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Offline LongTimeFordMan

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Fuel starvation in 73 wagon
« on: November 26, 2019, 09:31:02 PM »
About a week ago my wagon began to have a fuel starvation  problem.

Originally oem fuel pump, stock 32/36 holley webber carb.

 I was driving along in town and suddenly the car just quit with 3/4 tank of fuel i had just topped.tank off.

Limped.into a parking lot and discovered that the fuel filter between fuel pump and carb was empty and only bubbles were comming into the filter no fuel sort of like vapor lock but ambient temp was only about 70 farenheit.

Ive had no previous problems with vapot lock even in 100 temps in city driving.

Fiddled.with the hoses, blew thru the filter, blew into the carb inlet hose, blew into fuel.supply pipe and all were clear but the pump wouldnt pump anything.

After about an hour the car started and i was able to drive about 5 miles and same thing.

Replaced the fuel pump and stull no fuel at pump outlet.

Fiddled about an hour and car started but with very weak fuel output from pump.

Was able to drive 3 miles home.

Replaced the pump with a Facet Posi-Flo 1-4 pound electric pump which pumped about a quart in about 2 minutes,

I have used this pump previously to pump fuel.from.a tank and know from.experienc e that it will easily zoop fuel up abiut a foot or two.

But electric pump seems to click loudly for a few seconds up to about 20 seconde indicating there is no fuel at inlet.

Drove around a few days.

Did 80 mile test drive on straight flat road at 55-70 mph averaged about 21 mpg.

I relocated the elecfric pump at a position below the fuel tank level in the engine compartment so that when disconnected fuel will siphon from the tank.  Stream is full pipe crom fuel line from tank.

Electric pump still seems dry when first activated then fills and clicking diminises indicating fuel.at intake port.

Drove about 10 miles today and electric pump again clicked loudly indicating no duel at inlet every few minutes.

As I mentioned i can easily blow thru the fuel supply line from front to rear and the fuel.will.siph on out of the front of the line .

Seems like classic vapor lock where fuel.is vaporizing between tank and pump to me or perhaps an air leak somewhere in the fuel supply line

I checked under the car and there are no fuel.leaks or broken hoses at the tank.

I was wondering if there is anything inside the tank like a filter sock in the tank that could be plugging intermittently or perhaps a leaky rubber tube inside the tank.

In all cases fuel tank was topped off and had 3/4 or more of fuel.

Ive driven the car 15000 miles over the last 5 years and have had no difficulties before this..

And since the problem occurred ive tried 3 pumps, the original, one new, and the electric all.with the same results.

I know that pulsed electric pumps but as I mentioned above I know that tbis pump will lift fuel.at least a foot and it is mounted below the tank now.

Since this just started I was wondering if perhaps it might be that the "winter gas" designed to vqporize more easily might be vaporizing in the line between the tank and pump.

Next step.is to drain the tank and remove the fuel pickup to see if there is a problem.there.

Any ideas?
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline Wittsend

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Re: Fuel starvation in 73 wagon
« Reply #1 on: November 27, 2019, 01:03:46 PM »
I use the Facet type Cube pumps on two of my cars (Valiant and Studebaker). Being cheap like I am I use the $15 Chinese version. On the Valiant it is the only pump as the mechanical pump had a leaking diaphragm and I bypassed it. On the Studebaker it is assistive. The main reason I use them is to prime a car that has sat for a period of time such that the float bowls run dry. I have found that these types of Cube pump tend to "flow through" and I can shut them off and use just the mechanical pump after priming.  Because I drive these cars so infrequent I generally have no more that a 1/4 tank full at any given time.  That may be a factor in what I say below.

My experience has been that the angle of the road or the act of stopping the car will bring on the clicking sound. I presume the fuel is moving away from the pick up.  It can be unnerving when I'm stuck at a red light with road incline and the clicking starts.  That said, I can't recall a time that the car has stalled regardless of the clicking sound. So, what I'm wondering is, is this typical even with a mechanical pump and we never hear it? It does beg the question as where the pick up should be in a street driven tank. Too low and you might zoop up crap. Too forward and you zoop air going up a hill. Likewise too rearward and you zoop air going down hill (although that is probably the lesser evil).

