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  #11  
Old 07-08-2018, 11:15 AM
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JimN JimN is offline
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Originally Posted by mikeg205 View Post
That screamin' coming from fuel pump? If so, its about toast.

10 psi is correct for most tbi's some run at 30psi.



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The lowest MC injection used was 18 psi.
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  #12  
Old 07-08-2018, 12:43 PM
rossi_the_heeler rossi_the_heeler is offline
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So should I look at my fuel pressure regulator as well? Iím assuming itís not adjustable, just a spring/diaphragm...?
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Old 07-08-2018, 02:49 PM
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mikeg205 mikeg205 is offline
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Quote:
Originally Posted by JimN View Post
The lowest MC injection used was 18 psi.
User manual wrong again

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...A bad day water skiing still beats a good day at work...1995 Pro Star 205....
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  #14  
Old 07-10-2018, 05:36 PM
rossi_the_heeler rossi_the_heeler is offline
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Can anyone confirm that I should have 18 psi fuel pressure? Iím totally fine digging into it a bit but donít want to go down a rabbit hole if Iím not chasing the correct ďrabbitĒ.
I checked my timing and Iím at 10 deg before tdc with the engine at 1200 rpm at full operating temp (160). I had no codes, only 12-12-12.
My next foray is looking into my grounds. But I would like to be positive my fuel delivery is up to snuff!
I was getting 10 psi with both pumps so maybe itís a regulator issue.
Thanks!
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  #15  
Old 07-10-2018, 07:20 PM
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JimN JimN is offline
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Quote:
Originally Posted by rossi_the_heeler View Post
Can anyone confirm that I should have 18 psi fuel pressure? Iím totally fine digging into it a bit but donít want to go down a rabbit hole if Iím not chasing the correct ďrabbitĒ.
I checked my timing and Iím at 10 deg before tdc with the engine at 1200 rpm at full operating temp (160). I had no codes, only 12-12-12.
My next foray is looking into my grounds. But I would like to be positive my fuel delivery is up to snuff!
I was getting 10 psi with both pumps so maybe itís a regulator issue.
Thanks!
Look at the fuel line as it goes from the tank, into the bilge and along the stringer, then to the engine- make sure it's not kinked, crimped, pinched by a tie wrap that was over-tightened by an over zealous assembler. I would also recommend removing the rear seat and inspecting the line as it comes off of the tank. Many had a fuel shut off valve and if the lever isn't in line with the direction of flow, it can restrict. Also, many had an anti-siphon valve, which is a hose barb that connects to the fuel pickup and has a spring-loaded ball inside. If the spring has frozen, it won't open fully and they never imagined that Ethanol would be used in the gas when these were developed. In addition to all of that, you may find another fuel filter in the area- replace that and while you're at it, remove the fuel pickup tube and make sure it's clear of any debris or other obstructions. It may have a long spring inside (looks like a really long spring from a ball point pen) and/or a screen at the bottom end. You may find that it has a bunch of gook on/in it- microbes can and do live in gasoline and alcohol.

Since you'll be in the area and hopefully, the tank isn't completely full, slide it out and remove the plate with the fuel pickup, so you can look into the tank. In addition, remove the vent hose and make sure that and the vent aren't clogged.

Feel the fuel line- if it seems a bit soft, disconnect it at each end and make sure it allows fuel to flow from both directions at extremely low pressure- they had a service bulletin about the line developing weak spots and possibly de-laminating internally. I don't remember the year(s) affected, but in 24 years, most of which had ethanol in the gas, I would think about replacing the line if you think it's worth doing. It's not pressurized from the rear and that's one of the reasons it's important that it not be soft or de-laminating.

Since the gas is being pulled from the rear, have you considered the possibility that it's just a case of vapor lock? If the problem is reduced when the engine cover is left open, what is the outside temperature at the time? If it's high, vapor lock is a definite possibility.

You don't want to try to build an in-tank system unless you have a way to use high pressure hoses, crimped ends and some way to prevent the line being cut by sharp objects or materials. The Coast Guard have Alan a hard time about even developing the in-tank pump system until he showed them that he had been working on it for three years by that time (roughly 1998). A low pressure pump at the back might not hurt, but something has to be done about the excess fuel when the demand isn't as high as the rear pump wants to provide for and also when the main pump needs to deliver more fuel.
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