on my 89 4.3 4x4 blazer my oil pressure when i start it and leave it idle is maybe 15-20 psi tops acording to the dash. then once i get it going it completely flats out. no pressure acording to my dash. what's going on? i'm 99% sure that i'm not w/o oil pressure. lol. i drove it from salt lake city to eagle mt. (wheni brought it home from buying it; apx 40 miles) with itsaying it has no oil pressure. and it hasn't been leaking oil and it says it's at the correct opperating level. if there was no oil pressure (i myself have driven it maybe 70 miles total) wouldn't i have developed some much larger problem? and if i do infact have oil pressure which part is most likely the faulty one?

 

The best thing to do would be to check the oil pressure with a mechanical gauge. If you like to easter egg and are feeling lucky change the sending unit and hope for the best. It probally is the sending unit but reading the actual pressure with a mechanical gauge will let you diagnose the exact cause of the problem.

 

x2 on the checking the pressure with a mechanical gauge.

My guess would be that there is an intermittent connection causing the gauge to read zero pressure when you start moving, but that is only a guess. You need to verify.

 

damn digital dash. i swear wheni get some money it's going to analog.

ok so i have a 4x4 w/ the remote oil filter. can i just splice in a mech. gauge in there on the line exiting the oil filter?

 

I would remove the sending unit and attach a gage at the fitting for the sending unit.

 

alright and where exactly is the sending unit

 

Should be at the back of the engine block right by the distributer.