My '73 (Turbo 2.3) Pinto wagon uses an external (F-150) fuel pump to supply the 40+ PSI for the fuel injection.  This system needs a return line.  I opted to use the sender housing, drilling a hole, soldering an additional tube with the (hopeful) aspect of pointing it far enough away so the return did not push fuel away from the pick up.  When I initially started driving the car I had symptoms of running out of fuel.  The car would stall, then restart. My issues were compounded by the fact that I used the TC tach in the original Pinto cluster location and used the TC fuel gage that is not properly calibrated.  A few gallons down from full and the gage shows empty*. So, the tank/pick up design may well have issues but I keep it so full I might not show.

* I plan on hiding the original gage in the glove box at some point to avoid this "guessing game."  I need to put that on my 'to do' list.

Anyway, I can't give a definitive statement other than to say that I too have the loud clicking from the cube type fuel pumps. Fuel slosh seems to be an issue. And I have had somewhat suspect aspects of the Pinto fuel tank/pick up and the amount of fuel in the tank. But to pinpoint or correct the problem other than say keep the tank full I'm at a loss.

Offline LongTimeFordMan

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Re: Fuel starvation in 73 wagon
« Reply #2 on: November 27, 2019, 01:33:44 PM »
Hi..
Thanks for the input.

More info.

I have a fuel pressure gauge and when then the pump is oumping it reads about 4 psi.

When no fuel it drops to about 1-2  psi.

I drove the car about 5 miles with no problems and when i got home  today fuel pressure was steady 4 psi but air temp here is about 45 farenheit.

I was also able to blow easily back thru the vapor return / vent line connectex to the canister so no obstructed lines.

I know that fuel.slosh is a factor but in all cases there was mor than 3/4 tank of fuel because i had just topped off the tank.

I use the black plastic facet and from experience using the pump on a generator and as a siphon to zoop fuel out of the tank when i calibrated my fuel gauge that the facet clicks when there is no fuel at the input..

Makes me think it might be the winter gas which is designed to vaporize more quickly and 8s vaporizing in the fuel line from the tank.

This wouldnt be a problem with modern fuel injected cars since the pump is in the tank and the line would be pressurized..

I think i will move the pump to the rear near the tank.

Will post more as i discover more
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline Wittsend

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Re: Fuel starvation in 73 wagon
« Reply #3 on: November 27, 2019, 01:56:21 PM »
That is interesting in that you have the pump rather forward. Although a small amount, the fuel in the line you would think it would be a buffer but maybe it draws air and once it the line it has to go through the pump???

On most cars even though they always say to mount the pump low, the flow is typically through the sender unit which ironically is at the TOP of the tank. So, regardless of how low the pump is, it is still up hill until past the tank output. And as such the lower mounted pump might struggle with more air in the line then if the pump was higher. it would seem one needs to experiment with each different application.

Oddly enough the Pinto Wagon fuel sender is in the middle of the tank and actually has less drawing distance and one would think it would be easier on the pump. Go figure.


One last thing. One of the most painful experiences in my life was getting gasoline in my ear while working on a tank  :'( . Be careful. Those foam earplugs might help.

Offline ponyboy

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Re: Fuel starvation in 73 wagon
« Reply #4 on: November 30, 2019, 01:28:57 PM »
The Pinto fuel system is pretty simple and straightforwar d. Not much that can go wrong with it that would be hard to find. If a new stock oem fuel pump is not pumping, and there is gas in the tank, then there is something plugged up farther back, or there is an air leak in the line between the pump and the tank. Try pumping gas from a gas can with the stock pump and a hose between the pump and gas can. The pump is self priming, and if it doesn't work, either the pump is defective, or possibly the pump arm is bent, The pushrod is worn, or the cam on the auxiliary shaft is worn down. What engine do you have, the 1600cc or the 2000cc? If the fuel line to the gas tank is plugged, compressed air might clean it out. Otherwise you would have to remove the sending unit assembly. I have not had this problem so far with the Pinto, but I have had a lot of damage done to motorcycle fuel systems due to ethanol gas. It melts rubber and plastic, corrodes aluminum and rusts iron and steel. Bad stuff.

Offline LongTimeFordMan

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Re: Fuel starvation in 73 wagon
« Reply #5 on: November 30, 2019, 01:50:56 PM »
I suspect that there might be a problem with the match between the auxiliary shaft cam and the push rod that activates the pump.

