Dead oil pressure gauge- Fixed

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Funner

Funner

10 Year
Joined
Jun 29, 2011
Threads
75
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3,535
Location
Phoenix, AZ
I do have oil pressure, but gauge is dead, indicator is sitting just below L.

I first threw some money at it thinking it was highly probable that the sender died just shy of 250K miles. Installed new sender and no go, same issue as before -gauge below L.

Checked wiring over and found some suspect PO splices. Pulled the harness for the AC switch and sender. tested continuity and even though it checked out I went ahead and cleaned up the crap wiring hack and put things back together.

Pulled out FSM and suspect the receiver gauge in the dash may be my problem. There is a test for this gauge in the FSM, but no instruction on how to get at it.

Has anyone had to replace the receiver gauge, any one ever tested it? Any tricks to getting to it that will save me some time?
 
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Calling @cDan and @beno, have either of you ever sold a new receiver gauge for an FZJ80? I have searched and have found nothing on them, wondering if I am missing something or if there is something else I should check...
 
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The sender is a resistor that changes resistance with pressure.

It would be safe to use a test light to connect between the feed wire (that hooks to the center top of the sending unit) to the ground wire (that connects to the body of the unit) and see if your gauge changes at all. If it moves, it is likely the sender. If it doesn't move, it could be the gauge but more likely a wiring issue.
 
If you need a gauge, let me know. I have one. It comes out of the instrument cluster with ease and a little finesse to prevent breaking tabs on the cluster...
 
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Once you get the dash apart, you can pull the instrument cluster. Notice, when this was pulled, a tab at the upper right was broken.
With the cluster out, flip it over and remove the silver screws in the area where I am pointing. Flip it over and the gauges should be loose and pop out easily
 
half k cruiser said:
There are two wires that go on the sender outside the engine block. Did you check to make sure the connections weren't corroded inside the wires? Have you put a manual gauge to it and checked that its not actually low ?
Click to expand...
Yes, I pulled the harness inspected, tested continuity, reassembled. All seems fine.
 
blkprj80 said:
The sender is a resistor that changes resistance with pressure.

It would be safe to use a test light to connect between the feed wire (that hooks to the center top of the sending unit) to the ground wire (that connects to the body of the unit) and see if your gauge changes at all. If it moves, it is likely the sender. If it doesn't move, it could be the gauge but more likely a wiring issue.
Click to expand...

I replaced the sender with a new one and same reading on gauge. I did connect the feed wire to a direct ground on the battery and the needle moved from below the L line to at the L line. I believe the FSM indicates it should move to the H line when directly grounded.
 
I would believe that to be the case, but any info I found on oil senders with a brief search indicated they may not go all the way to zero ohms. That's why I suggested the lamp in between to be safe.

It does sound like your gauge has failed. Hopefully that fixes it, and it is easy to fix.
 
Golgo13 said:
Once you get the dash apart, you can pull the instrument cluster. Notice, when this was pulled, a tab at the upper right was broken.
With the cluster out, flip it over and remove the silver screws in the area where I am pointing. Flip it over and the gauges should be loose and pop out easily
Click to expand...

Any advice to avoid braking plastics?
I will PM you about the gauge. Thanks!
 
Just be careful and treat it like old plastic. If you brake it, you can glue it back, but it's better to not break it.
 
Just following up on this thread to add closure. Upon reflection, the thread title was poorly worded, so others may not find this.
Initial searches led me to double check the wire connections at the pressure switch on the block. Everything looked good but i went ahead and cleaned them up, but no go.
So, I replaced the sender/pressure switch at the block and that did not fix it. I then (yes after replacing) tested the sender and found it not to be the problem, but it was 20 years old and figured for the minimal cost and simplicity I would just throw a part at it.

Still thinking it would/should be something simple, I dug into the wire loom for the switch and found some disturbing and well hidden PO hacks.:bang:
I made 4 repairs and thought I probably had it resolved.:rolleyes:

I tested the wires for continuity post repairs and all looked good (didn't check beforehand:doh:). I reconnected everything, jumped behind the wheel, but no joy. Gauge still showed zero pressure.

That left me with the dash gauge. A prince of a man hooked me up with a used dash gauge. That ended up being the problem. Installed new to me but used gauge and all is good again.

