New EB Bronco Owner Here...

[cgofort]

Hello everyone,

I purchased a new to me '74 Bronco, automatic with the 302 motor. LOTS of potential, and i'm quite excited. Of course, there's technical concerns, so I figure I'd ask a community of experienced owners for advice:

I'm worried about the stock dash gauges, in particular the temperature and oil pressure gauges. They both peak! The previous owner said that was just how they worked, and were inaccurate. To be honest, the voltage stays in the middle, the fuel doesn't work, and it doesn't light up at night.

Any suggestions about what to do to resolve the temp / oil gauges? I'd prefer to keep the stock cluster.

Thank you for any feedback!

 

[fordtrucks4ever]

LIkely a short or the voltage regulator on back of it is bad. Common problem on older vehicles. One other thing in case someone did an engine swap sometime in the past. It could have idiot light sending units on motor.

 

[sprdv1]

Welcome to the site. Lots of good knowledge here.

 

[JEFF76P]

I had that problem and it turned out to be a bad ground at my aux. gas tank. don't figure ?

 

[A4x4Junky]

Hello everyone,

I purchased a new to me '74 Bronco, automatic with the 302 motor. LOTS of potential, and i'm quite excited. Of course, there's technical concerns, so I figure I'd ask a community of experienced owners for advice:

I'm worried about the stock dash gauges, in particular the temperature and oil pressure gauges. They both peak! The previous owner said that was just how they worked, and were inaccurate. To be honest, the voltage stays in the middle, the fuel doesn't work, and it doesn't light up at night.

Any suggestions about what to do to resolve the temp / oil gauges? I'd prefer to keep the stock cluster.

Thank you for any feedback!

When I have seen gauges peg to the high side it has been because of a bad ground or the sensor just not hooked up.

Good luck and welcome aboard

Anthony

 

[70_Steve]

I'm worried about the stock dash gauges, in particular the temperature and oil pressure gauges. They both peak! The previous owner said that was just how they worked, and were inaccurate. To be honest, the voltage stays in the middle, the fuel doesn't work, and it doesn't light up at night.

Congrats on the Bronco purchase and welcome to the site.

The oil pressure, water temp and fuel level gauges are all powered by an Instrument Voltage Regulator (IVR), which is a smallish box mounted on the back of the instrument cluster. That other gauge is not a voltmeter, it's an ammeter, and is wired completely independent of the other three gauges. The backlighting for the gauges is also seperate wiring.

The IVR is actually more of a current regulator than a voltage regulator. It produces a pulsed voltage. To check the operation of the IVR with a voltmeter, connect between ground and the output of the IVR. You should be able to do this at the plug for either the oil pressure sending unit, or the water temperature sending unit. If you're using an analog meter, set on 20 VDC scale, and look for the needle bouncing, several times a second, between ~5 and 7 VDC. If you're using a digital meter, use the same scale, and look for voltages anywhere between ~0.5 and 10.5 volts.

The fuel level not working at all could be any number of reasons, mostly related to not having a complete circuit from the IVR, through the gauge, to the sending unit, and to ground. Get the oil pressure and water temp gauges working first, then troubleshoot the fuel level issue.

 

[Devin]

Welcome to the forum!

 

[cgofort]

So should I replace the thermostat, as precautionary?

 

[70_Steve]

So should I replace the thermostat, as precautionary?

Personally, I wouldn't bother, unless you have some other indication that the engine is overheating.

 

[73azbronco]

Buy books.

Lots of good used original ford truck manuals with bronco stuff on ebay.

Welcome to the money pit, although alot of the guys on this site could make a V-10 out of a six pack of coke... So listen up and learn oh grashopper...

 

[airman]

does the temp gauge peak with a cold engine? 70_Steve has you in the right direction. If you don't have a decent meter, you will soon.

You remind me of me a few years back. None of my gauges worked right. They do now. I'm also about 10 lbs lighter after removing all of the red control wires added by the previous owner. He removed the dash and painted it. Nothing went back right.

You'll get there and learn a lot as you go. Welcome to the site. I would have been screwed without it.

 

[cgofort]

does the temp gauge peak with a cold engine? 70_Steve has you in the right direction. If you don't have a decent meter, you will soon.

The temp gauge doesn't immediately peak, it will rise to peak within a mile of driving. It's a gradual, steady climb, but I never hear anything like boiling when I open the hood...


BTW, Thanks for the encouragement!

 

[70_Steve]

The temp gauge doesn't immediately peak, it will rise to peak within a mile of driving.

Check the IVR!!

Wiring diagrams may help. I usually go to N8's site for them.

http://www.wsu.edu/~i6735189/diagrams.htm