First Drive Today

[hubcityford]

I finally got my truck running and drove it home today around dusk. It was hard to see through 12 years of junk on windshield. Got it home and my two little girls were so excited they helped me wash it in the dark. Still got more to do but so far so good. It idles good in park and neutral but when it goes in gear is runs rough until I accelerate. I have not replaced plugs or wires yet and belts are original and whining. Any pointers on running rough in gear?

Thanks Jeremy

[Gary Lewis]

Congrat's! Getting to drive it is such a good feeling.

You say it idles well in neutral, but not in gear. However, then it runs ok once you accelerate? That sounds like an incorrect air/fuel mix at idle. Probably lean, which could be from a vacuum leak, and that could be due to a cracked hose, a hose that's come off, or a cap that's come off.

I'm sure it could use plugs and wires, but if it runs well other than idle I'd not rush to replace them as acceleration tests them far more than idle does. Instead look the vacuum hoses over very closely. VERY closely. They tend to get old and crack or even fall off, and that causes a lean air/fuel mix. The engine might run ok at idle with no load on it, but not with a load.

[hubcityford]

Congrat's! Getting to drive it is such a good feeling.

You say it idles well in neutral, but not in gear. However, then it runs ok once you accelerate? That sounds like an incorrect air/fuel mix at idle. Probably lean, which could be from a vacuum leak, and that could be due to a cracked hose, a hose that's come off, or a cap that's come off.

I'm sure it could use plugs and wires, but if it runs well other than idle I'd not rush to replace them as acceleration tests them far more than idle does. Instead look the vacuum hoses over very closely. VERY closely. They tend to get old and crack or even fall off, and that causes a lean air/fuel mix. The engine might run ok at idle with no load on it, but not with a load.

Thanks for the advice but I hate to sound stupid but how do I determine which hoses are vacuum? And would it be worth replacing all just to be on the safe side? I apologize for the hand holding but I am really ignorant on most of this until I start digging in.

Jeremy

[Gary Lewis]

Thanks for the advice but I hate to sound stupid but how do I determine which hoses are vacuum? And would it be worth replacing all just to be on the safe side? I apologize for the hand holding but I am really ignorant on most of this until I start digging in.

Jeremy

No need to apologize. None of us were born knowing this.

Basically all of the hoses under the hood are vacuum hoses except the radiator and heater hoses. The two radiator hoses run from the radiator to the engine and are probably 1 1/2" in diameter. The two heater hoses go from the engine to the heater core, are roughly 1" in diameter, and those connections are near the passenger's fender on the firewall.

All of the other hoses are, I think, vacuum hoses. They'll be roughly 1/4" to 3/8" in diameter and are connected to all sorts of emissions stuff. They'll look like spaghetti, running everywhere.

Does that help?

[hubcityford]

No need to apologize. None of us were born knowing this.

Basically all of the hoses under the hood are vacuum hoses except the radiator and heater hoses. The two radiator hoses run from the radiator to the engine and are probably 1 1/2" in diameter. The two heater hoses go from the engine to the heater core, are roughly 1" in diameter, and those connections are near the passenger's fender on the firewall.

All of the other hoses are, I think, vacuum hoses. They'll be roughly 1/4" to 3/8" in diameter and are connected to all sorts of emissions stuff. They'll look like spaghetti, running everywhere.

Does that help?

Great analogy, had spaghetti tonight. So I went and looked and there are definitely a lot of hoses. Should I start at the air filter and work myself back? Just trying to figure a plan of action. Or would it be hoses that are connected at carburetor?

Jeremy

[Gary Lewis]

Great analogy, had spaghetti tonight. So I went and looked and there are definitely a lot of hoses. Should I start at the air filter and work myself back? Just trying to figure a plan of action. Or would it be hoses that are connected at carburetor?

Jeremy

Hard to have a game plan with something so seemingly random. Just put a piece of tape on each hose you check and go until they are all checked.

But, there are a couple of other ways to do this:

• Brake cleaner: Get a can from the parts store and spray it around where there might be leaks. If the engine's idle speeds up you've found a leak. But, the stuff will mess paint up, so be careful.

• Smoke test: David/1986F150Six has a writeup on doing this here: http://forum.garysgaragemahal.com/Vacuum-leak-detection-effective-and-inexpensive-td11511.html

[hubcityford]

Hard to have a game plan with something so seemingly random. Just put a piece of tape on each hose you check and go until they are all checked.

But, there are a couple of other ways to do this:

• Brake cleaner: Get a can from the parts store and spray it around where there might be leaks. If the engine's idle speeds up you've found a leak. But, the stuff will mess paint up, so be careful.

• Smoke test: David/1986F150Six has a writeup on doing this here: http://forum.garysgaragemahal.com/Vacuum-leak-detection-effective-and-inexpensive-td11511.html

I went a played around this morning but mainly just looking. I started it up and one thing I did notice was a hiss from the AC control inside the cab. I flipped switches around and nothing worked but hiss was constant. I know AC has vacuum to help control some things but is that a separate vacuum system?

Being in South Mississippi I’ll be inquiring about AC issue soon.

Just thought I would ask about hissing sound in case it could be related.

Jeremy

[Gary Lewis]

I went a played around this morning but mainly just looking. I started it up and one thing I did notice was a hiss from the AC control inside the cab. I flipped switches around and nothing worked but hiss was constant. I know AC has vacuum to help control some things but is that a separate vacuum system?

Being in South Mississippi I’ll be inquiring about AC issue soon.

Just thought I would ask about hissing sound in case it could be related.

Jeremy

All vacuum comes from the engine. The only exception is the diesels, which have a vacuum pump. So it sounds like one of your vacuum motors in the HVAC system is leaking. And that is a sure source of air into the system that will upset the idle.

So use a hose to your ear as an aid to pinpointing the hiss.

[hubcityford]

All vacuum comes from the engine. The only exception is the diesels, which have a vacuum pump. So it sounds like one of your vacuum motors in the HVAC system is leaking. And that is a sure source of air into the system that will upset the idle.

So use a hose to your ear as an aid to pinpointing the hiss.

Using hose I started truck and started looking with hose to ear and seems to be immediately behind AC control dead center.

JV

[Gary Lewis]

Using hose I started truck and started looking with hose to ear and seems to be immediately behind AC control dead center.

JV

I think there are two vacuum motors back that. Best case one of the hoses is off. Worst case is that one of the motors has a split diaphragm. Anyway, take a look at this page from the 1981 EVTM: http://www.garysgaragemahal.com/heating-ventilation--air-conditioning.html.

And with a light go up under the dash and check the hoses. Also, you might remove the glove compartment liner as that gives you a view into that area that is hard to get otherwise.