502 mpi coil fuel pressure issue
05-19-2018, 12:17 PM
#1
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502 mpi coil fuel pressure issue
Hi
I messure my fuel pressure one week ago and the pressure whas 55 psi at idle. I disconnect the vacum hose from the regulator and nothing happend. The pressure did not change if I rev up the engine. Still 55 psi. I then ordered a new original regulator from a local store and mount it today. I messured the pressure at idle to 35 psi. I disconect the vacum hose and the pressure jumped up to 43 psi. The pressure did not change if I rev up the engine to about 3000 rpm with the vacum hose connected. Stable at 35 psi. Does anyone have a solution to my problem. I thought the pressure should be 43 psi with the vacum hose connected.
From What I have read before, this engine should have 43 psi at idle. Is that correct?
Hope you guys can help me 😀
Dan/Norway
I messure my fuel pressure one week ago and the pressure whas 55 psi at idle. I disconnect the vacum hose from the regulator and nothing happend. The pressure did not change if I rev up the engine. Still 55 psi. I then ordered a new original regulator from a local store and mount it today. I messured the pressure at idle to 35 psi. I disconect the vacum hose and the pressure jumped up to 43 psi. The pressure did not change if I rev up the engine to about 3000 rpm with the vacum hose connected. Stable at 35 psi. Does anyone have a solution to my problem. I thought the pressure should be 43 psi with the vacum hose connected.
From What I have read before, this engine should have 43 psi at idle. Is that correct?
Hope you guys can help me 😀
Dan/Norway
Last edited by danse78; 05-19-2018 at 12:22 PM.
05-19-2018, 01:57 PM
#2
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Reving the motor is not the same as getting up on plane. The vacuum will not change much just reving. To prove it, put a Tee fitting on the line with the vacuum gauge, then rev and also take it for a run
05-21-2018, 09:01 AM
#3
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I have always went by 38 psi. Merc manual #23 says 34-38 psi
05-21-2018, 08:58 PM
#4
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The fuel psi will most definitely reduce when you hook to vacuum which there is a lot of at idle.
