SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: NoRestraint on September 11, 2011, 10:15:20 PM

Title: Fuel pressure problem
Post by: NoRestraint on September 11, 2011, 10:15:20 PM
Hey guys, so I went to castaic today to set up my new bassett t-valve and had .5 lbs. of fuel pressure! Obviously the thing didn't start but I was wondering if there was any troubleshooting I could do before I break down and buy a new fuel pump. There was 9lbs. to the carb last night in the driveway and today nothin, any ideas? My friend was "helping" me clean some wires up the other day and wired the pump up wrong and I tried to start it once, maybe I fried the pump? :banghead: Any help is greatly appreciated and if I do need a new pump, which one do you guys recommend and how many GPH do I need? I'm pretty sure it's a close to stock 1986 454. Thanks guys 
Title: Re: Fuel pressure problem
Post by: crewchief22 on September 11, 2011, 10:36:03 PM
Start with testing the pump by by-passing the existing wiring, just to see if it pumps.  If not, you probably fried it.  If the pump runs but still doesn't have any pressure start inspecting your hoses and hard lines.  Do your tanks have any rust or debris in them, that could be plugging things up?

Necessary fuel pressure will be determined by what carb you are running.
Edelbrock/Carter AFB don't like much more than 6psi
Holleys will take up to 7-8psi without problems
Q-jet is about the same as the Holley

I'd recommend getting a quality electric pump with a regulator and adjust as needed.
Title: Re: Fuel pressure problem
Post by: 702Raleigh on September 11, 2011, 11:37:07 PM
Due you have duel tanks? one of your tanks might be sucking air! I had the same problem and had to put shut off valves on them!!!
Title: Re: Fuel pressure problem
Post by: ka0tyk on September 12, 2011, 12:48:05 AM
Due you have duel tanks? one of your tanks might be sucking air! I had the same problem and had to put shut off valves on them!!!

you should have shut off valves on EVERY tank... what if u get a leak? 


safety first! 
Title: Re: Fuel pressure problem
Post by: obnoxious001 on September 12, 2011, 01:34:06 AM
Any help is greatly appreciated and if I do need a new pump, which one do you guys recommend and how many GPH do I need? I'm pretty sure it's a close to stock 1986 454. Thanks guys

If you test the electric pump and it's not working, why not just put a mechanical low pressure pump that requires no regulator, since you state the engine is close to stock.  I run mechanical pumps on engines making 600-700 HP.  I just feel they are simple, and not as prone to having problems. 
Title: Re: Fuel pressure problem
Post by: NoRestraint on September 12, 2011, 07:03:21 AM
Thanks for the input guys. I do have dual tanks so I will test the lines. The pump sounds like it's on when i turn accessory on but I will take the fuel line off the regulator and wire it straight to the battery to see what happens there. As far as the shut off valves go, are we talking about a gate valve or something in line for each tank? or something $$electric that I can control from the dash? And deciding if I want an electric or mechanical is going to be a tough one for me haha. Thanks for the help :thumbup:
Title: Re: Fuel pressure problem
Post by: ka0tyk on September 12, 2011, 10:19:20 AM
Thanks for the input guys. I do have dual tanks so I will test the lines. The pump sounds like it's on when i turn accessory on but I will take the fuel line off the regulator and wire it straight to the battery to see what happens there. As far as the shut off valves go, are we talking about a gate valve or something in line for each tank? or something $$electric that I can control from the dash? And deciding if I want an electric or mechanical is going to be a tough one for me haha. Thanks for the help :thumbup:

its pretty easy to just reach back there.  a fuel system will always pull from the easiest/closest side.  mine pulls from my drivers side so when i drove from the dam to the canal at havasu it started sputtering about halfway back so i just stopped and shut the tank off and kept going.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.brainbox.us%2Fmisc%2FIMG_20110503_105029.jpg&hash=31856fdf4bc5101081526a6ecd6caa83f73b4a5a)
Title: Re: Fuel pressure problem
Post by: NoRestraint on September 14, 2011, 03:43:23 PM
Alright cool, I have a solenoid to switch the tanks but when I do my steel braid lines I will throw some valves in. Looks like I will need 4 more fittings now. Any idea how much it will be to steel braid everything?
Title: Re: Fuel pressure problem
Post by: NoRestraint on September 14, 2011, 03:44:39 PM
Oh and I got a new fuel pump, turns out that was the problem. Thanks for the help on that one guys it is much appreciated.
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