lower intake bolts

[Barlow]

what all does a guy have to take off to get at the lower intake bolts on the 2.5 ... i can only see one bolt ... either the gasket is bad, or it is lose, or both ... i know i sound stupid, but i have never worked on a 4cyl ford truck, and i dont want to take off any more than i need to ... another question, is the diverter or whatever it is called that makes the heat/ac fan blow out the correct vents vacuum, and if so where does vacuum go into the firewall ... my truck only blows out the defrost vents at the top

 

[Mark_88]

There is a blend door in the heater box that directs air and this can become broken needing replacement. There have been a few people documenting how to fix this...just search on "blend door repair" and you should come up with a recent document (I just read it not more than a week or two ago).

This can be fixed without pulling your whole cab apart...but may require a bit of flexibility in wrist and elbow joints...

Lower intake bolts? You want to remove it from the head? That can be done also but things like the steering shaft and fuel lines may be in the way...

Are you thinking there is a vacuum leak due to the gasket being destroyed? This is very rare and you can test it...needs something like carb cleaner or something similar...

With the engine running, spray carb cleaner around the intake area where you think the lead may be and listen for the change in rpms...if it revs up then you probably have a leak...

Be careful with anything and don't spray too much...there is no hot stuff on the driver side but any spark can set stuff on fire...

 

[tomw]

I think the 'blend' door is for temperature control, as cool and warm air are blended together to modulate the temperature. There is a 'mode' control flap that directs air to the floor, dash vents or defrost. It is likely vacuum operated, and will fail in the defrost position.
The vacuum source is generally on the passenger side and goes through the firewall near the under hood plenum. Depending on year, of course.
Given I don't have a 98, I'd check the vacuum following the large line from the manifold that goes to the 'tree' on the firewall. Pick the vacuum line from the tree that is labeled A/C or similar(I don't remember, but it has CC, PB(Power Brake) ans things like that), and follow that line.
tom

 

[Mark_88]

I might have misnamed the door that is at fault...so it might be a diverter...my 96 is very similar and it has two or three vacuum controlled doors...one of which closes or opens when the engine starts...you will hear an audible "clunk" when that one is activated. If you don't hear that then maybe it is a vacuum issue.

The vacuum on the 2.3/2.5 feeds in on the passenger side just below the heater box. I should be one line and it will also be connected to a plastic ball about the size of a softball (3-4" diameter). that is a Check valve.

if you don't have a check valve or there is a leak in it that may be part of the problem...it allows vacuum to remain in the system (instead of bleeding out) so that in times of low vacuum the doors don't all shut/open. Someone may have removed it thinking it wasn't needed...I almost tossed mine away when I first saw it thinking I would work around it not being there...good thing I've learned from past experiences not to do that...

So, yeah, check the vacuum...it actually feeds from around where your coil packs are sitting...red/green lines on mine...black to the check valve and inside....there is also a vacuum controller on the dash just below the radiol...behind the bezel about four lines connect there and very easy to disrupt...

Disrupting that may also cause rough idle...I just remembered that now...so it might not be your FPR or external vacuum leak...might just be the connector for the heater controls is loose...

 

[tomw]

The 'softball' is the vacuum reservoir, and it will hold vacuum using the check valve as stated. It also will supply vacuum for one or two power brake assists should the engine stall and lose manfold vacuum. Or not, depending on how it was plumbed in.
The vacuum source (manifold) will be on one side of the check valve, and the reservoir and vacuum 'motor's and any other vacuum thingy on the other side, provided vacuum from the reservoir, and not bleeding in air from the 'non-vacuum at that time' intake manifold.
A symptom of a failing check valve is that your HVAC goes to defrost mode when you accelerate hard. Manifold vacuum drops, and the check valve allows the vacuum to bleed off. A leaking vacuum line will or can cause the same thing. FWIW, the 'hard plastic' vacuum lines under hood can be fixed with a short length of rubber vacuum line as a 'union' should they get melted or squished.
tom

 

[Barlow]

There is a blend door in the heater box that directs air and this can become broken needing replacement. There have been a few people documenting how to fix this...just search on "blend door repair" and you should come up with a recent document (I just read it not more than a week or two ago).

This can be fixed without pulling your whole cab apart...but may require a bit of flexibility in wrist and elbow joints...

Lower intake bolts? You want to remove it from the head? That can be done also but things like the steering shaft and fuel lines may be in the way...

Are you thinking there is a vacuum leak due to the gasket being destroyed? This is very rare and you can test it...needs something like carb cleaner or something similar...

With the engine running, spray carb cleaner around the intake area where you think the lead may be and listen for the change in rpms...if it revs up then you probably have a leak...

Be careful with anything and don't spray too much...there is no hot stuff on the driver side but any spark can set stuff on fire...

i did the test for leaking/bad intake gasket, and unless there is a vacuum port on the underside of the intake that i can not see, the gasket is bad ... every port i sprayed raised the rpms (did this before i joined the group here) as far as the blend door, does the blend door not blend hot and cold air for the temp (sorry if i am sounding stupid, i really dont do much with fords) ... i will try to find that thread though ... thank you for the reply and the help

 

[Barlow]

ok, to mark and tom ... i dont think i have the ball with the valve, and right around there, i have a bad vacuum line (maybe that is the feed to the inside) so that is where i will start ... bad thing is, where i live i only know of one salvage yard, and everything they have is made of gold ... i am hoping to find someone in central illinois with a truck they are selling parts from, as i also need seats, a speedo, jack handle (cant get my spare out) and carpet ... the carpet i may be able to salvage when i get it out, but not sure yet ... i sure thank you both for your help and time

 

[Mark_88]

Hi Brian,

Thanks for the update and feedback. The vacuum lines for the door controls actually starts on the driver side of the intake. Spraying stuff around can that side may get sucked in through that opening and appear to be a bad gasket...unless you have one of those fine spray nozzles...just saying it might be misleading and could be the whole vacuum line is shot from the intake side all way around.

