Question about 1991 GMC Sierra
Posted by Anonymous on
Check wires from sender make sure they are not broken pinched grounded out i had this same issue with my 89 3500 454 and the wires were rubbing the balancer finally wearing through grounding them this told the computer there was an issue with oil pressure and blew the fuse to prevent engine damage i traced them out and fixed never had an issue again
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Posted on Jan 02, 2017
if it is electrical oil pressure sensor I would start there. The best way to see if you have a major problem is to use a mechanical oil pressure tester. Take off the oil pressure sensor and put the mechanical tester on. The tester should come with a Gage. If it comes within your trucks oil pressure range than all is fine and replace the sending unit and see if that don't help your problem.If the tester runs high then the oil pump is bad or your cam-bearings could be the problem. But with cam-bearings you would usually get a low reading.
Posted on Mar 14, 2009
SOURCE: My 2003 GMC Sierra Z71
the oil pressure is always high when you start it,the oil is cold and creates a different reading.
a few things...to consider
oil pressure sender defective
too much oil
wrong oil type
Posted on May 13, 2009
had this problem on my neighbors 98 chevy truck with the same engine !!
it turnd out too be the fuel pressure regulator,you have too pull the upper intake too replace it!!
Posted on Jun 06, 2009
the knock sensors are located below the intake plenum,or,upper intake manifold as some call it, they screw into the lower intake, the front one is sensor 1, the rear is sensor 2. it is wise to change both if you have some miles.since you are going to be buying a gasket set to do this job.the sensors are cheaper than the gaskets.
Posted on Jun 12, 2009
have it tested using a manual gage if still low then main baring ore most likely bad that would mean a over hall if is really low and bearings bad should be making rattle noise when started up first few seconds
Posted on Mar 11, 2010
Testimonial: "thanks alot.truck is not making a rattling noise.we did check it with a manual gauge.it read about 10 at idol. press. gets better as you incr speed"
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