88 GT Convertible vacuum/hoses

[MustangCop]

Howdy y'all


I have tried the search feature and am having problems locating the specific areas I am looking for, perhaps a little extra help is in order.

I recently acquired a '88 GT convertible, for the most part the vehicle is in good mechanical condition, however, I have observed some puzzling issues with the various vacuum lines throughout the engine bay. I shall elaborate.


Under the throttle body, there is what appears to be a solenoid with two hoses attached to it, these hoses are approximately 1" in diameter and they attach to two metal lines that dissapear behind the intake manifold and the firewall. This solenoid has a vacuum line in the top that is plugged with a screw, and another 1" hose that has apparently been cut and plugged that runs towards the front of the vehicle. Any thoughts on what this is and how to make it correct?

Also, towards the passenger fender, behind the strut tower, under the intake snorkel there is a rubber block with 4-5 vacuum lines running into it. It looks like a vacuum junction of some kind. On the other end of the block it is plugged with screws. I realize that none of this is correct and would like to make sure all vacuum lines are installed properly and everything is in working order. I just need some assistance identifying the lines and where they are routed to so I can get it correct.


Thank y'all for any help you can give. If need be I can attach pictures later of the specific parts I attempted to describe.


MustangCop

[MustangCop]

does anyone have time to help me?

[MustangCop]

Were air pumps optional, or not used on non-california emissions vehicles? Mine doesn't have one and I think that is where those hoses are suposed to go. But where does the vacuum line connect to from the air pump diaphragm?

Ok, I think I know what that mystery sensor is... perhaps a Diverter & Bypass valve? Now, I noticed in a picture of those valves that there are vacuum lines from each one, where do they plug in at? I will be purchasing a new air pump soon to replace the missing one, and want to get it connected correctly. A little help please?

[GTvert90]

How bout some pictures to help?

Do you have emissions testing? if not no reason to replace the smog pump.

[Whtstang]

Originally Posted by MustangCop

Howdy y'all


I have tried the search feature and am having problems locating the specific areas I am looking for, perhaps a little extra help is in order.

I recently acquired a '88 GT convertible, for the most part the vehicle is in good mechanical condition, however, I have observed some puzzling issues with the various vacuum lines throughout the engine bay. I shall elaborate.


Under the throttle body, there is what appears to be a solenoid with two hoses attached to it, these hoses are approximately 1" in diameter and they attach to two metal lines that dissapear behind the intake manifold and the firewall. This solenoid has a vacuum line in the top that is plugged with a screw, and another 1" hose that has apparently been cut and plugged that runs towards the front of the vehicle. Any thoughts on what this is and how to make it correct?

Also, towards the passenger fender, behind the strut tower, under the intake snorkel there is a rubber block with 4-5 vacuum lines running into it. It looks like a vacuum junction of some kind. On the other end of the block it is plugged with screws. I realize that none of this is correct and would like to make sure all vacuum lines are installed properly and everything is in working order. I just need some assistance identifying the lines and where they are routed to so I can get it correct.


Thank y'all for any help you can give. If need be I can attach pictures later of the specific parts I attempted to describe.


MustangCop

It sounds like the PO has disabled the Thermactor air injection system for some reason. From the front of the engine back, following the air stream, it consist of these parts:

The pump, complete with mounting brackets
short 1" hose into:
a vacuum controlled bypass valve
longer 1" hose connected to:
vacuum operated diverter valve
two 1" hoses out of the diverter valve, each connected to a check valve which is connected to:
one metal line connected to the back of each Head
one long metal line connected to the cats
& finally:

The TAB & TAD solenoids(mounted as a set to the rear(I think) of the passenger side strut tower) are turned off & on by the ECM in order to direct vac to the bypass and/or diverter valves based on engine operating conditions.


Depending on what you have or don't have, it could be a fairly involved process to get all the bits & pieces rounded up & put back in place. To say nothing about making sure everything is working properly. Since the Thermactor system was OE on all Mustang V8's from the early 80's with the ones from 87 through 93 being the most correct for your application, it would help to have a correct car from the later MY's to help out.

