Vacuum Sound & Injector Ticking?
Thread Starter
On The Tree
Joined: Oct 2010
Posts: 175
Likes: 4
From: PHX, AZ
Vacuum Sound & Injector Ticking? Hello,
I've done some looking on here and haven't found a post posing a similar question.
Upon startup, I hear this rather pronounced hissing/vacuum sound for about 30 seconds or so, then it stops with a dramatic winding down sound. After arriving at my destination about 45 miles away (highway speed), I stopped and noticed a slight ticking sound (concurrent with engine rpm). Investigation produced the absence of a PCV valve in the valvecover, but the ticking didn't sound like a lifter or rocker. (maybe injector?) Could the open valve cover produce such a sound? The car didn't make this sound when I purchased it and drove it 400+ miles home or on some of the other short drives around town. No codes were thrown nor was the vehicle any different to drive. Are LS1 top ends just that noisy?
I've worked on LS cars for quite some time, but this is my first ownership experience, so I want to know in which direction I should start investigating.
I can take a video if requested.
Thanks!
I've done some looking on here and haven't found a post posing a similar question.
Upon startup, I hear this rather pronounced hissing/vacuum sound for about 30 seconds or so, then it stops with a dramatic winding down sound. After arriving at my destination about 45 miles away (highway speed), I stopped and noticed a slight ticking sound (concurrent with engine rpm). Investigation produced the absence of a PCV valve in the valvecover, but the ticking didn't sound like a lifter or rocker. (maybe injector?) Could the open valve cover produce such a sound? The car didn't make this sound when I purchased it and drove it 400+ miles home or on some of the other short drives around town. No codes were thrown nor was the vehicle any different to drive. Are LS1 top ends just that noisy?
I've worked on LS cars for quite some time, but this is my first ownership experience, so I want to know in which direction I should start investigating.
I can take a video if requested.
Thanks!
When the hissing starts, is the sound steady, or does it vacillate? If the sound is not steady, it could be that your Idle Air motor/the plunger inside of it may not be able to find its’ proper setting. Can you make a video for us?
Thread Starter
On The Tree
Joined: Oct 2010
Posts: 175
Likes: 4
From: PHX, AZ
I was able to identify the vacuum sound as the air pump, which was not hooked up to the original system due to the H/C/I swap, so I pulled the fuse and that solved problem #1. I'm going to change over to a 5W-40 oil this weekend and see if the top end quiets down when at operating temp. I'll report back upon completion. I appreciate the insight!
