Gauge and electrical problems

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uted

uted

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Nov 19, 2005
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Tasmania. Downunder Downunder
:)Hello all. I'm having a few electrical problems with the cruiser i'm rodding. First up the vehicle is a 1964 fj45 with 1976 loom column and gauge cluster and has a late fuel injected v6 motor and auto trans

The loom is pretty much standard except for relocating some of the switches and it has had the external reg removed and an alt light wired in. The loom for the engine is an after market loom and wired as per instructions supplied . Oil pressure, temp, ign on, starter wires run from original loom to new loom and new wires for the reverse lights and fuel pump have been run

My problems are the oil pressure gauge is maxing out when ignition is switched on The fuel gauge is not working. Temp guage shows no sign of life, but i haven't run the car long enough yet for it to get hot. Radiator not plumbed in as yet
Also the wire to the horn is live all the time. other than that, lights, wipers etc all work as they should and the motor runs fine.

Ive been poring over wiring diagrams for days have tried different gauge clusters and anything else i could think of, and spent hrs here searching But i've run out of ideas:bang:
Anyone here have any tips or suggestions on where to look or what to do. Any and all help will be greatly appreciated. Thanx

PS oil and temp senders in engine have been changed to the correct Toyota ones
 
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Thanx for the reply and the link;) The senders i bought are aftermarket ones i got through CCOT when i ordered some other parts. Not sure if they are going to be an issue as yet. Hope not:rolleyes:. I've been out the shed checking things out and the oil gauge maxes out even when the wire is disconnected from the sender unit :confused:

Been checking wires out and i have power at the blue and red wire at the plug that goes to the back of the cluster. power to the oil gauge. none to fuel gauge and none to the temp gauge, and even if i bridge the circuit to the fuel gauge it still doesn't work. i know the tank sender is good and have tried a couple of other gauges, same deal

I've obviously stuffed something up somewhere when modifying the loom or it was an existing problem with the vehicle the loom came from. but i unwrapped and checked it before using it and it seemed to be in excellent unmolested condition.

The search goes on. hopefully the problem will turn up or some one will have some idea. I may just have to check through everything again when i pull the loom back out at final paint and detail time. I hate wiring:crybaby::bang:
 
So bit more testing. i was having a look through bj40greens awesome thread on gauge clusters last night and just got myself all confused. anyway i just ran the multimeter over things and have 12v at blue and red wire at cluster plug 7v at yellow and red wire on plug (fuel gauge). and across the pins on the back of the temp gauge 1.2 done to .2v Also checked plug at fuel sender 12v and ohms on sender 11.5. doesn't help me out still not working but might mean something to someone here. still have the problem with oil gauge and horn wires.
 
Hi,

I posted an answer and later realized that yours is a '64 so I deleted my previous posting.

So let's start with a picture. This represents the back side of your cluster.
Cluster Jeran.webp

And we start with the OIL pressure circuit.
If your OIL gauge pegs into the right corner it means that you have a short to ground.
1. The yellow/black wire makes contact to ground or,
2. The OIL sender is faulty (internal short)

Disconnect the yellow/black wire and check the OIL gauge.
If the problem is still there it's a wire problem.
If the problem is gone it's the OIL sender.

Rudi
Cluster Jeran.webp
 
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thanx for the reply Rudi. Tis a 64 but has 1976 loom, switches and cluster etc

I have pulled the wire from the oil sender and the gauge still maxed out so it's obviously a problem with the gauge itself. I'll swap it out for another
 
uted said:
thanx for the reply Rudi. Tis a 64 but has 1976 loom, switches and cluster etc

I have pulled the wire from the oil sender and the gauge still maxed out so it's obviously a problem with the gauge itself. I'll swap it out for another
Click to expand...

Ok, so it's a 3 generation cluster with the barrel connector on the back. Right?
In this case the OIL pressure circuit is the same as for the early ones. Only the wire colors are different.

I don't think that the gauge is bad. In your first post you said that you had tried several clusters. The problem stays the same so it's not in the cluster.
The gauge works, the needle moves but the needle goes into the corner because there is no resistance from the sender. In other words; the wire from the gauge has a short to ground or is connected to a ground wire somewhere in the loom. Cross wire? Mismatch?

Rudi
 
Check out the yellow/black wire on pin# 2 of the barrel connector with an ohm meter. One test lead to pin# 2 and the other test lead to ground (bare metal) while the sender is still disconnected.
barrel connector lay out mirrored.webp

My bet is that your reading is almost zero ohm.

Rudi
barrel connector lay out mirrored.webp
 
bj40green said:
Check out the yellow/black wire on pin# 2 of the barrel connector with an ohm meter. One test lead to pin# 2 and the other test lead to ground (bare metal) while the sender is still disconnected.
View attachment 759322

My bet is that your reading is almost zero ohm.

Rudi
Click to expand...

Thanx for your help Rudi. is much appreciated.

Did that test got a reading of 10 ohms

I'll add these. May be of no help what so ever, but anyway
this is the wiring diagram ive been using primarily. from coolermans site
http://www.globalsoftware-inc.com/coolerman/fj40/schematics/FJ40/1976FJ40/1976_Toyota_LC_FJ40.pdf

And this is the very limited instruction sheet that came with the new loom for the engine. Mine is the two bottom pics (vn-vp)
http://www.v6conversions.com.au/WIRING INSTRUCTIONS VN-VS.htm



 
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So, you have the barrel connector disconnected....
The sender disconnected......
That leaves a single wire open at both ends.
That reading (from pin#2 to ground) should be Infinity/ Open Loop / --.- or so but not 10 ohms.
In other words; that wire goes to something else. Maybe the temp or fuel sender? A mix up maybe?

Rudi
 
uted said:
Ok with barrel connecter disconnected from the cluster and ignition on, 0 ohms
Click to expand...

Ignition on or off should make no difference, but it's not wise to turn the power on when you do an ohm test.
The reading should be infinity when disconnected at both sides.
Follow the yellow/black wire and see where it's going.

Another solution is to cut the yellow/black wire from the barrel connector and run a new wire from that point to the sender.
The disadvantage of this is that you end up with a loose wire in your loom and don't find what caused the problem.

But..... you still have the TEMP and FUEL problems so my thinking is that there is a mix up some where in the loom/harness conversion. We'll figure that out later.

Rudi
 
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So found the problem with the oil gauge.
Engine has two oil pressure senders one has single wire. i assumed this was the one for light/gauge. Other has three wires. :hhmm:I pulled the plug off this one and gauge stopped maxing out:rolleyes: Traced back the wires and one of them is to oil pressure light Others run back into engine computer.
Did a bit of research on how to fit an oil pressure gauge to the engine i have installed and i need to fit an adapter between oil filter and block then fit my Toyota sender and run a new separate wire to the gauge. One problem solved:)

Sender 1; blue wire is for oil pressure light


And the sender i removed and replaced with the Toyota one. and have since put back in:rolleyes:
 
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Also started checking out the fuel gauge issue. using the pages from the FSM posted in Rudi's thread i've started testing.



This is what i get
12volts at terminal A
fluctuating at terminal B. highest 11volts down to 2. Digital multimeter used
ohms at terminals B & C 22.5

I'm now going out to pull the sender out of the full tank and check to see what readings i get
 
So your OIL gauge works now?

Here are 2 pics for easy voltage checking.
The first one is measuring Voltage with a meter
Image-25text3.webp

And this one is for checking with a test light
Image-25text_test_light.webp

Your testing around the FUEL gauge is OK.

Rudi
Image-25text3.webp
Image-25text_test_light.webp
 
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