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Guys - ok, I need help. I'm a natural DIYer, bought a 78 Spider about 10 years ago and have done quite a bit of work myself. About 2 years ago, it stopped running and I was too busy IRL to deal with it....until now....

I've trawled thru postings here looking for a similar issue, but cannot find a solution.

So, on to the problem.....I'm 99% sure it's fuel pump related (mechanical fuel pump)....
  • took the pump apart, cleaned it, reattached it....no fuel getting to carbs (Del Oroto, replaced my Solex)
  • ordered a new pump from Classic Alfa - same result
  • figured it could be the line between the tank and the engine so bypassed it - still no fuel
  • read about mechanical fuel pumps here - that there are TWO rods (a big one and small one)? I only have a big one, that is in the engine block that drives the pump
  • so at this point, am perplexed. perhaps there is a rod in the pump that I'm missing? Cuz no fuel is getting to carbs (also cleaned out the fuel filter - there is no blockage there).
  • and yes, there is fuel in the tank :)
Any suggestions?
 

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Discussion Starter #2
One follow-on comment / question - for such old cars, is air in the fuel line a problem? because obviously my fuel line at the moment is ONLY air. If so, a functional fuel pump would replace the air with fuel within a minute or two ...so I'm left with the same problem....?
 

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Process of elimination, I had this problem once. First, with a short length of fuel pipe fit that to the pump, the other end to a jar of fuel on the floor under the car, try starting the engine. Does this fix the problem? Yes? Then you have a problem with the fuel line, the tank or the rubber fuel line between the tank and the metal fuel line. If no, then for some reason the pump itself is not pumping, or the push rod is not long enough to activate it, you do have the fuel lines attached the right way around, dont you?

Going back to fuel lines, the problem I suffered was a perished fuel hose from the tank to the metal fuel line, just replace all the old fuel hoses, they are old and need replacing anyway, mine was just sucking air rather than fuel. The other option, which gets talked about is the possibility of rust and muck in the bottom of the tank blocking the intake.
 
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One follow-on comment / question - for such old cars, is air in the fuel line a problem? because obviously my fuel line at the moment is ONLY air. If so, a functional fuel pump would replace the air with fuel within a minute or two ...so I'm left with the same problem....?
It's not air, its vapourised fuel. I've found E5 fuel to do what I call "standing vapour-lock", and requires the pump to be primed after a few days sitting. Just like you, I also bought a new pump, and replaced the fuel lines. I would guess continental E10 and E15 is even worse at evaporating away. I installed a hand priming bulb, I didn't have the patience to keep cranking for minutes on end. It only needs priming after a couple of days outside in the summer or ten days in a garage in winter. Maybe I didn't need to install the bulb, but I flattened the battery twice trying to start the car before I fitted it, and now it starts reliably at all times.
 

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I'd go with Stephen on this one, air leaks are insidious little devils and the pump will always draw air rather than fuel, if you are at all unsure about the flexi lines between the tank and the pump I would replace them and the clamps, I use V Power and Momentum which are both E5 and have to be honest, as far as I know they haven't caused a problem because my starting has stayed the same for five years, it was better after i fitted a 123 but that's another story, however all Alfa's are different even the same ones
 

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Discussion Starter #6
Well, an update of sort. Firstly, thank all three of you. I tried the glass bottle of fuel next to the fuel pump (now why didn't I think of that :) - no joy. So fuel type and vapour locks could be an issue but I need to look again at the pump. Will take it off tomorrow and send pics. Clearly it's not working.

In the meantime, there IS only one rod in my mechanical fuel pump. But I've read here that there should be two - a long one & a short one. Is this the truth for ALL pumps? Cuz that would explain it. The only problem is - I don't recall a PLACE for the second rod....

#ConfusedAboutFuelPumps :)
 

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and regarding the hand priming pump, I like this idea. I've ordered one but seems to be a 2 week delivery time ..... :(
 

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I only have one rod driving my pump. Are you sure you have the pipes connected the correct way around? If the pump isnt lifting from the jar, its nothing to do with vapour lock or priming.
 
