2G Is it normal for the ISC sensor to have oil in it?

[VBR_DSM]

Is it normal for the ISC sensor to have oil in inside?

I have two brown ISCs, one from my 95 talon TSI and the second from a spare intake manifold that came with the car when I purchased it.

I’m getting idle surge between 1500-2000 so I started looking into a new ISC. I opened the ISC from the spare manifold and it has a lot of oil inside. The plunger that sticks out is also black, looks like carbon deposits but maybe it was leaking oil?
In contrast, the ISC from the car is bone dry. However, It looks like it has dried up oil residues.

Is having oil in the ISC normal?

Also, I tested the resistance of both sensors and they both have dead coils. Would I be ok with an aftermarket ISC from O’Reillys?

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[We're on Boost]

Would I be ok with an aftermarket ISC from O’Reillys?

I wouldn't get theirs. I only looked at their listing briefly. The one they show that looks correct for the car is the "6-terminal" which they want $122 for.
The "brand" of theirs is unfamiliar to me.

The brands that are known good for that part are available from Rock Auto for only about $50.
They are the Standard AC146 and the WVE 2H1098.
I've been using a Standard AC146 in my car for several years now and it's been perfect.

Yep it sounds like yours are bad, and a good new one is pretty cheap, so I would just buy a new one.
Here is the listing for 1995 Talon turbo in Rock Auto. Pick an "Info" button to see pics and more info on a particular part:
idle air control (IAC) valve

As for where the oil is coming from, it's not coming from inside the ISC. I would imagine it's coming from a leaky turbo. That could be an ongoing problem so keep an eye on that.

For reference, here's a pic of my old ISC. This was the original 1990 ISC that was in my car for about 130,000 miles. It was bad, but the coils weren't dead. That is, the coil resistance of both coils was normal, somewhere around 35 ohms. But it was definitely shot, I was having wild high idle all over the place.
You can see it does look like baked on oil a bit. It's about as bad as the dry one you showed. My engine and turbo were in fair shape when I took this out.

I'm wondering about your coils both being bad, in both ISCs. That's 4 bad coils all around. When one coil goes bad the ISC is shot. Then you replace it and the other coil still measures ok. So why are both coils bad. Could be, fine, maybe due to the oil in there, but make sure you are measuring correctly with your multimeter. When you get the new ISC, measure it too. The new ones are 40 ohms on each coil, not 33. If you measure them as being dead on the new one, you can be pretty sure you are measuring them wrong in some way.

Pic is not the best sorry. It's a crop from a much larger view:

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[steve]

Is it normal for the ISC sensor to have oil in inside?

No. There shouldn't be any oil inside.

Also, I tested the resistance of both sensors and they both have dead coils.

Define dead. If any coil is lower than 10 ohms there is likely ECU damage. Higher than 40 ohms won't damage the ECU but won't step the ISC very well.

The metal version like these are prone to problems and should be replaced even if the coils are good with the newer plastic ones to avoid the potential for blowing an ECU driver.

 

[VBR_DSM]

I wouldn't get theirs. I only looked at their listing briefly. The one they show that looks correct for the car is the "6-terminal" which they want $122 for.
The "brand" of theirs is unfamiliar to me.

The brands that are known good for that part are available from Rock Auto for only about $50.
They are the Standard AC146 and the WVE 2H1098.
I've been using a Standard AC146 in my car for several years now and it's been perfect.

Yep it sounds like yours are bad, and a good new one is pretty cheap, so I would just buy a new one.
Here is the listing for 1995 Talon turbo in Rock Auto. Pick an "Info" button to see pics and more info on a particular part:
idle air control (IAC) valve

As for where the oil is coming from, it's not coming from inside the ISC. I would imagine it's coming from a leaky turbo. That could be an ongoing problem so keep an eye on that.

For reference, here's a pic of my old ISC. This was the original 1990 ISC that was in my car for about 130,000 miles. It was bad, but the coils weren't dead. That is, the coil resistance of both coils was normal, somewhere around 35 ohms. But it was definitely shot, I was having wild high idle all over the place.
You can see it does look like baked on oil a bit. It's about as bad as the dry one you showed. My engine and turbo were in fair shape when I took this out.

I'm wondering about your coils both being bad, in both ISCs. That's 4 bad coils all around. When one coil goes bad the ISC is shot. Then you replace it and the other coil still measures ok. So why are both coils bad. Could be, fine, maybe due to the oil in there, but make sure you are measuring correctly with your multimeter. When you get the new ISC, measure it too. The new ones are 40 ohms on each coil, not 33. If you measure them as being dead on the new one, you can be pretty sure you are measuring them wrong in some way.

Pic is not the best sorry. It's a crop from a much larger view:

Thanks for the links! I’ll be ordering a new ISC asap.

I should clarify, the oily sensor is from a spare intake manifold, which to my knowledge, was never on the car. The previous owner handed it down to me when I purchased the car. I think its a coincidence that they are both bad.

No. There shouldn't be any oil inside.


Define dead. If any coil is lower than 10 ohms there is likely ECU damage. Higher than 40 ohms won't damage the ECU but won't step the ISC very well.

The metal version like these are prone to problems and should be replaced even if the coils are good with the newer plastic ones to avoid the potential for blowing an ECU driver.

Steve - I tested the resistance between the pins as follows: 1-2, 2-3, 4-5, 5-6. The ISC from my car had no resistance on 4-5 or 5-6, the other were within range. The oily ISC from the spare manifold had no resistance on 4-5, the others were fine.

I hope I don’t have a bad ECU, I just got it back from ECMTunning due to leaky capacitors. They repaired it and tested it, said it functioned normally after the repairs. I think you were helping me on that thread too

 

[steve]

No resistance means infinite resistance like in an open circuit. That should be cool once replaced.

 

[VBR_DSM]

No resistance means infinite resistance like in an open circuit. That should be cool once replaced.

Thank you both! As always, I appreciate the help!

The AC146 replacement ISC sensor has been ordered.