fuel pressure

[58prostreet]

I need help! I have a '52 wayfarer with stock 230. i installed Langdon headers and dual intake with 2 carter webers. When I first started it everything went good, ran very good. After about 15 minutes it started to starve for fuel. I proceeded to put a electric pump, pressure regulator and fuel pressure gauge on it. Started it up and fuel pressure was about 7lbs and it ran good, but after 10 minutes it started to fall off and got to zero in about 20 min., but continued to run good for another 10 minutes and then started to starve again...I then put a new manual pump on it and got about 5 lbs. of pressure, but after 10 min. or so started to fall and went to zero again.... I have tried every combination I can think of with same results....ie manual pump with regulator....manual with elec pump at same time with no regulator...manual, electric, regulator together. Today I ran a line out of a gas can and tried every combo. again thinking maybe the tank had trash in it....same thing...

Can anyone give me some ideas? I'm out of ideas.

Thanks Bob

[Plymouthy Adams]

Personally I would start looking at fuel supply..possibily a restricted fuel filter, dirt and junk clogging about the in tank oillite filter..or even a combination of them and the fact you dropping to zero says there is nothing to pump..

[58prostreet]

Tim

Today I ran clean fuel out of a gas can for reasons u stated, thinking maybe I had trash in tank....I have a new in line filter before the manual pump.

Thanks Bob

[moparalltheway]

Is the vent line clear? Try it with the cap off. Sounds like it is pulling a neg. vacuum.

[58prostreet]

I have disconnected the line from the tank and ran a line into a can of fresh gas to eliminate any trash problems with trash in the tank. The tank that is on it is a stainless tank that I had built. I thought maybe that was problem, but it did same thing out of a gas can. I blew air back thru the line to make sure it did not have any trash in the line....It really has me stumped.

The way it is plumbed is hard line out of tank over axle into a filter, then into electric pump, then into fuel pressure regulator, then hard line to front of motor, then small piece of rubber into glass inline filter, then short rubber to inlet of manual pump, then hard line short piece of rubber to fuel pressure guage then rubber to both carbs. Tonite I ran gas out of can thru elec. pump, regulator then manual pump...No luck...Next out of can to hard line to manual pump bypassing elec. pump and regulator...same thing.....same problem...runs with 5 to 7 lbs for about 10 min. then starts to fall and after about 10 more min. I am to zero..The gas can is above the elec. pump and the main gas line to assure gravity feed.

Thanks Bob

[moparalltheway]

Your problem is the fuel pressure regulator. Is it the dial type? If so not worth a shi-. If not what kind do you have. Also you need to locate the electric pump closer to the tank. They push much better than they pull.

[moparalltheway]

Also have you removed both fuel lines from carbs as soon as it stops pull coil wire and turn over engine. Place lines in a bottle and see how much if any and are they equal. Are both cards linked to work together? Have you pulled intake manifold vac using a vac gauge? How much at idle?

[martybose]

You definitely have a fuel supply issue. I run the same carbs on my motor with less than 3 pounds of pressure, and it runs just fine!

Marty

[58prostreet]

I don't think it is the regulator. I have a holley 1-4 lb. regulator with hex bolt to set pressure. At this point I have bypassed the elec. pump and the regulator and am running gas from gas can into line directly to manual pump.

The carbs are linked togehter. I have not pulled the gas lines as u have suggested nor have i hooked vac. to the intake...I will try that tomorrow.

Thanks for ur suggestions...I will let u know the results tomorrow.

thanks Bob

[58prostreet]

Marty

I know u are right. I can get 8 to 9 lbs if i hook up elec. pump and manual pump in tandem. I can get 4 to 5 with manual pump only. It runs great in either case, but in both cases fuel pressure starts to drop off in about 10 min. and eventually goes to zero. I even drove it about 10 miles the other day with pressure at zero....thought I had discovered the greatest alternative fuel solution in world until the da#@ thing started sputtering and quit. I will try suggestions from moparallthe way tommorow. Thanks for everyones help.

Bob

[Normspeed]

When it drops to zero and shuts off, remove the gas filler cap. Do you get a big whoosh of air? If so you may have an unvented fuel cap and may need a vented one.

[58prostreet]

It does it with the cap on or off. At present I am running direct of a gas can

and having same results.

Bob

[grady hawkins]

With the direct feed from a can of gas; it seems the trouble is inside the carbs.

Have you checkd proper oeration of float levels and movement? or perhaps you pumped trash into the carbs before the new filter

[Don Coatney]

Try this. Remove the fuel pumps and fuel lines from the equation. Set a lawn mower gas can on your fender above the carbutetor fuel line inlet. Use a rubber hose and connect one end directly to the carburetors inlet and the other end submerged below the fuel level in the gas can. You may have to "prime" this line to insure it is saturated with fuel. Start and run the engine. If it continues to run your problem is not internal to your carburetors.

A fuel pump (electric or mechanical) will not pump air. I believe you have a cracked fuel line, defective filter, or defective fitting somewhere on the suction side of your fuel pumps.

[moparalltheway]

I believe Don is right on. I forgot I had the same problems and had a fuel line sucking air. Those Murfreesboro guys are pretty sharp.

[58prostreet]

Well it's still doing the same thing. Don, I did what u suggested and it ran fine direct out can into carb feed. Tonite I ran thru manual fuel pump direct from gas can. Started out at 5 1/2 lbs. and after 4 min. climbed to 7 1/2. Then it started to gradually fall from 7 1/2 and after 20 min. got to zero....ran for another 2 to 3 minutes at zero and then died. I don't think it has anything to do with any of the gas lines from tank to fuel pump. there has never any indication of a leak, and it does the same thing no matter what the source of fuel is, ie tank or gas can.

I thought it could be lobe on cam not allowing pump to work properly, but it does same thing with electric pump.

HELP

Bob

[moparalltheway]

I think the pump is sucking air.

[T120]

You mentioned the engine runs fine using gravity feed.From reading your posts,the mechanical fuel pump you replaced seems to be the common denominator-possibly a faulty pump?

[hkestes41]

Don had a good suggestion and it sounds like when you ran his test the engine ran fine. I would suggest then that you start at the tank and move forward disconnecting at each connection point in the line one at a time. Run your test with everything behind that connection point eliminated. Once you get a good test you will know exactly the point where the problem is. It will be the section between the last connection point and the one immediately before.

Replace that section of the line and run your test again. Should eliminate the problem. If not continue forward again to see if you possibly have multiple failure points. If you make it all the way to the carbs without identifying the problem point you will at least know for certain that everything in the line is good and can focus on the carbs.

Just my $0.02. That and a five dollar bill will get you a cup of Starbucks.

[moparalltheway]

You mentioned the engine runs fine using gravity feed.From reading your posts,the mechanical fuel pump you replaced seems to be the common denominator-possibly a faulty pump?

I have bought everything from fuel pumps to batteries new and they were shot right out of the box. Does that pump have a warranty? Probably on shelf for years and dry rot took it's toll. Might try a kit and do a rebuild. Electric pumps are good for start up (good primmer)or back up. No need to run all the time.