49 replies to this topic

[Bart]

Hey Dr Terry or anybody
I have an LJ Torana with GTR dash, and the gauges, fuel, temp, oil pressure, go straight to full
I read somewhere its due to the voltage regulator short circuit??
Can the voltage regulator be replaced with a 12v reg from dick smith or similar?
Thanks
Bart

Edited by Bart, 02 February 2009 - 11:06 AM.

[Rockoz]

Have your senders been replaced with gauge units instead of idiot light units?
Does it happen with just ignition on, or when running?
Disconnect all sender wires and see if they read zero.

[Bart]

Have your senders been replaced with gauge units instead of idiot light units?
Does it happen with just ignition on, or when running?
Disconnect all sender wires and see if they read zero.

Yeah i disconnected fuel sensder and no difference, they go full with ignition on and car running
The gauges worked ok before with the current senders, the gauges stuffed up after i got the car back from ECU instalation
Voltage spike?
Anyway i need to fix them Replace regulators??

Edited by Bart, 02 February 2009 - 12:03 PM.

[Rockoz]

Dont think its a regulator issue.
More than likely something to do with the ECU
Going to full means that the input to the gauge is effectively earthed.
Would be thinking possibly bad installation.

[Bart]

Dont think its a regulator issue.
More than likely something to do with the ECU
Going to full means that the input to the gauge is effectively earthed.
Would be thinking possibly bad installation.

The ECU is seperate to the gauges
The ECU just controls the engine/fuel injection/timing, sorry i didnt mention that

[Rockoz]

Still basically means that the inputs to the gauges are effectively earthed.
+12V gets applied to one side of the gauges when the ignition is turned on.
0V or the body potential gets applied to the other side of the gauges through the switch, which varies the voltage.
Check for disturbances in the wiring starting from directly behind the dash. The connector may have been put in wrong, or maybe some wires squashed.
Some of the old connectors could be put together one pin out, and funny results happen.

Edited by Rockoz, 02 February 2009 - 01:40 PM.

[76lxhatch]

LH/LX and every other Holden I've seen around that era have a 5V regulator which is what you are talking about above. The only gauge that gets 12V is the voltmeter, the others run off the 5V so if it has somehow shorted then you would get the gauges going all the way up. Pull the dash binnacle and test the voltage going into any of the fuel, oil pressure or temp gauges on the positive side. Depends on how the dash is constructed as to whether the regulator is a separate piece (easiest to fix) or built into the instrument cluster somehow - I don't know what LJs are like.

[Bart]

LH/LX and every other Holden I've seen around that era have a 5V regulator which is what you are talking about above. The only gauge that gets 12V is the voltmeter, the others run off the 5V so if it has somehow shorted then you would get the gauges going all the way up. Pull the dash binnacle and test the voltage going into any of the fuel, oil pressure or temp gauges on the positive side. Depends on how the dash is constructed as to whether the regulator is a separate piece (easiest to fix) or built into the instrument cluster somehow - I don't know what LJs are like.

im getting 12v going into the gauge

[Rockoz]

Ok didnt know about the 5v thing. Just looked at a couple of dashes i have here. You could get a 7805 regulator from Dick Smith and try it. They are rated at 1 amp so may be up to the job. Just make sure you keep it in fresh air for cooling.

[Bart]

Ok didnt know about the 5v thing. Just looked at a couple of dashes i have here. You could get a 7805 regulator from Dick Smith and try it. They are rated at 1 amp so may be up to the job. Just make sure you keep it in fresh air for cooling.

yeah i think i have some 7805's laying around

[76lxhatch]

12V at the gauges means the 5V regulator is not working (again assuming the LJ has one). Yes you can use the packaged circuit type regulators as Rockoz suggests, I have done this in the past. However heat is definitely an issue (preferably use long wiring and screw it to the dash, alloy if you can find any, as a heat sink). Also the gauges don't respond as quickly with this type of regulator as the original VDO stuff although crude is designed to give the gauges a very short 12V hit when you first turn the key, which makes them go up faster. An original regulator is best if you can find one, trace the positive feed back from the gauges and you will see where the regulator is (the same 12V wire that feeds the voltmeter will feed the regulator).

[Bart]

LH/LX and every other Holden I've seen around that era have a 5V regulator which is what you are talking about above. The only gauge that gets 12V is the voltmeter, the others run off the 5V so if it has somehow shorted then you would get the gauges going all the way up. Pull the dash binnacle and test the voltage going into any of the fuel, oil pressure or temp gauges on the positive side. Depends on how the dash is constructed as to whether the regulator is a separate piece (easiest to fix) or built into the instrument cluster somehow - I don't know what LJs are like.

