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Emission sys. Problem's ???


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T-Bird
New User

May 27, 2009, 10:47 AM

Post #1 of 14 (2589 views)
Emission sys. Problem's ??? Sign In

1979 Ford, Thunderbird, 351W, w/auto, 56K (?). This is a really nice car inside and out, purchased as-is. It stall's out when you put it in drive or rev. , if you really rev. it up it will go ingear. Shift's normally after your under way. I don't have back ground info., but it has emission tubing going everywhere. I've tried for several wk.'s to get a diagram of emission sys..
Can someone healp Please ???? I really need some input's, I've replaced gas filter, spark plug's and rebuilt Carburator, all to no avail !!!

(This post was edited by T-Bird on May 27, 2009, 11:50 AM)


Loren Champlain Sr
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May 27, 2009, 2:28 PM

Post #2 of 14 (2583 views)
Re: Emission sys. Problem's ??? Sign In

T-Bird; One of the most common problems with this vintage was the EGR valve and spacer. The spacer that the EGR valve is mounted to is between the carburetor and the intake manifold. The spacer would get eaten away on the underside and cause a vacuum leak that would drive you nuts trying to find. Also, the EGR valves would get stuck in the open position, usually by a chunk of carbon. Be certain that you don't have manifold vacuum going to the valve. It should be ported.
Take precautions in doing this, but you can spray a light mist of carb cleaner into the carburetor at idle. (carb cleaner is flammable, so be careful). If the idle speed increases, it is running too lean. Of course, you can compensate for small vacuum leaks by adjusting air/fuel mix screws, but that's not the proper way, and will be just masking a problem.
If you need more, check the emissions label to see if this has CA or Fed emissions and let us know.
Loren
SW Washington

(This post was edited by Loren Champlain Sr on May 27, 2009, 2:29 PM)


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Anonymous Poster
slopshute@bellsouth.net

May 28, 2009, 8:58 AM

Post #3 of 14 (2577 views)
Re: Emission sys. Problem's ??? Sign In

Thank you for the reply, I think the EGR Valve is missing (removed ? ). In para #1 , you say " it should be ported" , what does that mean ???
I seached this thread for similiar ques. and found one witha reply by "Tom Greenleaf" . That post/'reply was pretaining to a 351M, do you think that would be a valid guide for the 351W??? Thank you , T-Bird

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Loren Champlain Sr
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Loren Champlain Sr profile image

May 28, 2009, 2:46 PM

Post #4 of 14 (2569 views)
Re: Emission sys. Problem's ??? Sign In

The EGR valve should be connected to a ported vacuum supply. You will only get vacuum at cruise speeds. If you have manifold vacuum to it, it will open the valve, even at idle which would create a 'massive' vacuum leak. The 351W and 351M are two completely different engines. The W is a small block...(a 302 with different heads to simplify it.) The M is a big block, similar to the 'Cleveland' engine that I'm sure you've heard of. Nothing on the W or C engines are similar.
The EGR spacer plate, and it should have one, unless someone has removed it, is below the carb. You will actually have to remove the spacer and examine the underside of it to see if it has been 'eaten away'. Be sure to replace the gaskets below and above it. I'll see if I can come up with a pic for you.
Loren
SW Washington


Loren Champlain Sr
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Loren Champlain Sr profile image

May 28, 2009, 3:02 PM

Post #5 of 14 (2568 views)
Re: Emission sys. Problem's ??? Sign In

Well, now I'm questioning myself. The '79 may be too new to be using that spacer? Can't seem to find any specific information for you. Look for the EGR valve on the engine. It should be to the rear of the carburetor. Let me know if it is mounted to the intake manifold or to the back of the spacer plate under the carb. It should look like this:

Loren
SW Washington


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slopshute@bellsouth.net

May 28, 2009, 3:31 PM

Post #6 of 14 (2567 views)
Re: Emission sys. Problem's ??? Sign In

That pic. is correct, the manfold is casted to accept it,however mine has a block-off plate (no EGR valve ) .
I Don't know the difference in a 351W & 351M or C for that matter. I can talk about the Y block's, 289,302 & 460.
Title say's Tenn. emission. I found some part's on the "Motorcraft" web pg. and ordered the EGR.
What I can't locate is a viewable diagram of the sys. showing part nr.s And routeing of Vacuum line's. I just cannot believe even FOMOCO or anyone for that matter is un- able to supply anything. T-Bird


