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senderoilpress.jpg | Hits: 18648 | Posted on: 1/15/06 | View original size (75.24 KB)

Oil Pressure Sender (Ford EOAZ9278A/MotorCraft SW1547B,SW873B, Standard PS60, NAPA OP6091, BWD S334)
IF THE IMAGE IS TOO SMALL, click it.

The old-style oil pressure sender is needed to convert a fake gauge into a real working one. For V8 engines, it's also necessary to space it out from the block using common 1/4" plumbing: a 4" nipple & a 45%uFFFD elbow, or if you can find one, and old factory "connector". A stainless reproduction is occasionally available. I6 engines don't need the spacer - the block is flat & open around the oil pressure port. But the factory oil cooler must be removed (if equipped), which changes the filter from FL820S to the larger more-common FL1A.

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Then the 20-Ohm resistor that goes to the pressure gauge must have a jumper wire installed across it. The cluster shown is for a '94 Crown Vic, but the location of the resistor varies, and it's in the wiring harness for some applications. In '96-04 trucks, it's integrated into the gauge head and can't be bypassed - the gauge head must be swapped for an older one. Don't mess with the 350-Ohm resistor for the ALT lamp, or any others. I used a short Wh/R jumper wire to remind me that it's for the oil pressure circuit, which is Wh/R on most Fords. But a longer wire that hangs well below the cluster may be preferable so that it's easy to cut the wire & revert to the switch if desired, without having to remove the cluster again. This process is the exact opposite of this TSB:


These pics show where the sender goes on a smallblock V8, on the L side just behind the timing cover, using common plumbing hardware to space it out from the block:
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This shows the plumbing to space the sender away:
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This pic shows where the sender goes on a pre-'96 modular engine:


On '96-up, the gauge is electrically different, so the sender won't work without swapping in an older gauge head. In this case, a jumper wire isn't necessary because there is no resistor on the film circuit. It was integrated into the newer gauge head, which is being swapped out.

The most-common fault in the oil pressure gauge (besides being a fake on '87-up trucks) is that the diaphragm in the pressure switch eventually leaks, and both sides fill with pressurized oil. When that happens, there is no pressure difference across the diaphragm, so it indicates 0 pressure, and the gauge drops to nothing. When oil flow in the timing cover changes, the oil leaking OUT of the switch can be greater than oil leaking past the diaphragm, and enough pressure can be indicated for the gauge to return to normal. That process can repeat rapidly, causing the needle to flutter or bounce, even when oil pressure is relatively constant & safe.

If the oil pressure ACTUALLY drops, the lifters will bleed down, causing the valves NOT to fully open, which will result in very rough engine operation & low power output. If the gauge shows low while those symptoms are present, then the engine probably IS actually starving for oil. If not, it's probably just a leaky switch.

Almost every leak on the engine will eventually run down & blow back to the bellhousing, so WASH the engine, and then check for new leak trails frequently enough to follow them forward & up to their sources.
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SSM# 19462 OASIS MESSAGE :
SOME 1997-2007 E150/F150, 1997-2007 CROWN VIC./GRAND MARQUIS/TOWN CAR, 1997-2004 MUSTANG GT, 1997-1998 T-BIRD/COUGAR AND 2002-2005 EXPLORER/MOUNTAINEER WITH 4.6L 2V ENGINE MAY EXPERIENCE AN ENGINE TICKING OR RATTLE NOISE THAT SOUNDS LIKE A STUCK TAPPET (HLA). THIS MAY BE DUE TO THE DETERIORATION OF AN AFTERMARKET OIL FILTER. VEHICLES WITH THIS CONDITION HAVE LOW OIL PRESSURE AT ONE CYLINDER HEAD ONLY, WHILE MAIN PRESSURES ARE NORMAL. DISLODGED MATERIAL FROM THE AFTERMARKET OIL FILTER BLOCKS THE CAM CAP OIL PASSAGE, EITHER AT CYLINDER #4 (RIGHT BANK REAR) OR CYLINDER #5 (LEFT BANK FRONT). FORD RECOMMENDS THE USE OF FORD APPROVED FILTERS ONLY. DAMAGE TO ENGINES CAUSED BY AFTERMARKET OIL FILTERS ARE NOT COVERED UNDER WARRANTY.