I treated the plastics around the cluster as gingerly as possibly, but it is a tight fit. Thanks for the warning/advice Golgo13.:clap:

Moral of the story is do whatever you want, but the fsm test for the sender switch is easy and would have saved me some time and a little coin. That said I probably would have just wasted that time too.:meh:

P.S. I have come across too many help needed threads that never conclude. If you are going to post up asking for help, please have the courtesy to conclude your thread with the resolution.
 
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Funner said:
Just following up on this thread to add closure. Upon reflection, the thread title was poorly worded, so others may not find this.
Initial searches lead me to double check the wire connections at the pressure switch on the block. Everything looked good but i went ahead and cleaned them up, but no go.
So, I replaced the sender/pressure switch at the block and that did not fix it. I then (yes after replacing) tested the sender and found it not to be the problem, but it was 20 years old and figured for the minimal cost and simplicity I would just throw a part at it.

Still thinking it would/should be something simple, I dug into the wire loom for the switch and found some disturbing and well hidden PO hacks.:bang:
I made 4 repairs and thought I probably had it resolved.:rolleyes:

I tested the wires for continuity post repairs and all looked good (didn't check beforehand:doh:). I reconnected everything, jumped behind the wheel, but no joy. Gauge still showed zero pressure.

That left me with the dash gauge. A prince of a man hooked me up with a used dash gauge. That ended up being the problem. Installed new to me but used gauge and all is good again.

I treated the plastics around the cluster as gingerly as possibly, but it is a tight fit. Thanks for the warning/advice Golgo13.:clap:

Moral of the story is do whatever you want, but the fsm test for the sender switch is easy and would have saved me some time and a little coin. That said I probably would have just wasted that time too.:meh:

P.S. I have come across too many help needed threads that never conclude. If you are going to post up asking for help, please have the courtesy to conclude your thread with the resolution.
Click to expand...

Glad to read you got it fixed!
To go along with your plea to add closure, you can also alter the thread title and let people know its fixed... When you view your own thread, you have options in the upper right which allow you to change the title...
 
Golgo13 said:
Glad to read you got it fixed!
To go along with your plea to add closure, you can also alter the thread title and let people know its fixed... When you view your own thread, you have options in the upper right which allow you to change the title...
Click to expand...
Just had same proble with my gauge..was driving it shot up to high then below low and never come back up..replaced sender and no joy spent days testing wires for continuity and connections done the test in the book grounding the sender connection the gauge went up so thought it had to be wiring we overlooked I managed to get a gauge out of an earlier 2h mines a Hzj 75 series by the way..same gauge minus the lens for the oil lvl light so.. put it in it worked but still not accurate I then gently bent mine back till the needle rest on the low mark with ignition off put it back and close enough to being spot on..when the sender failed it sends to much voltage to the gauge causing it to shoot up and bending the needle back past low causing to much tension on the bio metal strip for the low voltage from the new sender to make it react .. oh and we did find a faulty diode in the back of the circuit board we replaced which is part of the oil gauge circuit hope this helps and if you’ve checked for oil pressure and sure your sender meets the required resistance than don’t be fooled by the gauge test in the book grounding the connection this can actually destroy the gauge if done for to long
 
Another quick test is get yourself a 12 v variable adapter it is an adjustable plug which cost about $20 and can turn it back to low volts and connect it to the back of the gauge feeding it with the Same as the the sender I used a 9v torch battery at first and was under the impression the gauge was fine but the sender puts out much less and not enough to trigger a needle bent back to far
 
Destructor78 said:
Just had same proble with my gauge..was driving it shot up to high then below low and never come back up..replaced sender and no joy spent days testing wires for continuity and connections done the test in the book grounding the sender connection the gauge went up so thought it had to be wiring we overlooked I managed to get a gauge out of an earlier 2h mines a Hzj 75 series by the way..same gauge minus the lens for the oil lvl light so.. put it in it worked but still not accurate I then gently bent mine back till the needle rest on the low mark with ignition off put it back and close enough to being spot on..when the sender failed it sends to much voltage to the gauge causing it to shoot up and bending the needle back past low causing to much tension on the bio metal strip for the low voltage from the new sender to make it react .. oh and we did find a faulty diode in the back of the circuit board we replaced which is part of the oil gauge circuit hope this helps and if you’ve checked for oil pressure and sure your sender meets the required resistance than don’t be fooled by the gauge test in the book grounding the connection this can actually destroy the gauge if done for to long
Click to expand...
hello, maybe you will tell me the values of the diode you replaced please
 
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