Oil Pressure Low 1985 BJ73

[Pablito]

Hey

Recently my oil pressure has dropped. The oil level is about 30% (and i need to do an oil change anyway).

If I remember correctly the pressure gauge always showed half until I got the alternator brushes changed. While I trying to find the battery/alternator problem it was parked for about 10 days. Once the alternator was in and I was driving again, I noticed the oil pressure was just above the low mark, and while driving it does go up by a fraction sometimes.

Any ideas?

Cheers

 

[Roger Fairclough]

A few questions.

What engine is fitted?

How many miles has it done?

What oil are you using?

How many miles since it was last changed?

Roger

 

[Pablito]

Hey

It is a 3B diesel, 3.4L, 4 cylinder.
It has done 330,000km

I have recently purchased it and I'm not sure when the last oil change was or what oil they put in. I have driven about 4000km since buying it.

cheers

 

[Roger Fairclough]

That's 206,000 plus miles in old English.

As you don't have a history on the motor, you need to do a complete service. As far as the engine is concerned, this will include oil, air and fuel filters, plus a decent quality multigrade oil. I wouldn't bother with a synthetic oil until you are happy with the engines running, Take this oil change as a clean flush out. Do you have a workshop manual? It doesn't have to be the genuine article, just something that will explain the inner workings etc.

If you tell us where in the world you are, we can make assumptions for weather etc.

Roger

 

[roscoFJ73]

Do an oil change and then test the oil pressure with a plug in gauge. They should be able to maintain about 50 psi at 2500rpm for 2 mins and about 5-6 psi at idle.
I think the minimum is about 36psi
You plug the gauge into where the oil pressure sensor sits
Confirm these figures from the manual,they are off the top of my head but are much the same for all the diesels of that era.

Dont take too much notice of the gauges,its obvious that the gauge readings were skewed from electrical problems.
The gauge usually sits just below or just above halfway.

 

[Pablito]

I discovered that I have knocked the wires loose (when removing the alternator) that connect the oil pressure meter on the dash to the oil pressure sensor.

My problem is that there are 2 wires. Both of them reach the sensor and fit the connection. I cant see any other places for these wires to attach to, other than the pressure sensor. I tried plugging them both in (one at a time), checking the oil pressure gauge on the dash, and revving the engine while checking the gauge again on the dash.

I found the gauge on the dash did not move when the yellow wire was attached. When the black one was attached the gauge on the dash shot up immediately to well past high (and off the meter) and slowly dropped down to low after a 1 minute or so.

Are both of these wires supposed to connect up some how? Did the sensor have a double male plug thing??

I have just done an oil change as well.

Any advice on this one? I realise I should still check the oil pressure but I dont have a tester.

Roger, I'm in Sydney, Australia by the way.

 

[Crushers]

one is the low oil shut down, the one without the notch in the clip.
the other is for the "bell" on the oil pressure sender.

as others have said, change the oil. that would have been one of the first things i did when buying an unknown. for all you know the previous owner might be one of those ... individuals ... that adhere to the 15K or even 20K oil change intervals.

i would also install an after market oil, water and pyro since, as Rosco stated, the Toyota gauges are a glorified idiot light.

the good part is the 3B is a very robust engine that puts up with neglect better than other Toyota engines.

post up a pic of the oil that comes out ... curious.

 

[roscoFJ73]

The gauge works on very low amps and if you attach the wrong wire they burn out real quick and I suspect this is what you have done.
They go for around $70 at the wreckers.

You may also have a problem with the sensor,you can usually get them from parts stores for about $30-40.Lots of Toyota cars and other models of landcruisers use the same sensor or sender as some call them.