Pcv valve

[crownvic31]

This is for my 2007 escalade

So after replacing power steering pump and bleeding the system, i started hearing a constant vacuum. Following the vacuum and pinching hoses i came to the conclusion that its the pcv valve. So i have a catch can hooked up on this. Pcv valve goes to catch can and outlet of catch can goes to intake manifold.

Are the pcv valves on these trucks constantly open? This is something i have not paid attention to. I am getting horrible gas milage as per the gas mileage average on the dash and the oil catch can was full and its been only 3 months since last oil change.

I did replace the valve cover with a new one sometime earlier this year.

 

[donjetman]

2007 doesn't have a pcv valve.
The baffling inside the driver side valve cover serves as the pcv valve.

Vacuum line runs from the intake manifold to the catch can, out of the catch can, to the nipple on the rear of the driver side valve cover.

You should not have an audible vacuum leak. If you do have a leak it would cause check engine light.

 

[crownvic31]

2007 doesn't have a pcv valve.
The baffling inside the driver side valve cover serves as the pcv valve.

Vacuum line runs from the intake manifold to the catch can, out of the catch can, to the nipple on the rear of the driver side valve cover.

You should not have an audible vacuum leak. If you do have a leak it would cause check engine light.

The audible vacuum leak is there and till this day I have no check engine light. Smoke test showed no visible leak. The sound is there and pretty loud. If i pinch the hose coming out of the baffle, the vacuum sound stops. Is this normal or do I have another issue?

 

[donjetman]

spray flammable Brake Klean around all possible vacuum leak areas to see if engine rpm increases. If so, you found the leak.

Our engines can compersate for a vacuum leak by adding fuel (to a degree) before it sets a MIL/Check engine light.

Get a scanner and watch live data while idling and driving it and see if it is adding a + percentage of fuel to compensate for the vacuum leak.

 

[crownvic31]

spray flammable Brake Klean around all possible vacuum leak areas to see if engine rpm increases. If so, you found the leak.

Our engines can compersate for a vacuum leak by adding fuel (to a degree) before it sets a MIL/Check engine light.

Get a scanner and watch live data while idling and driving it and see if it is adding a + percentage of fuel to compensate for the vacuum leak.

Thread 'Bad o2 or bad cat?' https://www.tahoeyukonforum.com/threads/bad-o2-or-bad-cat.145812/

Thats my other post. Rather keep this in the same one. Thank you buddy

 

[j91z28d1]

spray flammable Brake Klean around all possible vacuum leak areas to see if engine rpm increases. If so, you found the leak.

Our engines can compersate for a vacuum leak by adding fuel (to a degree) before it sets a MIL/Check engine light.

Get a scanner and watch live data while idling and driving it and see if it is adding a + percentage of fuel to compensate for the vacuum leak.

I've actually tried this on new fuel injectioned cars and it responded so fast I couldn't tell a difference like with a old carb. I was able to pull up the fuel trims and spray while watching them and see it jump when I sprayed.

 

[houstontaylor]

I agree with the checking the fuel trims recommendation. Lots of things can cause rough idling and live data fuel trims on the scanner can narrow it down. Too much fuel, not enough fuel, fuel system fine.

 

[Fless]

I agree with the checking the fuel trims recommendation. Lots of things can cause rough idling and live data fuel trims on the scanner can narrow it down. Too much fuel, not enough fuel, fuel system fine.

Herein lies the problem of putting info like this on different threads. You can view the fuel trims in the other link -- the one in post #5 of this thread.

Might be wise to keep things to one thread.