lose power when driving

[buish]

i went home for college, which is a 230 mile drive. i took my friend with me, and a lot of items, i'm guessing 300 lbs more than usual. so on the way to my house, when i push down on the gas pedal, nothing happens. rpm does not pickup nor does speed. this happened 3 times. so i just stopped and turn off the engine and wait like 5 min then go on my way, until the next time it happens.

on my way back to college, i must have had to stop 7-8 times. i just changed my oil and replaced the fuel filter in the engine bay. i have a carb accord. i haven't replaced the fuel filter by the gas tank yet.

do you think my problem is a clogged up fuel filter(last changed 2 years ago), or should i invest in new plugs, wires, cap, and rotor(last changed 1 year ago)? what else could the problem be? it feels like its firing on 3 cylinders instead of 4?

i also flushed the cooling system and put in a new thermostat and gasket. when i drove on the way back to college, i felt my lower hose and it was cold, compare to a warm upper radiator hose. most of the threads i've looked at says the lower hose should be not that warm as the top, and like 20 degrees lower. i found one person saying the hose should be cold. is this normal?

[Tim Yoak]

The problem is carb Ice. Let me explain what happens. First it doesn't have to be cold out for this to happen, I've had a carb full of ice on an 80 degree day. When air goes through a venturi it picks up a tremdous amount of speed. this causes the air temp to drop below freezing. any moisture in the air then can sometimes build up and begin to form ice deposits. it takes just a little ice to block off jets and cause air restrictions in the carb. What will hapen is that the car will seem to lose power and after you sit for a while the ice melts from engine heat and it's as nothing had happened. Thats why it's so important that the heat tube from the shroud on the exaust manifold is connected to your air cleaner and is working right. The stock carb is prone to carb ice. If you do a high speed run then slow down suddenly this will sometimes happen. This is a very simplified explanation it is much more complicated then that.

[jim]

Originally posted by buish
i went home for college, which is a 230 mile drive. i took my friend with me, and a lot of items, i'm guessing 300 lbs more than usual. so on the way to my house, when i push down on the gas pedal, nothing happens. rpm does not pickup nor does speed. this happened 3 times. so i just stopped and turn off the engine and wait like 5 min then go on my way, until the next time it happens.

on my way back to college, i must have had to stop 7-8 times. i just changed my oil and replaced the fuel filter in the engine bay. i have a carb accord. i haven't replaced the fuel filter by the gas tank yet.

do you think my problem is a clogged up fuel filter(last changed 2 years ago), or should i invest in new plugs, wires, cap, and rotor(last changed 1 year ago)? what else could the problem be? it feels like its firing on 3 cylinders instead of 4?

i also flushed the cooling system and put in a new thermostat and gasket. when i drove on the way back to college, i felt my lower hose and it was cold, compare to a warm upper radiator hose. most of the threads i've looked at says the lower hose should be not that warm as the top, and like 20 degrees lower. i found one person saying the hose should be cold. is this normal?

[Tim Yoak]

Originally posted by jim
It wouldn't hurt to do a tune up if it hasen't been done in a while. Thats never a waste of money or time. but read above. I work on airplanes and carb ice is carb ice. whether it's on a plane or a car. all carbs have venturis and the effect is the same. the venturi causes the air to accelerate and this causes it to be supercooled. Then any moisture in the air can turn to ice in your carb. the hot air duct and vacumme controled heat door system keep the air going into the carb at a certain temp to prevent this. the only difference between the hot air system on the plane and the car is that the one on the plane is manually controlled and the one on your car is automatic.

[jim]

Tim what about the bottom return hose on the radiator... should there be a differential in temperature so extreme, ie, the top hose hot while the bottom hose is cool? My thought is there is blockage inside the radiator

[Lester Lugnut]

Carb icing most often occurs when the ambient temp is between 35F and 55F. It also happens when the air is saturated with moisture - foggy conditions - rain.

You start up first thing in the morning and drive about 8-10 miles; then begin to lose power. You pull over - shut off engine for an hr. or two and things are fine for another 8-10 miles. This is a sign you're dealing with carb icing.

It won't happen if the air is dry.

