Electric Fuel Pump and 97's question

[Missing Link]

Does anyone know if electric fuel pumps (for a carbuerated vehicle) utilize a check valve to keep the fuel from back bleeding into the tank? I can not find any specs that can help me. The pump in question is a small 4-6 psi universal Facet unit from NAPA.

I have noticed that after the car sits for a while (over night) there is no longer any fuel at the carbs. Seems like this should not be the case and I am trying to figure out why this is occuring. Obviously the introduction of air or lack of sealing somewhere in the system would create this problem. I can not find any leaks in the system but will double check clamp tightness again. This did not start to occur until recently. The last time I could use the car I ran into this problem and solved it by gently tapping on the fuel inlets on both 97's. The car then started up and ran fine and continued to start and run fine the rest of the day. The carbs have both been rebuilt recently.
I am also wondering if the metering rods in the 97's have anything to do with this. I would think that if they are not seating correctly this would also allow for the back feed or a wash down of fuel into the motor. Yes?

I would like to eliminate the problem because, as we all know, trying to get somewhere and having a car that refuses to start SuCks.

The setup is on a 59AB flatty with two 97's. Pressure regulator set to 2-1/2 psi. Translucent fuel line has allowed me to determine the lack of fuel.

Thanks

[fuel pump]

Get me the part number stamped on the mounting "ear" of the pump and I'll find out for ya.

[roaddevil]

I ran one of thouse pumps but in 6 volt from the great junk store (NAPA) and no i didnt have a check valve in it. I had the problem of the fuel back feeding when i left the car set for a couple of days. If i let it run before i even tryed to start it you could hear it run and then build pressure.

[fuel pump]

Roaddevil is correct. The Facet pumps available from NAPA and other automotive stores do not have a check valve. Facet does make some models that do have check valves. They make them for generator manufacturers like Onan and Generac. If you need the check valve you might try a motorhome parts suppliers that would sell them.

[tommy]

It seems to me that the problem you discribe is a carb problem. Fuel leaking down out of the carb. The carb should hold the gas in the float bowl. There is no way the fuel could syphon out of the carb back to the tank. If the pump has to run a while to refill the carb bowl in the mornings, you need to find out where the fuel leaked out of the carb. My carbs leak down after a couple of weeks but over night is a problem. Just my worthless opinion.

[Missing Link]

Thanks guys. I was suspecting that there was not an internal check valve on the pump. You are 100% correct sir roaddevil, if I kick the switch you can hear the pump run and build pressure/fill the float bowls.
Now I need to figure out why the carbs bleed down so quickly. Like tommy mentioned, if it took a few days or weeks I wouldn't be too concerned. The fact that it does it over night is what puzzles me. Mr. fuel pump, do I need a check valve? I don't think I would if everything is proper.

[roaddevil]

There are aftermarket check valves that you can install inline. you should be able ot find a fuel grade valve from grangers or other supply house.

This might save ya a few bucks instead of changing the fuel pump..

[CURIOUS RASH]

<font color="green">Have one of those on Mama's car. No check valve and the same problem with bowl running low/dry.

Just turn the key and let the bowl fill up before you try to start.

You can here the difference in the load on the pump in her car so you know it's caught up.

RASHY </font>

[AHotRod]

Link,
Get yourself a Carter #P4602RV pump, 12 volt, comes with a check valve, is a rotary vane design (quiet operation) pump, delivers 72 gallons per hour (way more than enough), internal built in pressure regulator, no points to burn out.

[Paul2748]

I have a "generic" (sold at all the local auto parts stores)elecric pump for my car (2 94's). The gas does flow back to the tank, but there is still fuel in the carbs. When I turn the ignition on I let the pump build up the fuel pressure before I start the car. Most electric pumps I ran across work this way, although I see from the replies there are ones with a check valve.

[desoto]

FWIW, the fuel pump in my ’34 runs for a few seconds if the car’s been sitting overnight. Evaporation in 4 Stromberg 97’s is enough to make it want to run.

