Takes forever to fire over

[dblupcobb]

I am out of town alot, leaving my EB to sit weeks without driving it. Typically when I get home and crank it up, I have to pump the gas while turning it over and over (usually about 5-6 sec) then it would fire and run normally. This usually was only the case the first time cranking after it would sit. This taking forever to fire has become more of a regular occurrence. Now every time I go to crank it up, it takes 10-20 sec of the starter rolling over before the engine fires, even if it has only sat for a couple hours.

Initially I thought it was a fuel issue, draining fuel lines when sitting for long periods. I re-routed my fuel line to carburetor and installed a fuel regulator w/ pressure gauge. It was my thought that the regulator would act as a one-way valve, hence prevent the line from draining when idle. The problem has still persisted.

I haven't had a chance to have a second person assist, to turn it over while I investigate if the carb is getting sufficient fuel while cranking, but plan to before proceding. If I'm getting fuel while the starter is turning, what could be other possible causes for it taking so long to fire?

I want to put an MSD 6AL ignition and possibly a new coil and distributor for added performance, but have been waiting for a real reason to. Could it be an ignition issue?

Any ideas?

 

[bronconut73]

Do the ignition upgrades.

But it's probably a fuel issue. Those fuel pump diaphragms don't like to sit and dry out. Try a new cheap fuel pump.

I once had trouble getting fuel up to my pump because my tank was not letting enough air into the tank. New breather line and a new gas cap fixed that.

By the way next time just look down into the carb and push the throttle linkage and see if fuel is spraying. If not then yes your fuel is flowing back down the line.

Could also be a little vapor lock. Engine is getting hot enough to boil the fuel out of the bowl when you shut it down.

And like I said above go ahead and replace your ignition components. Factory points and condenser is horse and buggy technology.

 

[Yellow75]

Fuel pump diaphram. Every spring I usually just bit the bullet, pulled the hose going into the carb and tried to get the gas just close enough to the carb but not get any in my mouth. Never worked. Gas tastes like hell!

Replaced the Fuel pump and I can't even get gas to come past the pump.

Moral of the story is, don't get caught sucking a gas hose. Replace the fuel pump :-X

 

[jckkys]

What carb do you have? The original 2100-2150 has a top that can be removed easily. Take of the top before you crank it. See if there's fuel in it. If the truck sits for more than a few days the gas in the float bowl will evaporate on any carb. With the top off crank the engine while standing where you can see the carb and note when fuel starts squirting from the needle valve. After the fuel gets to the carb the engine still cranks a few seconds before the bowl is filled. All this is normal it's not fuel injection.
Nothing you said indicates an ignition problem. If you have transistorized factory ignition you're not gaining anything with aftermarket peaces.
If you describe your Bronco and how it's equipped we can more easily answer your question.

 

[broncnaz]

X2 the fuel has most likely evaporated. Actually all you need to do before starting is look down the throat of the carb and crack the throttle open if you dont see fuel squirt when you do that the fuel bowl is empty from evaporation. The aftermarket ignition wont help that issue or increase performance. It will lighten you wallet tho. Of course if you have a points type ignition than electronic would be a upgrade. but still wont help the starting issue.
About the only way around it is a electric fuel pump as it can fill the fuel bowl before you start to crank the engine. All in all tho 10-20 seconds of cranking is not to bad when its been sitting for awhile.

 

[TwoDalesDad]

You can install a one way check valve in line....They Cost about $ 15-20 bucks with shipping....they add bling ...even....I installed one on my generator on the motorhome....way cool

 

[dblupcobb]

I appreciate everyone's response. I won't be able to wrench for a couple of days, but then I will let you know what I find. Fuel pump diaphram sounds most logical at this point. I will probably just bite the bullet and go with a new one. Any advantages to going with an electric fuel pump? I already have an electric fan which robs plenty from my battery.

jckkys, My carb is a Holley 625 cfm.

Thanks again for all your help! I'll let ya'll know how it turns out.

 

[broncnaz]

Fuel pump diaphram is probably not the issue. Your getting fuel up there in 10-20 seconds of cranking so the fuel pump is working. The only real advantage of a electric pump is it will prime the carb before you crank the engine. A carter p4070 only draws like 4.6 amps so you wont tax the electrical system.
About the only other suggestion I have is check your ignition timing things do wear and change that can cause longer cranking as well. If you have points they may be out of adjustment which throws the timing off.

 

[Explorer]

X2 the fuel has most likely evaporated. Actually all you need to do before starting is look down the throat of the carb and crack the throttle open if you dont see fuel squirt when you do that the fuel bowl is empty from evaporation. The aftermarket ignition wont help that issue or increase performance. It will lighten you wallet tho. Of course if you have a points type ignition than electronic would be a upgrade. but still wont help the starting issue.
About the only way around it is a electric fuel pump as it can fill the fuel bowl before you start to crank the engine. All in all tho 10-20 seconds of cranking is not to bad when its been sitting for awhile.

Definitely your first move. With your problem getting worse,(setting only a couple hours) it could even be draining into intake from an internal carb leak.

 

[blubuckaroo]

A bad power valve will allow the fuel in the bowl to drain into the intake pretty quickly.

 

[dblupcobb]

A bad power valve will allow the fuel in the bowl to drain into the intake pretty quickly.

I am well over due for a valve job. It is getting almost unbearable, the amount of gas/moisture/oil in exhaust. I've just about ruined anything sitting near rear end of my Bronco when I crank it up with that black soot. Didn't think about this being a potential cause for the slow to fire issue?

