2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Tried to fix a vacuum leak, now engine won't run.

Thread Tools
 
Search this Thread
 
Old 02-26-09, 06:59 PM
  #1  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Tried to fix a vacuum leak, now engine won't run.

So, I had a mechanic that I know look at an oil leak for me today, and he pointed out this unconnected vacuum line. (White circle)



The line with the yellow circle is just plugged. I looked in my haynes manual and decided that the unconnected line should be hooked up to my pressure sensor, which I discovered wasn't connected to anything! (that's the big hose in the picture.)

So, I connected them and my car immediately started running very roughly, with an erratic, low bouncing idle. I took it for a trip around the block to see if it would stabilize, but halfway around the block it died. (It was revved up to about 7k once in neutral right before it died.)

Now, the engine starts up easily enough but immediately dies. If I give it gas and keep it at 2k RPM or above it will run, but the moment it drops below around 1.5k RPM it dies. Also, it backfires after high revs now. It didn't backfire often before this happened. Any suggestions? This is my daily driver and I need it to drive to school tomorrow morning!



By the way, I unplugged the pressure sensor after this started and I still have this problem.
Old 02-26-09, 07:22 PM
  #2  
Full Member

 
danielson's Avatar
 
Join Date: Mar 2006
Location: Kansas
Posts: 147
Likes: 0
Received 0 Likes on 0 Posts
you didnt mess with the yellow circled one did you?
Old 02-26-09, 07:43 PM
  #3  
I "lost" my emissions....

 
DREYKO's Avatar
 
Join Date: Apr 2005
Location: lillington, nc
Posts: 1,764
Likes: 0
Received 3 Likes on 3 Posts
make sure you plugged your afm back in and you could try turning the flathead screw on top of the throttle body to rais the idle. it may have been adjusted to compensate for the leak to begin with.
if its niether of those id think you left a large vac hose off somewhere
Old 02-26-09, 08:01 PM
  #4  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
I'll try raising the idle, i remember lowering it when i first bought the car, so you're right it was adjusted for the leak.
Old 02-26-09, 08:12 PM
  #5  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
That wasn't it, i tightened it all the way down and it still wouldn't run, so I loosened it a lot and it still wouldn't run.
Old 02-26-09, 08:13 PM
  #6  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
No, i didn't mess with the yellow circled one. Why?
Old 02-26-09, 08:55 PM
  #7  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Bump. About 5 hours before I go to bed, it'd be nice to have my car running in the morning :]
Old 02-26-09, 11:01 PM
  #8  
rotorhead

iTrader: (3)
 
arghx's Avatar
 
Join Date: Aug 2004
Location: cold
Posts: 16,182
Received 429 Likes on 263 Posts
it sounds like a halfassed clusterfuck from a previous owner. Best way to do it is start from scratch. Pull the manifold and double check all the vacuum routing and gaskets. Check that all your sensors are plugged in and in spec, then set the idle according to the factory procedure using the initial set coupler.
Old 02-26-09, 11:38 PM
  #9  
I "lost" my emissions....

 
DREYKO's Avatar
 
Join Date: Apr 2005
Location: lillington, nc
Posts: 1,764
Likes: 0
Received 3 Likes on 3 Posts
ever check the afm plug? if you pulled off the intake snorkle you probably forgot to plug it back in. its the black plug that goes into the bottom of the silver box your intake air passes through directly after the air filter.
Old 03-03-09, 05:46 PM
  #10  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
OKAY, I fixed this. A little background info on my car:

Sometime this last year, i had some troubles with the O2 sensor, the car is consistently running rich. Because of this, I think that if both of the vacuum tubes shown in the picture above are plugged, the engine runs too rich and tries to bog. If one is left plugged and the other bare, the engine runs fine. If both are left bare, the engine runs faster, possibly because it's becoming more lean. Anyways, this had absolutely nothing to do with my car not idling. Hah.


On the air intake tubing, after the AFM but before the intake funnel, there is an elbow coming off of the bottom of the tubing. This was connected to the BAC like it is supposed to. For some reason, there's also ANOTHER elbow coming from the same rubber port or whatever you want to call it that the first is in. This wasn't connected to anything, and as far as I know never has been. I don't know why it recently prevented idle. Anyways, as soon as I blocked that second elbow my smooth purring idle returned.

Now I have one vacuum tube (yellow circle) bare, the other (white circle) connected to my pressure sensor, one elbow off of the intake tube connected to my BAC, and the other elbow capped. Anyone know what that second elbow was? Is my tubing from a different model or what? My Haynes only shows one elbow.
Old 03-04-09, 12:13 AM
  #11  
Full Member
Thread Starter
 
MDittz2ndGEN's Avatar
 
Join Date: Jan 2008
Location: San Jose, CA
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Bump. Any thoughts?
Old 03-04-09, 01:14 AM
  #12  
Registered Loser

iTrader: (6)
 
walken's Avatar
 
Join Date: Dec 2002
Location: Whiterock
Posts: 2,224
Likes: 0
Received 0 Likes on 0 Posts
I don't know what its for but on all the fcs I've seen that elbow is factory capped.

after you fixed that did you retry capping the circled nipple on the intake manifold?
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
Kyo
2nd Generation Specific (1986-1992)
6
04-13-19 09:24 AM
tsmith94FD
3rd Generation Specific (1993-2002)
4
08-16-15 05:41 PM
pzr2
General Rotary Tech Support
1
08-15-15 08:29 PM



Quick Reply: Tried to fix a vacuum leak, now engine won't run.



All times are GMT -5. The time now is 10:06 PM.