Gauges not working on my 74’

[74bronk]

Been putting my Bronk together and got it running last couple of years. Sent out my gauges cluster had it refurbished. I also had the the dash board “powder coated” front and back, wondering if this is the issue? I can get the dash lights to work speedometer works I just can’t get the fuel gauge to function (most important to me) does seem that the oil pressure gauge does work other 3 do not. I know they all work because I was working on another problem someone move something under the hood or I did something in the cab and the gauges all started to work for about a minute. Getting a little frustrated. I even ran a special ground specifically to ground all gauges. It is getting voltage and regulator on cluster is good. Any help appreciated.

Thanks

 

[Brush Hog]

Is your dash grounded? Needs to be grounded to bare metal. Just grind off small spot of the powder coating that’s what I had to do. Then attached ground wire from dash to windshield frame.

 

[DirtDonk]

Yep, powder coating is the bane of the existence of new wiring on an old vehicle.
You should run at a minimum:
1. Ground wire from the battery to body (in addition to the normal one to the engine).
2. Ground wire from the back of the engine to the firewall.
3. Ground wire from firewall or other body part to the dashboard.
4. Ground wire from the dash to the instrument cluster itself. Without a good ground connection your gauges will not work properly.
5. Make sure that the instrument cluster housing was not painted. If it was, then make sure that the IVR (instrument voltage regulator) is grounded to the housing. Or it won't work...

It's also not a bad idea to check the input of the IVR to make sure that 12v is getting to it reliably, and that approx. 5-6 volts is getting out of it to the gauges.
Is this a stock IVR or an electronic replacement?

And you didn't say, so we can only assume that you also re-wired the entire vehicle. If so, what harness did you use?
And either way, new or old wiring, did you make sure to put the body ground back in place? When you moved something under the hood and they worked for a bit, I wonder what you were messing with or bumped?

So more details please. And maybe even some pics.

Good luck.

Paul

 

[74bronk]

Yep, powder coating is the bane of the existence of new wiring on an old vehicle.
You should run at a minimum:
1. Ground wire from the battery to body (in addition to the normal one to the engine).
2. Ground wire from the back of the engine to the firewall.
3. Ground wire from firewall or other body part to the dashboard.
4. Ground wire from the dash to the instrument cluster itself. Without a good ground connection your gauges will not work properly.
5. Make sure that the instrument cluster housing was not painted. If it was, then make sure that the IVR (instrument voltage regulator) is grounded to the housing. Or it won't work...

It's also not a bad idea to check the input of the IVR to make sure that 12v is getting to it reliably, and that approx. 5-6 volts is getting out of it to the gauges.
Is this a stock IVR or an electronic replacement?

And you didn't say, so we can only assume that you also re-wired the entire vehicle. If so, what harness did you use?
And either way, new or old wiring, did you make sure to put the body ground back in place? When you moved something under the hood and they worked for a bit, I wonder what you were messing with or bumped?

So more details please. And maybe even some pics.

Good luck.

Paul

Yes wiring was replaced about 10 years ago. I do need to add all those grounds the IVR should be new when I ordered a referbished cluster along with the gauges

 

[DirtDonk]

I was thinking you had a new harness when you said the lights worked. The aftermarket harnesses have separate grounds for the lights, illuminating the dash.
Whereas the factory relied on the dashboard to ground.

 

[sprdv1]

Yes wiring was replaced about 10 years ago. I do need to add all those grounds the IVR should be new when I ordered a referbished cluster along with the gauges

maybe time for new? I guess it could still be okay tho

 

[74bronk]

Yep, powder coating is the bane of the existence of new wiring on an old vehicle.
You should run at a minimum:
1. Ground wire from the battery to body (in addition to the normal one to the engine).
2. Ground wire from the back of the engine to the firewall.
3. Ground wire from firewall or other body part to the dashboard.
4. Ground wire from the dash to the instrument cluster itself. Without a good ground connection your gauges will not work properly.
5. Make sure that the instrument cluster housing was not painted. If it was, then make sure that the IVR (instrument voltage regulator) is grounded to the housing. Or it won't work...

It's also not a bad idea to check the input of the IVR to make sure that 12v is getting to it reliably, and that approx. 5-6 volts is getting out of it to the gauges.
Is this a stock IVR or an electronic replacement?

And you didn't say, so we can only assume that you also re-wired the entire vehicle. If so, what harness did you use?
And either way, new or old wiring, did you make sure to put the body ground back in place? When you moved something under the hood and they worked for a bit, I wonder what you were messing with or bumped?

So more details please. And maybe even some pics.

Good luck.

Paul

Wiring harness is a Centec

 

[74bronk]

When I had the dash powder coated I had front and back done does the whole cluster rely on the body of cluster touching dash board for a ground? Or can I just run a wire from cluster to dash etc?

 

[DirtDonk]

The original dash lights relied on the dash to ground, but the Centech illumination sockets come with their own ground wires. The gauges do not need to ground, they are just "pass-through" circuits for the power out to the individual sending units.
But the IVR most definitely does for proper function.

Re-reading your first post, if one gauge works then it's not the IVR. If someone messing with wires under the hood caused the others to work, then it's not the IVR. The harness out to the sending units for water and oil, or even the sending units themselves, would seem to be the next on the list to check.

With all the powder coating, you will need to run a dedicated ground wire to the IVR mounting screw if you have not already. You said you ran a ground to the gauges already, but where did you connect it?

Bottom line though, is if the fuel gauge is the only one not working, then it's only one circuit that needs looking at.
Your fuel, temp and press gauges all take their power from the single IVR and then pass it out to the individual sending units. Which are essentially variable grounds.
The ammeter depends solely on the one 10ga wire passing through the loop. If you have replaced it with a volt-meter, it depends on where you're getting the power sample from, and in the case of a volt-meter, you probably need to ground the gauge.
But I'm not 100% sure about that.

Paul

 

[74bronk]

Thanks guys got it my gauges working!
Question: my oil gauge is pegged passed 90. Bad sending unit or is it the high volume pump i put in the motor?

 

[DirtDonk]

High volume alone won’t raise the pressure without a stiffer bypass spring as well, I would not think.
Does it go down when warm? Does it go high only when the key is on, or does it at least rise only after the engine fires up?
How do the other gauges read?