Missing Vac Line

[rickelusfxp]

hello all,

I have a 92 explorer that is having a rough idle. I know its a vac line problem and I know which one. There is a cluster of vac lines near the firewall on the driver side of the motor. The back vac line that points straight into the firewall is missing. There is a 2" rubber vac hose that isnt hooked up to anything and I can find the line that is supposed to be connected to it. When the car is at idle the motor shakes and when I cap this open nipple it smooths out. Please let me know what this needs to be hooked up to. If pics are needed let me know and ill post them.

 

[boggs1227]

if what you say by the re-connected vac line makes the engine idle rough then the problem lies else where ...trace the line in question .this may be a egr related problem or don't quote me but maybe a bad tranmission modulator and or bad fpr (fuel pressure regulator).... do any of the vac lines have transmission fluid in them ?? if so then it's the modulator ...if not i betting on a egr problem.have you pulled any codes ? cel on ? etc.........

 

[rickelusfxp]

if what you say by the re-connected vac line makes the engine idle rough then the problem lies else where ...trace the line in question .this may be a egr related problem or don't quote me but maybe a bad tranmission modulator and or bad fpr (fuel pressure regulator).... do any of the vac lines have transmission fluid in them ?? if so then it's the modulator ...if not i betting on a egr problem.have you pulled any codes ? cel on ? etc.........

Problem is i dont know where the vac line is. I just have an open nipple with a 2" vac hose extension and I can find the vac line that it hooks up to.

 

[boggs1227]

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[boggs1227]

hello all,

I have a 92 explorer that is having a rough idle. I know its a vac line problem and I know which one. There is a cluster of vac lines near the firewall on the driver side of the motor. The back vac line that points straight into the firewall is missing. There is a 2" rubber vac hose that isnt hooked up to anything and I can find the line that is supposed to be connected to it. When the car is at idle the motor shakes and when I cap this open nipple it smooths out. Please let me know what this needs to be hooked up to. If pics are needed let me know and ill post them.

ok....sorry haveing problems here tonight with this ...you re-connect and it rough idels right? and you can find the line the 2 inch nipple(thats on the tree) connects to right? i know this is a dumb question and i know your the one asking it but you need to trace that line .....does it go back into the engine compartment or does it go back twards the rear of the truck ??? this is the million dollar question .some pics would be somewhat helpfull here .

 

[rickelusfxp]

ill take a pic tomorrow morning and post it. thanks.

 

[rickelusfxp]

I dont know what this is supposed to be hooked up to. If you could let me know it would be great. Its on the back driverside of the engine. Thanks.

 

[Michiganbear]

just went out and looked at my 91. I have plugs on 2 of the ports you have lines on (and the one you have circled has a plug also, so 3 plugs total). Now, mine is a 5 speed, so I dont have a vacuum modulator, that the automatic would have.

in fact, all three ports that are partly or entirely in the circle are plugged on mine.

my vac lines go to the brake booster (seen on yours), the cruise servo (also seen), small lines going to the vacuum source for the heater stuff (seen), and the Fuel press reg (also seen).

so, all the stuff that my 5 speed needs is there, it must be for either egr, or trans modulator.

*note* my 5 speed does NOT have an egr valve.

 

[rickelusfxp]

just went out and looked at my 91. I have plugs on 2 of the ports you have lines on (and the one you have circled has a plug also, so 3 plugs total). Now, mine is a 5 speed, so I dont have a vacuum modulator, that the automatic would have.

in fact, all three ports that are partly or entirely in the circle are plugged on mine.

my vac lines go to the brake booster (seen on yours), the cruise servo (also seen), small lines going to the vacuum source for the heater stuff (seen), and the Fuel press reg (also seen).

so, all the stuff that my 5 speed needs is there, it must be for either egr, or trans modulator.

*note* my 5 speed does NOT have an egr valve.

From what i've read the egr wasnt installed until 05 if im correct. I wonder if it should just be capped then since I cant find any vac line that is loose anywhere. Thanks for the input. Doens anyone have an automatic that can confirm this for me? Or tell me where the hookup is for the Trans modulator? Thanks agian.

 

[boggs1227]

nope , i got a 94 and i have a egr system .....91- i think 92 maybe 93 did'nt have egr systems.



i would just go ahead and cap it off on the tree and make your engine idle smooth once more .i'm betting that the nipple was just used to cap that port off and most likelly had a bolt stuck in the end to seal the nipple then the bolt fell out due to age and heat ( cheap capping method ) .cap it off and see if you have issues .btw when i was replaceing my egr system i had all the vac lines off the tree and "yepper" i had one port witha small piece of tube with a bolt in the end ...just went to the parts store and spent 1.25 on a pack of misc. sized rubber vac caps .

 

[rickelusfxp]

thanks for the adivce. i put a autozone cap on it and its running fine now.

 

[Blacksheep Josh]

if you want a double check, i believe there is a vacuum diagram on teh sticker under the hood. you could trace everythign to make sure everything is hooked up.

 

[Michiganbear]

unfortunatly, them underhood stickers only list the emissions related hoses, not any for the hvac, cruise, ect..

 

[Shen2187]

Mine is capped as well, always has been. Maybe it does nothing. Perhaps it had a cap on it to begin with.
Mine is 4WD Automatic btw.

 

[Michiganbear]

Knowing about ford's cost cutting, and really just common sense too, that vacuum fitting is probably used on a dozen or maybe even hundreds of different engine/drivetrain/body/chassis combos. just makes sense to have 1 part built a million times, as opposed to 100 different parts built 10000 times each.