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Discussion Starter · #1 ·
This really spooked me this morning.. I got about 1/2 mile from home this morning, and I realized that the oil gauge was reading ZERO... I killed the engine and started looking around for a catastrophic failure, and found none.. I just changed the oil last week, and it was still full on the dipstick, then when I turned the key on again (not started), I noticed that the oil light didn't come on. Now I really don't know if it came on when I started it first thing this morning, but I know it doesn't work now.. I even pulled the dash apart right there and changed the bulb... It don't work... So what is going on? All my other gauges work, and I assume the light gets its power from the computer, so........... Anyone? Bueller?? Do I have a pressure problem or an electrical problem? I had a friend pull me home because I don't know what to think..

TIA
Matt {peace}
 

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Do you have the factory oil light and an aftermarket elec. gauge or mech gauge?....is this on the 85 or 89 you have listed?

If electric gauge, could just be the sender that screws into the block. If mech gauge, maybe the oil tube is afu somewhere along the line.

Did you have any pressure after your oil change? Did you use a Fram filter? (I had on shit out on me once--but wait, I still had a little pressure..nevermind)

Since the light doesn't come on when you turn the key, I would check the electrical lead off the sending unit first.

Ted

One more thing...the best way to check your actual oil pressure would be to take a known good mechanical gauge and screw it into the block. That would tell you if the engine is ok.
 

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Discussion Starter · #3 ·
It's the '89, with the stock electric gauge and the light from the computer. I had pressure up until this morning,and yeah, I did use a Fram, but the dipstick showed full... Something tells me it's electrical, since it just so happens the light and gauge seemed to quit at the same time, but I don't want to risk any damge... I just bought her!

The thing I don't get is WHY both would go at the same time?? Two different electrical circuits, two different senders..

Matt {peace}
 

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I'm looking at a 90 fsm (for 318 tbi). What I call the sending unit is actually called the oil pressure combination unit switch.

In a nutshell, the fsm says that if the bulb is good and the wiring is good, then the switch is bad. **AS LONG AS OIL PRESSURE IS WITHIN SPECS**

The fsm shows a pic of the connector on the switch. It has leads that go to both the light and the gauge.

Hopefully it's just your switch.

Ted
 

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Discussion Starter · #5 ·
Cool... That's what I want to hear.. I didn't even check yet, I thought it was two senders.. I really need one of those fsm's.. No one seems to have an '89 on ebay tho.. I have a mechanical gauge in the '85, Iguess I can kidnap it to test this out..

Thanks
Matt {peace}
 

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Here we go.

"To test the sending unit, measure the resistance between the sending unit terminal and the metal housing. The ohm meter should read open. Start the engine. The ohm meter should read between 30 to 55 ohms, depending on engine speed, oil temperature, and oil viscosity. If the above results are not obtained, replace the switch"

Ok, now to describe which terminal is the sending unit....bear with me (I really need a scanner ::))

When you pull the connector off the switch, there will be two terminals side by side. If you look at them with the key for the terminal at the top (key=the raised plastic on the connector so it can only be installed one way), the gauge terminal is the one on the right, the light terminal is the one on the left.

Hope that makes sense.

Ted
 

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Get a Mechanical Guage!!!!!!!!!!! forget that crap.

But i am so very proud you pulled it home rather than taking a stupid chance.

I recommend and run Auto-Meter mechanical oil psi guages
 

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If you care about your engines, ditch the Fram filters. They suck very much bad. A Wix only costs about an extra $1.
 

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MudFlap said:
If you care about your engines, ditch the Fram filters. They suck very much bad. A Wix only costs about an extra $1.
NAPA Gold filters are made by Wix.
 

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Discussion Starter · #11 ·
The switch was in fact bad.. It had actually sprung a leak, and the electrical plug was full of oil. So all is well. Thanks Ted.. Marty - New gauges are in the future, there's just many other things that need to be done first.. I have Autometer in the '85, and I like 'em.. Are there A pillar pods for our trucks? I want to put 2 or 3 on there and I don't want to use individual cups if I don't have to.

I didn't know Fram was THAT bad... I'll get a Wix next time..
Matt {peace}
 

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Glad to hear you made out ok, and don't hesitate in getting a pull when the guage goes to zero, that was very good on your part i would have done the same thing
 

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Glad to hear all is well. It's never that easy for me.
 
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