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914World.com _ 914World Garage _ Intermittent fuel pressure drop (carbs) daily driver

Posted by: theo Jul 10 2010, 04:20 PM

Hi ,I have a 1.7 with a single webber. Most of the time everything is normal with 5 lb of fuel pressure however, recently it began to completely randomly drop fuel pressure, (many times to the point of stalling the engine). I would be driving at a constant speed… and all of a sudden there would be no power and it would just stall. Anyway I have yet to track down the problem and would appreciate any input or advice. I have a pressure gauge on the fuel line before it enters the carb. And there is a notable fuel pressure drop. I installed stainless steel fuel line most of the way from the tank to the engine. I relocated the fuel pump forward to the cavity under the car below the tank. The pump is a low pressure in line pump, (recently replaced) . The pump is wired with the ground to the frame and the positive wire is connected to the coil (so there is 12 volts to the pump when the key is in the on position). I have tested, and connected the pump directly to 12 v battery and there is still no pressure at the gauge. Recently I removed and cleaned out the tank and screen in the bottom, and of course I have replaced the filter several times. Anyway this one has me stumped… I would appreciate any input and suggestions… could it possibly be a faulty fuel pump? Its under a year old
Thanks,
Theo B

Posted by: 9146986 Jul 10 2010, 05:25 PM

I'd carefully examine the routing of the fuel lines. Sometimes if you have too much fuel line, or too much bend it can kink and restrict fuel flow.

Posted by: jmill Jul 10 2010, 06:12 PM

Is it the clicky clacky faucet style pump? If so I'd lose it and get a rotory.

Posted by: ME733 Jul 10 2010, 09:15 PM

Some fuel filters will just "clog up" when there is excessive water....the water will just not flow through, or flows thru much slower than gasoline . This is particularly a problem with cars that sit ,without use, for extended periods of time.(one week).Gasoline, alcohol, and water seperate....1.(test) Run fuel line into clear container.,let sit overnight.,water will be at the bottom.2.drain off(pump off) at least two gallons of fuel....3.replace fuel filter....4., Remove carburator, dump out fuel in float bowl...5. I have tried many brands/types of fuel line dryers, but I cannot detect that any are better than any other...A fuel line dryer will not solve the problem if their is severe water contanination.