What is typical fuel pressure with stock fuel pump? If I remember correctly, last time I was under hood it was running at 9 psi.

 

[addicted]

I have the exact same problem. Im installing the Carter pump. That way Im not killing the battery with long crank times and if it sits for to long it makes it really easy to drain the tank and put it fresh gas.

 

[ugly74]

I am well over due for a valve job. It is getting almost unbearable, the amount of gas/moisture/oil in exhaust. I've just about ruined anything sitting near rear end of my Bronco when I crank it up with that black soot. Didn't think about this being a potential cause for the slow to fire issue?

What is typical fuel pressure with stock fuel pump? If I remember correctly, last time I was under hood it was running at 9 psi.

He meant the power valve within the carburetor. Its what helps to enrich the mix when you romp on the gas pedal. It sits in the metering block on the primary side of your carb.
Sometimes when this part fails, it allows all of the fuel in the bowl to trickle out in to the manifold.

 

[dblupcobb]

He meant the power valve within the carburetor. Its what helps to enrich the mix when you romp on the gas pedal. It sits in the metering block on the primary side of your carb.
Sometimes when this part fails, it allows all of the fuel in the bowl to trickle out in to the manifold.

Gotcha, after I posted I thought that might have been what you meant. I haven't changed anything on the carb other than replacing a jet since I put it on over 15 years ago. Might be worth getting a rebuild kit and going through it.

I'm going to change the fuel pump and pcv valve since they are relatively cheap easy fixes, then will maybe delve into the carb if my problems persist.

Thanks again for the help and I'll keep ya'll in the loop.

 

[dave67fd]

I am well over due for a valve job. It is getting almost unbearable, the amount of gas/moisture/oil in exhaust. I've just about ruined anything sitting near rear end of my Bronco when I crank it up with that black soot. Didn't think about this being a potential cause for the slow to fire issue?

What is typical fuel pressure with stock fuel pump? If I remember correctly, last time I was under hood it was running at 9 psi.

Moisture in the exhaust can happen with any car that sits for periods of time. Carb could be running abit rich and maybe some of your starts could have resulted from periodic flooding.

Fuel pressure on a stock pump should be around 4 or 5psi and as little as 3 without any problem. If your running 9 that is too much so your pump is fine but you need to reg. it down to at least 6 or 5.5. That probably is the cause for the difficult starting and excess fuel in the exhaust and doubt it's a stock pump or your gauge is not working or your reading it upside down "69"? ;D

 

[Keek]

Just a couple of thoughts and ideas.

Fuel leaking down out of the carb might be a problem.

Fuel evaporating might be a problem.

Sitting long periods and not being driven much might also be a problem.

I put Sta-Bil in everything that might sit long periods of time. Generator, Boat Motor, Bronco are all included. I also put Marvel Mystery Oil in the tanks of anything that sits for a long time. My boat motor once sat for 7 years without being run but I'd run MMO in it and then drained the carb via the built in drain valve. Gassed up the tank, pressurized the fuel bulb and carb and pulled it three times before it cranked over and ran.

Pop the air cleaner off and pull the throttle back by hand while looking down the top of the carb to see if gas squirts out after it's set a while will almost certainly let you know if the fuel is draining down. I think this would be the first thing I'd do.

With fuel injection and an electric fuel pump, if you turn on the key, you hear the whine of the fuel pump charging up the system. So if your fuel pump is weak and needing replaced, that might influence you to put in an electric pump as it would have the same benefit.

 

[deltarat]

My bronco has done that since it was new. The first cranking after sitting several days and it has to turn over for 30 seconds or more. It still does it after my restore with all new carb,fuel pump and lines.After it starts, it starts right off unless it sits for a couple of days again. I wish I could solve the problem. It has all new parts and it is no better.

 

[blubuckaroo]

I've had that happen too. After replacing my fuel selector valve with an electric, the problem went away. I think the valve packing o-ring was leaking in air reducing the fuel pump vacuum.

 

[broncnaz]

A bad power valve will allow the fuel in the bowl to drain into the intake pretty quickly.

Unless you have idling issues the power valve is not the problem. A bad power valve causes a rich mixture which will cause poor idling and fuel economy

 

[cclay]

I have had trouble with my fuel system since I bought it last year. Same thing as everyone here is describing. '74 351 and a big ass over the top 800cfm Edelbrock on the manifold. Way too much carb for that motor. Constant stalling offroad.

So I traded with a buddy for the stock 2bbl. Stalling problem solved but carb was leaking internally so I rebuilt it. Purrs like a kitten now.

Unfotunately, I was still having some issues with fuel delivery. I totally agree that if it sits for weeks and weeks it will take awhile to get fuel back up into the carb. But not days. I've had tons of carb motors in cars and bikes over the years and have NEVER had this issue.

But, for some reason the brilliant minds at Ford decided to take the fuel into the carb at the BOTTOM of the bowl. Why? If there a valid engineering reason for this I don't know it and I'd sure like to hear from anyone that does. Fuel delivery on every carb I've ever had has always been to the top. Hmmm.

Anyway, I was having the quick drain back issue after just a short time sitting AND, offroad at real slow speeds, like idling up a wash scouting for quail, the motor would die. I have a clear glass inline filter right before the carb so I could easily see that there was no fuel getting to the carb. Happened to me Saturday as it has ever since I bought the vehicle. It almost seemed like a vapor lock issue because if I let it sit for 20 minutes or so, it would pump fuel again and fire up.

So, yesterday I decided to gamble 25 bucks on a new fuel pump. Put it on and went for a 30 mile offroad cruise. No issues at all.

Fingers crossed that that's the end of it.