Oil Pressure Gauge FIX

[barkgrind]

hi all

I have a 1985 rj70 22r bundera

the only wire i can find near my sender is black and bare wire ?

am i right in assuming the bare wire is the ground? and the black wire is the centre?

 

[ToyotaMatt]

hi all

I have a 1985 rj70 22r bundera

the only wire i can find near my sender is black and bare wire ?

am i right in assuming the bare wire is the ground? and the black wire is the centre?

please attach seveal photos to help us help you ..........

 

[barkgrind]

finally got the car back

here is a photo of the wire

I put the lugs on myself

there is a aftermarket gauge installed I am not sure if the original gauge is working either

With the ignition off my wiring is reading roughly 28 ohms

 

[barkgrind]

finally got the car back

here is a photo of the wire

I put the lugs on myself

there is a aftermarket gauge installed I am not sure if the original gauge is working either

 

[ToyotaMatt]

I have takin a fresh look at taking this on , regularly

Keeping it in stock several units , so to prevent any

Leed time Vehical down time relayed issues

 

[ToyotaMatt]

 

[John Young]

My needle is dead at the bottom. It looked like the pressure sender had been changed fairly recently.

And when I looked close I saw that the wiring harness looked like it had been repaired several times:

And the little box of 'resistors and diodes' looked pretty awful.

And one of the spliced wires going to the little box felt broken under the heat shrink.
I threw both ends of that into the ultrasonic cleaner

And it looks much better now.

 

[John Young]

I redid the harness with some care--heatshrink and self vulcanizing rubber tape.

My harness was hardwired to the sensor on the AC compressor and I had to cut that. Does anyone happen to know off the top of their head what the part number is for each of the two halves of the 1-pin connector that goes to the AC compressor? I'd like to put that in. It bothers me to have to cut a connection to remove the harness.

So I put everything back together and still nothing.

I then tried the LED test from the FSM. I used an dashboard LED replacement for 12v the mini incandescent bulbs used in the 80's dash. The current draw is tiny and they have the resistor built in. The bulb was off with the ignition on. When the engine starts cranking it turns on. Completely on. And it does not flicker at all or change with RPM. I've got a replacement sender on order and it arrives in a couple of days.

In the meantime I'd be grateful for information on....

1. what is actually in the little box and why it is there? I can't find it in the FSM circuit diagram--I can't even find the oil pressure sender circuit in the FSM circuit diagram--which I don't understand.
2. What each of the part numbers are for the 1-pin connector ends for the wire going to the AC sensor?
3. What is the theory of operation for this thing? From the first part of the FSM test procedure I infer that maybe the sender does not send a linear resistance depending on the value of the oil pressure but rather pulses each time the pump vanes come around. This seems kind of crazy to me. I also have seen in other threads that the gauge in the dash has a bimetal strip that heats up and moves the needle depending on, I suppose, the fraction of time that the sender circuit is closed -- kind of a pulse width modulation affair. But I'm just speculating. If someone could really explain what is going on I think it would really help the troubleshooting process.

 

[ToyotaMatt]

I offer the Early oil harness now DISC. by toyota NLA , i 100% period correct format , fit and finish , using 100% toyota genuine electrical service parts for my personal spot ON assembly ........

PM me if i can help ?

matt

 

[ToyotaMatt]

82221-60010-R

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[ToyotaMatt]

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[Mat Jadamec]

I wrote up my harness diagnosis and rebuild (1994 FZJ80 1FZ-FE) here:

Oil pressure sender

My oil pressure sender has a broken wire, possibly a ground! Anyone know where it goes as there are 2 plugs?

forum.ih8mud.com

After putting the rebuilt cable in my gauge read consistent with the owner's manual (see pic below). The "funny box" had a toyota part number and as I mentioned in the post it comes up as a "filter" used in the power system for earlier model truck stereo power sources (I think). It was in there when the gauge worked so I left it in. I am not good at electrical engineering so won't even try to guess why it is in the cable.

