80's BMW's with Bosch ICV's and back in the day when they went bad (or got gunked up) the cars would hunt from about 600 RPM's (or just before dying) up to about 2000 RPM's (run away cutoff). There was so much forum hype back then about whether to clean or not clean your ICV and whether it would destroy it or not if you sprayed anything in there. That's why I was curious to know whether anyone had an issue with theirs, cleaned it, then found that it actually solved an issue.

I still have more debugging to do on my car. It runs fine for the most part, just every so often the throttle sticks about 2000 RPM's when I let me foot off the gas. The other day it was cycling/hunting between about 600 and 2000, but not for very long, which made me wonder about the ICV (i.e. it was behaving like the old BMW's would). As I investigate this it got me thinking about the cleaning idea - and if anyone has actually solved anything by doing that.

[Pedro '84 Coupe]

The first time I cleaned it, the part was pretty nasty. After making sure it was getting power, I dismantled the ICV to check the o-ring, which was surprisingly in great shape. Then I reassembled and cleaned it, which solved my "hunting idle" at start up.

When I cleaned it last week, it wasn't because of any idle issues, I just wanted to take a look to see how dirty it had gotten the past 3 1/2 years. It wasn't as bad as the first time, but there were still what I guess were carbon or oil deposits in there. From what I understand, the part gets dirty over time because of its location on the intake assembly.

[911obgyn]

It depends on how many miles and how much blowby, oil vaporization has occured. Oil change frequency, valve guide condition and how hot the engine gets as to how frequently it needs cleaning.

[markmalin]

Originally Posted by Pedro '84 Coupe

I've done it twice since I bought the car in 2017. Last time was just last week. Used brake cleaner both times with good results. Brake cleaner leaves little to no residue unlike carb cleaner or similar products. Be sure you let it dry completely before hooking it back up. You want to clean so that the valve moves freely. If yours is really gunked up, try using a small brush to help with the cleaning.

So I cleaned mine today. Not too bad gunk wise. I decided to dismantle it. I cleaned the contact surfaces on the rotor with some emery paper and carefully put a little contact cleaner on the contacts that ride on the rotor. Re-assembled it. No change. My idle issue is intermittent. Sometimes it idles fine, sometimes it hunts at idle.

For what it's worth, here are some pictures in case anyone is interested in what these things look like inside.

[boyt911sc]

Mark,

Before you decided to disassemble your ICV , did you test the valve for its operation? The valve should switch back and forth (open/close) positions when electrically energized. If it did not, you had a defective ICV. But it is not clear that you tested the ICV using a 9-volt battery. Did you?

Tony

[mysocal911]

Originally Posted by boyt911sc

Mark,

Before you decided to disassemble your ICV , did you test the valve for its operation? The valve should switch back and forth (open/close) positions when electrically energized. If it did not, you had a defective ICV. But it is not clear that you tested the ICV using a 9-volt battery. Did you?

Tony

The resistance of each winding needs to be tested and should measure about 20 ohms from the center lead to each other lead.
Typically when the valve fails, the windings become shorted and cause the DME ECU to also fail.

[dg567]

I cleaned mine last week, tested it after and it opened and closed as it should. Before this, after the car would start, if I wouldn't let it warm up for a few minutes it would hunt a bit for idle, and if I touched the throttle at all it would just die. After I cleaned it, the car started on the first crank and didnt die when I pulled it out of the garage before it warmed up. I'm happy!

[FrankM_]

Nice to see the inside of it for once.
Was the contact surface of these copper pins really dirty ?

I cleaned mine but it didn't have the effect I was after (still hunting @idle). After replacing the O2 sensor and readjusting the idle mixture, it ran smooth. It idled OK when cold but started 'hunting' when warm, also when bypassing the ICV (test port, bridge B and C) it really didn't idle that much better.

As far as I could tell from the paperwork, it was still the original O2 sensor from 1985 that was on the car (88K miles) and it is a replaceable item at 60K miles.

Unfortunately this check is well down on the table in the Bentley manual, so I did a lot of checks before that !

[markmalin]

Originally Posted by mysocal911

The resistance of each winding needs to be tested and should measure about 20 ohms from the center lead to each other lead.
Typically when the valve fails, the windings become shorted and cause the DME ECU to also fail.

Mine measures about 20 and 22 ohms from the center to the outer pins. I also measured for continuity from the pins on the connector to the copper pins inside the housing and they measure 0 Ohms.

If I apply 9 volts from center to either outside, it moves a little sometimes, but sometimes not. Should this snap open and closed quickly? I know it's getting contact to the windings. i also measured from the winding contact at the top of the shaft to each other winding, seems fine. I'm wondering if the magnets tend to lose their effect with time? Granted, it's tight putting the rotor back in because of the magnetic field.

I'm suspecting the ICV because the issue is intermittent. Sometimes it's fine. Sometimes I lift off the gas and the tach stays at 2000 RPMS. Sometimes at idle it will rev up to 2000 RPM's and back down. The fact that 9 volts across the pins doesn't drive the valve open or closed makes me suspect the valve, unless because these are driven by a PWM amplifier that's not a very accurate test. Anyone else notice this with a battery test?

[3rd_gear_Ted]

My understanding is that the ECU sends a frequency and varying voltage and the rotor oscillates according to the combo of the two???
Is this the case???
Classic case of Chicken(hardware) or Egg(signal) as seen a lot in any ECU controlled system troubleshooting.

[jlex]

Heidi and Franny posted videos of a 911 engine drop/re-do. When it was finally back together, the idle was hunting. She went thru a number of different things to isolate the idle problem. Final resolution was the base idle was incorrect. Once adjusted, the idle was ok. Watch the video for some tips in hunting down your problem:
https://www.youtube.com/watch?v=u512ogk5trA&ab_channel=HeidiandFranny%27sGarage

[mysocal911]

Originally Posted by 3rd_gear_Ted

My understanding is that the ECU sends a frequency and varying voltage and the rotor oscillates according to the combo of the two???
Is this the case???
Classic case of Chicken(hardware) or Egg(signal) as seen a lot in any ECU controlled system troubleshooting.

The two 12V signals are PWM (pulse-width-modulated). When the two signals have the exact same duty cycles (DCs), the bypass air passage is 1/2 open.
To regulate the idle, the two signals vary their DCs in opposite directions to vary the opening of the air passage.