problem starting engine

[akhordelex86]

I was hoping you guys can help me on this problem. When I turn the key, The engine won't start, it only makes a sound.

The engine starts only when I pump gas twice first, step on break and turn the key. Do any of the experts know why this is? ( I don't mind a long list of possible explanations, as long the the major things to check are listed first).

Thanks a lot. I have a 1986 LX 4door with BS1 engine I suppose. I just recently bought this car and the engine was rebuilt 2 years ago.

Thanks again

[86LXItooFAST4me]

what do you mean by "it only makes a sound"?? so when you turn the key is the engine spinning freely or is it just hardly turning or not turning at all??

[HondaBoy]

are you saying you can crank the engine over? if so, its pretty common with your carb engine to have to pump the gas some to get it to start. so that wouldnt really be a problem. now, if your saying that when you turn the key to start it, and it makes a clicking sound, i really dont know exactly what that would be. considering it'll start after you pump the gas. anyway, when you say it just makes a noise, that makes it sound like you're saying it doesnt crank over, just the starter makes a click sound as if its not getting enough power. so tell which it is.

[akhordelex86]

ic, so it is normal to all carbed engine to pump gas first before starting the engine? because I have a camry 2001 and it starts right away when I turn the key. I'm really new to cars so I don't really know exactly.

"it makes a sound", i meant the sound that an engine makes when you try to start the engine but it never really start,(not spin freely?).

Thanks.

[86LXItooFAST4me]

yeah, the 01 cav is fuel injected, on fuel injected cars you actually SHOULD NOT pump the gas because as soon as you put the key in the "on" position it turns on your electronic fuel pump to deliver the gas. on carbs, it is a mechanical fuel pump so the cars engine has to be turning over in order for the fuel to be delivered. also, carbs dont like cold weather at all (like all cars but carbs particular) so they are a little harder to start on cold mornings.

[Roach412]

lol, LITTLE hard to start on cold days? :lol:

w/ the windchill down in the -30s during the days recently...my car doesn't want to start AT ALL!!

have to pump the gas like crazy and floor the accelerator in order to get it fired up.

-Roach

[86LXItooFAST4me]

we are lucky if it actually reaches freezing temp in Texas. so -30 isnt even in my vocabulary :D

[A20A1]

We have an electric in-tank fuel pump for the carb.

Pumping the gas helps prime the carb. The pumping action activates the accel pump on the carburetor... the accel pump moves automaticly everytime you press the pedal and it squirts out fuel as long as there is fuel in the float bowl... the float bowl is what holds the fuel the carb is using or will use. The float level is important and pumping the accelerator too much can send most of your fuel thru the accel pump and leave not enough fuel for the rest of your carburetor to use. Fuel is metered thru the carb based on pressure drop. Pressure drop or VACUUM is created at the venturies and booster venturies. The venturies and boosters are inside the barrels of the carburetor so that the air sucked in flows past them...
Because the pressure inside the booster is lower then the air pressure on the fuel inside the float bowll fuel starts to move from the area of greater pressure to the area of less pressure. A low fuel level will need a geater drop in pressure to cause the fuel to flow. A higher fuel level will need less pressure drop for the fuel to flow. Too high a float level will cause the fuel to simply overflow. You don't want to fil the float too high. usually the float level is set on the carb and shouldn't need to be set again, unless you do a carb rebuild.

Priming helps by adding more fuel so to help start a cold motor.

A cold motor on a EFI / FUEL INJECTED motor doesn't need to worry about adding excess fuel into the manifold since the path of the fuel is short, basicly fuel is sprayed right near the valves all the car needs now is air.

A cold motor on the carb engine has a few problems getting the fuel to the valves.
Fuel doesn't vaporize when cold.
Vaporized fuel has an easier time flowing from the carburetor to the valves because it mixes with the air.
Air will flow without a problem to the valves cold or hot.
Cold air can turn vaporized fuel back into dropplets that puddle at the bottom of the intake manifold and will reach the valves much slower then the air around it... for example try getting a vacuum cleaner and using it to suck up dropplets of water on a table or something... the droplets move slowly while the air is being sucked in easily all around it. Oh hold the hose paralel to the surface of the table not perpendicular.

Anyways back to priming... when you add more fuel you end up having more reaching the valves and so the car starts. It still takes a while to start cause the fuel is still trying to slug itself along the botom of the manifold. Too much fuel can foul the spark plugs and make the car hard to start.

Fouling basicly can cause the spark plug not to make a spark, or the spark is weaker, since the gap in the plug has been breached. The gap is needed to create the spark or else the spark plug would just become a fancy wire... and current will flow thru it and never ignite anything.

[akhordelex86]

good to know about this stuff. Thanks guys! :thumbup:

[HondaBoy]

another thing your carb doesnt like is wet air! the more humid it is, the harder it can be to start the car. i know about the damn humidity, it sucks. before my car was running good, humid days would be a bitch to start it up from a cold start. hey i was just wondering this, on older cars with mechanic fuel injection i've had to pump the gas a little bit, maybe they are just not running right? but like with our '02 accord, you never ever have to press the gas pedal before a start, that car always starts right up in any weather, hopefully it always will.