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What is this???

sxorpionfox

New Member
Joined
October 28, 2010
Messages
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City, State
Las Vegas
Year, Model & Trim Level
91 XL
I have jiggled it, wiggled it, and turned my head at different angles while scratching it, but I still can't figure out what this is or how to fix it. No, I am not mechanically inclined beyond basic brakes and tires and oil. Here is the events... I started the truck (1991 Ford Explorer XL), and it sounded like a air hose popped. Now when it drops below 1000rpm, it dies. I looked inside, and discovered where the sound was coming from and replaced that particular hose. It did not fix the idle problem. Then today, the engine felt like it lost a lot of power when I was driving and I could smell gas coming from the engine and exhaust pumping in to the cab. I rolled up the windows for a few minutes for fun, then I rolled them down because my eyes were on fire. I came to a stop and the truck died. It turns over, but won't start. So anyways, I get it into a parking lot and open the hood and see the same little wtf ever part that I replaced the hose from (you can see the new hose in the pic) is now leaking gas. Apparently this is like a tree of **** that has vacuum hoses and pressurized fuel line stuff branching out of it and I have no idea what it is. This part is on the rear of the driver's side of the intake manifold. It has a monster beast hose (top) that goes to the brake cylinder thing, a vacuum hose that goes to the cruise control box? (I replaced that hose), 2 pressurized fuel lines that go to the other side of the intake manifold. There is one connector that is missing a hose and spitting gasoline at me, and I have no idea where it connects to. I can get a new hose for the connector, but where does it go? I bought a Chilton Guide, but it is no help unless I know what the hell I am looking for. I can't find a vacuum line diagram or fuel line diagram that helps me, and this seems like something a trained mechanic would know right away. More importantly, the pressurized fuel lines that come off the tree branch thing are old and easily broken, but I am missing a hose from one of the little holes that spits gasoline all over the place if not connected. I don't know what to connect it to, and I don't know what the hell this part is.

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one of those thin lines going in there is for the "Fuel Pressure Regulator" If you are getting bogging down, a rich gas smell and hard to start and idle there is a good chance the FPR is bad. Further if you pull off the thin line or any line close to it and fuel is coming out it is verification that the FPR is bad. Perhaps someone has a pic of where it is on a gen 1. I don't know off hand.
 






one of those thin lines going in there is for the "Fuel Pressure Regulator" If you are getting bogging down, a rich gas smell and hard to start and idle there is a good chance the FPR is bad. Further if you pull off the thin line or any line close to it and fuel is coming out it is verification that the FPR is bad. Perhaps someone has a pic of where it is on a gen 1. I don't know off hand.

Thank you. So I can replace the FPR, that will resolve gas spitting at me through the connectors. But I am still thoroughly confused as to that connector in the back (can't see it in the pic I provided) and what it connects to. I assume that it popped off when I was driving which is why I don't know where it goes to. I can follow alll the other lines and see what they connect to, it is the open one that is killing me and I can't find a diagram from this tree branch piece that tells me what I am looking for.
 






That "part" you keep referring to is a vacuum tree. It screws into the upper intake manifold and as air is drawn through the upper intake manifold, it creates a low pressure zone inside the intake. Since air pressure in nature likes to equalize, you create a vacuum effect on any open port. Each port on the tree is either connected to something or has a cap on it.

Now, the vacuum line that runs from the vacuum tree to the fuel pressure regulator comes off the vacuum tree, behind the upper intake manifold, around to the passenger side of the upper intake and then goes under the bracket for the ignition coil pack then to the regulator.

First picture shows a red arrow pointing to the fuel pressure regulator on my 94.
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Second image is the vacuum line behind the upper intake manifold. The vacuum line itself is inside the corrugated tubing.
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If there isn't a line for it, theres a possiblility that its just supposed to have a cap/ plug over it cause it could be a spare.
 






Iron Weasel- Thank you for the info, that tells me what I should be looking up, and the pics help. I am assuming I need to replace the FPR, and then maybe I can at least get the lines in order to fix some issues.

ahodges- I plugged the hole with my finger and it choked when trying to start. So my assumption was that it needs to be open and leading to somewhere. The gas leaking out of it may be because the FPR is bad from what I learned here, but it still choked and wouldn't even begin to start when I plugged the hole. I just don't know what it connects to even if I had a new hose for it..
 












If the FPR is leaking that much fuel into the vacuum line that gas made it all the way up to the vacuum tree then it's possible that you need an open port to provide extra air.

First step should be to replace the FPR, you can find them at Rockauto.com ranging from $53 - $113. Autozone and the other parts places are usually around $100. After you've replaced the FPR, worry about the open port. If the FPR quits spewing gas into the vacuum lines, then you can probably cap the open port. Out of the 6 ports on mine, only 4 are in use, the other 2 are capped off.
 






If the FPR is leaking that much fuel into the vacuum line that gas made it all the way up to the vacuum tree then it's possible that you need an open port to provide extra air.

First step should be to replace the FPR, you can find them at Rockauto.com ranging from $53 - $113. Autozone and the other parts places are usually around $100. After you've replaced the FPR, worry about the open port. If the FPR quits spewing gas into the vacuum lines, then you can probably cap the open port. Out of the 6 ports on mine, only 4 are in use, the other 2 are capped off.

Thanks. I was looking at some other info on the vacuum tree and saw that perhaps the A/C goes to it as well? The A/C was taken out of this vehicle before I got it, so could that be the open port? I am going to get a new FPR right now and will worry about the open one later, but if that is probably it, then maybe the problem is solved?

Also, the pressurized fuel lines made of brittle plastic aren't sold at auto part stores for some reason. Should I replace all of them somehow?
 






There's a vacuum line that comes off the tree and goes to a vacuum reservoir over by the heater core, but that's for the HVAC control head.

The plastic lines are easily replaced by buying a section of rubber vacuum hose....you can usually buy it by the foot at any parts place. 5/16" & 3/8" are usually the most common sizes and if you're planning on replacing some of the plastic lines, just buy like 5 or 6 feet of each size. Vacuum hose is usually pretty cheap....I think the last time I bought some 5/16" from Napa it was like $1.50 per foot.

Here's the diagram from my 94, yours should be pretty much the same.
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Perfect, thank you. I am going to try to get this done today. I will post later tonight with an update. Thanks very much for the help, I learned a lot.
 






Problem solved. I replaced the FPR and some hoses and it runs great now. It has a lot more power, the idle issue is fixed and I plugged the extra connector and it solved the vacuum leak that I was hearing.

Thank you all for your help and advice. I am truly grateful for your knowledge.
 






There's a vacuum line that comes off the tree and goes to a vacuum reservoir over by the heater core, but that's for the HVAC control head.

The plastic lines are easily replaced by buying a section of rubber vacuum hose....you can usually buy it by the foot at any parts place. 5/16" & 3/8" are usually the most common sizes and if you're planning on replacing some of the plastic lines, just buy like 5 or 6 feet of each size. Vacuum hose is usually pretty cheap....I think the last time I bought some 5/16" from Napa it was like $1.50 per foot.

Here's the diagram from my 94, yours should be pretty much the same.
42370904.gif

This is EXACTLY why I absolutely love this forum! Where else would you be able to type in a question and get a vacuum, schematic? Where else?:thumbsup::thumbsup:
 






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