I have a couple of problems with fuel delivery. I cannot keep fuel pressure in my line. When I start the car my gauge reads 5 lbs. but after I drive a few miles it drops down to 1 or 2. I have an electric Holly red pump, new flex line from the pump to the carb. Original steel line from tank to inline filter before pump. Inline filter is a 100 micron canister filter. I have lined the gas tack. Cleaned the fuel pick-up. I am at a loss. Getting ready to go on a road trip and I don't want to drive 9 hours on a carb that runs to lean.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> <o></o> My other problem, I have a 17 gallon gas tank and I can only get 13 gallons in it. I have checked the tank vent, which is located at the top of the tank to the rear, and it seems clear to me. The only thing I can figure is the air in the tank cannot be displaced for some reason. But why? That is the mystery.<o></o> <o></o> Any suggestions or knowledge much appreciated.<o></o> <o> </o> Jeff
is the pump located low enough. some pumps wont pull fuel from the tank. they need to be mounted lower than the pick up. and double check the tank vent, i had a customers windstar that wouldnt take fuel. found a spider built a home in the vent line. a couple blasts of shop air cleared it right out.
The pump is only a couple months old however it was abused before I could get the tank cleaned up last week. It is mounted on the frame towards the rear of the car well below the tank. I will blast some air through the vent.
You mean "abused" as in it got trash and rust ran through it for a few months ? It sounds like you have the pump mounted like you should in the rear by the tank .Im betting its the pump.You could remove the pump (which you will have to do anyway if its bad) and hook a temporary fuel line and gauge to it with a few gas cans to transfer and watch the pressure .That would isolate metal lines on the car ,vents ,etc...
Hard to tell without being there, but heres a few ideas. -Cant fill the tank: Some cars have "vent lines" that run from the tank to the top of the filler neck. If that gets clogged, pinched, etc, it can be hard to fill the tank. Ask me how I know... -Fuel pressure drops: Could be the venting of the tank. You could be building up a vaccum in the tank. Leave it for a while and it goes to atmospheric. Run it a while unvented and you get a restriction. Check for a cap that isnt venting or some sort of clogged vent circuit. Good luck! -
Good idea shocker. The abuse part of the fuel pump would have been starving it of fuel and possibly damaging it because of lack of lubrication. I run a 100 micron canister style filter between it and the tank so no junk has made it to the pump. After I cleaned the tank I opened up the filter to clean it and there was only a couple of tiny pieces of debris in it.
The Y block is a John Mummert built motor. Block has been bored, heads decked and ported. 284 cam. Running Edelbrock 650 on a blue thunder intake. Stock duel exhaust. Cannot remember if it was the builder or the edelbrock specs that recommended 6 lbs.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> <o> </o>
No problem ,happy to help .I had a Holley red that got weak like that once and the gas can and gauge trick was how i found it.I had a high dollar Mallory pump that crapped out on me once as well.Turns out it was a bad connection internally and it would cut on and off ,but i couldnt hear it over the exhausts while driving.It would only cut on and off after about 15 minutes of driving.Sum think that an electric fuel pump either works or it dont and thats not always the case with them from my expierence .Good luck with the test ...
Yea, do like Shocker told you....everytime I have a fuel system in question.....I put it on my "Fuel Test Stand"....I have a 5 gallon lawnmower tank 5/16 to 1/2 in lines and adapters, a new battery in, plastic case. a place to bolt the pump, all the different nipples for the regulator and right after the regulator, I have a pressure guage. I hook everything up with whatever size line is on the car, then I hook up my regulator and pressure guage behind the pump. I make the pump work by pumping thru a short piece if line with a old Hilborne 1/16 pill in the fuel line before returning to the tank. I write all my pressures and reg. setting down. Then I take the reg. fuel filter off the car, along with the guage used, and put it on the test stand. I also hook up my pressure guage, protected by a 5 micron filter. Power that puppy up and see what you got.... amke sure your getting full battery voltage and be protected by a fuse. Sparks on a fuel test stand are a complete NO-NO!!!! If everything checks out.....you might have something stopped up someplace. Also, some of those fittings are really restrictive.....check them out too...... Test the pump as low as it'll go up to as high as it'll go. and let it run and work.....sometimes they don't show bad until they get warm.......
Guessin 70's? My 40 Dodge has a vent line from the tank to the top of the filler neck. Took me a while to figure out why it would only take a half gallon at a time!
have had problems with the liquid filled gauges changing as temperature underhood changes.heard of a lot of other racers having the same problem.might want to try non filled gauge if you can find one. not saying you don't have another problem though. good luck.
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