Safari Oil Pressure Switch Question

[ceevester]

I have a 2000 Safari, 4.3L, AWD, with 71,000 miles.

Two weeks ago, I started it up, and started to drive off for work but the engine quit running about 100 yards down the block and would not restart.

I returned home and took another car. My wife went and picked up the Safari, and she said it started right up.

When I got home three days later, the Safari started up on a regular basis and I drove it several times with no problems.

Last tuesday morning, I went out to go to work and the Safari refused to start at all, so I again took another car to work. The weather both times was clear and about 60 degrees F.

The fuel pump comes on with the key, and the engine turns over well, so it is not a starting system problem. My Chilton manual says if the fuel pump relay is okay, that the oil pressure switch could be bad. To test the oil pressure switch, the manual says to pull the fuel pump relay out while the engine is running and the engine should continue to run due to a signal from the oil pressure switch. My engine would die when I pulled the fuel pump relay so I assumed the oil pressure switch was bad. I replaced the switch, but the engine still dies when I pull out the fuel pump relay. I have had no starting problems, but I am worried now about the van dying on me while away from home.

Is there another way to test the oil pressure switch, or is there something else I should check? Is this info about the oil pressure switch even true?

Right now the Safari is starting and running fine, but I am leary of it now.

[old_master]

Welcome to the forum!
The oil pressure switch has three wires connected to it. The tan wire goes to the oil pressure gauge in the dash. The orange wire is fused and is hot at all times. The grey wire goes to the fuel pump. When the switch senses oil pressure above approximately 7psi it connects the orange and the grey wires together. When the engine is shut off or stalls, the oil pressure switch will continue to send current to the fuel pump until the residual oil pressure drops below 7psi. This is why the fuel pump continues to run for a few seconds after you shut the engine off.

If the engine stalls when the fuel pump relay is removed, it indicates that there is an open circuit somewhere from the fuse through the orange wire, through the oil pressure switch, through the grey wire to a splice near the fuel pump.

The symptoms you are describing could be due to low fuel pressure or volume which could be caused by a clogged fuel filter or weak fuel pump. Your Chilton manual will have fuel pressure specifications in it. Hope this helps.