On the way to work this morning the chevelle cut out on me. I had just under a 1/4 tank of gas and I have driven her down to Empty before. I had enough to get me through the day at least.

As I rounded a corner the car stumbled and quit. I tried to crank it up and it sputtered for a second then died. At the psi needle by the carb I had a ~0psi shutter. To make a long story short I had to add 2 gallons of gas for the pump to give me 7psi up front.

This put my fuel gauge at exactly 1/4 tank.

Questions:

1.) where is the fuel pick up in the tank? how high off the floor is it?

2.) why does my Mallory 140 make damn awful sounds when I first give it power, as if it's tryin' to lift the world. (she runs fine after it "spins" up) Almost like an old oscilating fan spooling up. Mallory is getting a call ASAP!

3.) why didn't I go with a manual pump!! http://www.chevelles.com/forum/mad.gif

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71' 3880# with me. Big Block 402, TH400, 3.73 posi,
13.1sec @ 105 MPH (poor 2.1 sixty foot and rookie tuning)
--will be racing at Chevellebration 2001!--
Picture of me roasting the tires and other guy stuff (http://www.auburnextremeracing.org/drivers/mike/)
Video of me staging (smoke of course) (http://www.notabusinessracing.org/videos/mike_chevelle_burnout.avi)

[This message has been edited by BB_Mike (edited 03-16-2001).]

If it's the same as mine, the highest open point in the end of the suction line is about 1/2" off the floor of the tank (rough estimate).

Is your pump mounted higher than the bottom of your tank? If so, you may want to consider adding a bracket to get it a little lower. This will help a little, but you'll still be over-working your pump on start-up. You'll get the "siphon effect" as an assist when the fuel level is higher than the pump. My guess is that you lost this assist when you rounded the corner and the pump was unable to reprime without it.

You need to remove your tank and have a 1/2" bung welded to the bottom. Then you can plumb it correctly and the fuel pump won't have to fight so hard to do something it wasn't designed to do.

Remember, these pumps are "pushers", not "pullers".

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My Elky Page (http://www.geocities.com/chadjlandry/index.html) (updated 3-15-01)
"Think for yourself. Don't let popular opinion make your decisions for you."
Chad Landry
TC Member #643
'68 El Camino

[This message has been edited by cjlandry (edited 03-16-2001).]

I can understand about the syphoning effect. I just can't justify it being THAT much of a problem for my very expensive pump to handle. There wasn't mention of this being an issue in the paper work I got with the pump.

so CHAD, this bung is just an 'el cheapo sump? I don't have the extra down time and money to pull off the gas tank!

So, lowering the pump some will help for he mean time. I will also try to keep the tank above 1/4. Guess I should buy a stock manual pump and keep it in the tool box! http://www.chevelles.com/forum/rolleyes.gif Along with my stock HEI stuff http://www.chevelles.com/forum/smile.gif I'm going to have to toat a spare car for long trips http://www.chevelles.com/forum/frown.gif

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71' 3880# with me. Big Block 402, TH400, 3.73 posi,
13.1sec @ 105 MPH (poor 2.1 sixty foot and rookie tuning)
--will be racing at Chevellebration 2001!--
Picture of me roasting the tires and other guy stuff (http://www.auburnextremeracing.org/drivers/mike/)
Video of me staging (smoke of course) (http://www.notabusinessracing.org/videos/mike_chevelle_burnout.avi)

Dude, what a hassle. I just bought one of those Holley 454 110gph manuals. Hope its enough.

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Gene Chaas
Gold Member 62/ACES
67 SS 427 (http://www.chevelles.com/feature/october2000.html)

An Autozone (or other) fuel pump for 13 bucks, push rod, hose clamps, a couple feet of hose and a F%&$ remote solenoid already wired are cheap insurance. Placed in a cloth bag these items fit nicely into the center of your spare tire. Power Tour goes along way in teaching you what to carry. Bill

Mikey, Mikey, Mikey...BTDT too my friend. http://www.chevelles.com/forum/rolleyes.gif Sorry to hear about your hassles...bummer. In my case I had no working gas guage - bad sending unit. http://www.chevelles.com/forum/frown.gif I do now though! http://www.chevelles.com/forum/smile.gif

Hey, just to add what Chad was mentioning about electric fuel pumps being gravity fed...siphoning gas up and out of the tank is forcing your Comp140 to work extra hard to get the fuel up to the front.

I managed to ruin a set of brushes on a new Mallory Comp 140 pump in less than a 1.5 years. I had the electric fuel pump mounted below the fuel tank but the fact that it was having to siphon gas up and out of the gas tank (was using a 1/2" aluminum pickup tube at the time) is what prematurely killed the electric motor brushes. Fortunately, Mallory sells replacement brush kits for cheap! But they didn't cover the tow fees back to my house. http://www.chevelles.com/forum/frown.gif

My solution was to go with a 16 gallon RCI fuel cell (flat bottom - no sump) mounted in the trunk. You can also drop the gas tank and have a shop weld in a bottom sump kit to the stock gas tank. Jeg's sells them for around $50, I think. Either way, your fuel pump will thank you because then it will be truly gravity fed.