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compare the old and the newside by side.
I think I read somewhere that the mechanism the rod presses on can be different...set back further or something with some of the new pumps...?
this thing: (pump is obviously different type, just for illustration purposes)
pump.jpg
 

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and regarding the hand priming pump, I like this idea. I've ordered one but seems to be a 2 week delivery time ..... :(
I got my inspiration from my aircraft installation, I think I fitted one of these:
For the first few times driving I was convinced it was going to split open and catch the car on fire. It hasn't yet, but everytime I use it I check it very, very carefully. It may be you only need to prime your fuel pump one time to wake it up from is long sleep on the suppliers shelves, then you can disconnect it.
 

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Discussion Starter #11
Thanks Alfahaze - I gave that some thought and had already decided to remove it (assuming I CAN get the car started!) each time.

Top Down - it's good to see someone else out there with only one rod. Frankly, I'm questioning everything now. Logic WOULD imply it's connected the wrong way. Can you tell from this pic? Essentially the left side (the side closest to the cockpit) I have connected to the fuel filter. The currently unconnected receiver on the fuel pump is the one I have connected to the tank (and tried your idea of the jar of fuel)...
938992
 

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That is the same as on my fuel pump, but the pump top looks different so, well, it might still be wrong. However! Fuel filter/pressure regulator!! Do you have enough length in the hose from the carbs to be able to put it directly on the pump, to bypass the filter/regulator?
 

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Progress of sorts to report. I took off the pump again (50th time it seems) JUST to ensure the rod moves smoothly. it does. hooked it all back up and put a small glass jar of fuel under the car (as you suggested - the first time I just ran a line into my jerry jug).

Well...the car still didn't start but the fuel was sucked out of the glass jar...so I refilled it and it was sucked dry again. So...fuel pump works!

I suppose there isn't enough fuel in the carbs to start the engine so now I'll just wait for the hand primer.

In the meantime, any idea how much fuel is required to start the car (in order words, the fuel filter was dry and the carbs were dry - so both need fuel before the fuel hits the cylinders. I'd estimate about 10oz / 300ml are now in the system..
 

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Check to see if the glass bowel has fuel in. I'd just keep applying fuel until it wont draw any more. You could also check to make sure there is fuel coming out the pipe that goes to the carbs, I did wonder if the filter/regulator had a stuck valve causing the whole problem.
 
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Progress of sorts to report. I took off the pump again (50th time it seems) JUST to ensure the rod moves smoothly. it does. hooked it all back up and put a small glass jar of fuel under the car (as you suggested - the first time I just ran a line into my jerry jug).

Well...the car still didn't start but the fuel was sucked out of the glass jar...so I refilled it and it was sucked dry again. So...fuel pump works!

I suppose there isn't enough fuel in the carbs to start the engine so now I'll just wait for the hand primer.

In the meantime, any idea how much fuel is required to start the car (in order words, the fuel filter was dry and the carbs were dry - so both need fuel before the fuel hits the cylinders. I'd estimate about 10oz / 300ml are now in the system..
The hand primer takes five or six good pumps before the floats stop the fuel going into the bowls and it becomes rigid. So I guess about 5 egg cups full ? The filter can retain vapour in it even though the carbs are full up. The accelerator pumps squirt out quite a lot, and the pump chamber usually has enough in it to start the car for about a half second. Good luck, sounds like you are nearly there.
 

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Discussion Starter #17
Spiderserie - yes, that's exactly the fuel pump that I have. It works. Just need to figure out why the car still doesn't start....
 

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I couldn't sit back waiting for some priming gadget!

try to start it on starter spray...if it runs, even for only some seconds at a time, that ought to help suck fuel through the carbs (if they are not blocked)
 

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I couldn't sit back waiting for some priming gadget!

try to start it on starter spray...if it runs, even for only some seconds at a time, that ought to help suck fuel through the carbs (if they are not blocked)
Spiderserie4 - you're right. I couldn't wait either. And I'm glad I couldn't!!

Also to all - thank you for the insight, advice and support. I'm happy to report that it STARTS! After 2 years lying dormant (yes, I realise this last statement will not go over well within this enthusiastic group :)

Listen to that most fabulous of sounds...a 1978 2litre Alfa engine :love: IMG_6491.MOV
 

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Well done, any idea what it the problem was?
 
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