wrigglypig
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| posted on 30/5/09 at 07:28 PM |
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Fuel Starvation update
Still got problems with the fuel starvation
New fuel pump fitted ( mechanical) pushrod free and moving ok ( no wear)
Drive it hard in 1st then second and before you can get 3rd it dies. The fuel pick up is on the horizontal at the bottom of the tank and at the
front.... so I think that with the inertia the fuel washes to the rear of the tank. This seems to be borne out by the fact that when the tank is full
it does nt seem to happen, but it isnt always possible to keep it full. I have read about swirl pots are these just for EFI's or would a
seperate swirlpot sort the matter out?
Ps its a pinto 2.0l with std carb
Any ideas??
Kev
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mark chandler
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| posted on 30/5/09 at 07:39 PM |
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Swirl pot will sort if thats your issue, just need two low pressure pumps.
Does the car do this if you go flat out up a hill? If so it could be the float valve being to small stopping the carb from filling.
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wrigglypig
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| posted on 30/5/09 at 07:42 PM |
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I havnt tried the hill bit yet, I obviously dont understand the swirl pot bit and 2 pumps. I thought it was just a seperate reseviour for the pump to
pump from
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02GF74
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| posted on 30/5/09 at 07:45 PM |
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quote:
Originally posted by wrigglypig
The fuel pick up is on the horizontal at the bottom of the tank and at the front....
sorry but I don't understand that.
what is the size of your tank? how far from the bottom of the tank is the pick up end?
is the tank vented?
you can verify your theory by fitting a hose to the pump feeding from a petrol can mounted securely.
or maybe temporarily fit a transparent section that you can see from the driving position.
my gut feel is that you would need acceleration that is far in excess of what F1 cars achieve.
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wrigglypig
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| posted on 30/5/09 at 07:56 PM |
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The tank is 13 gallon rectangular tank 8mm o/d take off horizontal position on the bottom edge of the tank the outlet faces forward, there is an air
vent on the top of the tank which is clear. I suppose it could be an issue with the float level? I bet thats a bugger to set though?
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Dusty
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| posted on 30/5/09 at 08:11 PM |
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Just fill the tank full and try driving. If all is well, it accelerates normally then it is indeed fuel starvation due to surge. If it is still
happening then you have eliminated surge in the tank and you need to go through the fuel system bit by bit till you find the fault.
Sorry just re read your post and you say this sorts it. Still sounds like you are emptying the float chamber which means the pump is not supplying
enough fuel. Pinto pump can do twin 45's and then some so think blockage in the pipes, air leak between tank and pump (the sucking side) crap in
the tank blocking pickup pipe, worn and thus short pushrod or worn cam lobe on the jackshaft failing to move the pump mechanism to and fro. Blocked
float valve.
Could also pull the pipe off the carb and feed it into a bottle and crank the engine. Should get a good flow of fuel, one spurt of about 5ml with each
revolution of the engine.
[Edited on 30/5/09 by Dusty]
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mark chandler
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| posted on 30/5/09 at 08:24 PM |
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Hello,
A proper swirl pot is a seperate tank from the main fuel tank that holds around 1 litre of fuel, could be more or less does not really matter.
This tank provides fuel to the engines fuel pump and is designed to keep fuel over the outlet in variopus angles, its called a swirl pot as the fuel
enters at an angle so make ths fuel 'swirl' within the pot which aids in keeping the outlet covered.
The main tank pumps fuel in to the secondary tank to keep it full.
Looking at this another way, if your main tank was a 6" wide tube 6 foot tall sat behind you when full unless you were on your side the engine
would never suffer from fuel starvation.
An 'in tank' swirl pot is a poor mans substitute, put the fuel pickup in a small pot within the tank, when you corner hard although the bulk
of the fuel moves away the pickup is in its own mini tank effectively.
Anyway a picture paints as they sayImage deleted by owner
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mark chandler
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| posted on 30/5/09 at 08:28 PM |
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I should add, you do not need to spend £££ on a pucker pot, just make something with fuel in at the top and fuel out at the bottom, I capped a bit of
tube to make mine.
 
Rescued attachment Swirl_pot.JPG
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wrigglypig
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| posted on 30/5/09 at 08:50 PM |
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Cheers Mark, I think I have to prove the pump and float bowl by using a seperate tank in the car as a temporary measure, the pump pushrod moves about
10mm and it squirts plenty of fuel so I think that is ok. SWont get to do it till next week as it is hoing for a custom stainless exhaust making in
leeds on Wednesday, might post a piccy or two when its done.
Kev
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Chippy
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| posted on 30/5/09 at 10:13 PM |
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Could you not extend the pick up pipe further into the tank, I know that means draining it down, but you should be able to slide a piece of 6mm copper
tube into the 8mm, and extend to be an inch or so from the back of the tank. 6mm is plenty big enough to supply fuel to your engine, (my 24V Cosworth
has 6mm pipe to the fuel rail). Just a thought. Cheers Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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wrigglypig
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| posted on 30/5/09 at 10:30 PM |
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Now that is a distinct possibility, thank you for all your suggestions, I will come back you you in the next 10 days or so and see how its gone.
Cheers Kev
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