Vindi_andy
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| posted on 23/4/10 at 01:22 PM |
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Spluttering engine
Ok fellow hydrocarbon heads quick challenge, I think i know the answer just want some confirmation before spending hard earned cash
Got a ford Twincam with EFI in my vindicator Family and under normal driving have no problems, however under hard driving particularly when cornering
or when fuel level is lowish the engine splutters and misses then picks up again.
Got a large tank across the back of the car with what the manufacturer called a swirl pot, which is about 3-4" cube mounted below the main tank.
The fuel return goes into this and I have a high pressure fuel pump between swirl pot and engine but the feed from main tank to swirl pot is gravity
fed.
I suspect the engine is suffering from fuel starvation and i need a low pressure pump to fit between main tank and swirl pot.
I know its difficult to diagnose without experiencing it but in your combined esteemed opinions is this likely the case. Is a low pressure fuel pump
likely to cure it. And finally do the low pressure fuel pumps run contiuosly or do they have an internal pressure switch such that if the swirl pot
is full they wont continue to try and pump fuel into it.
Also posted on rhocar so if you have answered there no need to answer twice
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big-vee-twin
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| posted on 23/4/10 at 01:28 PM |
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see below
Image deleted by owner
Both pumps just circulate the fuel around their respective circuits
[Edited on 23/4/10 by big-vee-twin]
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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Vindi_andy
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| posted on 23/4/10 at 01:32 PM |
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Thanks for that however there is a slight problem.
Only got 3 connections to the swirl pot and that drawing says I need 4
Havent got a spaer connection for the overflow return
[Edited on 23/4/10 by Vindi_andy]
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big-vee-twin
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| posted on 23/4/10 at 01:46 PM |
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Thats probabily why you havent got a low pressure pump - it does sound like starvation to me though, but the pic is pretty much how most people do it.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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Vindi_andy
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| posted on 23/4/10 at 02:22 PM |
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thanks for that.
Just one thing to say. BU66ER I didnt make the swirl pot and i dont fancy welding a new threaded fitting in it now
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PSpirine
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| posted on 23/4/10 at 02:37 PM |
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As a thought, could you not run your return from the fuel rail straight back to the main tank, and then use the 3 connections on the swirl for Low
Pressure Input, High Pressure Output, and Overflow?
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bbwales
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| posted on 23/4/10 at 03:06 PM |
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Could you put a "T" into the swirl pot to tank return and then put the fuel return into the "T" too?
Bob
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Vindi_andy
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| posted on 23/4/10 at 03:15 PM |
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thanks guys knew I could rely on you
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Vindi_andy
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| posted on 23/4/10 at 03:25 PM |
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quote:
Originally posted by PSpirine
As a thought, could you not run your return from the fuel rail straight back to the main tank, and then use the 3 connections on the swirl for Low
Pressure Input, High Pressure Output, and Overflow?
OK this kinda makes sense and shortly after Big Vee posting the picture this crossed my mind, however without putting the T in the return line where
do I take the swirl pot overflow. Can this be taken to the main take breather, problem I see with that is im then creating a closed loop system.
And sorry if this seemed like a daft question but im sure youve all suffered from being too close to the problem to see the solution.
[Edited on 23/4/10 by Vindi_andy]
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PSpirine
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| posted on 23/4/10 at 03:32 PM |
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Ah, didn't realise your main tank was also lacking one connection!
In that case, yep you'll probably need a T-piece (don't use the breather as you'll just create an airlock). I'd be tempted to
stick the T piece so that it's between the main tank and swirl overflow, with the main fuel rail return tapping into the T.
The only thing you might get is backflow into the swirlpot from the rail return... which isn't ideal as all your fuel pressures will be all over
the place depending on fuel usage.
Does your main tank only have 2 connections + breather?
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Vindi_andy
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| posted on 23/4/10 at 03:54 PM |
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yes main tank only has 2 connections and breather. the more answers I get on this the more it seems the manufacturer who supplied me the tank and
swirl pot (at the same time under their recomendation) has dropped a cod
I have already fitted a non-return valve in the fuel rail return, because i didnt want the tank emptying via the fuel return, so if I fit the T piece
between the main tank and the non return it shouldnt affect the pressures
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dlatch
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| posted on 23/4/10 at 04:29 PM |
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i think it makes more sense for the fuel return to go to main tank where it can lose heat, rather than go back into the swirl pot and straight back to
engine, i know i would do that myself
then just T into the return from the swirl pot onto the main tank
jobs jobbed 
ps also i think the pressure reg should be before fuel rail on the drawing them injectors will be getting whatever pressure pump is running, i would
also have the pre filter before inlet into LP pump
[Edited on 23/4/10 by dlatch]
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PSpirine
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| posted on 23/4/10 at 04:43 PM |
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The way you suggested with the T between the valve and main tank is a good way of doing it I think.
Ideally, I'd try and weld a connector onto either the swirl pot or your main tank to be honest.
(Personally if it was my car, I'd probably chemical metal a nipple on top of the main tank, use that for the little breather hose, and then
connect the swirl pot overflow to the current, properly welded breather connection!)
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Vindi_andy
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| posted on 23/4/10 at 07:43 PM |
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there is a threaded fitting welded to the top of the tank for the breather with is a metal hose fitting and a length of fuel hose. If I do as you
suggest PS and chem metal a breather onto the top of the tank then I could use that fitting to connect the swirl overflow to.
Post stoneleigh mods methinks. want to use Tango while the sun is shining.
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