Topic: Vacuum lines

[ta78w72]

I'm very confused.  I'm missing the ported vacuum switch (TVS) on my 1978 4-speed 400.  The service manual says "V8 400 engines with manual transmission use ported vacuum for distributor spark with a coolant overheat TVS which provides full manifold vacuum to the distributor when the engine coolant temperature is above apporximately 225 degrees F."

The schematic, figures 6E-27, 28 and 29 show a TVV for manual and a TVS for automatic.  This is exactly opposite of the text.  Which is correct for a 4-speed?  I assume the schematic is incorrect.

Does anyone have a picture of where this vacuum switch is located?  I need to get the vacuum hooked up according to the schematic on the radiator bracket in order to pass the California smog test.

[Black78TA]

I'm very confused.  I'm missing the ported vacuum switch (TVS) on my 1978 4-speed 400.  The service manual says "V8 400 engines with manual transmission use ported vacuum for distributor spark with a coolant overheat TVS which provides full manifold vacuum to the distributor when the engine coolant temperature is above apporximately 225 degrees F."

The schematic, figures 6E-27, 28 and 29 show a TVV for manual and a TVS for automatic.  This is exactly opposite of the text.  Which is correct for a 4-speed?  I assume the schematic is incorrect.

Does anyone have a picture of where this vacuum switch is located?  I need to get the vacuum hooked up according to the schematic on the radiator bracket in order to pass the California smog test.

 I think I might be able to help.I also have a 78 W72 4-speed.  I still have all the emission controls intact. Schematic 6E-27 is correct for your car. Forget about the other diagrams, they are not correct for your car anyway.
The TVS is located on the air cleaner. The pic is big to show detail. There are also two TVV "posts". One is on the intake manifold,the other is near the exhaust manifold on the right side. If you need some more detailed pics let me know.[img][/img]

[ta78w72]

Hmmmm,  Thanks for posting the picture.  But I think your picture shows the sub TVS.  I found where the DS-TVS is located, in the head between cyclinder number 6 and 8.  I think the schematic incorrectly lists it as a DS-TVV.  Mine was not hooked up.  I got lucky with the smog test last time.

[Black78TA]

Hmmmm,  Thanks for posting the picture.  But I think your picture shows the sub TVS.  I found where the DS-TVS is located, in the head between cyclinder number 6 and 8.  I think the schematic incorrectly lists it as a DS-TVV.  Mine was not hooked up.  I got lucky with the smog test last time.

I have the same drivetrain as you and can provide any pic that will help you make your car factory correct. Ask and you shall receive.

[ta78w72]

Thanks for the offer, I appreciate it.   I've taken out all the non factory stuff.  The next project is replaciing my heater core....then it's on to replacing the manual roll up windows with power windows, new glass and power door locks.

I get the car back from the shop tommorw.  It's getting the transmission rebuilt.  Someone also did some welding on the hurst linkage.  That's getting fixed too.  When it comes to transmissions, I let someone who knows what they're doing handle it.  All those gears, clips and needle bearings give me chills!  Also, a new clutch, pressure plate and flywheel.  I'll be ready to go for summer!

[ta78w72]

Hey, Black78TA
I sent you a message but thought you might not see it.  Can you please post a picture of the EFE Valve?  I think it goes on the opposite side of the air cleaner base from the Sub TVS.  My car has holes where the sub tvs and the EFS valve are suppose to go.  Once I find those parts, my vacuum system will be back to original and I may just pass California emissions.

Does anyone have a clue as to where I could find an EFE Valve?  I think I've got a source for the sub tvs and they may have an efe valve but I need a picture to determine if theirs  is correct.

[Black78TA]

Hey, Black78TA
I sent you a message but thought you might not see it.  Can you please post a picture of the EFE Valve?  I think it goes on the opposite side of the air cleaner base from the Sub TVS.  My car has holes where the sub tvs and the EFS valve are suppose to go.  Once I find those parts, my vacuum system will be back to original and I may just pass California emissions.

