QuestionHello;
This time i have a question,regarding a 1989 Chevrolet Cheyenne k-2500 with a 350 motor. two days ago i took the truck out of a 4 month winter storage and began driving it .I noticed that the oil pressure gague ran up to 45 psi,60 psi being the last gauge mark.No matter how fast or how long i drove the psi ranged 30-45psi,but once i slowed down to a crawl (5-10 mph) the pressure shot up to the end at 60 psi.It stays at 60 psi at that crawling speed for 2 -3 minutes than drops to 30-45 psi, not lower. Is this something wrong ?
Thank you;
Tom S,
AnswerHi Tom,
I would suspect the oil pressure sending unit. Or the wire is loose from it.
You have two oil pressure units on that truck.
One is beside the distributor, and is an oil pressure switch. It has a orange wire, and a pink/black wire that sends battery power to the fuel pump in the fuel tank whenever there is 4 PSI of oil pressure. This is in addition to the fuel pump relay, or actually it is a backup system for the relay.
But that is not the sender for the oil pressure gauge.
The sender for the oil pressure gauge is beside the #1 spark plug, and has a single tan wire going to it.
If you disconnect the wire, with the ignition in run and the engine off, the gauge should go to one end. If you touch that wire to ground, the gauge should go to the other end.
If that is the response you get, the sender is probably bad.
If you don't get that response, first check the gauges fuse.
To check the sender, if you have an ohm meter...with the engine off, the sender should show 1 ohm. With the engine running, the sender should show 44 ohms....at 40 PSI oil pressure.
You could also have a gauge that is bad, or just a loose connection.
There is a chapter in Mitchell manuals, as well as Motors manuals, that will give a step by step test proceedure. I would sure get one and look at it if a loose wire isn't found right off.
The public library, refference section, has all the manuals.
Van