This problem is often times mis-diagnosed as a faulty transmission as your engine speed will increase, but actual car speed will not.

[Tim Yoak]

Originally posted by Lester Lugnut
Carb icing most often occurs when the ambient temp is between 35F and 55F. It also happens when the air is saturated with moisture - foggy conditions - rain.

You start up first thing in the morning and drive about 8-10 miles; then begin to lose power. You pull over - shut off engine for an hr. or two and things are fine for another 8-10 miles. This is a sign you're dealing with carb icing.

It won't happen if the air is dry.

This problem is often times mis-diagnosed as a faulty transmission as your engine speed will increase, but actual car speed will not. iT ACTALLY CAN HAPPEN UP TO 85 DEGREES FARENHEIGHT REMEMBER YOU GET A TEMP DROP PF AROUND 55 DEGREES AFTER THE AIR GOES THROUGH THE VENTURI THE AIR SPEEDS UP AS IT GOES THROUGH IT DUE TO PRESSURE DIFFERENTIAL. THIS INCREASESD AIRSPEED CAUSES ENOUGH VACCUME TO PULL FUEL OUT OF THE JETS. iT'S MORE IMPORTANT TO LOOK AT THE AMOUNT OF MOISTURE IN THE AIR. i HAVEN'T SEEN TOO MUCH OF A PROBLEM WITH AFTERMARKET CARBS, THIS PARTICULAR CARB IS JUST SUSCEPTABLE TO IT. iF YOU HAVE BEEN CRUSING AT A CONSTANT RPM FOR A LONG TIME AND THEN SUDDENLY SLOW DOWN IN COLD DAMP AIR THIS WILL HAPPEN TOO. iT'S BECAUSE THE CONSTANT HIGHSPEED AIRFLOW KEEPS ICE FROM FORMING THEN WHEN YOU SLOW DOWN, THE CARB IS SUPERCOOLED AND YOU GET FLASH ICE IN THE THROTTLE BODY.

[Tim Yoak]

sorry cap lock was on, I'm not yelling

[89AccordNate]

Yes carb ice can be a very scary thing at times. Mine did this today, and its very frustrating. My car had been sitting all night, and it was rainy and kind of cold. I had to drive home at 3k rpms in 3rd gear, when I should had been in 4th gear at 2k rpm. It would have a sputter in 4th and would have no power. I really had to get on it to get it up hills. It will idle, but it just doesnt sound right when it does idle. My manifold to heater hose is in good condition, but what about the vacuum control valve that allows warm air to enter and exit? I lubed this thing up, but I have a feeling mine might be dead. If the hose going to the warm air control valve (not sure if thats the real name for it) has a hole in it, then the vacuum system cannot create a vacuum, therefore it cannot pull the rod up that opens and closes the flap to allow more or less warm air in. If this valve has a problem then that could be why your car has these problems. Also check the condition of the hose that goes from the manifold. They arent the strongest hoses in the world, and it may have holes in it like mine did.

Nate.

[Tim Yoak]

:) ok first heres the diagram for the hoses. you have a hose off the manifold that goes to the bottom of the aircleaner. this hose connectsto a check valve attached to the bottom if the air cleaner. it should be attached to the side with one inlet. the other side has a t fitting. one side of the t fitting goes to the temp control valve, and one side goes to the air door vac motor. what happens is that the temprature control valve bleeds off vacume to cause the air door to close. when it need to open it causes more vacume to go to the motor. pretty simple right?

[Tim Yoak]

:D NOTE: this check is done with engine off.
Make sure the engine is cold before beginning this test.
Always check the vacuume source and the integrity of all vacuume hoses between the source and th air control diaphram before beginning the following test. Do not proceed until they're ok.

Apply the parking brake and chock the wheels

detach but do not remove the air cleaner housing and element.

Turn the air cleaner housing upside down so the air control door is visible. The door should be open. If it isn't it might be sticking or binding. Make sure it's not rusted in an open or closed position by attempting to move it by hand. If it's rusted it can usually be freed by cleaning and oiling the hinge. If it fails to work properly after servicing replace it.

