Pumping the heck out of the gas pedal to get it starter [Archive] - Chevelle Tech

: Pumping the heck out of the gas pedal to get it starter


ryan_pope
Jan 5th, 07, 6:47 PM
Pumping the heck out of the gas pedal to get it starter

Hi, thought I would ask another question because this is a very knowledgeable group. The 1970 chevelle carb float is not sticking now. But when the car/engine is very cold, I have to pump the gas pedal like crazy to get the engine to fire and start up. If the carb choke is not working {at all}, could I press the gas pedal 1/2 way down and turn the engine over with the starter instead of pumping and pumping and pumping the gas pedal?

The reason this came to mind is because the last time I started the engine [Dec. 28] I was watching the fuel in the gas filter and very little gas flowed through the filter while starting the engine. And noting the quantity of fuel in the gas filter after it had been running for a short period of time…. there was much more gas flowing in and through the gas filter. I need to get the gas into the carb more easily while starting the engine.

Comments would be greatly appreciated.

2BlueLS6's
Jan 5th, 07, 9:40 PM
Cold engines have to be REAL RICH to start. That's the reason for the choke.............. actually it's an enrichening device. If the choke isn't working as you say, what you're doing is using the accelerator pump to enrichen it. It's unlikely that holding the pedal half way down and spinning the starter will start the car anywhere near as fast as pumping the gas as you're doing because half way down and you're only getting one squirt from the accelerator pump.

hrd
Jan 6th, 07, 12:57 AM
does it start if you just crank it?....if youre not seeing a full filter (i assume its the glass type) you maybe arent getting enough fuel pressure (fuel pump, maybe you need a new filter?) all the ones ive dealt with are plumb full when functional, the best way ive found to start a cold engine is to pump manically and then hold it to the floor as you start cranking and then let off right away as you crank (i assume the butterflies act as a choke, somewhat) also check by hand if youre getting a fuel squirt right away after it sits awhile, maybe the float bowls are draining?, or, make/get a little funnel and fill the bowl(s) with fuel through the vent tubes that stick out the top and try to start it (my money says it will fire right up) ...i'd check that first, then the filter, then the fuel pressure after its running, my first guess is, if your bowls arent going dry, is that you need a new/better fuel pump, all else fails, hook up a choke.........good luck

Junkyard Dawg
Jan 6th, 07, 11:54 AM
Cold engines have to be REAL RICH to start. That's the reason for the choke.............. actually it's an enrichening device. If the choke isn't working as you say, what you're doing is using the accelerator pump to enrichen it. It's unlikely that holding the pedal half way down and spinning the starter will start the car anywhere near as fast as pumping the gas as you're doing because half way down and you're only getting one squirt from the accelerator pump.

I have a similar issue on my Chevelle. My 750 Holley has no choke. I have to sit there and pump it 7 or 8 times, then it will fire and run a few secods, die, then I have to pump it 2 more times and it'll fire and run as long as I sit there and blip the throttle.....I'm guessing my 240/246 duration .574/.578 lift cam isn't helping much either.....real cold natured animal....maybe that's normal?

Schurkey
Jan 6th, 07, 1:35 PM
I have to pump the gas pedal like crazy to get the engine to fire and start up. If the carb choke is not working {at all}, could I press the gas pedal 1/2 way down and turn the engine over with the starter instead of pumping and pumping and pumping the gas pedal?
So...Does the choke work? How cold is it? Half-a-pump, and then release the pedal should get the engine started if it's 40F or warmer provided the choke is working properly. If the choke doesn't work, yeah, you're gonna pump and pump and pump. Good luck. Fix the choke.

I was watching the fuel in the gas filter and very little gas flowed through the filter while starting the engine. And noting the quantity of fuel in the gas filter after it had been running for a short period of time…. there was much more gas flowing in and through the gas filter. I need to get the gas into the carb more easily while starting the engine.
Yup. Do keep in mind that an engine-driven fuel pump is pumping very slowly at cranking speed. But it sounds like at least one of two things is happening: The float bowl of the carb (is it a Q-Jet???) is empty when you first try to start the engine (you're pumping the pedal, but there's no accelerator pump shot 'cause there's no fuel in the bowl;) and the fuel tubing from pump to carb is empty or nearly empty--indicating defective check valves in the fuel pump. (The fuel pump may not be pumping properly at first because it's lost it's prime--and then has to fill the fuel tubing before delivering any fuel to the carb.)