Loren Champlain Sr
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May 28, 2009, 3:52 PM

Post #7 of 14 (2565 views)
Re: Emission sys. Problem's ??? Sign In

>>the manfold is casted to accept it<< Okay; That blows the whole EGR theory. You do need to install one, as it is needed. Not that it matters right now, during cruise speed operation, the EGR valve opens and allows inert exhaust gasses into the engine to lower combustion temperatures. Originally, it was to lower NOX which is a major contributor to 'smog'. It also helps prevent pre-ignition (pinging) by lowering the combustion temps. Higher octane fuel burns cooler than low octane...that's why if you have a pinging problem, going to premium fuel usually helps.
Now...back to your original problem. I know that I have the hard-back type manuals at work that will cover the emission routings. Not sure how I'll forward them, but I'll check tomorrow.
The 351W started out as the 302, which came from the 289, which came from the 260. And Lot beget...oh, different story. The 351M (Montreal) and it's predecessor, the 351C (Cleveland) are 'big block' engines, more similar to the 400 or 460 block. Both were high torque, stump pullers. The 351W, being a 'small' block was a 'smogged down' version of the more popular 302. Kind of like what they did to the 283, turning it into a 307 which was a POS. The later 305 and 350s were much better engines. Chevy also had a 400 small block and a 400 big block if you really want to get confused. Wink Talk about straying from the subject...Sorry. Got me going.
Loren
SW Washington


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Anonymous Poster

May 28, 2009, 4:16 PM

Post #8 of 14 (2563 views)
Re: Emission sys. Problem's ??? Sign In

Loran, if you have the diagram's i'll be forever in your debt, T-Bird


Loren Champlain Sr
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May 28, 2009, 4:19 PM

Post #9 of 14 (2559 views)
Re: Emission sys. Problem's ??? Sign In

Oh, I know I've got them, just not sure how I'll be able to copy them from the manual and forward them to you. Not that computer literate, if you know what I mean.Unsure
Loren
SW Washington


Loren Champlain Sr
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Loren Champlain Sr profile image

May 28, 2009, 4:22 PM

Post #10 of 14 (2558 views)
Re: Emission sys. Problem's ??? Sign In

A light bulb just flashed somewhere in the universe. If you have a public library available, they should have the Motors, Mitchell, Chilton, ect. manuals that you can copy....And, it's free! But, I'll check on it tomorrow, just in case.Wink
Loren
SW Washington


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Anonymous Poster
slopshute@bellsouth.net

Jun 14, 2009, 5:31 AM

Post #11 of 14 (2537 views)
Re: Emission sys. Problem's ??? Sign In

Loren; I'm finally back. I've been chasing spurious problem's. Fuel not getting to carburatou? I've rellaced the filter, fuel pump and blew out the line's back to the tank. Got fuel to carb for one start-up and then the filter clogged up. Small dark particles, blew out lines again and replaced filter, cant get any fuel now. Tried to get fuel tank off but there's some type of mechinisum at the bolt's that just let bolt turn and not loosen the nut ? T-Bird


Loren Champlain Sr
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Jun 14, 2009, 9:00 AM

Post #12 of 14 (2533 views)
Re: Emission sys. Problem's ??? Sign In

T-Bird; Those nuts can be a real pain. You'll have to get a wrench, socket, something up in there to hold the nut from turning. Very common for them to rust. You may end up having to break the bolts and replace them afterwards. Spray 'em down with a good penetrant. You might be able to grab the nuts with a pair of channel lock pliers or vise grips? Worse case, the straps that hold the tank in place are usually fairly inexpensive. Check availability of course, first, but you could cut them, drop the tank, then should be able to access the bolts/nuts.
Loren
SW Washington


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Anonymous Poster
slopshute@bellsouth.net

Jun 15, 2009, 1:10 PM

Post #13 of 14 (2528 views)
Re: Emission sys. Problem's ??? Sign In

Can't get anything except thin screw driver. I,m trying to locate the strap's and then go from there. Thank you for your patience (mine about gone). T-Bird


Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

Jun 15, 2009, 2:58 PM

Post #14 of 14 (2521 views)
Re: Emission sys. Problem's ??? Sign In

ST102 Warranty:
2 YR This is from Auto Zone. Shows $35.99.
Loren
SW Washington






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