1st Gen Durango 1998 - 2003 Durango's

3.9 vacuum leak?

Thread Tools
 
Search this Thread
 
Old Sep 17, 2018 | 01:00 PM
  #1  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default 3.9 vacuum leak?

Ok, I've tried and tested everything,and can't find what appears to be a vacuum leak in the manifold. I plugged off all vac lines from the manifold and TB. Still rough idling. I ran the crankcase pressure test too. I get positive pressure and no oil pooling in the plenium. Ideas? Suggestions? Anyone else run into this situation before?
 
Reply
Old Sep 17, 2018 | 03:15 PM
  #2  
HeyYou's Avatar
HeyYou
Administrator
Veteran: Air Force
Community Favorite
15 Year Member
Community Builder
Joined: Apr 2010
Posts: 87,465
Likes: 4,220
From: Clayton MI
Default

What is manifold vacuum at idle?
 
Reply
Old Sep 17, 2018 | 07:58 PM
  #3  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default

Hey You, it's the Dakota guy you've been assisting me with. Thanks for your help! Much appreciated! Anyway, it's 19 in Hg pulled from the plenium port, and the MAP reading is 5 psi
 
Reply
Old Sep 17, 2018 | 08:02 PM
  #4  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default

Hey You, it's the Dakota guy you've been assisting me with. Thanks for your help! Much appreciated! Anyway, it's 19 in Hg pulled from the plenium port, and the MAP reading is 5 psi.

It's also smelling rich when cold ( open loop)
 
Reply
Old Sep 18, 2018 | 09:20 AM
  #5  
HeyYou's Avatar
HeyYou
Administrator
Veteran: Air Force
Community Favorite
15 Year Member
Community Builder
Joined: Apr 2010
Posts: 87,465
Likes: 4,220
From: Clayton MI
Default

That's actually quite close to where it should be. The map reading seems a little off though..... (by about 50%) is the little rubber elbow from the throttle body to the map damaged?
 
Reply
Old Sep 18, 2018 | 10:15 AM
  #6  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default

No. It seals fine. The symptoms don't go away, even when cold if I remove every single vacuum line coming off the intake stack, and plug the ports off, including the MAP sensor.
 
Reply
Old Sep 18, 2018 | 11:36 AM
  #7  
HeyYou's Avatar
HeyYou
Administrator
Veteran: Air Force
Community Favorite
15 Year Member
Community Builder
Joined: Apr 2010
Posts: 87,465
Likes: 4,220
From: Clayton MI
Default

What are your symptoms?
 
Reply
Old Sep 18, 2018 | 02:49 PM
  #8  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default

rough/shakey idle at all temps and rich when cold. (idle warmed up is about 670 RPM. It holds idle well and same 670 in gear, or not, and with A/C on or off.)
Cold idle is about 900 RPM
 
Reply
Old Sep 18, 2018 | 02:50 PM
  #9  
restlessswind's Avatar
restlessswind
Thread Starter
|
Amateur
Joined: Jul 2018
Posts: 36
Likes: 0
Default

Is there a way to test the accuracy of the MAP sensor?
 
Reply
Old Sep 18, 2018 | 08:35 PM
  #10  
HeyYou's Avatar
HeyYou
Administrator
Veteran: Air Force
Community Favorite
15 Year Member
Community Builder
Joined: Apr 2010
Posts: 87,465
Likes: 4,220
From: Clayton MI
Default

Compare the reading you are getting from the vacuum gauge, do some math, (convert in/hg to psi, or whatever measurement the PCM reports) and see if they are even close.....

How old are your tune up parts? What plugs ya got in there? Are the wires routed per the TSB?
 
Reply



All times are GMT -4. The time now is 03:26 PM.