Next time you go to start the car, pop the air cleaner, check the choke, whack the throttle open and LOOK FOR ACCELERATOR PUMP SHOT. If you have fuel at the carb, the thing should be starting RIGHT NOW.


the best way ive found to start a cold engine is to pump manically and then hold it to the floor as you start cranking and then let off right away as you crank (i assume the butterflies act as a choke, somewhat)

If the choke works properly, that it TOTALLY unneeded. With a stock or mild cam, and an engine in good condition, at -30F, you might need to pump the pedal a couple of times. Warmer temps mean less pumping. 'Course, you'd also need fuel blended for cold temps--that's handled by the refineries.

I have a similar issue on my Chevelle. My 750 Holley has no choke. I have to sit there and pump it 7 or 8 times, then it will fire and run a few secods, die, then I have to pump it 2 more times and it'll fire and run as long as I sit there and blip the throttle.....I'm guessing my 240/246 duration .574/.578 lift cam isn't helping much either.....real cold natured animal....maybe that's normal?

Again, define "cold". That sounds fairly normal, though, for a car with no choke and a hot-rod cam.

Chevy 70 SS vert
Jan 6th, 07, 11:46 PM
I have a similar issue on my Chevelle. My 750 Holley has no choke. I have to sit there and pump it 7 or 8 times, then it will fire and run a few secods, die, then I have to pump it 2 more times and it'll fire and run as long as I sit there and blip the throttle.....I'm guessing my 240/246 duration .574/.578 lift cam isn't helping much either.....real cold natured animal....maybe that's normal?

Mine was the same way until this weekend WHEN Installed the choke. Now it starts so easy!

BlueSS454
Jan 7th, 07, 12:33 AM
My 70 starts with 3 pumps on the Holley 3310, no choke on it. The 350 in my Cutlass has a Q-jet on it. So long as the choke is working properly, 2 pumps and it fires right off. If the choke is not working, you have to pump it about 10 times to get it to fire off. The 2 BBL on the 307 in my 69 starts with 3 pumps, no choke. The moral of the story, Q-jets need to have a properly functioning choke to fire off easy. Holleys and Rochester 2 BBL's are a little more forgiving.

68 SS boy
Jan 7th, 07, 11:24 AM
[usually if the car sits for any length of time all the fuel will seep back down out of the carb & filter. I have this problem now, but on my previous car I installed an electric fuel pump & problem solved. no more pumping the pedal to get it to the carb, turn on the switch, wait a few seconds & it fired right up

ryan_pope
Jan 8th, 07, 4:51 PM
Update on my 1970 Chevelle Malibu.

I must tell you that this is a 2 barrel Rochester carb, 350 cubic inch engine. And I did replace the fuel filter, 4 bucks, it just looked to old and I had no idea when it was replaced last. Plus, cold for El Paso, Texas is an average of 32 in January but I am trying to start the car at about 40 degrees. So, the temperature really should not have much to do with my issue. What I don’t do is start the car every week it may go a month b4 I start it. For this conversation it has only been 10 days since it was last started.
Well, my wife got in the car and operated the gas pedal and the starter / ignition switch.
First, the gas pedal was pumped halfway down to see if the carb shot some gasoline into the carb from the Bowl. And…..It Did!! [So, one thing known and documented the bowl had fuel in it.]
Second, the pedal was pushed all the way to the floor and released slowly, this was done to verify that the mechanical choke worked or Not. Well, the butterfly on the carb remained completely vertical and thus I believe I can easily say the choke does not work…am I correct?
Third, I instructed my wife to turn the starter switch and pump the gas pedal. She turned the switch and tried to start the engine for a few seconds at a time (2 or 3 seconds) then stopped trying the starter. On the third attempt the carb / engine back-fired flames out of the carburetor. [Short, quick and slightly exciting]. She trying again and the engine started to fire {run}. That is when I knew it would turn-over and run within a few more times. And maybe two more times the engine was running and doing its normal run and die routine. It would fire and run as long as she sat and blipped the gas pedal. We got the engine to stay started and it warmed up and all was great with the world.

