My son has a '88 NA that he bought and drove home a while ago. On the way home it smoked a little, but not excessive. I don't know what the oil pressure gauge was reading on that drive home.

We've been going through a lot of stuff and finally started it up for the first time in a few months today.

We changed oil (Rotella T6 15-40 Synthetic) and a new filter. We replaced the Oil Cooler lines with the Corksport lines. We replaced the anti-freeze and some hoses. We had the dash out and he painted it. We had what we thought was a wiring problem and looking for a short, but found out later it was a bad headlight switch. He replaced the dash lights with LEDs. Replaced the transmission. Lots of stuff.

The oil pressure gauge is reading 110psi (or, maxed out I suppose) at idle. He didn't drive it very far, just a few blocks so it probably didn't get up to temp, though the temperature gauge was 1/4 the way or so. The Oil pressure gauge goes back to 0 when the car is off. I don't think the needle really moved when the car was running.

I've searched the forum and some people have said the oil pressure senders are not very accurate. But, I'm thinking that 'inaccurate' doesn't mean what we're reading.

Are we in danger of harming the engine if driving the car with this high oil pressure reading? The car still has blue smoke out the exhaust, though we really didn't exercise the engine and make sure it was at operating temp either.

Any suggestions?

 

I guess that we might have something hooked up wrong.

Just saw that when turning the key on, but not starting the car, that the oil pressure gauge slowly creeps up to 110 and the car is not even on.

 

The wire that connects the gauge to the sender is grounded.

 

I checked the wiring. It appears to be correct.

I removed the Yellow/red wire from the oil pressure sender and the gauge does not go up when I turn the key on.

As soon as I connect the wire to the sender, the pressure gauge needle rises.

I measured resistance from the sender to ground. 85 Ohms.
I measured the resistance from the yellow/red wire to ground. 87 Ohms. I'm suspecting this us supposed to be infinity ohms (open)?

Is this a bad sender? Does this wire go to some other device (capacitor?) that could be bad?

 

There is a condensor (little, sugar cube sized black thing) tied into the circuit.
It doesn't really hurt if it's missing (probably half of them are) but the lead must not be grounded.

The condensor left the factory bolted to the slave cylinder mount but may have migrated (or gone missing) since.

 

So, if the oil pressure gauge doesn't move when the Yellow/Red wire is disconnected from the Sender, the wire is not shorted to ground, right? Otherwise it would be pegged at max whether the wire is connected to the sender or not. I did disconnect the condenser. It was connected by the wire, but it was not grounded on the condenser itself.

The sender must be suddenly bad?

 

yep, replace it

 

We put in an aftermarket oil pressure gauge. It works nicely. The cheapest electronic gauge from O'Reilly. Reading at 25psi at idle. Haven't driven on the road to see any higher rpm readings.

 

a new sender likely woulda been less in cost and less additional clutter

 

The price was the same but we didn't have to wait the couple days for shipping of the OEM sender None of our local auto stores had the OEM sender in stock. The OEM sender was about $48 for the cheapest I found.

Less clutter..I can agree with that.