Hey guys, i recently put a new knock sensor on my Subaru, and i noticed it idles a bit more high than preferred. Well i was wondering if there is a way to adjust the idle? like a screw or something? i know you could on carburetors but im not sure on the fuel injection....any help would help. Thanks!

When it's warm what does it idle at?

Keep in mind, having AC running with bump the idle so it doesn't stall running the compressor.

Hey guys, i recently put a new knock sensor on my Subaru, and i noticed it idles a bit more high than preferred.

Are you saying that the high idle speed began occuring right after you replaced the knock sensor?

 

 

Well i was wondering if there is a way to adjust the idle? like a screw or something? i know you could on carburetors but im not sure on the fuel injection....any help would help. Thanks!

No, there is no "screw" adjustment for idle speed -- the ECU controls it, based on data from the engine sensors. If the change in idle speed occured after replacing the knock sensor, then it might be that the ECU will need a few drive cycles to adjust to that. Or, you could try resetting the ECU.

 

Another possibility is that in the process of replacing the knock sensor, you did something to create a small vacuum leak, which sometimes can cause what you're experiencing.

I know I have done it a few times, make sure you didn't pull the cable out of the cruise control when you were doing the knock sensor. I always end up leaning on it and pulling it out. That usually makes for a really high idle though,lol

Ok cool help guys, i noticed today that it runs at 1k rpm. thats decent, so you were right about the ECU, i think i needed to drive it some. Also my CEL is off now(cross fingers). But really 1k still seems a little high but i think im comfortable with it. Tomorrow i will check my intake and see if i accidentally knocked off a vacuum tube or something.

[...] But really 1k still seems a little high but i think im comfortable with it. [...]

That is a higher than normal idle for a warm engine -- it should be closer to 700 rpm.

Edited October 8, 201015 yr by OB99W

yeah i thought so to. im getting it inspected today and while im at it ill check the hoses.

well checked the hoses and cant find anything wrong. so not sure. Got it inspected but not long my cel came once again with the codes for the EGR valve. ive replaced it twice and the second one was not that long ago, so im at a "i dont know" right now haha.

Getting "codes for the EGR valve" doesn't always indicate the valve itself is at fault. Specifically which codes (Pxxxx) are being triggered?

dont know, the guy who hooked it up told me that. dont know the specific codes.