pwrboatn

Are you guys adjusting it to 43 psi at idle or wide open? also how would i go about checking for clogs on land?


I have a vortec adjustable regualtor im going to install just wondering what to set the rail pressure to at idle and so on....

92nsx

Per Merc Manual pump pressure should be 34-38 PSI.

pwrboatn

Hmm Op said book says 43 psi?

92nsx

I dont care what he posted, LOL! Im just posting what merc manual #16 says on pg. 5C-60 - ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY)

(yes I have heard other's also say 43)

Griff

Manual 16 only covers up to 1997 VST 502EFI systems and not the 502MPI Cool Fuel systems.

You need #23 for 1998-2001 502mpi's.

mike tkach

iTrader: (3)

if it has a cool fuel unit pressure needs to be at 43 lbs,end of story,i went through this last year on one of these.

92nsx

What page do you find that on? I am un able to locate it. Here is what I find on Page 5E-73, merc manual 23. Im just curious not out to step on any toes.

Chart A-4 (2 of 5): Fuel System Diagnosis

TEST DESCRIPTION:

2. Wrap a shop towel around the fuel pressure connector to absorb any small amount of
fuel leakage that may occur when installing the gauge. Ignition “ON,” pump pressure
should be 34-38 psi (234-262 kPa). This pressure is controlled by spring pressure within
the regulator assembly.

NOTE: Fuel pump pressure will read lower if battery is not fully charged.

airjunky

iTrader: (2)

Have one of these coming down the pike with fuel issues so I'm keeping a eye on this one . Hey 92nsx, do you have the aluminum car your user name suggests ?

mike tkach

iTrader: (3)

i got this information from a merc tech that works on them all the time,he told me that i should have 43 lbs with the engine running,guess what,i had exactly 43 lbs.that ruled out fuel pressure being the issue.i will add that with the key on but engine not running the pressure will be lower.

pwrboatn

What should the fuel pressure be with key on engine not running while the fuel pump is running?