Oil Appearing on OEM Airfilter - CTSC

[jmp]

I replaced my oem air filter and there was oil residue on the lower 1/3 of the filter element and when I pulled it out there was a lightly wet amount of oil on the oem airbox at the point closest to the throttle body. I have a '91 with Autorotor CTSC and methanol injection, stock airbox and intake and throttle body. My only thought is that as rpm's drop backflow and blowby is being created through the throttle body into the lower 1/3 of the airbox??? Maybe I overfilled my CTSC oil resevoir when I replaced the oil??? I do not appear to be losing CTSC oil.

Anybody have any thoughts on what would be creating this situation? Has anybody experienced this? Is it problematic? Comments are apreciated

 

[RON98]

check your compression.

 

[jmp]

Ron98,

I have seen your comments and they seem very informed so thanks for the reply. Can you tell me what you are thinking/theorizing (as the car is running very very strong and shows no sign -- to my relatively untrained "eye" - of weakness)?

Thanks!

 

[prestonmay]

mine has light oil residue but it was dry..none in airbox....so i cleaned the filter and plan to look more often

 

[RON98]

Ron98,

I have seen your comments and they seem very informed so thanks for the reply. Can you tell me what you are thinking/theorizing (as the car is running very very strong and shows no sign -- to my relatively untrained "eye" - of weakness)?

Thanks!

there should be little chance that oil is working up complete intake system into your air filter.

i suggested checking compression is due to pvc and when compression is low, excessive blow by can cause extra oil vapors to enter into the intake system which in extreme cases might work its way to the filter on closed throttle. i cant think of any other way oil can get in there.

regards

rob:smile:

 

[Tanto2]

JMP- don't panic and don't bother with the compression check, this is very common, especially with IEH cars. Unfortunatly my feeble memory precludes my explanation, but if you search you will find many posts on the issue. Assuming of course you are talking say 3-4 tablespoons of oil

 

[goldNSX]

JMP- don't panic and don't bother with the compression check, this is very common, especially with IEH cars.

I'm sorry to contradict but this is very uncommon. A compression test will tell you more.

 

[RON98]

I'm sorry to contradict but this is very uncommon. A compression test will tell you more.

+1:wink:

 

[LJSB]

I replaced my oem air filter and there was oil residue on the lower 1/3 of the filter element and when I pulled it out there was a lightly wet amount of oil on the oem air-box at the point closest to the throttle body. I have a '91 with Autorotor CTSC and methanol injection, stock airbox and intake and throttle body. My only thought is that as rpm's drop backflow and blowby is being created through the throttle body into the lower 1/3 of the airbox??? Maybe I overfilled my CTSC oil resevoir when I replaced the oil??? I do not appear to be losing CTSC oil.

Anybody have any thoughts on what would be creating this situation? Has anybody experienced this? Is it problematic? Comments are apreciated

I have seen a condition similar to what you are describing before and I have a few questions to help diagnose your problem. I need more information.
Prior to your discovery:

1) What was the mileage interval since your last air filter element replacement?

2) How many miles has your CTSC been on your vehicle?

3) How much oil was found? Was there a enough for it to move or run if you lifted and tilted the tube or was it it more like a trace, perhaps like it had been very lightly misted in a small area?

4) Do you track your vehicle?

You can PM your responses if you prefer.

Joe

 

[jmp]

1) 15,000 miles since last air filter element replacement.

2) About 20,000 miles on my CTSC. 9 lb pulley + methanol inj -- about 5000 of the 20k total +/-.

3) The bottom 1/4 (ie referring to the area closest to the throttle body and farthest from the air intake) was stained a dark color and the rubber edging at "the bottom" was lightly moist but not dripping.

4) I do you not track my vehicle but I do drive it relatively hard but street driving (ie occasional rev limiter hits).

Your insight is appreciated.

 

[jmp]

I took Ron98's advice and did a compression test. All cylinders were at 222-226. Cyl #2 was 214. and #4 was 230. While #2 is low, I believe this is still within the normal range.

Anyone have any further comments? Appreciate the input.

 

[LJSB]

I don't think you have much to be concerned about.
I have seen this before when the air filter element is dirty especially on Uni or oiled style filters which I believe need more maintenance.

Your CTSC wants to breathe very deep and hard and if the air filter is restricting the flow it can pull vapor from the oil breather coming from the valve cover. It could create the condition you have which sounds slight.
Keep an eye on the air filter and perhaps change it more often. Instead of 15k try 10k miles.

 

[jmp]

Thanks for the comment spbasso

 

[nuccaJB]

You should put in a catch can for your PVC system so the blow by is trapped in the can and then you can drain it every once and a while.

 

[nsxjopio]

I think your wife need that.
best regards Jopio:tongue: