Trouble with Hot Starts
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
Trouble with Hot Starts
Hey guys,
I found some info in other forums by doing a search, but still would like to see what you guys think.
I brought the '79 to work today and it started fine when cold this morning. When I went out for lunch it was hard to start. When I went to come back from lunch it was also hard to start and I had to put the pedal to the floor. It idled ruff for a second, puffed some blue smoke, then smoothed out and ran fine.
It did this a while back right before I tuned it up--but that was only about two months ago. This is the first it's given me any problem at all since then.
Could this be as simple as leaning out the automatic choke? It suddenly got a lot cooler around here this week--maybe in the 60's today. Would temp have anything to do with it--especially the choke?
Thanks!
I found some info in other forums by doing a search, but still would like to see what you guys think.
I brought the '79 to work today and it started fine when cold this morning. When I went out for lunch it was hard to start. When I went to come back from lunch it was also hard to start and I had to put the pedal to the floor. It idled ruff for a second, puffed some blue smoke, then smoothed out and ran fine.
It did this a while back right before I tuned it up--but that was only about two months ago. This is the first it's given me any problem at all since then.
Could this be as simple as leaning out the automatic choke? It suddenly got a lot cooler around here this week--maybe in the 60's today. Would temp have anything to do with it--especially the choke?
Thanks!
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
I think your choke is actually not rich enough. If the truck sits for 4 hours in 60 degree weather, the choke should have some tension and be close to shut by then. Coming out of the grocery store or pulling out of the gas station is a hot start, but sitting in a parking lot for half a day in cool weather is more of a cold start.
The next time it gives you problems, pull the air cleaner off and look at what it's doing. Remember, on any carburetor engine, you have to pump the gas once to close the choke, so do that too. If the choke is not anywhere near closed, the choke needs to be more rich. If you do so and you still have problems, it's possible the choke has lost tension. This is a common problem with original choke springs after 30 years or so.
The next time it gives you problems, pull the air cleaner off and look at what it's doing. Remember, on any carburetor engine, you have to pump the gas once to close the choke, so do that too. If the choke is not anywhere near closed, the choke needs to be more rich. If you do so and you still have problems, it's possible the choke has lost tension. This is a common problem with original choke springs after 30 years or so.
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
Yea, it's turning over fine--just doesn't want to fire right away. Again, when it does it's blowing some blue smoke and smells rich.
How much would you turn the automatic choke?
How much would you turn the automatic choke?
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
If you look on the rim of the choke cap, there is a small notch. On the radius of the choke housing which the choke is held against, there are 7 raised notches. Going from the back of the truck toward the front of the truck, the notches are referred to as 3 Rich, 2 Rich, 1 Rich, Index, 1 Lean, 2 Lean, 3 Lean. If you look on your emissions sticker, it will tell you which raised notch to align the other notch to. If your emissions sticker is gone, Index or 1 Rich is a good ballpark.
It's not too uncommon to have to move forward a notch in the lean direction during the summers, and to move backward a notch in the rich direction during the winters. It also depends on where you live (I assume it's colder up in PA than it is down here in TX). If you refer to my other post - you need to be going in the rich direction for the reasons I described.
It's not too uncommon to have to move forward a notch in the lean direction during the summers, and to move backward a notch in the rich direction during the winters. It also depends on where you live (I assume it's colder up in PA than it is down here in TX). If you refer to my other post - you need to be going in the rich direction for the reasons I described.
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
I think your choke is actually not rich enough. If the truck sits for 4 hours in 60 degree weather, the choke should have some tension and be close to shut by then. Coming out of the grocery store or pulling out of the gas station is a hot start, but sitting in a parking lot for half a day in cool weather is more of a cold start.
The next time it gives you problems, pull the air cleaner off and look at what it's doing. Remember, on any carburetor engine, you have to pump the gas once to close the choke, so do that too. If the choke is not anywhere near closed, the choke needs to be more rich. If you do so and you still have problems, it's possible the choke has lost tension. This is a common problem with original choke springs after 30 years or so.
The next time it gives you problems, pull the air cleaner off and look at what it's doing. Remember, on any carburetor engine, you have to pump the gas once to close the choke, so do that too. If the choke is not anywhere near closed, the choke needs to be more rich. If you do so and you still have problems, it's possible the choke has lost tension. This is a common problem with original choke springs after 30 years or so.
It did it when leaving for lunch after, like you said, sitting about four hours. Then did the same thing after only sitting a few minutes on my way back. Anything to that?
Thanks for the feedback!
