when i turn the truck on I never have oil pressure. I have to turn the key on and off lots of times to get oil pressure. Oil sending unit??? Other Ideas? What does the oil sending unit look like? I know its next to the distributor cap but where? How do you diagnosis?

 

Does the engine rattle when you start it? If so, there may not be oil pressure. It is beside the distributor at the rear of the block...not the easiest place to get to. Check that connector is tight on sender.

Did this just start? Did you do some other work on the truck when this started? If so, check for all the ground wires. There are several under the hood. Bad ground could casue some instrument issues.

 

no other work other than the tranny. its been a problem since i bought the truck. no it doesnt rattle.

 

plumb in a mechanical gauge to verify oil pressure. either remove the oil pressure sending unit, and plumb in a mechanical gauge, or remove sending unit, and plumb in a t fitting with a mechanical gauge.

 

if you truly have no oil pressure, you'll have valve rattle at idle.

most likely causes are bad sending unit, or sludged up pickup screen on the oil pump.

do the basics first - make sure its full of oil and has a fairly new oil filter. if oil pressure is low - clean or replace oil pump, if zero check/replace sending unit and wiring. make sure a rat hasn't eaten the wiring.

az calls it an oil pressure switch. it mounts vertical on the back of the block, to the passenger side of the dist cap.
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