Jump to content
CaddyInfo Cadillac Forum

Vacume Leek ??


Matt

Recommended Posts

True I have been looking for a reason to explain the rough idle and hesitation that sometimes only starts after 30 to 40 min of driving. I also have to note however, that the idle has not been perfect since I got the car.( 6 or 7 weeks) But today on the way home from work was the pits. The engine was loosing power at steady speed (50-60 MPH) and at take off it was bucking and trying to stall out. I did the old pull over and shut down and re start to fix it but it did not work this time. I got it home and just had had enough. I ate dinner and then went out to find the problem. With the engine running I started to search,it was searging up and down.I looked around for a wile but found nothing. I then took off the air cleaner and after my ears got used to the air sound rushing past the butterflys I detected another sound of air. It was a vacume leek. Off the throttle body intake is a vacume hose, on the water pump side of the intake. (front of engine-still not used to sideways mounted engine) This line goes to the top of some kind of sensor, the bottom of this sensor has another vacume line that goes to the EGR valve. This sensor also has an electric line to it. Ware this line comes out of the throttle body is a rubber reducer elbow. That elbow was cracked and not like rubber any more. It was brittle like a rock. I dont know if its been leeking vacume for a long time or if its been part or all of the cause for all my rough idle and hesitation problems. It may have been leeking slightly for a wile giving me problems and finally got so bad tonight that all heck broke loose. I will know more Friday when I drive it for a wile. I was able to find some fittings to fix it till I get new parts and the engine did smooth out somewhat but I need to drive it for a least 40 min. I'm falling asleep. Been up since 4:45 AM it's now 10:15PM Later...

Link to comment
Share on other sites


IS this what you found, I think its going to the EGR solenoid, its a rectangular box, and a hose goes from there to the EGR, See Number 15, Mike

That would be a pretty large vacuum leak but I dont know why driving it 40 min would make any difference, this may be unrelated to that, BUT very related to your rough idle! Mike

post-3-1111720454_thumb.jpg

Link to comment
Share on other sites

My Gosh Mike, That is it. How do you come up with these pictures so fast. On the second drawing is # 2,hose set up. I need that setup. The entire thing is brittle and should be replaced. I riged a hose but need the new parts. I will try and locate them Friday someware. So you say it would cause my idle problem? By the way, what should idle RPM be ? I have about 575 in drive, it is to low. How do you increase that?

Link to comment
Share on other sites

The engine feels like it is hunting a bit. If I hold it slightly higher it smothes out. That is why I was wondering what the book says. What is it with the AC on?? Also, how do you increase the idle. Is it as simple as turning that screw out on the Idle speed control motor ??

Link to comment
Share on other sites

My Gosh Mike, That is it. How do you come up with these pictures so fast. On the second drawing  is # 2,hose set up. I need that setup. The entire thing is brittle and should be replaced. I riged a hose but need the new parts. I will try and locate them Friday someware. So you say it would cause my idle problem?  By the way, what should idle RPM be ?  I have about 575 in drive, it is to low. How do you increase that?

I was able to buy the exact vacuum hose with both ends from the dealer, but it was not cheap at about $20, but its a necessity. Its not three components its a single assembly. With that hose broken you should have been getting an E048 code. Try disconnecting the battery for five minutes and letting the system go through a re-learn, my 91 used to idle about 600 to 625... Mike

PS: I have have a folder full of scans that I have saved over the years that cover most of the major components on the 4.9 and I am building my 'collection' on the NS...

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...