That my 99 SSEi must have had something wierd from the factory.

The 99 SSEi I've had since July 06 has a full gauge cluster, 4-pin oil pressure switch/sensor, but only 2 wires going to a 4-pin connector on the harness. The extra two pins holes have plugs.

Anyone want to guess what this means?

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DHP Powrtuner & Tech 2
1998 GTP Coupe
1999 SSEi 70k miles
2000 Silverado 2500 Ext Cab 4x4/6.0L/4L80E
2000 Trans Am WS6 LQ3 (LQ4 w/LS3 top end) 4L60E
2001 SLE
2002 Monte Carlo SS Top-swapped FSIC Gen V TOG's, Mezeire.....
2002 GTP 40th Anniv Ed Coupe
2004 GTP Comp G 'Bottom-swapped'

Should be 3 pin if its a gauge.

Means your gauge really isn't a gauge?

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

A wiring diagram will come in handy here.

_________________

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers & a 10" Alpine Type R Sub, all the watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override, Monroe Reflex struts, red calipers
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights

Here is the connector and schematic

So where do the other two sensor wires go? Fuel pump power circuit?

_________________

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers & a 10" Alpine Type R Sub, all the watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override, Monroe Reflex struts, red calipers
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights

We followed the wires from the connector back into the harness about 2 feet and found no cut wires and no splices.
My oil pressure gauge has never worked. Always sits at the bottom.
The oil filter seal blew out last week when I jump started the car and drove it 120' into the shop. Luckily that was as far as I was going.
I figured it was either the oil pressure switch/sender or the oil filter seal, so I bought a new oil pressure sensor (figured I could kill two birds with one stone.

Unfortunately my car appears to have come from the factory with a non-functioning gauge.

I'm going to be working on the new 99 SSEi here in the next week or so and will check the wiring on that just to see what that has for a wire count and pinout at the connector.

Travis -Thanks for the schematics. That's going to be my next purchase (FSM's) as Cameron and I were wishing we had the wiring schematics for it.

_________________
DHP Powrtuner & Tech 2
1998 GTP Coupe
1999 SSEi 70k miles
2000 Silverado 2500 Ext Cab 4x4/6.0L/4L80E
2000 Trans Am WS6 LQ3 (LQ4 w/LS3 top end) 4L60E
2001 SLE
2002 Monte Carlo SS Top-swapped FSIC Gen V TOG's, Mezeire.....
2002 GTP 40th Anniv Ed Coupe
2004 GTP Comp G 'Bottom-swapped'

schematics say that its only a 2 wire... that doesn't make sense either.

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

Hmm, I saw the schematics, but didn't look at them yet.
At first, way back when, I swapped 2 different instrument clusters in and none of them indicated a working oil gauge.
1 was out of my brother's 97 SSEi, which had a working oil pressure gauge, so I figured it was down to wiring or pressure sensor/switch.
I put in a new sensor/switch 2+ years ago so I was down to wiring, from what I can tell, and now I've dug into 2' of wiring from the sensor, but haven't gone beyond that.

_________________
DHP Powrtuner & Tech 2
1998 GTP Coupe
1999 SSEi 70k miles
2000 Silverado 2500 Ext Cab 4x4/6.0L/4L80E
2000 Trans Am WS6 LQ3 (LQ4 w/LS3 top end) 4L60E
2001 SLE
2002 Monte Carlo SS Top-swapped FSIC Gen V TOG's, Mezeire.....
2002 GTP 40th Anniv Ed Coupe
2004 GTP Comp G 'Bottom-swapped'

2' into the engine harness, right?

Possible that it has a w-body harness on it?

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

I doubt it- the H-body has wiring for 2 MAP sensors and the W-body has 1 MAP sensor. No signs of hacking around there either.

_________________
DHP Powrtuner & Tech 2
1998 GTP Coupe
1999 SSEi 70k miles
2000 Silverado 2500 Ext Cab 4x4/6.0L/4L80E
2000 Trans Am WS6 LQ3 (LQ4 w/LS3 top end) 4L60E
2001 SLE
2002 Monte Carlo SS Top-swapped FSIC Gen V TOG's, Mezeire.....
2002 GTP 40th Anniv Ed Coupe
2004 GTP Comp G 'Bottom-swapped'

Anyone think a 2-pin oil pressure sender would be the fix? I've got several around so I may as well give it a shot I guess.

