phaeton
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| posted on 20/2/06 at 01:40 AM |
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Fuel starvation
Currently running an x flow 1600 with 2 twin down draught weber carb’s (DCNF40)
When taking a left hand corner the engine starts to sputter sometimes in combination with a back-fire in the carb. Right hand bends aren’t a
problem.
This looks like the 1 or more carbs doesn’t get enough fuel.
To determine if the float level or the fuel delivery is the problem I want to plumb in a pressure meter.
I have lying around a mechanical oil pressure meter. Can I use this?
Any input appreciated.
Thanks in advance.
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nitram38
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| posted on 20/2/06 at 05:41 AM |
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I would suspect the floats in the carbs first as this is the more likely culprit.
You do not say wether it is a mechanical fuel pump or not, but if it is I would check that the diaphram is not punctured aswell.
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phaeton
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| posted on 20/2/06 at 08:48 AM |
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it's a electric fuel pump.
I suspect the floats also, but before opeing up the carb's it's maybe wise to measure if there is fuelpressure during those bends.
Can I use a (old) oil pressure gauge to do this?
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JAG
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| posted on 20/2/06 at 09:04 AM |
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If it's an old Mechanical Oil Pressure gauge then 'Yes' you can use it to monitor fuel pressure.
I have one in my car.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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phaeton
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| posted on 20/2/06 at 09:12 AM |
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Oke, I will give it a go then.
Thanks
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paulf
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| posted on 20/2/06 at 09:48 AM |
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Fuel pressure for carbs may not show up on an oil pressure gauge, as it will only be 2 or 3psi you need a special gauge to read low pressure, I bought
one from a motorfactors that shows vacuum and pressure to 5 psi .I had a similiar problem with an MGB the pump was weak and giving low pressure but it
showed up mainly under acceleration with misfiring and flat spots.
Paul
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02GF74
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| posted on 20/2/06 at 09:57 AM |
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Does it happen all the time?
It is not because of fuel surge in the tank? Fill tank right up and if it goes away, then it is not that.
Also are your carbs plumbed one after the other? Is it the carb first in line or the other?
If it is the last one, then maybe there is fuel restriction in the piping?
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phaeton
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| posted on 20/2/06 at 03:04 PM |
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Under acceleration is everything allright. So no restrictions or to small fuel pump. It happens only with lefthand bends. Righthand bends are ok. So
fuel surge isn't the problem. The carbs are plumbed in with a T-piece in the middle with the same length fuel line. To be sure i want to know if
the fuel pressure in those bends is the same. Before opening up the carb's.
Does anyone have/ know a cheap solution to measure the fuel pressure?
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02GF74
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| posted on 20/2/06 at 03:12 PM |
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quote:
Originally posted by phaeton
It happens only with lefthand bends. Righthand bends are ok. So fuel surge isn't the problem.
bu if pick up in feul tank is off to one side, then that is symptom of fuel surge?
Is the tank baffled?
Weird problem, that's for sure.
Is is defnitely fuel and not igniton? Something loose on/in the dizzy or wires shorting out???
Has it always done this or just started recently?
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phaeton
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| posted on 21/2/06 at 08:04 PM |
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In my tank (original escort) is the pickup pipe in the middle. So fuel surge shouldn'tbe the problem. The tank isn't baffled.
Ignition shouldn't either be the problem. I have just updated it to a megajolt system (which run very fine by the way).
That's why I suspect a float level in one of the carbs. Just to be shure I want to measure the fuel pressure. If that is okay the only thing
left is the float level i think
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