Slant Six Forum
https://slantsix.org/forum/

65 D100 temperature and fuel gauge issue?
https://slantsix.org/forum/viewtopic.php?t=42168
Page 1 of 1

Author:  mc_ryan [ Wed Oct 06, 2010 10:01 am ]
Post subject:  65 D100 temperature and fuel gauge issue?

So I was driving yesterday and all of a sudden I smell burning electrical and my temp gauge is pinned at hot. My gas gauge was also working... which was strange because since I bought it it NEVER worked! lol
I check the motor and radiator and they are happy as a clam...
SO, since I was only 2 miles from home and was paranoid to drive it and start an electrical fire, I had it towed home.
When I pulled the dash gauges the temp gauge was totally fried inside so I have to try to find one of those now. Anyone know where I can find one for less than $50?
What confused me is that my gas gauge now works... It never worked and I thought I just needed a new sender but NOW it is working? I don't know if it is accurate but WTF? Do I have a voltage regulator for my gauges? I know some dodges do but I have a 1965 Dodge D100 with a slant 6. Granted I have not REALLY looked that hard for it. lol I know that the temp gauge is powered via the gas gauge. Is it possible that the temp gauge has been failing for some time and just robbing the gas gauge of proper power to work?

Any ideas?

THANKS!

-Marc

Author:  emsvitil [ Wed Oct 06, 2010 4:30 pm ]
Post subject: 

Both the temp gauge and fuel gauge are supplied by the same (roughly) 5V voltage regulator.

I'd say the wire to the temp sending unit or the sending unit is shorted to ground.

Which caused all the power to go thru the temp gauge until it couldn't take it any more.

Once the temp gauge was out of the circuit, the fuel gauge finally had some current to work with..............

Author:  mc_ryan [ Wed Oct 06, 2010 6:27 pm ]
Post subject: 

oooo that makes sense! I will check that tomorrow. Also, I measured 11.8 volts going out of the fuel gauge to the temp gauge and I measured 12.1 volts AT the fuel tank sender connection... Could this mean that my regulator is fried?

Author:  emsvitil [ Wed Oct 06, 2010 8:19 pm ]
Post subject: 

The voltage regulator is a old-style pulse regulator that on AVERAGE is around 5V.

So the on pulse could very well be 12V.

Use an old analog voltmeter and see if it pulses.

Author:  mc_ryan [ Wed Oct 06, 2010 10:08 pm ]
Post subject: 

awesome... will do. I think I have an old analog meter stuffed in a toolbox somewhere. lol I will keep you posted. Thanks a TON!

Author:  mc_ryan [ Wed Oct 20, 2010 5:59 pm ]
Post subject: 

OK sooooo.... I can not find a voltage regulator for my gauges. I read that some 65's still had the regulator as part of the fuel gauge. This sound familiar to anyone? I thought my fuel gauge was working but it turns out that it just sits at 3/4 tank... weird....

ALSO, I tried to put in an aftermarket mechanical gauge and of course it will not thread into the same place as the stock temp sensor. lol Is there a way to get an aftermarket temp gauge on this slant six? or does it look like I have to buy new fuel AND temp gauges?

Suggestions? :)

-Marc

Author:  lancer61 [ Thu Oct 21, 2010 3:03 am ]
Post subject: 

Get an adapter for the sending unit.

Author:  wjajr [ Thu Oct 21, 2010 5:43 am ]
Post subject: 

Hit the plumbing section at a hardware store, or fitting section of auto parts store for 3/8th x 1/4th (I think is the size) Reducing Bushing. Take the old & new sending unit with you to check the fit & threads.


Image

Author:  mc_ryan [ Thu Oct 21, 2010 8:57 am ]
Post subject: 

Ok. Let me be more specific. My original in-dash temp gauge that is driven by the original temp sensor went boom. My original temp sensor is brand new. I didn't want to drive around with no temp gauge so I thought I would install one of those mechanical gauges. The one with the thermocouple covered by a spring that goes from the head all the way through the firewall to the aftermarket gauge. The threads/hole for the original temp sensor are like 1/4" and every adapter for the thermocouple, AND the thermocouple for that matter, seem larger than the hole in the head. Making it look like if I wanted it to work I would have to drill out to a larger size and tap threads in the original hole in order for the NON original temp gauge's thermocouple to even fit in the head.
Wjajr: In your pic you have the original sensor going into an adapter that seems much larger than the hole in my head. For me it is the opposite. I have a really small hole in my head and a larger size adapter I have to fit on. If I get a 1/4" adapter to make it bigger threads the thermocouple will not fit.
I hope this makes my question more clear. Sorry. :)

Author:  mc_ryan [ Wed Nov 24, 2010 4:40 pm ]
Post subject: 

SO... Just to follow up on this here... I found that my gas gauge has the regulator as part of it. SO to get my gauges working again I would need to find a new gauge... OR.. I found a way to build a solid-state regulator for about $8 from Radio Shack. I think I found it on this site... I dunno. But it takes 12V and regulates it to a rock-solid 5.1V for the gauges. I did this and hooked it up and still nothing from the gas gauge. When I grounded out the wire to the fuel sender the gauge went to the "F" line and worked fine.
SO, I pulled my sender to see if the problem was there. OH WAS I RIGHT!
I found that not only did the float have about 4 holes in it, the part of the arm that has the little tab on it that brushes up against a coiled wire which tells the gauge what "level" the gas is in the tank was completely broken into pieces and worthless.
So, I got out some sand paper, flux, solder and my soldering iron. Fixed all the holes in the float, soldered the tab back on the non-float side of the arm, bent the tab to point to the right place on the coiled resistor wire (so the gauge would read correct) and popped it back in.
It works like a charm!! Gauge is properly regulated and tank sender is repaired and reading proper. All for the cost of $8 and about 3 hours of my time.
My temp gauge however got fried when the regulator in my gas gauge went out. So I have to get another one of those. Unless anyone knows the proper resistance that the coiled wire on the arm in the tamp gauge is? If I could get what the resistance is supposed to be I could bypass the old fried coiled wire??? Just trying to make this truck work with my wallet size. :)

-Marc

Author:  Fopar [ Wed Nov 24, 2010 5:02 pm ]
Post subject: 

You might just drill the small hole in the head out to the size for the adapter for the after market gauge. Lots of the heads had a larger hole in that position.

Richard

Author:  mc_ryan [ Wed Nov 24, 2010 7:31 pm ]
Post subject: 

I had that thought but was unsure of the amount of "meat" available. I have a 1965 head. I don't know if there are any differences in that part of the head that would prevent me from drilling it out and tapping it for an adapter.
If not... I might rather have a mechanical gauge telling me the actual temp in degrees of my motor, rather than a slightly unpredictable guess/mess of lines that really tell me nothing. lol

-Marc

Author:  Fopar [ Wed Nov 24, 2010 7:54 pm ]
Post subject: 

I had the hole on the engine in my Ford drilled and tapped, no problems.

Richard

Page 1 of 1 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/