The lines may be draining too for all I know but one thing’s for sure, if I don’t build fuel pressure (i.e make sure the carbs are full) the engine stumbles until the fuel pressure comes up.

If I let the pump run to fill the carbs before I start it, The engine fires right up and runs fine, even with the pump still shut off. (I shut the pump off while I’m starting the engine because my fuel pressure regulator is vacuum controlled and there isn’t any vacuum yet to work the pressure regulator).

[slingshot]

My past experience with electric pumps is that the fuel lines from the tank to the carb bleed down and you turn on the pump for a few seconds, it sounds like a really fast rattle ,then drops to a slow "click" when the pressure builds back up and the lines are full. BUT, the carbs should not lose any gas sitting over night. That would be like the amount of time from a start in the morning, say 8 am, then let it sit for 8 hours and try to start. It shouldn't matter. Day or night, The carbs are suppposed to hold a full fuel bowl. At least that has been my experience with generic parts store fumps. i always got into the habit of flicking the ignition on and letting it build up pressure before starting as I wanted gas ready to replace whatever I used, immediately. Also,I think it would be better with 4lbs fuel pressure than 2 1/2lbs.

[Missing Link]

Thanks all. I guess my only concern is burning up the points on the flathead by sitting there waiting for the carbs to fill. It shouldn't take long so it doesn't really matter does it? http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif

desoto - you made it home from macungie alright I see. I could have used your help on saturday night. Didn't know you were the "Wiring Guy" or I would have come looking for you http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif I lost all electrical power in the car on saturday night. Long story...still trying to correct the problem. What a mess. It was nice running into another HAMBer.

Ahotrod-thanks for the part number. sounds like that may be a viable replacement.

slingshot-I have tried a bunch of different pressure settings on car. I was running 2psi, 4psi, 3-1/2psi, all different settings just to see which one worked the best. I found 2 or 2-1/2 to be about the best for the application. Anything above 2-1/2psi has a tendency to over power the carb.

I don't really want to start replacing anything at this point as everything is new. Every electrical component on the car is brand new. When I rewired the car I converted to 12volts and replaced everything. The back feeding of the carbs had me curious and I thought I would start from the fuel tank out, so my first item is the fuel pump. I believe that it is working properly given the replies so far. Although I still have a sneaking suspicion about the carbs, and what I call, the metering rods. Let me better explain...With the carb top off there are two grooves, one on each side of the carb. at the end of that groove there is a "metering rod." It looks to me, correct me if I am wrong, that the passage connects the top of carb to the carb base and that the passage runs back into the mixture screw orifice on each side of the base...huh? http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif Just thinking "out loud"...

[Machinos]

I've got a related question...

I put a 6-volt fuel pump (I forget the brand name, I got it from Dearborn Auto in Minneapolis) on my hemi. I've hardly driven it at all since then, but it quickly started to not keep up when driving on the highway, like first it'd start faltering every once in awhile at 70mph, then towards the end of the end of that 60-mile trip it was lurching all the time at just 60mph. If I pulled over and let it catch up I'd be able to accelerate back up to speed and kind of maintain it for a minute...

It's a V8 with a 4-barrel carb, sure, but I don't think it uses THAT much fuel. Is it possible the wiring I used isn't getting enough power to the fuel pump, or is the fuel pump just crap?

[CURIOUS RASH]

<font color="green">Machinos,

Do you have a fuel filter BEFORE the pump?

If not, you probably have some particles in it.

Take it out and see if you can blow anyhthing back out of the thing.

I had that happen before on another vehicle. I cleaned it out and put a filter before the pump.

Fixed it.

RASHY </font>

[tommy]

I'd try disconnecting the fuel line over night. When you connect it in the morning and it still needs to fill the carbs you will be able to eliminate the rest of the system and not worry about a check valve. The needle and seat are above the fuel level in the carb making it impossible to get any syphon action to empty the carb through the fuel line. IMHO

[Missing Link]

Machinos,
The one thing I do know about electric fuel pumps is that they all have a GPH (gallon per hour) rating. It may be possible that the fuel pump you are using has inadequate flow rates.

