Powerhouse Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) Hello all, I decided to hook up an electric fuel pump on my 39. The old pump just wasn't working as good as it used to...or else it was just getting too hot under there, I had a shield over it too. The car stalled last week and wouldn't start for a while, and did the same this week. I checked for spark, had spark...checked for gas spray in the carb...nothin'! Then I checked for gas in the line before the filter to carbs, leaked all over. Checked filter clean and rather new. Must be getting vapor lock...I guess. SO, I decided to get an electric pump. $60 for a big carter rotary thing...bigger than I thought it would be. Mounted in back near tank. Directions said NO TEFLON tape to be used on fittings. But they still leak a little even when tightened all the way. One headache after another. Anyhow, my question is does the electric pump stay running or should it be turned off after start? I think it just stays on the whole time correct? An old timer told me to just use it to prime and then once the engine is running, kill the pump. I have mine running by toggle switch, seems to die off once the bowls are empty. Edited October 29, 2009 by Powerhouse Quote Link to comment Share on other sites More sharing options...
baldbusdriver Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) are you running the electric pump in series with the mechanical pump? or are you just using the electric? if its in series the pressure from it may blow out the diaphram in the original pump and cause even more problems. if using just the electric pump, you should use a fuel pressure regulator to keep the carb from flooding and such. the fittings for the pump should be treated just like a brakeline. when first screwed together you should back off and retighten 4 or 5 times to get the seal to form up and be leak free. is it possible the original mechanical pump has worn out? that can cause some probs like you are describing. I forgot to add, yes when using an electric pump it stays on, on for fuel, off for no fuel, make a simple antitheft if the switch is hidden somewhere. Edited October 29, 2009 by baldbusdriver Quote Link to comment Share on other sites More sharing options...
Cpt.Fred Posted October 29, 2009 Report Share Posted October 29, 2009 i switched from mechanical only to electrical only, no problems so far (the pump died on me a couple of weeks ago, but that doesn't belong here...) it's important to know the exact operating pressure of the pump when you do run it alone, too. if it's not to high, you can simply connect it to the carb, without a runback. i'm using a fly pump/ vane type pump producing about 0,4bar of pressure when run on 6V, and that's just fine. the float chamber valve is strong enough to close when the chamber is full and the pump just keeps on running without causing any trouble. i have a switch as well, so when i turn the ignition on i have to turn the pump on seperately. not original, but cheap and efficient, and you save a lot of battery power because you have correct fuel pressure from the beginning on and the engine fires up right away without endless turning after a long sit in the garage. if you run it in line with the old pump, you might as well switch it off, but only if that old pumps works correctly, otherwise i'd guess it wouldn't improve anything, car might still stall because of insufficient fuel / fuel pressure. Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) The venders are now selling the Airtex electric fule pump at the flea markets. If you look up Airtex on line they will list their fuels pumps. They make them in 6v and 12 v. the cost runs around $50.00. Airtex is now a major manufactor for factory fuel pumps and you can also get mechanical pumps from them for our cars. I do know that the 588 is the pump that fits my 39 DeSoto and is the replacement for the old AC588 pump. The Airtex electric pump is a real nice small unit and can be used now with the new gas with the ethinol. Here is the link to Airtex and their electric pump: http://www.airtexproducts.com/TSB/TSB-0108-01_ATX.pdf rich Hartung Edited October 29, 2009 by desoto1939 Quote Link to comment Share on other sites More sharing options...
greg g Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) Depends on the pump but most of them will shut off afer the line is full and pressure builds up, then they will run only long enough to refill and maintain what ever the preset pressure is. You can usually hear when they are running. Modern cars are a bit different running at much higher pressure for the fuel injector system and for the return line that nearly everyone has. They run constantly, the reason they are in the tank and runinng submerged in the gas to keep them cool. Edited October 29, 2009 by greg g Quote Link to comment Share on other sites More sharing options...
Powerhouse Posted October 29, 2009 Author Report Share Posted October 29, 2009 (edited) Thanks guys... I am running electric only...old pump is on my wall as an ornament...and backup. The pump is a NAPA bought Carter 6 volt pump(napa 4259 i think)...it was $60 some dollars...and a really nice rotary unit. I don't remember the pressure it puts out(maybe 4-7psi)...but I'll check the box after work. Edited October 29, 2009 by Powerhouse Quote Link to comment Share on other sites More sharing options...
NatesSedan Posted October 30, 2009 Report Share Posted October 30, 2009 The Carter rotary vane fuel pumps run all the time. They are also (at least for me) a royal pain in the you know what to make them quiet down. I ended up building a bracket to house the bracket with lots of rubber to take away some of the vibration. Its much better now and my glass filter has never been so full. Quote Link to comment Share on other sites More sharing options...
grey beard Posted October 30, 2009 Report Share Posted October 30, 2009 i have the same pump on my truck. It works just fine and needs no pressure regulator. Sure does save a lot of cranking after it has been sitting a while. Sure is noisy. I can handle the noise if it is dependable and lasts a while. The solid state Auto Zone pumps lasted only a short while for me, and cost nearly the same price. Good Luck Quote Link to comment Share on other sites More sharing options...
msawdey44 Posted October 30, 2009 Report Share Posted October 30, 2009 Something worth thinking about is to provide some means of assuring that the pump shuts off if the engine stalls, so there is no chance of it pumping the contents of the tank past a less-than-perfect needle valve. I put a plumbing Tee in the oil line, with a normally-open, 5 psi pressure switch (the Summit Racing folks carry these, since stock cars all use a system like this). I also have a toggle switch to override this so that, as noted in other posts, I can use the electric pump to refill the bowl after a long winter's nap. Another way of assuring safety in the event of a crash is to use a Ford OEM impact switch--they're cheap at the pick-a-part folks or on eBay, and they can be reset after an impact. And, yes, the pressure regulator is a good idea, even though the electric pumps are available in a 5 psi version--the old carbs only need about 2 psi to be happy. I did find that the no-name pressure regulators that various folks sell at swap meets are mostly junk--they either leak or simply don't work. I finally spent the money for a Holley unit, again from Summit Racing. I also plumbed in a cheap fuel pressure gauge, so that it would be possible to set the pressure to a specific figure. Quote Link to comment Share on other sites More sharing options...
Powerhouse Posted October 30, 2009 Author Report Share Posted October 30, 2009 thanks all. I just took a test drive. Runs great...actually feels better than before. I have it rigged so it's not too noisy...rubber pads and whatnot. I'll make a box to cover it from outsiders and also it will double as a heat shield. I'll keep it on a switch for now. I kinda like it...seems more old fashioned hahaha. Kinda like a B-17 or a P-39 or something...sorta. Well, I can dream can't I. Forgot to mention this pump is feeding two carter weber progressive 2 bbls. So I guess they can handle the pressure...which I haven't been able to pinpoint yet. Quote Link to comment Share on other sites More sharing options...
Normspeed Posted October 30, 2009 Report Share Posted October 30, 2009 I also plumbed in a cheap fuel pressure gauge, so that it would be possible to set the pressure to a specific figure. How much pressure do you run? Quote Link to comment Share on other sites More sharing options...
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