Need a vacuum line schematic for 1979 F150 Supercab, 351 Cleveland Engine. Anyone out there have one??? Trying to help a friend get on his way to Texas next week. Any help would be appreciated.

Santa Rosa Bob

 

Welcome to FTE!

No 351 clevelands were put in Trucks.. only cars up to 1972

Now if you really have an 351M in that truck I need to know.

Transmission Type AT or MT

4x2 or 4x4

Area of operation

Canada/49 state or California

from your user name I would say California or Texas

If you have this sticker ..get me the info from it.

 

Thanks Mil1ion,

I'm half deaf and probably heard my friend wrong...although that's a lot of info to mishear. I'll get back with you within two hours as he will be here with the truck by then. I thank you for your info.

Bob

 

I've found out a lot of people think the 351Ms are 351clevelands.. they're similer, they share a lot of parts, they even look a lot alike, the 351M is based on the Cleveland but they aren't the same engines.
I think Ford even called them Clevelands at one point, just caused more confusion..

 

Thanks ErrorS! Even more to know! Back with you all shortly.

 

Here's the scoop. The truck is a 1979 F150 Supercab with a 351M engine, AT, 4x2. Sticker shows

Unknown letter upper left/below is a 2.
9J588AP
CRS
60J
10
14

Letters/numbers punched out below 9J588AP is
L
2
7

After talking to friend, the problem may not be vacuum leak related. He says that the idle revs/slows/revs/slows. When he starts to come to a stop, it idles slow, then dies. He has to restart it (no problem there). We found the vacuum schematic which is legible but don't really understand it at this point.

Any ideas on where to start tracking this idle issue? Thanks everyone.

Bob

 

Calibration code: 9-60J- R10

 

Thanks for all the assistance. Got all the vacuums hooked properly, new spark wires and spark plugs, everything appears to be aligned properly. Start it up.....it runs pretty good for awhile but once warm, it starts to rev, slow, rev, slow, rev, slow...not dying, but not driving it either. Any suggestions out there?

Bob

 

is the choke operating correctly?

 

fixed the choke and still a problem

 

emissions nightmare

 

Take some carb cleaner with the wand attached and spray it around the primary throttle shaft bushings on both sides of the carb listening for engine rev change.


Those bushings could be worn out and throwing the mixture out.

I assume he or you have adjusted the idle air/fuel screws ?

 

Will give that a try with the wand.

Definitely adjusted the idle air/fuel screws.

Get back with the results. EVERYONE has been a help. With limited time and knowledge about this truck, this old backyard mechanic doesn't have the luxury of taking my time. THANKS AGAIN.

 

Just so you know, these carbs don't have any air screws.. the two in the front are both for idle and both for fuel.

You should get a vacuum guage ,they're about $10 at Sears.. you'll be able to get pretty close to finding out what's causing it with one, it tells a lot about what may be wrong.

From where I'm sitting, it sounds like it could be anytihng. From misadjustment of the carburetor to bad timing to bad valve train, etc. I can think of a million things that would cause this.. but I should point out that I'm really inexperienced, so I'm probably wrong on all of it.

Still, I recommend a vacuum guage asap. Right now you could find out exactly (within reason) what is going on in your engine. Once you get back with the reading some of us can tell you what it means, plus there are a couple of sites that show what each reading might mean.

It's one of the first diagnostic tools I hook up... and usually the last..

 

I know this is an old post, but I have this same problem with my truck.
It's a '75 F-250, 360 c.i., manual 4 speed. It's rated at 8,100 lb. (but it's registered at 5,000 lb.), GVWR. The engine has been professionally rebuilt, as has been the carburetor. I bought a set of Ford factory shop manuals, and got hold of the 'Volume 6 Engine and Emission System Diagnosis' manual for 1973, to try and locate the emission vacuum layout.
The reason for all the manuals etc., is the truck appeared to have had a small engine fire at one time - some slightly melted hoses and wire insulations, the ignition coil cap was partially melted and there was paint covering a burn mark in the hood.
After having the engine and carb rebuilt, I checked the vacuum hose layout and couldn't find an exact schematic. The closest I could find, that includes the two ported taps (one with two ports, and one with three ports), shows one line from the carb called the EGR port, should go to the lower port on the two port tap, then the upper port to the EGR valve. I corrected the hoses to this position.
There is another tap on the carb, called the Spark port, and a line from there should be connected to the top port, on the three port tap, the lower port from this tap should go to the intake manifold, while the center port connected to the distributer vacuum advance.

After reconnecting these lines, as just described, the engine ran a lot smoother, but left me with the problem you are having; It starts and runs easily, until it warms up. Just sitting in the driveway, it follows the same actions you describe, erratic idle speed, but, if I take it for a ride, when I push in the clutch and start to brake, the engine slows down so much it stalls, unless I slide my foot from the brake to the throttle to get the revs back up, then I have to put my heel on the brake and my toe on the throttle.

Does anyone have any suggestions, so I can use my truck.
Thanks,
Ed