Vacuum Lines Question......

[AnthonyR23]

Hi, with my idling problem I think it could be a vacuum leak... I just eliminated my a/c... not sure if that has anything to do with it.. I am looking at a vacuum hose kit for about 25 bucks.. Yellow.... from mustangs unlimited.. I am a little confused about what the vacuum lines actually do... How many of them are there or should there be.. Does anyone have a half decent vacuum hose/line diagram for a 88 mustang with speed density and no air conditioning.... I purchased a 65mm throttle body that comes with a spacer, tps, and iac. So that may clear up some idling issues.. and I'm working on that secondary air diverter solonoid.... with a battery tester light there is constant flow through the solenoid.... if I ground the green wire should it do something.....??? Does anyone know where I can replace that solonoid or how to find out if it works?

 

[v8only]

can you be a little more descriptive of your problem??
I just went through more speed density vacuum issues over the last year than any human should endure in a lifetime..

give me the complete symptoms.

also, there are some vacuum lines in the back that was used for the a/c, did you plug these off?

on a speed density system, the biggest symptom of a vacuum leak/problem will be a run rich problem, which of course could cause idle problems too.

if you're not sure, pull a plug and see if it's black or not.

 

[v8only]

as for the vacuum, basically here is how it should go:

thick line straight from the back of the intake to the vacuum tree on the firewall, which in return goes to the brake booster.

Make sure your fuel pressure regulator is hooked up straight to vacuum off the back of the intake.

also, make sure your map sensor on the firewall is going straight into vacuum.

off the vacuum tree on the firewall, is where your air conditioning gets its vacuum source, plug that off.

the charcoal canister will have a vacuum line going to it too, I "believe" it gets straight up vacuum likely from the front of the intake.....

besides that, the only other vacuum is vacuum for the tab/tad solonoids, and the egr. the egr vacuum comes from the egr solonoid located near the tab and tad solonoids. If memory serves, me, the tab/tad and egr all get it's vacuum source from the same port, and that's either straight off the intake, or the vacuum tree (vacuum tree on the firewall I "think")

so make sure your a/c stuff is plugged off correctly, and everything else listed above is getting the correct vacuum.

 

[AnthonyR23]

Hey, thanks for the reply... very much appreciated.. I will have to check out that a/c line because I don't recall blocking that off.. I found a pretty good vacuum line diagram. I will post the original and I will post one that's edited to show what I think I have... I will have to double check it tomorrow but it's 2 in the morning here so I can't go out and double check it right now... but just searching the internet to find some answers....

So I installed underdrive pulleys... a mark 8 electric fan.... bbk equal length headers....... and a new 3g alternator..... and moved the battery to the trunk..... oh and just installed the a/c eliminator kit with new belt..

Before all of that I was having a ticking problem and suspected my headers... I actually was just first able to fire it up a few days ago. The ticking is gone but it idles at around 1800....

So I am trying to get through the idle checklist...... but it says to make sure you have no vacuum leaks before moving on and to fix any error codes.....

So the way I am going about it is trying to fix any codes that came up in the engine off test because I think that could clear up some of the engine on codes... the 23 and 63 are both tps errors.... I am going to order a 65mm throttle body from ebay that comes with the throttle body spacer, gaskets, iac, and tps.. So hopefully it clears up those codes.. The 81 has to do with the tad tab solenoids failure.... or diverter failure... So that's what is pointing me in the vacuum line direction. I feel like I should clear up any possible vacuum leaks... reset the comp.. and then see what happens with another test...

ENGINE OFF
23, 81


ENGINE ON
63, 98


So another thing I really want to do is check my timing.... I just run with regular fuel so I am not exactly sure what to try to set it at... Most the responds to my posts about timing have just been what other people are running at most say 13 but that's with premium fuel... So I'm thinking 10ish.... any ideas??

 

[AnthonyR23]

Could there be something wrong with my throttle cable....?? Even though I doubt that.... I just found this article tonight... I am gonna leave out the edited one for know.. You know it is pretty tempting to pick up that yellow vacuum kit from mustangs unlimited for 24.99.. and just replace one line at a time and make sure that I work out whatever is missing.. My canister isn't hooked up to anything??