Should the butterfly have closed horizontally when the gas pedal is pushed down to the floor? {Of coarse only when starting the engine cold}

How do I fix the mechanical choke? It all seems to be there but it does not seem free to move the butterfly horizontally. I tried to manipulate it with my hand before starting the engine.

In this “thread” it is mentioned about a fuel pump check valve. Is this something that can be checked for a defect? If the car sits for another month which is normal will my results vary due to the check valve?

I did see that during the testing Sunday that the new clear plastic fuel filter which was completely empty filled up fast during the starting tests. I think replacing it helped my situation slightly

Schurkey
Jan 8th, 07, 6:31 PM
I am trying to start the car at about 40 degrees. So, the temperature really should not have much to do with my issue.
Nope. Still need a choke at 40F. (Especially so if your fuel isn't blended for the cooler temperature--and I don't know of any way to test that "in the field". It'd be a problem with "summer" gasoline--blended to resist vapor lock--used in the winter when some added volatility would be useful.)

the pedal was pushed all the way to the floor and released slowly, this was done to verify that the mechanical choke worked or Not. Well, the butterfly on the carb remained completely vertical and thus I believe I can easily say the choke does not work…am I correct?
Yup. Choke doesn't work properly.

How do I fix the mechanical choke? It all seems to be there but it does not seem free to move the butterfly horizontally.
Probably more of an adjustment than anything. There are several common problems, and the problems tend to be grouped together--one misadjustment done in an attempt to avoid repairing something else leading to some real oddball issues. I'd be looking for a choke coil or linkage rod that's been tweaked so that the choke won't properly close. This is often done because the crossover in the manifold is plugged, and/or the heat riser valve is stuck open. A plugged crossover or defective heat riser will prevent the choke coil from warming properly, therefore the choke doesn't release like it should. So guys set the choke extra-lean to band-aid the real problem. You'll also want to verify that the choke pulloff is working properly, and opening the choke blade an acceptable amount. If the pulloff is not opening the choke blade enough, some folks will adjust the choke coil (or linkage rod) extra lean--which doesn't work very well, but still seems to be a common thing.

In this “thread” it is mentioned about a fuel pump check valve. Is this something that can be checked for a defect? If the car sits for another month which is normal will my results vary due to the check valve?
Not easily checked. I suppose you'd draw a vacuum on the INLET of the pump, if it won't hold vacuum, the check valves are bad. Problem is, the leakage past the check valves is so small that it takes overnight (or days) for the fuel to drain backwards into the tank, so it's a VERY SLIGHT leak. I test the fuel pump indirectly: install a factory-style paper filter in the carb inlet having the "safety valve" in the filter. If the problem goes away or is much reduced--the pump is bad. The filter's check valve acts as a "crutch" for the problem. FIX THE CHOKE FIRST. Since you still have gasoline in the carb bowl, the engine should start. As soon as the engine is running, the pump should be pumping fast enough to overcome the very slight leakage--if there is any--in the fuel pump check valves.

charbilly2001
Jan 8th, 07, 11:00 PM
Hmmmm....well guys here in Southern California I have not found a use yet for my choke so it sits forlornly on my tool box, poor thing.

One or two quick jabs of the throttle and she fires right up. I have to massage the pedal till the engine warms up but thats only 10 seconds or so. I have the time :)


If its been a couple weeks I crank it maybe 10 seconds or so before gas gets to the engine then business as usual.

hrd
Jan 12th, 07, 3:57 AM
im originally from n. dakota so you learn the cold start tricks pretty quick, the hard part was grabbing the steering wheel and sitting on the seat without running it a half hour... i live in phoenix now so i dont even have a choke horn anymore let alone a choke, three pumps and it starts and idles, by the end of the block its running champ