Help with oil Pressure

[IFORDJC]

I've been driving around for a few years now with jacked up oil pressure. The PO replaced about everything on my 1978 FJ-40. When I start up the oil pressure is very high but within 10-30 seconds it moves to extreme low and stays there.

I am pretty sure I am getting oil pressure or my mechanical gauge would have heated up and destroyed my engine.

I was thinking a wire is hooked up backwards. I checked the single wire into the oil pressure sender but couldn't see anything TOO different.

I have a mechanical gauge ready to tap into the stock location but need a little guidance on that too. I was thinking of Teeing off the port and have both hooked up??? Anybody know what size T and mechanical sensor?

 

[crumbo]

I've had the same issue.. I rebuilt the engine replaced the electric sender installed a t junction and mechanical guage. I just went to the parts man told him what I wanted to do and he sold me the gear...about $70 ...the manual I have says 4psi + is the required oil pressure (very vague) When I start the engine the mechanical guage will read 65-70 psi and then slowly lower as engine temp increases and oil thins due to temp I did suspect the oil pump pressure relief valve so dropped the pan pulled the pump and made sure it was not sticking (cleaned it with emery and reassembled)...still the same symptoms have put about 3500kms on the clock since rebuild but always have an eye on that guage....

 

[crumbo]

the mechanical sensor wiil be in the guage itself it is the tubing and nut and olive that fit to the tee that you need

 

[IFORDJC]

Crumbo, thanks for the help. I never see the oil pressure off of zero after it warms up. Where did you say you got the T from? You wouldn't happen have a picture?
You are right about the mechanical gauge with the sensor being at the gauge. I guess I typed too fast or forgot. :whoops: I have the tubing sitting at the mechanical sensor ready to go.

 

[bj40green]

I was thinking a wire is hooked up backwards. I checked the single wire into the oil pressure sender but couldn't see anything TOO different.

It's a single wire circuit. There is no way of hooking it up backwards. The question is: do you have the OEM OIL pressure sender?

This sender has a build in voltage regulator, which is crucial for proper operation.


Rudi

 

[IFORDJC]

So there is the possibilty that a wrong sensor is installed. This pics shows the sensor and it doesn't look like a stock Toyota or even a CCOT. I know there could be hundreds of other sensor makers but I guess replacing a $20 sensor with a known good one should be the next step. Seem like the best move?

 

[crumbo]

here you go

 

[IFORDJC]

Crumbo, Thanks again. That looks easy enough. It shouldn't be hard to find that at an auto parts store. I guess I just needed to see a picture of it to actually get the picture.

 

[crumbo]

IFORDJC....that there is your problem in that pic you posted....that there is a sender which acts like a switch...on/off..... you need the bulky one like in the pic I posted....any performance auto parts shop should be able to supply you with the correct sender and tee piece ...have fun and post up you results

 

[crumbo]

That looks filthy I should have cleaned it first

 

[bj40green]

So there is the possibilty that a wrong sensor is installed. This pics shows the sensor and it doesn't look like a stock Toyota or even a CCOT. I know there could be hundreds of other sensor makers but I guess replacing a $20 sensor with a known good one should be the next step. Seem like the best move?

Looks like a brake pressure switch to me.
No pressure = closed. Pressure = open.
The OIL gauge is made of a Bi-metal system that needs time to heat up and therefore to move the needle.
When you turn your key to the on position, the gauge gets voltage, the switch is closed so the needle goes to the right (H). Once your engine is running you have pressure thus the switch opens and disconnect the gauge, resulting in a none/low reading.

My advice; replace the sender for the OEM 83520-55011.


For more info on clusters and gauges: -► https://forum.ih8mud.com/40-55-series-tech/544543-clusters-gauges-odo-meters.html

Rudi

 

[crumbo]

Would that be why mine give quite a low reading in comparison to the original sender....I will invest in one as soon as possible....the toyota dealer is an absolute rip off... what would I expect to pay for one

 

[bj40green]

Toyota price is

83520-55010 = 83520-55011
Prices vary between $15 used, $22 aftermarket and $72 OEM at CCOT, SOR, Cruiser Corps,....... and so on.
Shop around.

Rudi

 

[bj40green]

Food for discussion

The gauges on our Cruisers are "INDICATORS" and not calibrated meters.
Altough the markings on the OIL gauge should reflect 0 - 28.4 - 56.8 and 85.2 psi (or 0 - 2 - 4 and 6 kg/cm² for the metric boys) they are still indicators.
For me, I know my gauges. As long as my OIL gauge is between 2nd marking at idle and 3rd marking when at high rpm, I'm fine. Lower or higher means trouble under the hood (sometimes a warning light is a better option).

The same goes for my FUEL gauge. This gauge is 25% off. So 1/2 tank = 3/4 tank and 1/4 tank = 1/2 tank, E = 1/4 tank.

The same goes for my TEMP gauge.
I can live with this.

Once you know the deviation of your gauge compared to a real OIL, FUEL or TEMP meter, you're fine.
I've seen Cruisers with 3 mechanical gauges under the dash because the owners didn't trust the cluster gauges/indicators.

Rudi

 

[1911]

I've seen Cruisers with 3 mechanical gauges under the dash because the owners didn't trust the cluster gauges/indicators.

I've got three calibrated electrical gauges in mine; not so much that I didn't trust the stock ones, but I did want something more functional than stock and I was upgrading my cluster lighting and alternator anyway.

 

[IFORDJC]

Crumbo. Having a switch istalled would make sense. My gauge would only show High or Low.

Green, Thanks for some good explaining. On my last helicopter world we had a gauge of pressure and then a secondary low pressure switch. They would often contradict each other. Similiar to what I have installed. The CCOT Oil pressure sender is only $22. Is this a good replacement or should I spend the $70 for a Toyota Part? The CCOT sender also has a ground wire connector but I am not sure what for or where to connect it?

1911. Nice gauges. When I rebuilt my gauges I considered doing that. I instead went for mechanical gauges in the factory radio slot. I have a mechanical water, voltmeter, and soon to be hooked up mechanical oil pressure.

 

[IFORDJC]

1911. How did you attach the Tach to the steering column?

 

[bj40green]

The CCOT sender also has a ground wire connector but I am not sure what for or where to connect it?

The sender needs a ground to function. Some people use too much teflon tape so the sender becomes isolated from ground/engine. Smart thinking from the manufacturer.

Rudi

 

[crumbo]

Is there a particular base impedance on the toyota sensor so I can compare it with my after market one

 

[bj40green]

Is there a particular base impedance on the toyota sensor so I can compare it with my after market one

I don't know. I've never checked it out. When I look at the diagram above in post #5, the unit/circuit is "open" when there is no oil pressure. I'll check tomorrow morning and let you know.

Ru