Lotus Elan

SOLVED Electric Fuel Pump problem?

PostPost by: Tahoe » Thu Sep 27, 2012 4:03 am

So you don't have to read the rest of the thread I'm editing the original- What happens if the pickup tube is not sealed to the bottom of the tank? It can't suck gas (petrol), correct? I traced every inch of the fuel line from the tank to the Webers and finally got the pump to flow freely by bleeding all the air and by feeding the pump with a gas can. Then I hooked it back up to the tank and it wouldn't flow. WTF? So I removed the NPT fitting stuck a 1/4 inch pnuematic air line down the pick up tube and clamped it to the 5/16 inch fuel line feeding the pump. Guess what the pump worked perfectly and gas was getting to the Webers. Removed the pnuematic tube and put the fitting back on the tank (sealed) and guess what no gas flow! Now I can't prove that the pick up tube has an air leak without taking the tank apart can I? What are your thoughts? Am I right or could there be another issue?


When I bought my car it had one of the facet fuel pumps installed. It quickly was no good because of the rust in my tank and the PO never put a filter on the car. Bought a new one and added a fuel filter it worked great except the filter was being replaced every other week because they kept getting clogged up with rust. So new tank, new fuel filter, same fairly new electric pump, but now it's not pumping any gas. Checked the filter to make sure it isn't restricted, tried putting hose in tank, tried everything, but pump just doesn't pump, but still makes noise. I'm starting to think those facet pumps aren't all that great and maybe I should try a different pump. What electric pumps are you using and what psi is it pumping at? I used to here all the time that the side drafts shouldn't use a pump over 2 psi, but I've also heard that 2 psi is too little, and 4 psi is better. Any thoughts on the Carter P4070 pump?
Last edited by Tahoe on Fri Sep 28, 2012 4:48 pm, edited 1 time in total.
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PostPost by: 69S4 » Thu Sep 27, 2012 6:22 am

I've had a facet pump (silver top version I think) in my S4 for close to 30yrs now and it's been absolutely reliable. About 4-5yrs after fitting it the original fuel tank rusted through and after a few years of short term rust ridden repairs it was changed for a new one. I had no problems with the pump during the rust years. It's fitted in the boot/trunk next to the tank and uses the original fuel lines to feed a pressure regulator /filter mounted by the rad. The filter earnt its keep with the old tank but these days virtually nothing comes through. I've no idea what pressure it's running - I've adjusted the pressure setting to both ends of the screw and not noticed any difference so I just set it in the middle and left it. That's with Strombergs though, Webers / Dell Orto's may be more sensitive.
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PostPost by: Elanman99 » Thu Sep 27, 2012 7:43 am

Totally agree with Stuart, I have had a Facet pump on my S4 for over 40 years, its outlived three steel tanks and it never had a filter on its inlet (until a couple of years ago when I fitted an aluminium tank).

They are easy to dismantle, and if it making a noise then there cannot be much wrong with it so dont give up.

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PostPost by: robertverhey » Thu Sep 27, 2012 10:54 am

Mine came with one of these,mounted near driver's side headlight pod. I really like it, suits the car's period. Very solidly built, not too noisy.
http://www.ebay.com.au/itm/EP42-6471325 ... 1c2b37af75

Bit of a thread on it here (initiated by myself) elan-f14/anyone-recognise-this-fuel-pump-t22358.html , the forum pointed me at a supplier of replacement bellows. And I found another one cheap on ebay for spares. So that's me sorted, fuel-pump-wise.
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PostPost by: Tahoe » Thu Sep 27, 2012 4:22 pm

Not really sure if the pump has an issue or not. What I am sure of is its not pumping, but is making lots of noise. I tried to prime it late last night by making sure gas was at the inlet to the pump, but it still didn't work. The last pump I had I took apart, and the rusty crude had broken the diaphram. I haven't taken this one apart yet to see if the diaphram has an issue or not. The only thing I can think of that could cause it not to pump is an obstruction upstream somewhere. I don't think this is the problem, since it worked fine before. Sitting for 10 months while waiting for the new gas tank may have caused a problem I'm not aware of though. I guess I'll keep moving in the direction of the carbs until I find the problem.

Editing response because I looked up facet fuel pumps and it says they don't have a diaphram. My first one did (maybe it was really old), maybe this one does not. It also says they are self priming, so if thats the case the pump might have an issue.
Last edited by Tahoe on Thu Sep 27, 2012 4:44 pm, edited 1 time in total.
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PostPost by: RotoFlexible » Thu Sep 27, 2012 4:43 pm

I have been using the Carter pump (pretty sure it's the 4070) since the major overhaul four or five years ago. It is mounted to the front wall of the boot just to the side of the tank, and is on the noisy side. I run it through a regulator (set to about 3psi IIRC).