What does the reg look like? The ones i know are the 3 leg semi, middle leg gnd, Input and Output

Edited by Bart, 02 February 2009 - 06:08 PM.

[Bart]

12V at the gauges means the 5V regulator is not working (again assuming the LJ has one). Yes you can use the packaged circuit type regulators as Rockoz suggests, I have done this in the past. However heat is definitely an issue (preferably use long wiring and screw it to the dash, alloy if you can find any, as a heat sink). Also the gauges don't respond as quickly with this type of regulator as the original VDO stuff although crude is designed to give the gauges a very short 12V hit when you first turn the key, which makes them go up faster. An original regulator is best if you can find one, trace the positive feed back from the gauges and you will see where the regulator is (the same 12V wire that feeds the voltmeter will feed the regulator).

Cool, at least i have some clue now where to start. Im ducking out to have a looky, i love fixing stuff
Hope i dont blow anything up

Edited by Bart, 02 February 2009 - 06:16 PM.

[76lxhatch]

What does the reg look like? The ones i know are the 3 leg semi, middle leg gnd, Input and Output

Dunno, I've seen Commodores that have a packaged component like what you're talking about attached to the circuit board, HX/HZ incl GTS which have horrible little metal tags which are wire-wound and part of the instruments (near impossible to fix if you even bump the thing), and LH/LX Torana which have a nice little tin box a little like an old relay which just plugs in. I still don't know for sure you have one but it sounds likely and you'll soon find out, if you're lucky some of it might be labelled, the VDO instruments all seem to be.

[Rockoz]

About 30mm long 15 mm wide and bit over 10 deep. Metal can with terminal to ground. 2 other terminals on phenolic board like end of relay. Thats what the LX one looks like anyway

[Rockoz]

double

Edited by Rockoz, 02 February 2009 - 07:53 PM.

[Bart]

Ok this is what i have found, talk about a wild goose chase and i do feel like a goose

Fuel sender is rooted, the gauge goes to full so i tried a HZ sender (which is wrong resistance i believe) and the gauge moved although it went opposite from the sender, when sender was moved to full the gauge showed 1/4 when sender empty gauge went full

Oil sender is rooted but the gauge come to life and shows low, i know there is pressure as i checked with mechanical gauge.

Tempurature gauge is now working I suspect it just had a bad earth on the body of the gauge because all i did was remove it then put it back on but rubed the two metal surfaces together (body of the gauge to earth/dash and it came to life. BASTARD. Could have sworn i did that before
I will see about the fuel and oil sender at rare spares

[Bart]

Sounds like you installed it upside down as well.

I dint actually install it, it was just for testing the gauge
Actually it makes sense because the HZ sender is physically mounted the opposite way to the LJ as i compared them side by side

[Rockoz]

Thats why i said pull the leads off the senders. That should give them zero deflection, then when you ground them full deflection.

[Bart]

Thats why i said pull the leads off the senders. That should give them zero deflection, then when you ground them full deflection.

Yes youre right i did that

[Rockoz]

I think you mean that the output of the gauge is effectively earthed?, the input is 12V

Regulator/instrument voltage stabiliser?, according to the circuit diagram, there isnt one, but that could be an omission.

Ummmmmm. No.
All the gauges have a positive connection, apparently 5V through the regulator. Its common to all the gauges.
The output of the gauges is the movement of the needle, which indicates a variance in the measured value.
The input is the wire from the relevant sender unit which sends a value to the gauge with relativity to earth or 0V, which determines the amount of deviation made by the needle of the gauge. This is for sender units that have a single wire attached to them.
This allows basic tests to be carried out on the gauges.
With the wire from the sender unit disconnected, there should be zero deflection of the associated gauge needle.
If the wire was then connected to the chassis or earth of the vehicle, 0V, the gauge should then show maximum deflection.

[76lxhatch]

All the gauges have a positive connection, apparently 5V through the regulator. Its common to all the gauges.
The output of the gauges is the movement of the needle, which indicates a variance in the measured value.
The input is the wire from the relevant sender unit which sends a value to the gauge with relativity to earth or 0V, which determines the amount of deviation made by the needle of the gauge.

Semantics. Whether input, output or otherwise there is a power wire and a sender wire which is supposed to have a specific range of resistance (to earth) to suit the gauge.

My LX manual shows the regulator as a separate component so perhaps there isn't one on the LJ after all and you should be chasing shorts to earth? Seems strange that those three gauges would all have the same problem though.