And that this causes a difference in the pump.stroke.
 
I l9oked at  a "new oem" pump and noticed that the shaft protruding from the pump was about 1/8" inch longer than the pump previously installed on the car and it as well bottomed out about 1/8" from the mounting surface of the pump.

Noticing this i installed a 1/4" shim between the new pump and block and everything seemed ok.

After driving for a few days i removed the shim and ran the car, it ran for about 5 minutes and quit.

I removed the pump and saw that the circlip that retains the spring was broken as well as part 9f the pump housing.

Apparently the pushrod pushed it too far into the pump.

The block i have now including the auxiliary shaft was from a capri with reat oil sump.

I used the pushrod from my pinto block and noticed that the pushrod travel was from about 3/8" when at low point to about 1/8" at high point.

I am thinking that there might be a difference in the stroke of the aux shaft cam and rod.

I also noticed that on the Burton power website that they sell both  "thick" and "thin" pump to block gaskets. Possibly because there might be a difference in the aux shaft/ pushrod stroke.

Car is running ok with electric pump mounted low in engine compartment.

Next step is to insert pushrod into old block, rotate aux shaft and note the travel and depth into the block, also to relocate the electric pump at rear  near tank and just run the electr8c pump
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles

Offline ponyboy

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Re: Fuel starvation in 73 wagon
« Reply #6 on: November 30, 2019, 06:24:03 PM »
It's been a long time since I had a Pinto engine apart, and I have worked on a lot of other engines since, and I don't remember exactly how it goes together. But I would be careful with the pushrod length. I have seen engines with broken cams because someone installed the pump wrong. The last thing you want to do is break that auxiliary shaft. If an electric pump is working, I would just leave it that way for now. That rules out any problem between the pump and fuel tank.

I think pretty much any part for a Pinto these days is either going to be rebuilt, or be a Chinese reproduction. And there is a good chance of there being an issue with either. It is almost impossible to get good quality parts for vintage cars these days. I have bought a lot of brake, steering, and suspension parts for my 1964 Fairlane that are nowhere near the quality of the original parts. I've had rubber ball joint boots rot and fall apart in less than 2 years. They originals were still on there after 50 years.

Offline Wittsend

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Re: Fuel starvation in 73 wagon
« Reply #7 on: December 01, 2019, 04:36:03 PM »
"I I"I have bought a lot of brake, steering, and suspension parts for my 1964 Fairlane that are nowhere near the quality of the original parts. I've had rubber ball joint boots rot and fall apart in less than 2 years."


I hear that. I bought new ball joints for my Sunbeam Tiger and there is only ONE choice with those. Like you the rubber rotted out within a year.  The car never saw daylight and I'm far enough from LA that smog is not a contributing issue. Frustrating. Back in 2001 those ball joints were $89.99.

Offline LongTimeFordMan

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Re: Fuel starvation in 73 wagon
« Reply #8 on: December 01, 2019, 06:23:46 PM »
Update on fuel pump drive.

I inserted the fuel.pump drive rod and measured the retracted  and extended points of the travel

Retracted distance from rod to mounting surface was about .260"

Extended about .050"

For total.travel.o f about .200"

Then I measured the pump plunger travel from plunger tip to mounting surface.

Extended about .600" (5/8") bottomed out about .125 (1/8")

So apparently the pump shaft was pretty much depressed most of the way all.the time and the stroke with the different block and aux shaft the pump stroke was too short to draw in any fuel.

I added a 1/4" spacer between the pump and the block and the pump pumped.sfeadil y at almost 5 psi with no pressure drop.

I have a holley pressure regulator and pressure gauge and set the pressure down to about 4 psi and it held steady.

Shut off 3ngine and pressure held at 3 psi for over an hour.

Conclusion..

Apparently there are different combinations of auxiliary shafts and pushrods.

I am just thankful that the original pump wasnt damaged like the new one I installed.

Worst case I still have the electric pump mounted and wired as a backup if needed and plan to move the electric to the rear next to the tank just in case
Red 1973 pinto wagon DD, SoCal desert car, Factory 4 speed, 3.40 gears, Stock engine, 14" rims and tires, 60 K original miles