Oil Pressure Gauge Problem

Unless someone has modified the oil pressure gauge circuit, your friends Ranger actually has an analog idiot light. It looks like a gauge from the drivers seat view but it really functions as a light would, i.e., either up or down.

It's simple enough to remove the sending switch and connect a real gauge to see if it's the engine responsible for the erratic behavior or if it's in the electrical part.

Thanks for the reply,

I wonder why ford wouldn't just put a light there instead of a gauge. I was thinking about hooking up just a regular oil pressure gauge to see what is going on. Any other thoughts, let me know.

Thanks, John

Could be a broken wire at the sending unit. You wrote that it got a little better when you replaced the unit, so the wire on the clip may be broken and just barely making contact. Or the clip itself may be bad.

Did the replaced part look like this;

or more like this:

The part looks like the first one. We just bought a real oil pressure gauge, haven't had time to hook it up yet, but I'll let you know what it shows.

John

John,

I have a 2001 Ranger w/3.0L engine and mine did the exact same thing, I replaced the sending unit, no help. A little while later the valves started to tapping so I took it to Ford and they dropped the oil pan and found the oil screen on the oil pump was clogged. I also had them replace the gauge since it bounced so much it rapped around behind the post.

Boy, here's one of the greatest hits of Ford Usenet. I haven't heard this one in a while.

It is true, as others have posted, that Ford decided to use a "fake" oil pressure gauge on many of their trucks. So when the gage "flickers" just pretend it's an oil light flickering and act accordingly. The truck's got very low oil pressure, and that's the problem. It's not the gauge.

Yep, The truck sure does have low oil pressure, I put a real gauge on there and it only reads no more than 20 psi when the truck is warmed up and driving at 45mph. It reads less then 10psi at idle.

John

You know what to do now, right?

3 quarts of STP, right? ;-)

I had a '64 Galaxy with a 352 from a '59 'Bird back in 1969 when I got out of the Air Force. The motor was a quickie replacement for the 390 that was in it that I blew up racing it. I was moving from Alabama to Detroit, and didn't have time to rebuild the 352, and the oil pressure was so bad when hot that the lifters would collapse. I drained the oil out and put in a quart of SAE40 and 4 quarts of STP, and drove it from Mobile to Detroit that way. Surprised that it made it, but it did. After finding a job there, I fixed it the correct way.

SC Tom

While we're on the topic, can anyone shed any light on the approximate "real"- i.e. numeric values of a Ford oil gauge that says only "normal"? Assuming, of course, that one has the appropriate pressure sender.

The value is a simple switch point just like the IDIOT light, I don't have the values handy, but the pressure sensor is a simple open/close switch.

Restating the question- with the true pressure (resistive) sender, what would the approximate psi readings be for the "normal" range on an unmarked Ford OP gauge?

For the record, I have the true pressure sensor, and the gauge behaves as it should (low at idle, rises with RPM).

The idiot light sender is a normally open switch that closes at

4.5-7.5 psi and grounds a 20 ohm resistor that brings the gauge to about mid scale.