Fr-rel Pressrrre
Picturedat the bottomis the stockfuel pressureregulator(top),and the new adjustableregulator(bottom).This
is only necessaryon late model496 HO engines.496 Mag enginesDO NOT applyto this change.To
determineif your 496 HO requiresa regulatorupgrade,you will needto lookat the starboardside of your engine.lf
the fuel pumpand fuel coolerassemblyare mountedon the lowerstarboardside,the regulatorchangeis strongly
Our testingwas performedat 1200feet abovesea level.Afterthe Dana FlowTorqueexhaustinstallwe noticedthat
the exhaustgas temperaturereadingsshoweda potentiallydamagingleanconditionin the mid rangeof running.
This lean conditionwas foundin our dynotestingand in our testingthat was performedon the water.We foundthat
a 3-4psiincreasein the fuel pressuresolvedthis leancondition.Higheraltitudeapplications
may requirea lowerfuel
Preparati on an d In stalIatio n :
1. Locatethe fuel pressuregaugeconnectionon the intakerail.
A. Withthe enginecowlingoff, the fuel pressureconnectioncan be found
behindthe coolantreservoirtank on the fuel rail.
the coolantoverflowlinefromthe coolanttank. (takecaution,this line is oftenpressurized.)
3. Remove,theplasticcap from the fuelconnectionand attachyourfuel pressuregauge.(if you do not havethis
gauge,it can be purchasedat most NapaAuto Parts,or directlyfrom DanaMarinefor roughly$60.00).
4. By.tdrningthe key to the "on" position,the fuel pumpwill cyclefor roughly3 seconds.This will confirmyour
baselinefuel pressure.Due to the shortdurationof the fuel pumpcycle,you will most likelyhaveto havea friend
help in this operation.Oncethe fuel pumpshutsoff the pressurewill drop slightly.This readingmust be accurate,
so be sure to get your baselinereadingwhilethqprmp is cycling.
5. The stockfuel pressureshouldbe set at roughly43 psi. Once your baselinepressureis confirmed,bleed off
excesspressurethroughthe fuel pressuregauge blow-off.
6. Removethe vacuum line from the stock regulator.Usingan 8mm socket,removethe two boltsthat hold the stock
regulatorinto place.
7. Afterapplyingthe a small amountof oil to the o-ringsof the new regulator,installthe new regulatorusingthe
factory bolts.
8. With the fuel pressuregauge still attachedto the fuel rail repeatstep 4. You can now adjustyour fuel pressure
to decreasethe
accordinglyby adjustingthe set screw, (clockwise)to increasepressureor (counter-clockwise!
fuel pressure.
9. Once a 3 psi increasein fuel pressureis made (roughly46 psi), tightenthe jam nut on the adjustmentscrew.
10. Re-installthevacuum line onto the new regulator,removefuel pressuregauge, re-installfuelpressure
connectioncap, and re-connectthe coolantover flow line.
Be sure to read the fuel pressure gauge properly. Adjusfrng the fttel pressure too lean can result in engine
failure.Ihis is a very simple operation, but if proper care is not taken during installation, it can be a very
expensive mistake.
This complefes fhe fuel pressure regulator lnstaltetlon and calibration.