Engine, Exhaust, Transmission and Differential Post questions here that have to do with the engine, cooling system, air intake, exhaust, Transmission and Differential

Vacuum leak, high LTFT, pcv hissing, HELP!!!

Thread Tools
 
  #1 (permalink)  
Old 03-17-2015 | 09:14 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Vacuum leak, high LTFT, pcv hissing, HELP!!!

Hi, guys.

I definitely have the vacuum leak somewhere is pcv system which cause high LTFT values 15-20%, when i block pcv hoses then LTFT becomes zero and hissing gone, but when they are normally connected im hearing the air passing through and car drives badly, please HELP!!!

How pcv channels are going in to the engine? where can they get additional air(leak)?

Hoses and all rubber are new...
 
  #2 (permalink)  
Old 03-30-2015 | 04:21 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

it seams that no body know, if anyone faces this, please keep in mind that the cause could be valve cover seals.
 
  #3 (permalink)  
Old 03-30-2015 | 08:33 AM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

There is actually NO PVC as you are accustomed to on an American car, on this engine it is merely a couple of small holes in each valve cover that has a hose running to a point just in front of the throttle body on a "Y" connection.
The larger hose on the drivers side is the equalization vent hose that connects BEFORE the throttle body.
Check the hose going to the brake booster and the one going to the purge solenoid on the drivers fender well.
There is also a vacuum connection on the manifold itself ( not sure if front or rear ) that is not easily accessible that has caused issues with decayed hoses.
Word is that the intake manifold has to be removed to address this.
 
The following users liked this post:
Nynick8 (10-19-2022)
  #4 (permalink)  
Old 04-03-2015 | 01:19 PM
GraphiteGhost's Avatar
Senior Member
Joined: Jul 2009
Posts: 6,012
Likes: 516
From: Central South Carolina
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Originally Posted by ala_xfire
There is actually NO PVC as you are accustomed to on an American car, on this engine it is merely a couple of small holes in each valve cover that has a hose running to a point just in front of the throttle body on a "Y" connection.
The larger hose on the drivers side is the equalization vent hose that connects BEFORE the throttle body.
Check the hose going to the brake booster and the one going to the purge solenoid on the drivers fender well.
There is also a vacuum connection on the manifold itself ( not sure if front or rear ) that is not easily accessible that has caused issues with decayed hoses.
Word is that the intake manifold has to be removed to address this.





Awesome help aids George, you definitely research a lot and have a wealth of information available PLUS your eagerly willing to share said information... KUDO's George!
 
  #5 (permalink)  
Old 06-21-2015 | 05:47 PM
Gtsman's Avatar
Joined: Apr 2014
Posts: 103
Likes: 0
From: Upstate ny
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

George, I do have a leak in the hose attached to the drivers side valve cover, I see the y at the valve body, can it replace just the side that's leaking, will it come apart at the "Y" ? I tried to look up a part number and could not find one, if anyone has this number, it would help me. Thanks in advance!
 
  #6 (permalink)  
Old 06-22-2015 | 08:52 AM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

part number for the hose or the "Y" ?
I do not have any factory part number hoses on mine, just hoses that came with the oil catch can and the large one I purchased from an auto parts store.

Now, having said that, here is a part listing :
 
Attached Images
File Type: jpg
Capture.JPG (101.9 KB, 88 views)
  #7 (permalink)  
Old 06-22-2015 | 11:50 AM
Mrmiata's Avatar
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 22
From: Kellyville, Ok
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Ahhh.. so this just amounts to a "connector".. Would I be correct in thinking leaky valve covers could be a cause for increased LTFT?


List: PCV Valve - 2005 Chrysler Crossfire | O'Reilly Auto Parts
 
  #8 (permalink)  
Old 06-22-2015 | 11:54 AM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Greg, if you get that part from O'Reilly's, let us know where you end up putting it please.
( and be polite )
 
  #9 (permalink)  
Old 06-22-2015 | 12:09 PM
Mrmiata's Avatar
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 22
From: Kellyville, Ok
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

This looks like a couple "respectable" places.. LOL


 
  #10 (permalink)  
Old 06-22-2015 | 01:20 PM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Wrong, grasshopper, but good guess.
Those are but hose nipples. The MB M112 engine has NO PCV valve, it depends on little bitty holes under those 2 nipples to meter the amount of air/vacuum sucked out of the valve covers by the intake manifold.
 
  #11 (permalink)  
Old 06-22-2015 | 01:33 PM
Mrmiata's Avatar
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 22
From: Kellyville, Ok
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Originally Posted by Mrmiata
Ahhh.. so this just amounts to a "connector".. Would I be correct in thinking leaky valve covers could be a cause for increased LTFT?


List: PCV Valve - 2005 Chrysler Crossfire | O'Reilly Auto Parts


Reading is FUNdamental ..
 
  #12 (permalink)  
Old 06-22-2015 | 06:47 PM
Snake Eyes's Avatar
Joined: Jan 2014
Posts: 17
Likes: 0
From: Orange Park Fl
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Just go to a parts store and get vacuum hose of the correct diameter. It might be english to metric so get what fits nice and snug. Gates is a good brand.

Or.

Get the needswings oil catch can. It comes with the hose.

The hose comes right off of that plastic t fitting. Be careful not to break t fitting removing hose. Not difficult at all. You don't have to replace other side if running fine. However I would inspect and replace any vacuum hose with cracks, deteriations, or loose fittings
 
  #13 (permalink)  
Old 06-22-2015 | 07:50 PM
Gtsman's Avatar
Joined: Apr 2014
Posts: 103
Likes: 0
From: Upstate ny
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Excellent information guys! George , that picture is worth a million. I searched for that for hours in both Chrysler and Mercedes catalogs. Thanks for all of your time guys. John
 
  #14 (permalink)  
Old 07-23-2015 | 11:33 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

guys still cant find the issue, changed valve cover gasket plus exhaust manifold gasket too, but still no luck...
 
  #15 (permalink)  
Old 07-23-2015 | 11:54 AM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

You could try the unlit propane torch method, pass it around where you suspect a vacuum leak may be occurring, if the engine idle smooths out, you have a winner !
I only state this is a method I have used and seen used, but I disclaim any responsibility in event of any damage or injury incurred.
 
  #16 (permalink)  
Old 07-23-2015 | 12:59 PM
tunaglove's Avatar
Senior Member
Joined: Mar 2010
Posts: 1,413
Likes: 5
From: White Bear, MN
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

Check the seal for the oil fill cap and also the o-ring on the dipstick handle.
 
  #17 (permalink)  
Old 07-24-2015 | 03:33 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

already have replaced oil cap both seals, will check the dipstick, how tight should the dipstick seat in the oil check tube
 
  #18 (permalink)  
Old 07-24-2015 | 10:29 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

dipstick seal looks and feels good
 
  #19 (permalink)  
Old 07-24-2015 | 10:36 AM
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,779
Likes: 162
From: Lineville, AL
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

There is this hose that can rot and crack on the front of the manifold ( out of sight ) :
 
  #20 (permalink)  
Old 07-24-2015 | 10:42 AM
kai1's Avatar
Thread Starter
Joined: Apr 2013
Posts: 25
Likes: 0
Default Re: Vacuum leak, high LTFT, pcv hissing, HELP!!!

know that place, but no, the sound is coming from somewhere around the TB
 


Quick Reply: Vacuum leak, high LTFT, pcv hissing, HELP!!!



All times are GMT -4. The time now is 04:32 PM.