If the air control door is ok but the motor still fails to opperate correctly, check carefully for a leak in the hose leading to it.
Check the vacuume source to and from the intake air sensor with a hand vvacuume pump . If no leak is found replace the motor.
you can also check the motor with the pump. connect the hand vaccume pump to the motor inlet and see if the door moves.

to remove the air door vacuume motor twist it 90 degrees and pull it straight up.

[Tim Yoak]

:D NOTE: this check is done with engine off.
Make sure the engine is cold before beginning this test.
Always check the vacuume source and the integrity of all vacuume hoses between the source and th air control diaphram before beginning the following test. Do not proceed until they're ok.

Apply the parking brake and chock the wheels

detach but do not remove the air cleaner housing and element.

Turn the air cleaner housing upside down so the air control door is visible. The door should be open. If it isn't it might be sticking or binding. Make sure it's not rusted in an open or closed position by attempting to move it by hand. If it's rusted it can usually be freed by cleaning and oiling the hinge. If it fails to work properly after servicing replace it.

If the air control door is ok but the motor still fails to opperate correctly, check carefully for a leak in the hose leading to it.
Check the vacuume source to and from the intake air sensor with a hand vvacuume pump . If no leak is found replace the motor.
you can also check the motor with the pump. connect the hand vaccume pump to the motor inlet and see if the door moves.

to remove the air door vacuume motor twist it 90 degrees and pull it straight up.

[buish]

thanks tim. i was afraid of a hefty amount for a tuneup. yeah, i was driving at night both times, and it was chilly outside with fog.

especially when i go up hills, power drops and can't even pickup speed on flat ground.

do you have an answer for the cold radiator hose and the warm upper radiator hose? i flushed the cooling system by putting a hose in the thermostat housing and let water run through it, till clear water came out and no more coolant color.

here is the link where shepherd79 said it should be cold, but in other threads, most people says it should be warm.
http://www.3geez.com/showthread.php?s=&threadid=10643&highlight=cold+radiator+hose

[Tim Yoak]

it's hard to tell on this one without looking at it. If you disconnect the top radiator hose and the bottom hose you could run a hose through it and see if water is flowing through the radiotor eaisily. For one thing make sure you've got the right thermostat. Most auto parts stores sell ones that are complete crap. if it's not exactly the right temp some of the thermal switches for various vacuume lines won't function right and could cause problems.

[Tim Yoak]

Originally posted by Tim Yoak
it's hard to tell on this one without looking at it. If you disconnect the top radiator hose and the bottom hose you could run a hose through it and see if water is flowing through the radiotor eaisily. For one thing make sure you've got the right thermostat. Most auto parts stores sell ones that are complete crap. if it's not exactly the right temp some of the thermal switches for various vacuume lines won't function right and could cause problems. Oh, and the normal temp inside that air cleaner is 100degrees far. that seems high but remember thats what they planned on when they jetted the carb. The carb was supposed to run a certain air fuel ratio at 100 degrees far. cooler makes it run richer and hotter leaner.

[Tim Yoak]

Originally posted by buish
thanks tim. i was afraid of a hefty amount for a tuneup. yeah, i was driving at night both times, and it was chilly outside with fog.

especially when i go up hills, power drops and can't even pickup speed on flat ground.

do you have an answer for the cold radiator hose and the warm upper radiator hose? i flushed the cooling system by putting a hose in the thermostat housing and let water run through it, till clear water came out and no more coolant color.

here is the link where shepherd79 said it should be cold, but in other threads, most people says it should be warm.
http://www.3geez.com/showthread.php?s=&threadid=10643&highlight=cold+radiator+hose good luck

[buish]

i bought the thermsostat and gasket from the honda dealership, so i hope they are selling me the right one.

the temp. gauge is about 1/3 way up from the cold mark. doesn't even reach halfway. car blows hot air when put on heat. everything seems fine, just the cold radiator hose.

[Tim Yoak]

Originally posted by buish
i bought the thermsostat and gasket from the honda dealership, so i hope they are selling me the right one.

the temp. gauge is about 1/3 way up from the cold mark. doesn't even reach halfway. car blows hot air when put on heat. everything seems fine, just the cold radiator hose. thats normal for the temp gauge, maby nothins wrong at all