What do you have on the car in the way of an exhaust system? Does it have cats?

[MustangCop]

Originally Posted by Whtstang

It sounds like the PO has disabled the Thermactor air injection system for some reason. From the front of the engine back, following the air stream, it consist of these parts:

The pump, complete with mounting brackets
short 1" hose into:
a vacuum controlled bypass valve
longer 1" hose connected to:
vacuum operated diverter valve
two 1" hoses out of the diverter valve, each connected to a check valve which is connected to:
one metal line connected to the back of each Head
one long metal line connected to the cats
& finally:

The TAB & TAD solenoids(mounted as a set to the rear(I think) of the passenger side strut tower) are turned off & on by the ECM in order to direct vac to the bypass and/or diverter valves based on engine operating conditions.


Depending on what you have or don't have, it could be a fairly involved process to get all the bits & pieces rounded up & put back in place. To say nothing about making sure everything is working properly. Since the Thermactor system was OE on all Mustang V8's from the early 80's with the ones from 87 through 93 being the most correct for your application, it would help to have a correct car from the later MY's to help out.

What do you have on the car in the way of an exhaust system? Does it have cats?

The exhaust appears to be original, but the PO removed the mufflers and tail pipes from the cats back.... so after the cats I have nothing, and the cats sound clogged. I am going to install correct exhaust from the cats back but I would be willing to bet I am going to have to replace the cats, or at least open them up and remove the media.

I work part time at an Advance Auto Parts so getting the air pump, the proper solenoids, and appropriate hoses is not really an issue. I just need some kind of diagram and or pictures showing the correct routing. I do appreciate your help with this, it doesn't sound like it will be difficult to get it back together properly from the way you described it. If this were a '65 289 I would know what to do an how to do it, but alas it is not and I am a bit lost on these computer controlled vehicles.


MustangCop

[Diabolus]

Just gut the cats and be happier for it.

[MustangCop]

Originally Posted by Diabolus

Just gut the cats and be happier for it.

I think that's what I want to do, but will it mess up my O/2 sensor functions? I know it will get that traditional 5oh growl back, but at what cost to the electronic management of the engine?

[Diabolus]

I'm assuming all of the sensors are before the cat, therefore the computer shouldn't even know what's going on back there. You'll also loose some back pressure, which means a bit more power. But mind you, I only drive carburated vehicles because I think EFI is too frick'n complicated. Honestly, I think the only thing you have to worry about is if your state has emmissions testing. In Michigan my car can be throwing thick black sooty smoke all over the place and no one will care, but in New Jersey your not allowed to drive with your check engine light on.

[MustangCop]

Cool... That helps.

As for emissions, I live in South Carolina, we don't have emissions testing here or even an anual inspection. Of course, the traffic laws here give much leeway to police in determining wether your vehicle is safe for the road or not, and the penalties for driving an unsafe vechicle are pretty stiff ($1087.50 in my municipality plus 6 points off your license). If you have the "fortune" of being stopped by a car nut cop the chances of him writing you a ticket for the current tune of your vehicle resides in how cool he thinks your stang is.

[need4spd90]

i wouldnt waste any money on the smog stuff,none of it is needed,it just adds extra weight,clutters up the engine bay, and sucks up horsepower..your O2 sensors would be in front of the cats,so it wouldnt hurt them even if you had no cats..get a 2.5" h pipe and catback setup..i think the stockers are only 2.25..sounds way better and get a bit more power

[ALMOST STOCK]

Possibly this will help.

Flow from the Air Pump to the rear


The plastic lines


In and out colors lower right hand corner. In from the fender side out to the different locations.

[Whtstang]

MustangCop, What is the car going to be used for?

[MustangCop]

AlmostStock... none of the photos you uploaded are showing on my computer.

WhiteStang, the car is going to be used for pleasure driving/cruising and the occasional show or two. I'm not interested in racing it, modifying it, or increasing the horsepower, I just want a good, clean, nice car for my wife and I to enjoy. Nothing more nothing less.

[Whtstang]

There's nothing wrong with that.