_________________
DHP Powrtuner & Tech 2
1998 GTP Coupe
1999 SSEi 70k miles
2000 Silverado 2500 Ext Cab 4x4/6.0L/4L80E
2000 Trans Am WS6 LQ3 (LQ4 w/LS3 top end) 4L60E
2001 SLE
2002 Monte Carlo SS Top-swapped FSIC Gen V TOG's, Mezeire.....
2002 GTP 40th Anniv Ed Coupe
2004 GTP Comp G 'Bottom-swapped'

Just curios, but are the wires going into the weatherpak in the A & B cavities? Out of the hand full of oil pressure senders I have, I've seen two, three, and four wire setups using the same oval 4-wire weatherpak connector. I've seen combo sensors where two pins are the gauge sender and the other two were for the fuel pump relay, as well as a three-wire setup where the two functions share a common ground wire.

I'm just wondering if the wiring harness was accidentally pinned wrong during assembly so your two wires are in the cavities used by the pump relay.

BTW, if you have a compressor, you can use one of the quick-disconnect fittings threaded directly on to the sender's pipe thread and operate the sender on compressed air, just to see which terminals act like and on-off switch and which ones vary resistance to pressure.

Ok, went and had a cup of coffee, so my brain is starting to function normally (if such a state exists)...

How I would attack this problem is to first confirm the two wires in the weatherpak connector actually connect to the instrument panel gauge. You can unplug the sensor, and with the ignition in run and engine off, jump the two wires together. You should see the gauge in the panel jump as you touch the wires together.

If the gauge doesn't move, then the wires in the harness are not the gauge, but probably either an oil pressure idiot light or are set up for a fuel pump relay. If the gauge moves as the wires touch, then you know the gauge works and the wires in the harness are connected to it. Then I would move on to the sender to see which pins are the two that vary resistance with pressure (i.e. the pins the harness should be wired to connect.)

If the sender behaves funky...like an on-off switch that turns off as pressure increases, then your oil pressure sender is the wrong type (you got one that is for a simple idiot light in the dash.)

Hope that makes sense...the day is yet young here.

_________________
Bye Bye 1990 Bonneville LE... Now it belongs to my daughter
In the Garage: 2009 Subaru Outback, 1987 Camaro, 2006 SV650S, 1995 Regal 182 "ASANAGI", 1962 Ford Galaxie 500, 1995 Ford F150 XL 4WD, 1953 Farmall Cub

I don't see where the oil pressure switch has any connection to fuel pump relay.

When the ignition switch is first turned ON, the PCM energizes the fuel pump relay which applies battery positive voltage to the fuel pump control module. The fuel pump relay will remain ON as long as the engine is running or cranking and the PCM is receiving reference pulses. If no reference pulses are present, the PCM de-energizes the fuel pump relay within 2 seconds after the ignition is turned ON or the engine is stopped. The fuel pump delivers fuel to the fuel rail and injectors, then to the fuel pressure regulator. The fuel pressure regulator controls fuel pressure by allowing excess fuel to be returned to the fuel tank. With the engine stopped, the fuel pump can be turned ON by using the scan tool output controls function.

The PCM alters fuel pump speed by varying the duty cycle on the fuel pump speed control PWM circuit to the fuel pump control module. Under normal conditions, the fuel pump speed control PWM circuit duty cycle is set at 33%. When higher fuel volume is required due to increased engine load (MAP sensor value over 90 kPa), the PCM switches the fuel pump speed control PWM circuit duty cycle to 100%. At the higher duty cycle, the fuel pump control module increases the voltage to the in-tank fuel pump, allowing a higher volume of fuel to be delivered to the fuel rail. The PCM also compensates for low system voltage by switching the fuel pump control circuit PWM duty cycle to 100%.

And for this car, that is correct, the PCM controls it. The point I'm trying to make is, GM has done it multiple ways over the years using the same 4 cavity harness connector. Since the gauge hasn't worked for as long as he has owned the car, somewhere down the line the wiring or the sender got botched. If the two wires are inserted into the wrong cavities (as if it were being wired as a fuel pump relay switch) then it will never work right.

_________________
Bye Bye 1990 Bonneville LE... Now it belongs to my daughter
In the Garage: 2009 Subaru Outback, 1987 Camaro, 2006 SV650S, 1995 Regal 182 "ASANAGI", 1962 Ford Galaxie 500, 1995 Ford F150 XL 4WD, 1953 Farmall Cub