Novice question about Ohms test

[dan88911]

I did this ohms test on my ICV per the Bentley's Manual.
My results were as follows;
Between outer terminals........ 39.4
Between center terminal and each outer terminal..... 20.8 and 19.1

So anything other than the 40 ohms and 20 ohms per Bentley's
counts as faulty. Correct?

Sorry for the stupid question. Just want to make sure this is a zero tolerance issue.

I clean the unit awhile back , however I continue to get a very slight bounce at idle, between 880 & 980 rpm.

So was I was thinking of replacing the ICV.

Your shared knowledge is much appreciated.

[SteamWolf]

a few ohms either way won't be a problem. It is when it has gone open or closed circuit or starts reading in values vastly different from spec that it is a problem.

[911dean]

I think your well within specs. How accurate is your meter? If you had a reading of 75 and 35 then you would have a problem. Others might chime in.

[Bob Kontak]

You are within tenths of an ohm, right, on a static reference? I would leave it alone. Your MM is off that far.

[Bob Kontak]

Originally Posted by SteamWolf

a few ohms either way won't be a problem.

You know there is a book called The Steam Pig.

Have I told you about my 4.0L Defender?

[manbridge 74]

I believe you are close enough. Ohm readings can vary due to temperature and differences between meters. For example, many sensors on Japanese cars are to be tested at something like 75F degrees.

[Hunt3R]

So the fact that when I'm testing my ICV I get readings all over the place from the teens to the low 100's on every combo of the 3 terminals prolly means it's time for a new ICV eh?

I also have a problem with the idle bouncing 5 or 6 times or more on startup until it settles down and idles where it should be.

[kidrock]

before replacing the ICV, try giving it a good cleaning first. Remove it from its connections, thoroughly and liberally spray inside and shake it. You should be able to hear a gentle rattle. Repeat spraying and shaking until you can no longer see dirt in the escaping fluid. Then, give a quick spray of some clean, light oil (not WD-40). Re-install and test again, first with the idle and then with an ohm meter if necessary.

[SteamWolf]

Originally Posted by Bob Kontak

You know there is a book called The Steam Pig.

Have I told you about my 4.0L Defender?

[Hunt3R]

Originally Posted by kidrock

before replacing the ICV, try giving it a good cleaning first. Remove it from its connections, thoroughly and liberally spray inside and shake it. You should be able to hear a gentle rattle. Repeat spraying and shaking until you can no longer see dirt in the escaping fluid. Then, give a quick spray of some clean, light oil (not WD-40). Re-install and test again, first with the idle and then with an ohm meter if necessary.

Unfortunately I already tried cleaning mine with carb cleaner, it didn't seem very dirty but I sprayed it out really good and shook it around a lot. I can hear the piston making a low, dull thud back and forth when I shake it.

I also tested the ICV connector plug, it gets about voltage with the ignition on and none with it off. And when the car is idling it feels like the ICV is vibrating.

Hey Dan you said that you get a "very slight bounce at idle, between 880 & 980 rpm", is that only when you first crank it or does it constantly happen everytime you come to a stop at a light or only when it's warming up or what?

[kidrock]

Originally Posted by Hunt3R

Unfortunately I already tried cleaning mine with carb cleaner, it didn't seem very dirty but I sprayed it out really good and shook it around a lot. I can hear the piston making a low, dull thud back and forth when I shake it.

I also tested the ICV connector plug, it gets about voltage with the ignition on and none with it off. And when the car is idling it feels like the ICV is vibrating.

Hey Dan you said that you get a "very slight bounce at idle, between 880 & 980 rpm", is that only when you first crank it or does it constantly happen everytime you come to a stop at a light or only when it's warming up or what?

Then I would venture to guess you have a different issue than your ICV. Most likely your O2 sensor or a vacuum leak somewhere.

[Hunt3R]

Originally Posted by kidrock

Then I would venture to guess you have a different issue than your ICV. Most likely your O2 sensor or a vacuum leak somewhere.

Well I wasn't gonna divert the topic here... but yeah I suspect my O2 sensor is bad because I also tried to set my base idle mixture in order to rule it out for causing my idle bouncing problem on startup.

So when reading the voltage from my O2 sensor at fully warmed up idle, no matter how I adjust the AFM screw I always get a lean reading around 0.0-0.2. I can spray carb cleaner into the intake and the idle surges temporarily but my readings from the O2 sensor still do not change, 0.0-0.2, and I would expect them to jump up around 1.0 or so to indicate that it was running rich eh?

I gave up on that and screwed my AFM screw all the way in, then backed it out a couple full turns and then set my base idle and everytime I start my car it's a little hard to start and takes a few seconds of cranking, then it surges and the idle bounces 5,6,7 times before it finally settles where it should be. After this the car drives perfect, no more issues until I crank it again. I assume this is happening because my base idle mixture is too rich but I'm not getting accurate readings from the O2 sensor to set it properly.

I was also checking the ICV just to be sure it's good and like I said my ohm readings are not what Bentley says they should be. Sometimes I get the expected 20 or 40 and it starts dropping and dropping, then I remove the multimeter contacts and touch them again and it'll be in the 60's, then in the 100's, then in the 40's, then in the 100's, etc...

[kidrock]

I don't have the expertise to adjust the mixture screw in the AFM...it just seems like messing with the "Dark Arts" to me. Without the proper reader, adjusting that screw seems a bit futile, especially when there is a known vacuum leak and/or other issues.

You state that you've "set your base idle". Are you referring to the base idle which is set at the throttle body? And if so, did you remember to jumper your B&C plugs in your diagnostic port? I've read here several times of similar issues that were solved when the base idle was re-set correctly, the idle issues disappeared.

I'm not an expert...and I'm not sure you can get a reading on a lean/rich mixture from reading your O2 sensor from an ohm meter. IIRC, you need to read the mixture with the proper equipment. The DME, which is much smarter than me, makes a lot of adjustments in "real time", so if there are leaks or one of your parts (O2 sensor, ICV, etc) isn't working correctly, the DME tends to compensate for such issues...or so I've read.

Check the back of your throttle body, there are supposed to be 2 small hoses connected to a small port back there. This is also common.

I'm not saying that the ICV isn't your issue, but my limited experience has shown that the ICV is rarely the problem. Especially since you've stated that your surging idle is "temporary" before eventually settling. If it were "constant", I'd be more inclined to believe that the ICV is the primary issue.

Hopefully, the experts will chime in on this. Good luck.

[dan88911]

Originally Posted by Hunt3R

Unfortunately I already tried cleaning mine with carb cleaner, it didn't seem very dirty but I sprayed it out really good and shook it around a lot. I can hear the piston making a low, dull thud back and forth when I shake it.

I also tested the ICV connector plug, it gets about voltage with the ignition on and none with it off. And when the car is idling it feels like the ICV is vibrating.

Hey Dan you said that you get a "very slight bounce at idle, between 880 & 980 rpm", is that only when you first crank it or does it constantly happen everytime you come to a stop at a light or only when it's warming up or what?

Hunter3R, I clean mine just as you stated. With the same results.

As to the other question, at one point following the cleaning and after a long drive the bounce in the range I mention cease.

Mine car was and is a low mileage garage queen I bought it a few yrs. ago.

Could be I need to drive it more and longer.

Thank you and the others for responding.