PS: Being paranoid about the second set of brushes, I pulled the Comp140 apart about 5 months ago and there was barely any material eroded from the brushes. Lots of brush material left. This after about 1.5 years of useage.

Hope you're back on the road soon Mike.

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502 Rat Infested 1970 Malibu - Gold Member #39
Keep America Beautiful - Drive A Brute Force Chevelle!
http://pages.about.com/wescolby/personal.html

El Cheapo sump would work, but as an alternative you could just weld a short 1/2" coupling in there.

As an alternative that will take less time and money, (though not as professional), read below.

Around 11 years ago had a 77 Omega (read "Nova")that I setup with a simple bulkhead connector for a fuel pickup.

I drilled a hole in the bottom of the tank where I could reach it from the top with a long extension through the oem pickup/sender opening. Taped the nut and top washer onto the socket so it would pull off easily once I got it started. Used gasoline resistant washers and sealant to prevent leaks. Then just plumbed it from there. Never had a problem with it. Check for leaks with a piece of toilet paper. If it gets wet, it's leaking.

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My Elky Page (http://www.geocities.com/chadjlandry/index.html) (updated 3-15-01)
"Think for yourself. Don't let popular opinion make your decisions for you."
Chad Landry
TC Member #643
'68 El Camino



[This message has been edited by cjlandry (edited 03-16-2001).]

I thought that someone should state the obvious:

DON'T TOUCH THAT TANK WITH A DRILL ETC. UNTIL YOU HAVE IT STEAMED AT A RAD SHOP, AND THEN FILL IT PART FULL OF WATER ALSO.

I don't think that your siphon tube is the problem, since there are much faster cars that get away with this.

Electric fuel pumps don't live forever, especially in a dead-headed situation. IE idling around, your pump is trying to pump against a closed regulator, with only a small internal bypass to take off the load.

If you want to make it live forever (almost), run a return style regulator from the front back to the tank, OR get a pump with an external bypass.

Ryan

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RH
NX505-1 (http://members.home.net/30145365113/NX505_01.jpg) NX505-2 (http://members.home.net/30145365113/NX505_06.jpg) Gemini Quad (http://members.home.net/30145365113/NXQuad01.jpg) 505-1 (http://members.home.net/30145365113/505_Malibu11.jpg) 505-2 (http://members.home.net/30145365113/505_Malibu12.jpg) 505-3 (http://members.home.net/30145365113/505_Malibu04.jpg)

here's my experience:

electric fuel pump = long walk home http://www.chevelles.com/forum/smile.gif

Tom

Mike, Just run a carter high performance mechanical for street driving. and hook your mallory up to a switch and just use it at the track. I tryed the holley 110 gph pump on my 70 and it wouldn't keep up. My buddy turned me on to the carter.And i had no more trouble.

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Don Edmonds
T.C.Member 1033
1969 Chevelle
2000 Harley softail deuce
www.bottlerats69.homestead.com

That's what I was thinking, bottlerat. Why not plumb both pumps in. That way you can use the electric when you need it, and you have a back-up if the mechanical ever fails.

Of course, if you go this route, you're running the mechanical 100% of the time and that's taking a little power that you hoped to pick up when you went with the electric pump, right?

How much power does a mechanical pump take from the engine anyway? And how much current does the electric pump draw (this is your department, BB_Mike http://www.chevelles.com/forum/smile.gif )? Sure, it's electric, but that doesn't mean the engine doesn't indirectly supply the power to run it.

Now the question is whether the electric is more efficient than the mechanical. It probably is, but by how much?

My dad used to always ask me how much I was willing to pay to be 1/100th quicker or 1/4 mph faster. These days, on my daily driver, the dependability is worth more.

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My Elky Page (http://www.geocities.com/chadjlandry/index.html) (updated 3-15-01)
"Think for yourself. Don't let popular opinion make your decisions for you."
Chad Landry
TC Member #643
'68 El Camino

I think it was Car Craft that ran a test of electric vs. mechanical pumps and they showed that the mechanical did not take away any hp from the engine. Also, if you use a electric pump and put a mechanical on also, the electric pump will pump the fuel past the mechanical pump and into your crankcase. It's either one or the other...so I've heard.

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Justin Earnhart
TC member #657
502 4-speed 67 SS
"Suckin' gas and haulin ass!"

Justin, you'd have to plumb the two pumps separately all the way from the tank and "Y" them together before the carb with valves on each line. You definitely wouldn't want to run the two pumps in series on the same line.

Chad, that's what I meant, is that you couldn't have them on the same line. Just an FYI for Mike.

i have been running a carter elec. pump with the enging mounted pump for the last 13 years....never a problem...anything over about 2000r's then it needs the elec. on....at least i can get home if it goes out..