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Very sorry, I must have missed the part about it doing it after short sits too. In that case, I would pull off the air cleaner and look at the throat of the carb the next time it is giving you trouble. Look at the position of the choke plate, feel its tension by pushing on it, and try to see if you notice any obvious gas smells that don't belong. There have been issues with fuel draining out of the fuel bowl past the power valve and flooding the engine while it sits, but they are rare cases.
Trending Topics
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
Very sorry, I must have missed the part about it doing it after short sits too. In that case, I would pull off the air cleaner and look at the throat of the carb the next time it is giving you trouble. Look at the position of the choke plate, feel its tension by pushing on it, and try to see if you notice any obvious gas smells that don't belong. There have been issues with fuel draining out of the fuel bowl past the power valve and flooding the engine while it sits, but they are rare cases.
For a while I think you and I were posting at the same time and just missing each other's posts!
Yea, there was a bit of a gas smell last time I was in it. That and the blue smoke is what led me think it's running rich.
Thanks for all of your replies and help.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
That's exactly what I do too. On a cold start, you pump the pedal once. The reason for this is the throttle pins the choke plate open through the fast idle linkage. Opening the throttle releases the linkage enough to let the choke snap shut.
To start warm, I usually have the pedal maybe halfway down while cranking, just enough to let some more air\fuel in. That makes my motor start instantly. Anything more than pumping the gas once will usually flood it.
I let a buddy borrow my old LTD and he couldn't get it started because he didn't know you have to pump the gas once to start it cold.
To start warm, I usually have the pedal maybe halfway down while cranking, just enough to let some more air\fuel in. That makes my motor start instantly. Anything more than pumping the gas once will usually flood it.
I let a buddy borrow my old LTD and he couldn't get it started because he didn't know you have to pump the gas once to start it cold.
Cargo Master
Joined: Mar 2008
Posts: 2,409
Likes: 1
From: Goliad, Texas
Jolly, this problem you're having is like the exact opposite of what's going on to me. the first start of the day is the hardest....3 or 4 cranks to get it started while pumping it (easier if pumped before turning the key). the next time during the day it starts right up.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Jolly, this problem you're having is like the exact opposite of what's going on to me. the first start of the day is the hardest....3 or 4 cranks to get it started while pumping it (easier if pumped before turning the key). the next time during the day it starts right up.
If you pump the gas once and turn the key and the truck does not start, you have a problem with your choke and\or fast idle linkage. Any pumping after the first time is just going to flood the engine.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
When you press the pedal down, the accelerator pump shoots 2 streams of gas onto the venturis, whichs makes them wet and can drip some down onto the throttle plates. A little extra fuel helps it in really cold temps. It's the same idea behind shooting it with starting fluid (just not as flammable). My dad has always done the same thing too. A "shot" of fuel isn't really necessary for normal temperatures; the first pedal pump on a cold start is really to mechanically snap the choke shut. A second push sometimes helps richen it even more for really cold temperatures.
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
Well, the rest of the day yesterday (after I posted) everything worked fine. A guy at work was looking at my truck yesterday before I left for lunch, when I thought I had the problem--and he was sitting behind the wheel a minute before I jumped in to leave. I wonder if he hit the gas and flooded it? I didn't think about that before.
Ben, As far as starting procedure--cold starts I actually hit the gas twice. I know one pump sets the fast idle, but she always fires right up with two. My dad always gave it two pumps on cold starts too.
After she gets warm for the first time, I never have to hit the gas at all to start it for the rest of the day. Really--it fires right up by just turning the key--foot OFF the gas on warm starts. Yesterday I had to put it down to the floor like it was flooded though--on about three starts. On the trip home, and on a short trip in the evening though, it was business as usual.
I'm going to give it another day of running her before I start to adjust or mess with anything to see what it's doing. I didn't drive that truck to work today though. Should have. I'll take her out tonight.
Thanks for all the input. You guys rock!
Ben, As far as starting procedure--cold starts I actually hit the gas twice. I know one pump sets the fast idle, but she always fires right up with two. My dad always gave it two pumps on cold starts too.
After she gets warm for the first time, I never have to hit the gas at all to start it for the rest of the day. Really--it fires right up by just turning the key--foot OFF the gas on warm starts. Yesterday I had to put it down to the floor like it was flooded though--on about three starts. On the trip home, and on a short trip in the evening though, it was business as usual.
I'm going to give it another day of running her before I start to adjust or mess with anything to see what it's doing. I didn't drive that truck to work today though. Should have. I'll take her out tonight.
Thanks for all the input. You guys rock!
Thread Starter
|
Senior User
Joined: May 2008
Posts: 310
Likes: 0
From: Clearfield, PA
I certainly trust what you guys have to say though, so I'll see how she's doing and try something different if it's still giving me fits. I totally agree, I don't want to mess with the carb if I don't have to!