 

[ToyotaMatt]

I wrote up my harness diagnosis and rebuild (1994 FZJ80 1FZ-FE) here:

Oil pressure sender

My oil pressure sender has a broken wire, possibly a ground! Anyone know where it goes as there are 2 plugs?

forum.ih8mud.com

After putting the rebuilt cable in my gauge read consistent with the owner's manual (see pic below). The "funny box" had a toyota part number and as I mentioned in the post it comes up as a "filter" used in the power system for earlier model truck stereo power sources (I think). It was in there when the gauge worked so I left it in. I am not good at electrical engineering so won't even try to guess why it is in the cable. View attachment 2657457

DO NOT guess or you fry the gauge in dash

post photos of your 2 different spade and button connectors , ill walk you through the correct hook procedure

 

[John Young]

I would like to comment at the outset that CruiserMatt's harnesses look very nice. And the prices seem very reasonable. If I had more time or I had not already redone my own harness in very non-OEM form, I would be sending $$.

So just to share where I am in the process, I replaced the sender/sensor with a new, non-OEM one, and still no effect that I could readily see. I decided to try the second test with the light bulb load to manually drive the dash gauge. I really did not want to go out and buy yet another thing for this so I hunted around and tested a few 12 volt bulbs. I have replaced most of the instrument cluster bulbs with LEDs so I had the old incandescent bulbs at hand. It turns out that the large green instrument cluster bulb (at least the one I have) drew .22 amps for about 3 ma at battery voltage. Close enough and lower amps so it would not destroy anything in any event.

With the ignition on the bulb glowed dimly, as you can see in this photo.

Here's what the dash gauge looks like with the ignition off:

And here's what the gauge looks like with the ignition on:

I infer from this that the wiring is working but the gauge is faulty. Maybe it got grounded out and bent like others have reported. Or maybe it's just gummed up from almost 30 years of being in the desert. I'm going to take a long drive tomorrow and watch the gauge. I know there is oil pressure, so I'm not worried about driving it. I don't really want to pull the cluster out yet again because we are about to take the truck down to Florida on the Auto Train for my son to use there and I have a junk cluster back in Dubai. I think I will just let this particular sleeping dog lie until I have a spare, verified working instrument gauge to swap in.

I want to mention again for the benefit of others that the large green bulbs in the instrument cluster work for the second test in the FSM.

 

[William BB]

John, This is Will across the way in Bahrain. I recommend you stop running your engine and open up your oil pan. I spent 3 weeks chasing what I thought was a bad oil pressure sender and wiring--same problem- I was watching my oil pressure gauge slightly move. I was too late ignoring it and I caused major damage to my engine (rebuild and 6 pistons later). My oil pan was full of soot and at the beginning of start up my oil pressure gauge moved up slightly because the oil was clean and cold; however, once I idled it, the soot got loose and clogged my sump inlet strainer causing needle to go down. From you pictures, I truly believe your sensor works, you just have low oil pressure. I will post my nightmare photos shortly. My rule of advice- if your needle says its low oil pressure--assume you do. Don't fall for the "I just did an oil change or my dipstick is clean" The soot is thick and will not leave the bottom of the pan after an oil drain. Gotta love the dust in the middle east

 

[ToyotaMatt]

I would like to comment at the outset that CruiserMatt's harnesses look very nice. And the prices seem very reasonable. If I had more time or I had not already redone my own harness in very non-OEM form, I would be sending $$.

So just to share where I am in the process, I replaced the sender/sensor with a new, non-OEM one, and still no effect that I could readily see. I decided to try the second test with the light bulb load to manually drive the dash gauge. I really did not want to go out and buy yet another thing for this so I hunted around and tested a few 12 volt bulbs. I have replaced most of the instrument cluster bulbs with LEDs so I had the old incandescent bulbs at hand. It turns out that the large green instrument cluster bulb (at least the one I have) drew .22 amps for about 3 ma at battery voltage. Close enough and lower amps so it would not destroy anything in any event.
View attachment 2659808
With the ignition on the bulb glowed dimly, as you can see in this photo.

Here's what the dash gauge looks like with the ignition off:
View attachment 2659811
And here's what the gauge looks like with the ignition on:
View attachment 2659814

I infer from this that the wiring is working but the gauge is faulty. Maybe it got grounded out and bent like others have reported. Or maybe it's just gummed up from almost 30 years of being in the desert. I'm going to take a long drive tomorrow and watch the gauge. I know there is oil pressure, so I'm not worried about driving it. I don't really want to pull the cluster out yet again because we are about to take the truck down to Florida on the Auto Train for my son to use there and I have a junk cluster back in Dubai. I think I will just let this particular sleeping dog lie until I have a spare, verified working instrument gauge to swap in.

I want to mention again for the benefit of others that the large green bulbs in the instrument cluster work for the second test in the FSM.

