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1996 502Mag MPI Fuel Pressure

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Old 07-29-2008 | 08:25 AM
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Default 1996 502Mag MPI Fuel Pressure

Hi Guys,
I've been having trouble with my engine and need to check the fuel pressure. It sounds like the pump is cavitating or going bad.
Its a 1996 MEFI-1 ECM with the Cool Fuel System.
What should the fuel pressure be?
Thanks.
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Last edited by Pat McPherson; 07-29-2008 at 09:08 AM.
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Old 07-29-2008 | 08:53 AM
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My Mercruiser shop manual only goes back as fare as 1997,the fuel pump pressure specifications are 42 psi for a 7.4MPI, 454 MAG, 502 Mag.
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Old 07-29-2008 | 09:08 AM
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Originally Posted by Ken N
My Mercruiser shop manual only goes back as fare as 1997,the fuel pump pressure specifications are 42 psi for a 7.4MPI, 454 MAG, 502 Mag.
Thanks but I think that is for the MEFI-3 ECM engines.
This 1996 I have seems to be an odd duck...
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Old 07-29-2008 | 09:22 AM
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thought the 96's had the VST tank up top.....with no cool fuel.
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Old 07-29-2008 | 09:40 AM
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I'm not positive, but I think it's 32 psi.
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Old 07-29-2008 | 10:05 AM
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It's 36PSI for MEFI 1, 43PSI for the MEFI 3.
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Old 07-29-2008 | 10:26 AM
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Thanks Dave...
36psi sounds right.
Speeking with Mark at Precision he knew it was more than the low 30s for the VST tank engines but less than the 40+ for the MEFI-3 engines.
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Old 08-11-2008 | 09:20 AM
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Originally Posted by Pat McPherson
Thanks Dave...
36psi sounds right.
Speeking with Mark at Precision he knew it was more than the low 30s for the VST tank engines but less than the 40+ for the MEFI-3 engines.
Pat,

any updates on your engine problems?
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Old 08-11-2008 | 09:23 AM
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i concur 36 for the mefi1 which is the 1996
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Old 06-25-2013 | 03:32 PM
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Hmmm, I'm only getting 27-30 psi. Think that would cause the engine to run a little hotter?

I'm getting 180-185 with a 160 thermostat and this trouble began when I had a fuel pump fail.
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