Vacuum line Question

The haynes manual I have says it covers through 2001 XJs, but the diagrams for the vacuum lines they show haven't been updated since the '87, and it doesn't seem to match up with my engine. There's 3 nozzles on the side of the block (intake manifold?). When viewing it from the driver's side fender well you can see them all. The first (left) and last are plugged, but the middle one was open when I got my rig. With it unplugged the motor idles around 1100-1200 rpms but throttles up and down on occasion down to 900. Lots of air pushes through there and its loud enough to drown out the motor. Very occasionally with this setup, the vehicle will backfire when driving when the light turns green, but this is maybe 1/20 times.

When I plug it, the motor almost wants to die initially but then it adjusts and idles at around 800rpm and settles nicely. At first, I figured this was perfect and that was what I needed to do. But, after driving it for a couple days, having that hole plugged caused a few issues such as whenever the vehicle idles for more than 30 seconds after being warm it sputters and then dies until you restart the vehicle and then it takes another couple minutes before it does it again. The backfiring I indicated with it unplugged (above) does not happen when it is plugged.

Also, I should mention that I have 2 engine codes at the moment .. O2 sensor 1/2 & 1/1. I picked them up today and plan to put them in tomorrow night.
FYI, off topic, but AutoZone's computer said that my rig has SIX O2 sensors, 3 downstream and 3 upstream .. are they on crack or is that right? I could only see one each when I was looking around.


Anyway, thanks for any advice you may have. I can take a better picture when it stops hailing but for now I just drew on this vaccuum line diagram I found online about where the nozzles on the manifold are. Hope that helps =)

spinaldex said:

The haynes manual I have says it covers through 2001 XJs, but the diagrams for the vacuum lines they show haven't been updated since the '87, and it doesn't seem to match up with my engine. There's 3 nozzles on the side of the block (intake manifold?). When viewing it from the driver's side fender well you can see them all. The first (left) and last are plugged, but the middle one was open when I got my rig. With it unplugged the motor idles around 1100-1200 rpms but throttles up and down on occasion down to 900.

Click to expand...

Are you saying there are no lines connected to the nipples? They all have plugs?

FYI, off topic, but AutoZone's computer said that my rig has SIX O2 sensors, 3 downstream and 3 upstream .. are they on crack or is that right? I could only see one each when I was looking around.

Click to expand...

Crack. You either have 2 (fed package) or 4 (cali package)

No lines to the nipples. When i bought the rig it had a plug on the left and nothing on the middle one. I can't find any hoses missing or dangling to connect to the middle one.

I figured Autozone was on crack. I'll get those sensors replaced tonight =)

Thanks!

What are these nipples you are talking about?

I just took pictures of it.

#1 is plugged.

#2 is unplugged.

#3 is connected to a hose.

So, it's #2 I don't get. I'm leaving it unplugged right now since the truck behaves much better that way, but I know it's not the way it is suppose to be because it idles a little higher and fluctuates too much. I'm guessing its suppose to go to a hose but I have zero idea where!

Pics:

To orient yourself:

http://i.imgur.com/trb22gY.jpg



http://i.imgur.com/X54ysAk.jpg

Close up (the middle one)

http://i.imgur.com/FeMaILS.jpg

2 and 3 go to the same evap sensor on passenger side firewall.1 stays plugged

Awesome! Now I can either trace it or possibly split them using an adapter?

Thanks!

Go to a scrap yard and look for the hose. They stay right next to eachother all the way from manifold ,along firewall to the sensor. Im not sure about a splitter but in theory sounds like it would work

20jeep00 said:

2 and 3 go to the same evap sensor on passenger side firewall.1 stays plugged

Click to expand...

Not sure about that. One has to go to the HVAC system. Edit: From a quick google, rear one is for HVAC. middle is for EVAP, front is for cruise.

spinaldex said:

Awesome! Now I can either trace it or possibly split them using an adapter?

Click to expand...

Take a look at this pic: http://i.imgur.com/FeMaILS.jpg

Look past the rear most one toward the ground. The one for the middle one is just dangling right there.

The front most one is probably for cruise control.

Just looked again. From front of motor back its
1.plugged
2.evap
3. Cruise, hvac and for the axle according to underhood tag

Eyes were playin tricks on me

Your 1,2 & 3 nipples on the drawing are in the wrong place, you have them shown being at the side of the valve cover, the pictures show the on the far drivers side of the intake manifold. Big difference!!!

spinaldex said:

The haynes manual I have says it covers through 2001 XJs, but the diagrams for the vacuum lines they show haven't been updated since the '87, and it doesn't seem to match up with my engine. There's 3 nozzles on the side of the block (intake manifold?). When viewing it from the driver's side fender well you can see them all. The first (left) and last are plugged, but the middle one was open when I got my rig. With it unplugged the motor idles around 1100-1200 rpms but throttles up and down on occasion down to 900. Lots of air pushes through there and its loud enough to drown out the motor. Very occasionally with this setup, the vehicle will backfire when driving when the light turns green, but this is maybe 1/20 times.

When I plug it, the motor almost wants to die initially but then it adjusts and idles at around 800rpm and settles nicely. At first, I figured this was perfect and that was what I needed to do. But, after driving it for a couple days, having that hole plugged caused a few issues such as whenever the vehicle idles for more than 30 seconds after being warm it sputters and then dies until you restart the vehicle and then it takes another couple minutes before it does it again. The backfiring I indicated with it unplugged (above) does not happen when it is plugged.

Also, I should mention that I have 2 engine codes at the moment .. O2 sensor 1/2 & 1/1. I picked them up today and plan to put them in tomorrow night.
FYI, off topic, but AutoZone's computer said that my rig has SIX O2 sensors, 3 downstream and 3 upstream .. are they on crack or is that right? I could only see one each when I was looking around.


Anyway, thanks for any advice you may have. I can take a better picture when it stops hailing but for now I just drew on this vaccuum line diagram I found online about where the nozzles on the manifold are. Hope that helps =)

Click to expand...

20jeep00 said:

Just looked again. From front of motor back its
1.plugged
2.evap
3. Cruise, hvac and for the axle according to underhood tag

Eyes were playin tricks on me

Click to expand...

Do you have cruise?

My 2000 has all 3 used, but I can't remember what the front one goes to. Its probably not cruise though as that needs the vac canister as well as the HVAC. Perhaps its part of the cali emissions package.

The evap lines should be detailed on the sticker on the driver's side of the firewall.

Talyn is correct; the missing line is hanging there next to the manifold, and you should find that the loose line runs along the firewall over to the purge solenoid.

At least on mine, the HVAC and cruise are teed into the same line that connects to the rearmost nipple, and runs to the vacuum reservoir in the bumper.

Ya ive got cruise. Mine has a cap in 1 and the sticker says not used vacuum port

Talyn said:

Take a look at this pic: http://i.imgur.com/FeMaILS.jpg

Look past the rear most one toward the ground. The one for the middle one is just dangling right there.

Click to expand...

I'm an idiot. Talyn, that was it. From everytime I would stand up and look around I never saw it. But since I could hold my phone in there at an angle I couldnt get my head in that was what was missing. Everything is working well now, and the O2 sensor errors from the engine went away after I cleared the engine codes and drove it another 1/2 hour today.

Thank you all for the help. I'm going to go hide now >.>