1990 wrangler 4 wheel drive vacuum line?

Page 1 of 2  

I have a 1990 Jeep Wrangler who's vacuum lines have been disconnected. I need help sorting them out as to what goes where. I think I have most of them connected properly but my 4 wheel drive light is on, but when you ramp up the rpms it goes out. I just need some help getting the lines in their proper places so the Wrangler idles rather than stalling.

Thanks for the help Jeremy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

To fix the stalling, there is a black plastic line that goes from the driver's side of the engine down to the vac switch on the driver's side of the transfer case. Find the line and plug it, that should get your engine running correctly. If not, keep working on the vac lines.

To check out the vac operated axle disconnect, hook up the vac line to the transfer case switch. With the engine running, CAREFULLY pull the connector to the front axle off the vac motor. The green line should have a slight vac with the transfer case in 2wd, the yellow line should have vac in 4wd. If it doesn't switch back and forth, replace the vac switch on the transfer case, $25 from the dealer. If no vac on either, you have a bad vac line somewhere.

Your symptoms sound like a cracked vac line or trashed rubber connector for the line to the switch or vac motor. Pretty common for that vintage Jeep.

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What engine?

Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I've got an 87 YJ with a 258 that I did that to once. If I recall, I accidentally switched 2 vacuum lines 'somewhere near the distributor cap'.

Sorry I don't recall clearer.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Jeremy wrote:

Sorry I forgot to mention its a 6cyl. 4.2L. Automatic.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Jeremy wrote:

Here is a good site for most things to do with the 4.2.

http://home.sprynet.com/~dale02/list.htm

Is the emissions computer still in the loop? That can mean lots of the vacuum line stuff is not needed.

The bad idle can be unrelated to the vacuum lines. That carb is notorious for getting plugged up idle tubes. Here is a site on the test for this and the fix: http://www.off-road.com/jeep/tech/engine/carter.html

If you have oil blowing into the air filter, that can be another reason for bad idle with an easy fix.

Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the site. I looked up the vacuum lines and to the best of my knowledge hooked them up. Only problem is my set up varies from that on the site and Im not sure of I hooked up the lines correctly to the carb. That is the only problem I am having know is the lines from/to the car. IE the decel valve and I am pretty sure I do not have a pulse air valve on the drives side. If anyone can help that would be awesome

Thanks Jeremy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the site. I looked up the vacuum lines and to the best of my

knowledge hooked them up. Only problem is my set up varies from that on

the site and Im not sure of I hooked up the lines correctly to the carb. That is the only problem I am having now is the lines from/to the carb. IE the decel valve and I am pretty sure I do not have a pulse

air valve on the drives side. If anyone can help that would be awesome

Thanks Jeremy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you don't have the decel valve or the pulse air system, no worries. There are a ton of varieties of emissions components according to what part of the world the Jeep was sold in.

Oh, both pulse air valves if you have them are on the passenger side. That drawing is just a schematic, not a design.

If the decel valve is what I think it is, it is a factory defective part that doesn't work. It was or another one was behind the carb and was tied into the charcoal canister as well. The replacement is just a T or straight fitting to have air flow.

Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Oh, the straight fitting would be in the pulse air tube, you don't want that sucking in the back side of the carb or it won't run for crap.

The purge from the canister should also just T into the PCV line behind the carb with not valve in the way.

Mike

Mike Romain wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yeah I got that much. The Jeep now wont fire it turns over fine. Also it kinda sputters when I first turn the key on and or off.

Here are a few pics of my carb hopefully it works...

<a href="http://tinypic.com" target="_blank"><img src="

http://i10.tinypic.com/30tntwy.jpg" border="0" alt="Image and video hosting by TinyPic"></a>

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yeah I got those hooked up. Just now it turns over but will not fire.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Is it flooded out? They can flood bad enough to need the plugs aired out.

Is the carb getting gas? If you look down the throat of the carb and give the throttle a shot with your hand, you should see two streams of gas squirting.

Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Its not flooded and it is getting gas. I'm thinking the distributor line might be hooked up wrong. That or maybe my TAC vacuum line that goes to the carb is in the wrong place. I'm trying anything and everything at this point. It all looks good until I get to the carb. I think I may have lines in the wrong places.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Stock your distributor should be hooked to a bottom plate nipple off the carb on the right side facing the engine from the front. The nipple might branch off the brake booster line.

The TAC comes off the back drivers side corner of the carb bottom plate.

Mike

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have checked and re-checked all vacuum lines they look good. Engine turns over but will not fire. But every now and then it will fire up and run fine. If anyone has some more advice that would be greatly appreciated.

Jeremy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Maybe spin it faster with another battery jumped? Coil bypass at solenoid may not be connected or powered. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com http://www.billhughes.com /

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Dead body ground will cause symptoms like that. There is supposed to be a wire mesh strap from the engine head to the firewall. When this goes bad, you can get those symptoms.

Bad connection on the starter relay that sits on the firewall at the end of the small battery cable. The green wire I believe is the one to clean.

Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)

Jeremy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ok so I checked all of that and cleaned them. It seems like its getting to much gas and choking its self out. But it runs for a few minutes slowly dies out and will only start back up after it has been sitting for a couple of minutes. Git any other ideas lol.

Thanks Jeremy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Has the catalytic converter been checked to see if it is clogged?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.