I read on here not too long ago of someone having to order vacuum lines from an auto parts store. I'm pretty sure LMC has the lines and can probably source a new check valve for you.

Funny you should mention junkyard gold...lol...everything I have bought recently is almost double what I paid about two years ago. I know the price of metal has gone down so the yards need to make up the difference somewhere...so we get gouged...

This should get you to the catalog but it is searchable. I didn't see the check valve and if I had a spare I'd send it to you. Might be going to the junkyard next week but waiting till the snow melts up here.

http://www.lmctruck.com/icatalog/fr/full.aspx?Page=134

I will give the on-line manual a look too...that is a great resource for determining if something is missing sometimes...there is a link on the main page under the Submit articles section...

Edit: couldn't find anything...not sure when that ball was first used...

 

[Barlow]

ok, thank you mark, going to that page now ... it is only about 15 degrees out right, and it is driving fine right now, so not going to be getting under the hood right now ... about 40 on sunday though and that is my day off, so i may look for that vacuum on the drivers side and start tracking things from there ... when i got the truck there was a piece of hose from what looked like fix-a-flat taped in the place where i think that ball would go ... neither of the lines going into that hose seemed to pull any vacuum so i didnt think much of it ... guess it is time to buy some new wire loom and take some things apart ... would like to get it fixed right before spring when i stop driving it again everyday and switch back to my car

 

[tomw]

For what it's worth, the vacuum reservoir on my old truck is underneath the air intake box. It is not a ball or sphere. Back when, the reservoir could look like a 'tomato juice can', i.e., was a can with both lids still attatched, that had a pressed in place (into a grommet) check valve. They can be hidden anywhere, but all have to have a connection to vacuum.
On the underside of the intake up near the throttle body, there may be a largish vacuum line attached at an elbow. If you can take a look from the front, peering just above the radiator, you may be able to see it. It is pretty well hidden. I think it is the PCV connection, or the vacuum source for the power brake booster, HVAC, etc.
tom

 

[Barlow]

brakes are another problem with this one ... it goes, nothing nothing nothing (in several inches of travel) then all at once it is almost full brake (in less than 1/2 inch travel) with a "funny feel" when they grab hard (like something is clunking up front) i know i should get it off the ground and pull the front wheels, but it is cold, snowy, and i work 6 days a week ... so until spring when i can get the gta back on the road, i will just be hoping it does not brake something ... still to cold to get out and check the vacuum lines (still only 20 degrees out there)

 

[tomw]

Unless your insurance covers everything, having bum brakes is not a good idea. At least brave the cold and wet and check that things are still bolted under hood. The power brake booster uses engine vacuum -- here we go again -- to help you press the brake pedal. If the problem is the vacuum to the booster, it may not be applying until late in the pedal travel.
With the engine off, press the brake pedal 3-5 times. That will bleed off any vacuum assist from the reservoir. Press the pedal until it stops. Check travel without vacuum assist. If the 'slack' is gone, you might want to check the power brake booster and vacuum source.
If you need to 'pump' the brakes to get a full pedal, then you may have an adjustment problem, or air in the brake line(s).
Once you have done all that, whichever case you find, you can check the booster by stepping on the brake, and starting the engine. Engine vacuum should energize the booster and the brake pedal should drop slightly as the booster works.
tom

 

[Barlow]

i do not think it is the booster, pedal feels good ... does not feel at all like it has any air in the lines either ... although my abs light is not on, it is what i suspect will be the problem, and i do not know one thing about abs ... when i get around to that, i will have to start a new thread about that one ... about the vacuum though ... on the passengers side, i found a gray line broken, 2 black lines that go nowhere and a red line that seems to lead into the gray one ... all this is right in front of the hvac box on the firewall ... i have not had much luck in locating a color coded vacuum diagram online, but i did not get much time to look, ill get back to looking for one today though ... i think i should have gotten a co-gm-ugh, i know so much more about them ... lol

 

[tomw]

Most vehicles will have a vacuum diagram underhood. Either on the radiator support or the underside of the hood. If it is missing, you might find a picture of one on google or a web site. I have seen them posted here and there, but did not take note.

A mis-adjusted valve inside the booster can cause no help until you reach a certain position in the movement, and then will apply full 'help'. As the pedal is depressed, the brake rod moves forward, and moves a valve in the power brake booster to allow vacuum to get on the 'front' side of the diaphragm, which will pull it forward, and also pull the 'center' of the booster forward, and push on the piston in the master brake cylinder. That 'push' is the help. If the valve is sticky or out of adjustment, it won't 'help' until the vacuum is allowed to apply to the diaphragm. Thus you can push, and push, and then whammo it "HELPS" push. Sticky or mal-adjusted, maybe?
tom

 

[Mark_88]

The two black lines that go nowhere sound like the missing valve location. Mine has black lines connected to it and one black line feeds into the firewall to connect up with the controller on the dash.

If you pull the radio out it is much easier to see if the dash connection is tight and check for leaks...but that can be a pain to do and I don't recommend that unless you have a few hours that you want to do something frustrating with...although it may be better on your truck than it was on mine.