Rashy's solution is a good place to start.

The wiring will have nothing to do with the amount of fuel the pump supplies to the carb.

[Machinos]

Yeah, the filter's (just a generic clear-plastic Fram thing) before the pump. Actually, the pump has a sticker on it saying "REMOVING FUEL FILTER WILL VOID WARRANTY" or something like that, but it didn't come with one as far as I can tell. But it DOES have a little thing screwed onto the fuel-intake end of it... luckily I found an eBay auction showing the exact pump:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&amp;category=34198&amp;item=2431031 263

Mine came out of the box 100% assembled, though. The thing I'm referring to is the smaller cylindrical object in the picture, below the 4 hose clamps. Is it possible I've got two fuel filters and it's restricting flow too much?

Also, it's rated 4-7psi I believe, so I don't think it's technically inadequate. As for the wiring, I thought it might not be good enough to supply enough electricity to make the pump work fast enough.

[Missing Link]

That item below the hose clamps is a fuel filter. It looks like it may thread directly onto the pump (?)
It is possible to create a flow restriction by having too many filters in line. I would take the plastic in-line filter you mentioned earlier off and see if it makes a difference.
The reason that the pump you are using says removal of item voids warranty is because manufacturers specify fuel filtration between the tank and pump to eliminate contaminates (dirt and sediment in the gas tank) which could mangle the pumps internal workin's.

[Missing Link]

The "metering rod" I was refering to is item 9542 in the attached picture. Can someone 'splain to me what this item is and how it functions?

[Bruce Lancaster]

That's the idle jet. It feeds the actual idle holes that are metered by the two adjusting needles and is the metering restriction for the off-idle holes right above the idle outlets. This circuit feeds the car from off-idle until there is enough airflow to get a pressure drop at the venturis and bring in the main jets.

[Machinos]

Ahhh, thanks Link. I'll try that ASAP.

[Machinos]

Well, I eliminated that extra fuel filter (and an unnecessary 90-degree junction in the flexible line going from the hardline to the pump), but now the damn thing won't run. Let me start from the beginning:

I apparently left the fuel pump on the other night after driving it around back to unload some stuff from the trunk, then drove it around front and onto the street again. When I went back out to fire it up again it had probably been 12 hours or so that the fuel pump was running...the battery was 100% dead despite even though the pump should shut itself off when there's full pressure in front of it, right?

I jumped it last night and it started instantly, but while I was unhooking the jumper cables it killed. I jumped it and it started right up again, but killed almost immediately, then wouldn't start at all. I gave up, then early this morning I tried again. It fired up and killed almost immediately, then wouldn't do anything. So, I put it on the battery charger and tried again a couple hours ago. Fired right up, ran for 3 seconds, killed. Tried it again, it didn't even fully start before killing. Just tried it AGAIN right before posting this, same deal. Doesn't seem to matter how long I run the fuel pump, it just keeps going and going, every so often it'll slow down a bit, but then it goes right back. I know it's not out of gas (I put like 5 gallons in last time during the barely-running-at-60mph trip and have only driven it 15 miles since then), and back when it was working fine, even after a week of sitting I'd only need to let the fuel pump run for 10-20 seconds before it would peter off and be silent, then the car would start right up and stay going.

This is such a pain in the ass http://www.jalopyjournal.com/ubbthreads/images/graemlins/mad.gif

[Machinos]

I'm not sure what you mean...you mean the fuel pump will just keep pumping and pumping even if the fuel on the "out" end of it has nowhere to go?

I think it was someone else that mentioned points, I don't have a clue as to how electric pumps work. Mine has a manual switch 'cause the car came with an electric pump installed by the previous owner that way...when I tried hooking it up, it made noise but didn't actually pump any fuel, so I got this new one.

Charging system is stock, positive-ground 6 volt with generator. There was a regular Fram fuel filter (clear plastic, paper element inside) but I removed it since the electric pump has one already on it.

(post deleted? zuh?)

[CURIOUS RASH]

<font color="green">Holy shit!

