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98 454 Mag Mpi mid range missfire

Old 05-12-2019, 12:14 PM
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Originally Posted by Sean400
Applied vacuum to this and it doesn’t open is this a valid test and I’m assuming this would cause my excessive fuel pressure.
Do yourself a favor and replace rusted parts whether or not they're working properly. That fuel pressure regulator hat is just waiting to rust through and cause problem, most likely on the water.
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Old 05-12-2019, 01:54 PM
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^^ Agree, would be a good idea

Also check for a blockage going back to the canister filter. If the line is blocked, pressure cannot be regulated. Need to find out why pressure exceeded limits. Was the screen clogged?
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Old 05-12-2019, 02:48 PM
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Originally Posted by AllDodge
^^ Agree, would be a good idea

Also check for a blockage going back to the canister filter. If the line is blocked, pressure cannot be regulated. Need to find out why pressure exceeded limits. Was the screen clogged?
screen was surprisingly clean no debris in it at all, was hoping it could be something simple like that. Took the line off the fuel separator and blew air through it no blockage in there. The vacuum line to the regulator appeared to have a little sludge in it hoping I can replace the line from cooler to motor this week and test the pressure again.
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Old 05-13-2019, 06:52 AM
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A clogged vacuum line wouldn't cause pressure to get that high. The vacuum just changes the pressure a few psi
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Old 05-13-2019, 08:52 AM
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Originally Posted by AllDodge
A clogged vacuum line wouldn't cause pressure to get that high. The vacuum just changes the pressure a few psi
yeah waiting to get back to the boat and look at the fuel rail I’m gonna post a picture of the Engine when I get back there. It’s been raining for the past 3 days here on the east coast.
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Old 05-13-2019, 11:02 AM
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Originally Posted by RBeyer
Is it a green and white named Yea Rite?
so I'm assuming this isn't the boat being discussed. If it is I have a lot of insight.
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Old 05-13-2019, 11:35 AM
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Originally Posted by RBeyer
so I'm assuming this isn't the boat being discussed. If it is I have a lot of insight.
its a 98 260 velocity no name purple and pink stripe white base. Sorry missed your comment before
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Old 05-13-2019, 10:51 PM
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Originally Posted by Sean400


its a 98 260 velocity no name purple and pink stripe white base. Sorry missed your comment before
No need to apologize and I'm really glad that is not the boat. Not that it's a bad boat actually was awesome but it is/was ProCharged same year approximate hours and other mods. It has been for sale for a while and I was hoping nobody did something dishonest. This is a tight group and we watch out for each other.
The modifications are really unique for a naturally aspirated boat and I hope you sort out the issue. It truly sounds like the wrong tune in the computer, there are so many variables it would almost be worth talking to someone who can look at the setup on it.

Last edited by RBeyer; 05-13-2019 at 10:53 PM. Reason: typo
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Old 05-14-2019, 06:34 AM
  #39  
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Originally Posted by Sean400
Applied vacuum to this and it doesn’t open is this a valid test and I’m assuming this would cause my excessive fuel pressure.
No, it is nit a valid test. PSi opens it. It is a fuel psi regulator. VAcuumjust changes the psi (ust a few psi) needed to open it .

The return on the regulator opens at the preset psi.Sp, if it's 40psi regulator,the regulator should be partially open just after that psi.
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Old 05-14-2019, 08:57 AM
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Originally Posted by SB
No, it is nit a valid test. PSi opens it. It is a fuel psi regulator. VAcuumjust changes the psi (ust a few psi) needed to open it .

The return on the regulator opens at the preset psi.Sp, if it's 40psi regulator,the regulator should be partially open just after that psi.
yes, someone mentioned that and I tested the regulator is working properly.
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