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Fuel pressure for 330 GTC

Discussion in 'Vintage (thru 365 GTC4)' started by JimEakin, Jul 15, 2020.

  1. JimEakin

    JimEakin Formula Junior
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    Jun 13, 2015
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    I'm finding out what can go wrong when a car is only driven 2,000 miles in 13 years.

    Yesterday, I lost fuel pressure on a hot day. I had about 15 miles to get home on a winding road. At least the electric fuel pump didn't quit completely. I was able to get home but I needed to stop every few miles to let the pump catch up a little. The mechanical fuel pump didn't seem to work at all.

    Tom Yang has a post about a neat way to add a separate electric fuel pump in parallel with the original pump. The referenced article showed a Facet Gold-Flo electric pump, but there are different pressures offered.

    Does anyone know the nominal fuel pressure for the 330 GTC?
     
  2. DWR46

    DWR46 Formula 3
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    Jun 19, 2012
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    You want a 3-4.5 psi pump. This is a "normal" occurrence with these cars and today's fuels. The best way to deal with this is to think ahead and as your see heavy stop-and-go traffic ahead, turn on the electric pump so it can get a head start on the situation. Tom's solution is also a good option for those that don't mind altering the original system.
     
  3. JimEakin

    JimEakin Formula Junior
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    Thank you, DWR.
    The problem is the electric fuel pump was on the whole time when I was running out of fuel. About half a tank, so not low on fuel. When I pulled over, I could hear the electric pump run free (fast clicking) then slow down when it caught again.

    As for the mechanical pump, it doesn’t work at idle or above 3,000 rpm. I ordered a rebuild kit for that primarily because the seal is leaking.

    I also ordered the bypass fittings that Tom Yang posted. Not planning to rebuild the original pump now, just adding a second pump.
     
  4. TTR

    TTR F1 Rookie
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    When was the last time the entire fuel delivery system (filters, hoses, tanks, etc.) got thoroughly serviced ? If more than 10 years ago, now might be a good time to do it.

    I currently sorting all that on a Daytona that has been driven less than 14K miles since new, +/-1000 miles in past 15 years and even sitting in a climate controlled SoCal private collection, lack of exercise and over-extended maintenance/service intervals had wreaked havoc on all of it.
     
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  5. christc

    christc Karting

    Mar 3, 2013
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    I also run two pumps in parallel. I use the facet solid state pump with lower range (I think up to 5 psi) and the original. I can have either running. You can rebuild the original one. If the membran itself is ok but the pump stoped working it is very probably the contact mechanism under the cap at the top of the pump. Clean it, especially contact surfaces, and try to adjust so that you get it running without fault. I used a bench setup to test it and had it running about an hour before installation. There is a kind of flat spring which needs to be ok for the plunger to work right. My english knowledge of the special terms is not sufficient enough to describe it better. You will find posts on the fispa pump here as well as on Tom Y. site.
     
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  6. DWR46

    DWR46 Formula 3
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    Jim: Another item that will help your situation is to add Marvel Oil to your fuel at the recommended dose of 4 oz/10 gal. Fuel today is very "dry" and the Marvel oil adds lubricity to help the valves in the pumps seal. The fuels in the 1950-60s, especially in Europe, was quite "oily" and this added lubricant provided a "seal" for the valves in the fuel pumps. We have done this for many years and find the pumps work noticeably better.
     
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  7. Edward 96GTS

    Edward 96GTS F1 Rookie
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    dyke, will adding marvel oil to the fuel possibly cause plug fouling? any adjustments required?
     
  8. DWR46

    DWR46 Formula 3
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    Ed; No, no effect on plugs. The amount is so small percentage wise that the mixture is unaffected. Never had to make any carburetor adjustments. In 1957, Maserati encountered fuel pump problems, just like we are discussing, at Sebring. They eventually determined it was the Amoco unleaded (yes, unleaded) fuel. Amoco was the race sponsor and everybody had to use their fuel. Maserati started adding a quart of motor oil to every 40 gal tank and the pump problems stopped.
     
  9. christc

    christc Karting

    Mar 3, 2013
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    How about using modern two-Stroke (API TC) oil as an add on in fuel (about 1%). I heard only good about this in relation to K Jetronic systems and fuel system components?
     
  10. JimEakin

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    Good advice all. Thank you

    I had to rebuild one fuel hose already, so likely when I get under the car I’ll see more to do.

    Tom Yang pointed me to the Facet Gold-Flo FEP60SV pump, which I ordered today. T Rutlands has the special fittings that Tom had made for the parallel install. The fittings replace the banjo bolts and provide rubber hose flair fittings to connect to the Facet pump. Super cool.
     

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