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View Full Version : Bouncing fuel preasure needle.....Update.



Last Real Texan
02-01-2007, 07:31 AM
Well after going in steps trying to narrow down the problem I have made no headway...added fuel to the tank and ran it.........still there, removed the added shut off valve......still had it. So I figured I would give the guage a rest and decided to call Mark @ precision marine. He said to me, First are you using a dampened preasure guage? I said no, first problem he said , was it a quality guage I said no, get a new one you have quickly worn the guage out with the pulses in the injector firing. Second thing he asked was where did you return the fuel to? I said to the filter head after running it through a fuel cooler....He said,"wrong" for the best consistant fuel preasure and longevity of the pump return it to the tank making it an open system. He told me closed EFI systems in this application are hell on the pump and really do not work well in the long run says almost no matter what you do the pump will cavitate introducing air to the fuel and reaking havock on the system. All sounds reasonable to me.
So I removed the inspection plate for the tank filler , removed the hose to the tank and am now making a return fitting to put inline with the filler hose @ the tank , with a 3/8 fitting welded inplace to return the fuel to the tank. I am making one similar to the MOROSO one pictured here. I would have ordered one of these but the fitting is for 2 inch ID hose and my filler tank is only 1.5 inch ID, not to mention I like to make parts. So he told me this all together will make things better.
I wont be able to test for about a week and a half......HAve to go to Amsterdam NE. Ciaro and Alexandria, Egypt on business, sucks but somebody has to do it. Not leaving till Saturday .....btu rain is in the forcast for the next couple of days......Anxiously looking forward to getting a test run with the new set-up and the Pro charger but do not want to rush it and not have everything done right and risk a bad result....you know what they say Measure twice......cut once!
Bryan

BigGrizzly
02-01-2007, 06:02 PM
Good info I forgot you can't run the return like that on a high pressure system. On a carb system you can get away with it. Take your time I did and don't regret it in the least.

mrfixxall
02-06-2007, 09:42 PM
Well after going in steps trying to narrow down the problem I have made no headway...added fuel to the tank and ran it.........still there, removed the added shut off valve......still had it. So I figured I would give the guage a rest and decided to call Mark @ precision marine. He said to me, First are you using a dampened preasure guage? I said no, first problem he said , was it a quality guage I said no, get a new one you have quickly worn the guage out with the pulses in the injector firing. Second thing he asked was where did you return the fuel to? I said to the filter head after running it through a fuel cooler....He said,"wrong" for the best consistant fuel preasure and longevity of the pump return it to the tank making it an open system. He told me closed EFI systems in this application are hell on the pump and really do not work well in the long run says almost no matter what you do the pump will cavitate introducing air to the fuel and reaking havock on the system. All sounds reasonable to me.
So I removed the inspection plate for the tank filler , removed the hose to the tank and am now making a return fitting to put inline with the filler hose @ the tank , with a 3/8 fitting welded inplace to return the fuel to the tank. I am making one similar to the MOROSO one pictured here. I would have ordered one of these but the fitting is for 2 inch ID hose and my filler tank is only 1.5 inch ID, not to mention I like to make parts. So he told me this all together will make things better.
I wont be able to test for about a week and a half......HAve to go to Amsterdam NE. Ciaro and Alexandria, Egypt on business, sucks but somebody has to do it. Not leaving till Saturday .....btu rain is in the forcast for the next couple of days......Anxiously looking forward to getting a test run with the new set-up and the Pro charger but do not want to rush it and not have everything done right and risk a bad result....you know what they say Measure twice......cut once!
Bryan

I would angle the 3/8 tubing so the fuel go twards the gas tank. teyed one of those moroso things and it didnt work so good because we had a high pressure fuel pump and the fuel splash up the fuel inlet..

The Hedgehog
02-07-2007, 10:36 AM
I would angle the 3/8 tubing so the fuel go twards the gas tank. teyed one of those moroso things and it didnt work so good because we had a high pressure fuel pump and the fuel splash up the fuel inlet..


That is good advice. I believe that he is going to do that. I also plan to do this mod with my setup. No problems but don't like the idea of buying a new fuel pump.

Any reason why the coast guard does not like this setup? My mech told me that it was a no-no. He also told me that he did not think it was a bad idea.