John, This is Will across the way in Bahrain. I recommend you stop running your engine and open up your oil pan. I spent 3 weeks chasing what I thought was a bad oil pressure sender and wiring--same problem- I was watching my oil pressure gauge slightly move. I was too late ignoring it and I caused major damage to my engine (rebuild and 6 pistons later). My oil pan was full of soot and at the beginning of start up my oil pressure gauge moved up slightly because the oil was clean and cold; however, once I idled it, the soot got loose and clogged my sump inlet strainer causing needle to go down. From you pictures, I truly believe you sensor works, you just have low oil pressure. I will post my nightmare photos shortly. My rule of advice- if your needle says its low oil pressure--assume you do.

i have a outside the box quickie needed diagnostic technical solution to share , i use this approach personally 24/7

its accurate , safe , and black and white spot on !

zero grey area of interpretation like the fsm little light bulb approach , i never personally use at all anymore

takes only single minutes to install and do a test base idle engine start up and verify engine oil specs and presence of there of ...
or not ...

so here we go :

- go to advance auto parts or auto zone

- pick up one of these ........

- a mid grade to high end assy. 2 5/8 " stand alone full sweep manual oil pressure gauge

- all the ones i have purchased over the years have Indeed come with the correct TOYOTA fitting threaded fitting adapter

- my SUNPRO is excellent quality at a fair price

- so , i can take glove and hand turn off the big bell shape oil sender we all are familiar with , care fully hand thread the Sunpro adapter with the capularay tube still attached


- the IMPORTANT note : hand tighten then use a open end wrench stubby, ONLY a 1/4 to a 1/3 more of a wrench turn to seal brass to the alloy land cruiser sender port

- never had a leak ever

- turn on engine , after you set gauge in a safe and stable location , maybe tie off with a zip tie or mini bungee too

- i have always found the SUNPRO to be very accurate in relationship to the FSM PSI specs once warmed up and oil is thin , and normal viscosity

- cold oil shows a higher pressure

- vibration can make it dance around and fall into engine bay

- here is my sunpro manual SST shop made oil pressure verification devise ...............

- i have never looked back !

 

[ToyotaMatt]

 

[John Young]

John, This is Will across the way in Bahrain. I recommend you stop running your engine and open up your oil pan. I spent 3 weeks chasing what I thought was a bad oil pressure sender and wiring--same problem- I was watching my oil pressure gauge slightly move. I was too late ignoring it and I caused major damage to my engine (rebuild and 6 pistons later). My oil pan was full of soot and at the beginning of start up my oil pressure gauge moved up slightly because the oil was clean and cold; however, once I idled it, the soot got loose and clogged my sump inlet strainer causing needle to go down.

Hi William. Thank you for the advice. I take your point. I will say that when I did the lightbulb test the meter barely moved which suggests the meter itself is stuck. That said, this is a desert truck and it shows signs of heavy use. I'm going to heed your advice and measure the oil pressure. I happen to have a transducer handy so I can see with some precision what the oil pressure actually is.

Input: 0-100 psi

Output: 0.5V~4.5V linear voltage output. 0 psi outputs 0.5V, 50 psi outputs 2.5V, 100 psi outputs 4.5V.

Accuracy: within 2% of reading (full scale).

The tricky bit is getting the 1/8 BSPT Male Thread to 1/8-27 NPT Female Thread Port because Mr. Toyo decided BSPT was best.

 

[William BB]

It doesn't hurt to verify. I'll keep an eye on the thread to see your progress. Agreed- if oil pressure is good, turn to the cluster for troubleshooting; you've eliminated everything else.

 

[ToyotaMatt]

Hi William. Thank you for the advice. I take your point. I will say that when I did the lightbulb test the meter barely moved which suggests the meter itself is stuck. That said, this is a desert truck and it shows signs of heavy use. I'm going to heed your advice and measure the oil pressure. I happen to have a transducer handy so I can see with some precision what the oil pressure actually is.
View attachment 2662203
Input: 0-100 psi

Output: 0.5V~4.5V linear voltage output. 0 psi outputs 0.5V, 50 psi outputs 2.5V, 100 psi outputs 4.5V.

Accuracy: within 2% of reading (full scale).

The tricky bit is getting the 1/8 BSPT Male Thread to 1/8-27 NPT Female Thread Port because Mr. Toyo decided BSPT was best.

this thread pitch , taper & diameter topic you mention above is why i chose my recommended method to manual field test

the auto gauges come with a JIS Pipe taper fitting , easy low risk in , easy issue free out

done ...