Does anyone have a clue as to where I could find an EFE Valve?  I think I've got a source for the sub tvs and they may have an efe valve but I need a picture to determine if theirs  is correct.

Check your e-mail.  I responded with some pics and help.  If you didn't get it let me know.

[ta78w72]

That's the beauty of this forum.  Thank you so much for the pictures and information.  I have learned a whole lot here for all of you!

[Eagle 1]

I have just about got all of my emmissions and vacuum hoses connected but I still need to find a TVS as mine is missing too.
The picture helped me figure out what was missing, thanks.

Also what connects here to the tube coming out of the back of the EGR valve?

[ta78w72]

That tube connects to one of the connections under the air cleaner.  If you're really stuck I'll figure out exactly how it connects.

You need a two port TVS.  You can get one for $37.20 plus shipping from Clean Air Products Inc.  Their number is 1 (800) 544-4357.  They're located in California.  I ordered my TVS on a Thursday or Friday and got it on Monday.  The auto parts place didn't carry this part.  

Oh yeah, they send you the retaining clamp along with the TVS so you'll have everything you need to hook it up.

[Eagle 1]

That tube connects to one of the connections under the air cleaner. If you're really stuck I'll figure out exactly how it connects.

Ok, now I am confused.  There are two connections under the breather.  I thought one of them hooks up to the choke heater tube and the other to the TVV in the intake.
If you have the 78 TA manual from Brett, take a look at figure 6C-94.  It shows the modulator in the breather connecting to the choke heater tube.

Does your car have an EFE valve, and if so where is it located?

Thanks for the tip on the TVS in the breather,  I'll call about it tomorrow.

[ta78w72]

First the EFE, Black78TA set me straight on where that is located.  Drivers side, exhaust manifold between number 3 and 5.  See figure 6E-1 in the service manual.

I think that tube on your manifold goes to the modulator in the air cleaner.  In fact, my car is connected exactly like it shows in figure 6C-94.  The modulator is a small metal thing that attaches to the bottom of the air cleaner.  The TVV is located on the side of the air cleaner as in the picture of Black78TA's car.

You need to look at the vacuum diagram in the emissions section to figure out how the TVV connects.  It's too bad that the emissions vacuum setion doesn't show how to connect all the vacuum lines.  It makes it kind of confusing when you have to go between different sections of the manual to figure out all the vacuum line routings.

[Eagle 1]

First the EFE, Black78TA set me straight on where that is located. Drivers side, exhaust manifold between number 3 and 5. See figure 6E-1 in the service manual.

Ok, mine dont have an EFE.  At sometime it must have been removed.  I spoke to the original owner and he seems to remember wiring it open, but dont recall taking it off the car. :?   Who knows.

So do you think that the tube behind the EGR valve (in above photo) connects to the hoses under the breather that goes around the breather and hooks into the damper on the air inlet tube of the breather?   Is that correct?

I understand about the the one tube for the choke heater hooking into the modulator under the breather.

[ta78w72]

I believe that's how it should be connected.  What do you plan on doing for an EFE?  I'm not even sure if you can buy one now.

[Eagle 1]

Im really not worried about the EFE.  The epa laws are not as strict here in Texas, besides I have an shop here in town that I can get any of my old hotrides inspected and they will pass. :wink:
Im just trying to make everything else as correct as possible.
I also ordered a TVS from Oriely's here and it will be in on Thursday.  We looked it up in the book and think its the right one, so I am keeping my fingers crossed.  If its not, then Autozone thinks they can get me one if I can get the OEM number.   However, if its the wrong one, I may be asking you if you can get the part number off yours if you can or still have the box it came in.
I also got the vacuum check valve that goes between the vac. manifold port and the TVV on the intake as well as the retard delay orfice that goes between the distributor and carburetor.
Do you have all of your vacuum lines connected?
Also, does your EGR valve have a tube like mine coming out of the back?
Thats the first one I have ever seen like that.  I plan on looking at my sons 1981 Z28 tomorrow.  Its an orginal car so most of his stuff is still on it.