The following may not apply to you since you have tried a separate tube feeding from the tank, but it's a worthwhile cautionary tale nonetheless. Ever since the aforementioned overhaul, I have had occasional fuel feed problems. During the overhaul, the tank was reconditioned and sealed. After the most recent round of problems, a few months ago, I applied my Mity-Vac to the tank's fuel line. I was rewarded with a little glob of silicon sealer - just the right size to clog the fuel pickup line. When I replaced the fuel gauge sender, I applied a very thin coat of sealer - not thin enough, apparently, as some had oozed to the mounting screw holes, and been pushed into the tank by the screws. I am embarrassed to say that this is not my first time for this. I drained the tank through a filter (finding a few more globs) and everything has been fine since.
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PostPost by: rgh0 » Thu Sep 27, 2012 6:33 pm

Not sure what style Facet you have but the cylindrical ones have an internal filter. If this is blocked the pump would run and you would hear the piston moving but it would not move the fuel.

The inlet end of the cylindrical pumps has a hex head on it a some lugs on the side - rotate to remove the head and you will see the filter mesh inside.

The square facet pumps may also have a filter inside but I dont know for sure as i have never opened one up.

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PostPost by: Tahoe » Fri Sep 28, 2012 5:07 pm

B.umped so you read first part of post. Problem Solved I believe, need you opinion
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PostPost by: rgh0 » Fri Sep 28, 2012 5:20 pm

The pick up tube could have cracked or it could be blocked with rust. Try blowing compressed air back down it to clear it and then see if it flows - if it does then was blocked with rust and you need to clean out the tank. If it still does not flow you need to clean out the tank and replace the pickup tube

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PostPost by: Tahoe » Fri Sep 28, 2012 5:23 pm

Rohan,

It's a brand new Aluminum Tank and it is clear and clean. Even put a Borescope through the filler to confirm everything is nice and clean.
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PostPost by: rgh0 » Fri Sep 28, 2012 5:36 pm

i would still blow the pick up tube to verify its clear and then if it still does not work it clearly has a leak. Then I would send the tank back to the supplier to fix the problem with the pickup

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PostPost by: Tahoe » Fri Sep 28, 2012 6:18 pm

Removed pnuematic tube, used air compressor to back blow through pickup tube, put fitting back on and connected fuel hose, no fuel flow! Removed fitting, stuck pnuematic hose back down pickup tube, fuel flows again and engine runs. Has to be a cracked or pinhole leak in fuel pickup tube inside the tank. Very frustrating as there is absolutley no way to see where the problem is and the hole could be tiny. I just don't see any other answer except the pickup tube inside the tank is not air tight above the fuel line. By the way I put 2 gallons in the tank and with the borescope I could see the fuel level above the pickup so I know the fuel level isn't too low. What I can't see is the welds etc. that could be at fault. Has anyone any ideas on how to fix this issue without sending the tank back?
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PostPost by: archigator » Fri Sep 28, 2012 7:25 pm

Do you have an in-line filter between the tank and the pump? I had a similar issue, blamed it on my mechanical fuel pump, but found the problem to be a brand new in-line filter that I had recently installed. The filter was too restrictive for the pump to move fuel through. A second brand new filter did the same thing. Your electric pump may or may not have a similar issue with an upstream filter. Just a thought...

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PostPost by: Tahoe » Fri Sep 28, 2012 7:41 pm

archigator wrote:Do you have an in-line filter between the tank and the pump? I had a similar issue, blamed it on my mechanical fuel pump, but found the problem to be a brand new in-line filter that I had recently installed. The filter was too restrictive for the pump to move fuel through. A second brand new filter did the same thing. Your electric pump may or may not have a similar issue with an upstream filter. Just a thought...

Gary
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It's not the pump as I found out, it's not fuel filter (which is new) that I took off and made sure it was clear of anything. The fuel filter is see through, and there is no crude showing. Car runs when bypassing the internal pick up tube by putting another tube inside the pickup tube. Car runs fine when doing this, but doesn't pump gas or run (obviously) when using the tank pick up tube alone. This is a new tank, it's clean, etc. but I'm assuming it has an air leak preventing fuel to be picked up internally.
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PostPost by: richardcox_lotus » Fri Sep 28, 2012 8:38 pm

" Car runs when bypassing the internal pick up tube by putting another tube inside the pickup tube". You may well be right re your hypothesis - if so & you have a workaround - why not use that as the fix rather than having to remove & send back the tank ?

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