No oil pressure while cranking

[gnx547]

I disabled the fuel & ign and I cranked the motor for a few secs to build oil pressure through the engine. While cranking the oil pressure needle did not move at all. I checked to make sure the oil sending unit is plugged in and it is. I removed the sending unit and oil did come out, so I know there is some pressure. I hooked up an oil pressure gauge and cranked the motor for a few secs there is no pressure reading on the gauge. I removed the distributor and spun the drive shaft with my drill and I have oil pressure reading on the gauge. Why is it that I don't have any pressure reading on the gauge when I'm cranking the motor? Any ideas?

 

[ttocs]

I am not all that sure that the gauges have power while cranking. There are two types of ignition wires regular ignition and true ignition. A true ignition wire will have power on it with key on AND while cranking but this is mainly for the ECU/fuel pump/necessary items. I would not be surprised that the gauges are on a regular ignition(that does not have power while cranking).

 

[RichV]

Because you need some RPM on the pump driveshaft. A drill will be anywhere from 1000 to 2000+ rpm. If you watch a distributor move while you crank the starter it moves much slower.

I wouldn't be concerned. If you had pressure with the drill you should be fine. Although I forgot a galley plug on my build once, but I didn't know until I started the car.

 

[whiplash473]

I haven't ever payed attention to this in my Mustang but I do know in my Silverado there's no oil psi while cranking. About a couple seconds after it fires up the gauge needle moves to it's reading.

 

[evilcw311]

Don't forget that in the 94-95 cars the oil "gauge" is not really a gauge. It only shows in the normal when it sees a certain amount of pressure. Our cars have an oil pressure "switch", not a true sending unit.


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