 

[v8only]

your charcoal canister NEEDS to be hooked up for vapor return......

sounds like you've got vacuum issues, and before you start throwing more parts at it, fix what you have.

check your tps voltage, keep it between .90 and 1, that may fix your codes.

your tab and tad and ac lines were likely disconnected and left hanging when you pulled your ac, I'd check there first.

I run 14 degrees on 87 octane with no issues.

 

[jrichker]

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

 

[AnthonyR23]

I have a question about the charcoal canister.. I think it is hooked up actually... but can someone check too see if there is two open holes at the top of the charcoal canister... There is two lines going to it though... maybe it should be open at the top.. And does anyone know what I could use to cap off the a/c vacuum lines... and another thing... After I replace the vacuum lines on the tad tab solenoids/diverters... if I am still getting errors... is there anywhere you can get those parts... .or is there other parts that would work because ford doesn't make them anymore....

 

[iwashmycar]

i am battling that code 81 right now too. I checked the red wire on the solenoid and got 12 volts....then i checked the green/black for 1 volt and it was there. supposedly when you ground out the green/black its supposed to operate a valve somewhere but i hear nothing, and dont know if i even should be able to hear it.
i looked for those solenoids at the parts store too...no luck

im going to go out and check my timing in a few minutes and also clean the air filter as a precaution.

its driving me nuts!

 

[v8only]

I've never heard anything coming from a valve when I check my tps...as well, you won't find the tab and tad solonoids at the parts stores....

according to the diagram, the tab and tad solonoides feed into the same vacuum line as the evr (egr feed solonoid) then they go together into that blue check valve, which then get direct manifold vacuum....check this, as if that's not right, your tab/tads won't work.

 

[jrichker]

IF and only if you do not have a cat converter H pipe, the TAB & TAD solenoids can be mimicked if they are damaged or missing. Running a cat converter H pipe without a working Thermactor Air System (smog pump) is just asking the cat converters to die and clog.

See www.Newark.com for the resistors to replace the TAB & TAD solenoids

http://www.newark.com/jsp/Passives/Wirewound/OHMITE/43F82RE/displayProduct.jsp?sku=64K8974
If the link fails do a search using the park number
82 ohm, 3 watt wirewound resistor, 94 cents each.
Newark P/N 64K8974
Ohmite part # 43F82RE.

Pay a visit to your local Radio Shack to get some heat shrink and some crimp on tap terminals. They do not stock the resistors. Or you can use the Ford connector pin kit from AutoZone.

18 gauge crimp on taps Catalog #: 64-3053

Put the resistor inside the heat shrink tubing and crimp the connectors on. I would choose the Ford pin connectors since they should plug in the TAB & TAD wiring. That way you haven't modified the wiring so it is easy to re-install the TAB & TAD solenoids if emissions testing comes to your area.

This isn't a guaranteed fix, but it is cheap enough (less than $10) that you can experiment with it.

 

[AnthonyR23]

I am gonna fight this little idle virus!!!! lol.... IWashmycar... someone responded to another thread with this link www.latemodelrestoration.com they have a sensor and relay package for 89.99 which contains dual-oxygen sensors; EGR solenoid, TAD and TAB solenoids; fuel, air-conditioning and EEC power relays. Engine-mounted and BAP sensors NOT included. V8only we were referring to hearing the tad and tab solenoids opening and closing the diverters.... reference is code 81.. I have been getting .78 volts out of my tps... So not sure if it is that.. was told to try to adjust it to between .9 and 1. So I am gonna try that too.. I still have speed density not mass air... and have emissions here so I don't want to bypass anything... Have bbk equal length headers with the original gt h pipe with cats......