I deleted that post as soon as I wrote it because I realized I was getting you two mixed up and wanted to return to this when I could concentrate.

[ QUOTE ]
I'm not sure what you mean...you mean the fuel pump will just keep pumping and pumping even if the fuel on the "out" end of it has nowhere to go?

[/ QUOTE ]

Yep!

That's how they work.

Yeah, I figured out that I was mixing you guys up.

Sounds like you somehow hurt your ignition/timing system, or hurt that pump leaving it on all night.

I have mine on a supply that is only on with the ignition. You could also hook it to such a line AND put a switch in line in case you wanted to turn it off when the car is running. This would keep it from staying on all night.

Now, we gotta figure out if it's a fuel supply problem, ignition problem, or generating/charging problem.

The problem I see with leaving the pump on all night is that the fuel is not moving at all. This must be harder on the pump. I guess you can disconnect the fuel line and see that the pump still pushes fuel. Do you have any kind of gauge you can test pressure with? I don't know how you can test volume.

Igniton. I'm assuming that since you have a stock 6-volt that you also have points. I used to have a 72 Dodge Dart with a dual point Mallory and as I would sit and wait for my girlfriend to get off of work I would listen to the radio. Ignition mode was the only way I could figure out to hook up my radio. Took me a while to figure out why I was always replacing the points.

All that to say you probably hurt your points.

Charging system. You can test your generator, see if your battery is good and check the regulator. I had to hit my regulator with a hammer once. Some dude I worked with told me that was my problem with my charging system. said they could "stick" open, or closed, don't remember which. It worked.

That's all I can think of right now, hope something here helped.

I never recommend pouring gas down a carb as you try to start it, or starter fluid. But, if you wanted to rule out thye fuel delivery problem, that would do it.

I would definitely not use a glass jar and if your carb is prone to back fire.... I never even brought this up.

RASHY </font>

[lowsquire]

sorry if this is stupid but have you worked out where the fuel goes?if its in your sump your motor wont last too long...petrol diluted oil aint much of a lubricant http://www.jalopyjournal.com/ubbthreads/images/graemlins/frown.gif

[Missing Link]

Good point lowsquire. Before you do anything else Machinos, check the oil to make sure it is not diluted with gas. Just pull the dipstick and take a good sniff. If the pump was running all night the gas had to go somewhere, well at least some of it. I would take a look to see how much overflowed from the carb (i.e. take a look at the gaskets and see how soaked they are, check around all seams and the base too.) If I am correct, the pump will provide constant pressure with a flow correction when required. It may not have made that big of a mess, but I don't know if I would trust that pump anymore. If it emptied the tank, chances are it is going to provide you with future grief.

[Machinos]

I'll check the oil and stuff...I don't think it made that big of a mess OR emptied the tank, I didn't smell any overwhelming amount of gas or see any mess around. I think the pump is still under warranty, too, so maybe I can get it replaced for free.

I do need to replace the guts of the distributor (it needs a tune up), but luckily I got all the horrible charging/ignition stuff sorted out awhile ago http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

[CURIOUS RASH]

<font color="green">Why did the fuel have to go somewhere?

If the float, needle and seat are functioning properly, and the pressure does not excede the ability of them to function properly, the fuel has no where to go.

Did I miss something?

Checking the post..... </font>

[CURIOUS RASH]

<font color="green">Amazing what you notice when you reda everything...

Alright, you said that it's NOT out of gas so the fuel float/needle/seat were probably able to do their jobs and shut the fuel feed into the bowl.

That's what they do.

I missed the point that was made about inadequate fuel flow.

You mentioned the pressure is right on but that has nothing to do with volume.

It is entirely possible that a pump produce 7 lbs. of pressure but only 30 gph.

Trust me, I have this problem right now.

I just slapped a pump on the 41 "back in the day" and forgot about it. Had it at the HAMB drags with the new engine and it runs out of gas at the 1/8. </font>

[Machinos]

I sniffed the dipstick...I guess it kind of smelled like gas, but not very strong at all. And honestly, I've never smelled a dipstick before so I wouldn't know what to expect http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif