1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Trying to Identify Vacuum Leak, lots of problems (pics)

Thread Tools
 
Search this Thread
 
Old 01-12-09, 07:07 PM
  #1  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Trying to Identify Vacuum Leak, lots of problems (pics)

I'll start by saying that I've read the FAQ's, downloaded all the manuals, blah blah blah...

1985, 12a

Just to start, I had my motor built by a guy locally, had him remove the rats nest also, along with any other emissions. The car hasn't ever really run right since its been rebuilt, constant issues keep coming up since it sat for a while, so other things have had to be replaced, like the distributer/cap/rotor, wires, plugs, replaced with "new carb," then rebuilt it again. I just removed the A/C today so I can get my engine bay down to the bare minimum.

The car runs fine from 2k to 6kish, then has issues stuttering when getting close to the engine bay. Also, it won't idle below 1800rpm, so I know there has to at least be a vacuum leak SOMEWHERE.

There are lots of loose connections hanging everywhere, random unlplugged vacuum lines, etc. So I'm needing some help on the big ones to check that people overlook.

Here are a couple pics I snapped to see if any of you can spot any obvious screw ups. This is the first carbed car I've owned and am trying my hardest here, so any help works.






I can take any pictures, there's no A/C, rats nest, real open, I just want to double check that everything was done right, and what other things I can do. Trying to make this a reliable daily
Old 01-12-09, 07:44 PM
  #2  
weak minds wear the crown

iTrader: (2)
 
blackdeath647's Avatar
 
Join Date: Oct 2006
Location: Hudson, NC
Posts: 2,105
Likes: 0
Received 1 Like on 1 Post
i see one right away,first and second picture, near center-bottom, there's a nipple there that needs to be plugged, it doesn't look like it is capped off.
Old 01-12-09, 08:07 PM
  #3  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts


Is it "C" that needs to be plugged?

"B" - Is that just where some bolt when when something was mounted there?

"A" - What is it?

"D" - What is it, and why is it unplugged. How can I "clean that up?" Just snip it with wire cutters close to the block? lol
Old 01-12-09, 08:09 PM
  #4  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Oh yeah, this is stupid, but what is that little blue tube pointing down on the filter-cover thing for?

I had a 400hp FC not that long ago, and this is a whoooooole different thing for me, I feel dumb, thanks for understanding and bear with me
Old 01-12-09, 09:04 PM
  #5  
weak minds wear the crown

iTrader: (2)
 
blackdeath647's Avatar
 
Join Date: Oct 2006
Location: Hudson, NC
Posts: 2,105
Likes: 0
Received 1 Like on 1 Post
A- Don't worry about it, i believe that's the cold start assist, and it only opens up in like extreme north pole like cold temperatures
B- don't worry about
C- THIS IS THE ONE, i forget what this little thing is called(shutter valve?) and exactly what it does, but it needs to be capped if you don't have the rat's nest. so cap it.
D- don't know what it does, mine is connected to a wire that comes off the alt. but if i forget to plug it it don't make a difference so..yeah.

and the blue hose adaptor, it's just there so you can plug vacuum lines to it and what not, but it doesn't affect anything. kinda like the ones on the other side.
Old 01-12-09, 09:38 PM
  #6  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Just checked "C" and its definitly capped, looks like they put some JB weld type stuff, it was solid
Old 01-14-09, 09:19 PM
  #7  
weak minds wear the crown

iTrader: (2)
 
blackdeath647's Avatar
 
Join Date: Oct 2006
Location: Hudson, NC
Posts: 2,105
Likes: 0
Received 1 Like on 1 Post
alright, well easiest way to find out is to break out a can of starting fluid/carb cleaner and begin spraying around the intake/carb area(when the engine begins to stumble or revs up that's where your leak is)...also, there's a hose on the passenger's side of the manifold, that goes to the "anti-AFterburn?" it's in shape of an "L" and that usually goes.
Old 01-15-09, 12:24 AM
  #8  
Round and Round

iTrader: (10)
 
74RX4's Avatar
 
Join Date: Aug 2002
Location: SW Florida
Posts: 1,516
Likes: 0
Received 3 Likes on 3 Posts
Check the hot start assist lever (attachment). Make sure it is not catching on anything. It is attached to the throttle linkage. It moves when the throttle moves.

Check the throttle return. Make sure it is hooked up properly. Like this.

Not like this
Attached Thumbnails Trying to Identify Vacuum Leak, lots of problems (pics)-to1.jpg  
Old 01-15-09, 09:36 AM
  #9  
1st-Class Engine Janitor

iTrader: (15)
 
DivinDriver's Avatar
 
Join Date: Jun 2008
Location: Chino Hills, CA
Posts: 8,376
Received 26 Likes on 24 Posts
A is the inlet for your crankcase vent, I believe. I'd have to check to be sure - - could be the connection point for the charcoal canister.

B is not actually a hole anywhere - - manufacturing process leftover. It's plugged by a pressed-in plug, as is the one on the other side.

C... not sure what it was, but it should be tightly plugged, as it's a manifold vacuum source for something.

D is the connector for your float bowl vent solenoid. Controls venting bowl fumes into the canister.
Old 01-15-09, 12:01 PM
  #10  
Full Member

 
lascelles's Avatar
 
Join Date: Apr 2008
Location: Cincinnati, ohio
Posts: 169
Likes: 0
Received 0 Likes on 0 Posts
Your Vent solenoid "D" needs to be plug-in or gutted.
Old 01-15-09, 09:27 PM
  #11  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by 74RX4
Check the hot start assist lever (attachment). Make sure it is not catching on anything. It is attached to the throttle linkage. It moves when the throttle moves.

Check the throttle return. Make sure it is hooked up properly. Like this.

Not like this
About the attachment that you posted, here's a quick video I took to show you what its like



Its really loose, moves freely all ways, doesn't look like it really does anything. I had her start the car and it moved, but not enough to convince me its "doing" anything, like the movement could have been cause by engine shake...

Here are some pics of the hot start assist system you posted. I'm not too sure if its attached right, it looks wrong to me?





These are all prolly stupid questions, but I'm trying everything here, lol
Old 01-15-09, 09:29 PM
  #12  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by lascelles
Your Vent solenoid "D" needs to be plug-in or gutted.
Couldn't find a plug for it, how could I gut it?
Old 01-15-09, 09:44 PM
  #13  
weak minds wear the crown

iTrader: (2)
 
blackdeath647's Avatar
 
Join Date: Oct 2006
Location: Hudson, NC
Posts: 2,105
Likes: 0
Received 1 Like on 1 Post
Originally Posted by The AntiRice




These are all prolly stupid questions, but I'm trying everything here, lol
the rod should be connected up top, and you should do a search on mechanical secondaries and make sure that everything is hooked like it should, since i believe that's what whom ever did that job was trying to accomplish, that would explain why that linkage is loose and not connected to anything.....and the wire coming off the carb, should have a place to connect off a wire coming from the Alt.
Old 01-15-09, 10:07 PM
  #14  
Senior Member

Thread Starter
 
Join Date: Jan 2004
Location: Texas
Posts: 278
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by blackdeath647
the rod should be connected up top, and you should do a search on mechanical secondaries and make sure that everything is hooked like it should, since i believe that's what whom ever did that job was trying to accomplish, that would explain why that linkage is loose and not connected to anything.....and the wire coming off the carb, should have a place to connect off a wire coming from the Alt.
The rod should be connected on top? I don't quite see what you're talking about in that pic, any way you could MS paint it or something for me?

Also, theres only one plug coming form the alt. one of the wires in the plug is black wire with a white stripe, same color as the wire coming from the carb with the open plug. But from what I can see, coming from the alt, that wire gets taped up, then theres a random wire just hanging (cant see from the pic, its just below where I took it.) Do I need to make a clip or something? I suck at this
Old 01-16-09, 06:58 AM
  #15  
Round and Round

iTrader: (10)
 
74RX4's Avatar
 
Join Date: Aug 2002
Location: SW Florida
Posts: 1,516
Likes: 0
Received 3 Likes on 3 Posts
Take a few in focus pics of the linkage on the front of the carb (side facing front of the car) so we can see if the secondaries are mechanically activated. If they are modified correctly to activate mechanically you don't need the throttle return rod hooked up. Here's the "teeter totter" thread that has several pictures of the stock hook up with vacuum controlled secondaries. https://www.rx7club.com/1st-generation-specific-1979-1985-18/common-cause-power-loss-nikki-carbureted-models-632007/

The stock configuration for the vent solenoid valve (driver's side wire) is 12v when the car is on 0v when car is off. 12v opens the float bowl vent to the atmosphere. 0v vents the fumes to the charcoal canister. If gutted or the canister removed it does not need to be hooked up.

The hot start assist lever (attachment) is fine hanging there as long as it is not catching on anything and limiting the range of your throttle linkage.

It looks like your guy knew what he was doing.
Old 01-16-09, 10:53 AM
  #16  
weak minds wear the crown

iTrader: (2)
 
blackdeath647's Avatar
 
Join Date: Oct 2006
Location: Hudson, NC
Posts: 2,105
Likes: 0
Received 1 Like on 1 Post
seems like 74rx4 has you covered on the rod, and yeah i forgot it was called teeter totter lol...anyways, as far as your bowl vents, take a picture of the wires coming out the alternator that way we can help you, as far as i know, there should only be one wire coming out, but you have two.
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
pzr2
General Rotary Tech Support
1
08-15-15 08:29 PM



Quick Reply: Trying to Identify Vacuum Leak, lots of problems (pics)



All times are GMT -5. The time now is 10:59 PM.