I ordered a vacuum hose kit (yellow) from mustangsunlimited for about 30 dollars... and am going to try to replace as many vacuum lines as I possibly can.. I need to block off my a/r line since I deleted my air conditioning.. That could be causing a vacuum leak... once I do that.. I am going to run the test.... could a vacuum leak be causing code 81 to appear.... or is it definetely refering to those tad tab solenoids/diverters... I took the upper solenoid off and checked it with a tester light so assuming that my solenoids are working and wiring is correct it could be the diverters... I am going to take them off one at a time and see if they can be cleaned or whatever.... we'll see...

Anyways I ordered the lines yesterday and mustangsunlimited is excellent when it comes to shipping so it wouldn't shock me if I got the lines by friday.... I have a cost analysis exam on friday.... and three assignments due by sat. at midnight.. which I'm hoping to have submitted by friday night.. then I have a few weeks off and I am going to attack this problem with everything I have!!!! lol

I'm not ordering a new throttle body, spacer, iac, and tps until I'm sure they are toast... You can get the package on ebay for about probably 260ish.. So hopefully I can avoid that..... I will be on here on the weekend with updates!!!

Good luck with it IWASHMYCAR, keep me posted if you figure anything out with your error!!!

 

[AnthonyR23]

I also have a new cold air intake on the way.... but I definetely need to check my timing!!!!

 

[iwashmycar]

ill keep you posted anthony....my filter is drying as we speak and ill see if it was that simple, but i doubt it


ok i think i see the resistor fix,....

So there are the 2 plugs for the solenoids. Each plug looks to have 2 wires down there.

am I just bypassing the solenoid then, by connecting the 2 wires togeather with a resistor in the middle? I would leave the solenoids unplugged after that it sounds....Like they aren't even there.

at least by bypassing ill be able to maybe tell if they are bad

 

[iwashmycar]

im gonna order some resistors lol.

the timing and air filter cleaning did nothing

 

[AnthonyR23]

You know, the most frustrating thing about this code 81 problem is that I would like to understand it.. I understand what parts are being issolated as problems but I don't understand exactly how they work and what they do.... I don't want to just replace something that may not be broken... Ok from the vacuum diagram that I will attach...

It looks like the smog pump goes to a thermactor air bypass...
then there is a solenoid for that bypass that is powered by the comp.. the comp sends it power when it wants to let air from the smog pump through and when the solenoid activates it allows vacuum through which opens and closes the bypass which in turn lets the smog pump air continue through the hose...

Ok so from there... the air is running through the tube/hose and hits a diverter (thermactor air diverter) that either goes to the h pipe or to (it says head)?? and there is a solenoid that the computer gives power to turn on the diverter to divert the air... which is also vacuum controlled...

The computer is giving me error 81... so it has to be one of these things.... ok can anyone clear up two questions I have....

1 --- what is the usual way that the air is diverted... when the tad solenoid is powered does it switch it over (to head)assuming heads... or is it normally going to the heads and then diverted to the h pipe/catalytic converter when the solenoid turns on...

2 --- when the first tab solenoid isn't activated where is that air dumped off????

I am going to try to take the tad components off and see if I can jumper them to get them to work... then I will take the other two components off to check the same thing... If they both work.. I will assume it is a vacuum problem..... Somehow the computer knows by sensor I guess somewhere that this is the problem...

Could it actually be working and just be a general vacuum leak...???

 

[iwashmycar]

oook...i got 2 of the resistors and some connectors and such to try it out. I want to see if its the fix for 81 before i shell out $85 on solenoids.

Ill get it togeather sometime tomorrow and let you know. I was going to just plug the resistor in and give it a little test but I remembered how hot they can get and didnt want them touching anything.

 

[iwashmycar]

put em togeather. ill test it out later this evening....its raining, and I washed my car ...

View attachment 392485
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[iwashmycar]

nope...didnt do anything. if anything it ran worse

 

[AnthonyR23]

I think it is probably best to replace those parts... I know 89.99 is a bit steap... but at least you will be able to rule that out... after hooking up my vacuum lines and putting everything back together I am hopeing everything runs good... I am gonna adjust the idle and make sure the tps is at .9 volts....