Gauge Problems

sbreedlv · Post by **sbreedlv** » Tue Oct 23, 2007 11:25 am

I have a '54 M37 with a dump bed which I had been using to haul "garden fertilizer" for several days. Last week I had a fuel starvation issue which turned out to be a very dirty fuel tank. I pulled the tank, had it boiled out at a radiator shop, and reinstalled in truck. Nothing else was touched. After adding 10 gal of fresh fuel, my gauge still shows empty. When you "tap" the gauge, it jumps to full. Searched the archives @ PWA, added a second ground wire from under a sender screw to frame and also jumped another ground from gauge mount to dash. Same problem. Removed sender wire from sender, same thing. switch "on", nothing. Tap on dash, jumps to "full". Ran an "outside" sender wire to back of gauge to eliminate stock wire. No difference. Truck runs alot stronger now, better all round, but no fuel gauge. Still have 3 hairs on my head before going completly bald!!!!! Any help would be greatly appreciated.

Steve

MSeriesRebuild · Post by **MSeriesRebuild** » Tue Oct 23, 2007 2:46 pm

Most likely is a bad sending unit.

Lifer · Post by **Lifer** » Tue Oct 23, 2007 5:57 pm

I thought about that, too, Charles. Since he said that a "tap" on the dash (probably more like a "thump" or a "whack") sent it back to a full reading, it's possible that the guage itself is sticking.

rixm37 · Post by **rixm37** » Tue Oct 23, 2007 10:21 pm

bad ground at the instrument panel it grounds through the mounting bolts try tightening them or a little sandpaper then tighten the bolts that hold the gauage to the panel

sbreedlv · Post by **sbreedlv** » Wed Oct 24, 2007 10:25 am

That you all for your help and guidance. Will give the dash and gauges a good going over for "ground" before replacing sender. I would guess that sources such as Memphis Equipt. and VPW would carry the correct fuel sender?

Thanks again,

Steve

PeteRuffing · Post by **PeteRuffing** » Thu Oct 25, 2007 1:01 pm

I changed out the military gages to Datcon 24 volt gages. Same dimensions as the military ones but he Datcon gages are modernized and backlight. I got the fuel sending unit from Datcon as well as an electronic speedo. I'll try to upload pics tonight.[/img]

m-37Bruce · Post by **m-37Bruce** » Fri Oct 26, 2007 3:07 pm

Hey Pete, Have you figured out "How to Post A Pic?
Are you two still launching your surf boat from the M?

MSeriesRebuild · Post by **MSeriesRebuild** » Sat Oct 27, 2007 7:53 am

sbreedlv wrote:I have a '54 M37 with a dump bed which I had been using to haul "garden fertilizer" for several days. Last week I had a fuel starvation issue which turned out to be a very dirty fuel tank. I pulled the tank, had it boiled out at a radiator shop, and reinstalled in truck. Nothing else was touched. After adding 10 gal of fresh fuel, my gauge still shows empty. When you "tap" the gauge, it jumps to full. Searched the archives @ PWA, added a second ground wire from under a sender screw to frame and also jumped another ground from gauge mount to dash. Same problem. Removed sender wire from sender, same thing. switch "on", nothing. Tap on dash, jumps to "full". Ran an "outside" sender wire to back of gauge to eliminate stock wire. No difference. Truck runs alot stronger now, better all round, but no fuel gauge. Still have 3 hairs on my head before going completly bald!!!!! Any help would be greatly appreciated.

Steve

Depending on what you want, Pete has made a great suggestion in his post. It will cost a few hundred $$ to make a complete instrument panel change over to some current production instruments, but is truely a vast improvement. We use either Stewart-Warner or Datcon when upgrading, both offer a huge selection of superior quality gauges & sending units. All our rebuilt trucks get these. Stay away from lesser quality gauges as they aren't of the "heavy duty" variety & will not perform well.

DDoyle · Post by **DDoyle** » Sun Oct 28, 2007 7:01 pm

Are all the other gauges operational - only the fuel does not work?

Regards,
David Doyle

sbreedlv · Post by **sbreedlv** » Thu Nov 01, 2007 9:25 am

Sorry for the delay in responding, had 20 more loads of "garden fertilizer" to haul and several gardens to plow before bad weather hits. More to do now that I'm "retired" than before!
Yes, all the other gauges work, though I do have a condition that is somewhat puzzleing to me. For about the first 30 minutes of operation, the charge rate stays high into the green zone and the temp gauge reads about 200. Then the charge rate drops to right between yellow and green and the temp gauge reads right at 180. Have a new 180 t-stat, new generator and voltage regulator. Didn't start doing this until I installed a 24v maintenance charger to the batteries. I also have a batt cut-off switch installed on the ground cable to the frame. Always starts right up, runs great, just has that fluxuation each time after about 30 min. Ordered a NOS fuel gauge in yesterday to see if things straighten out. Sending unit tested out .078 to 31.7 ohms empty to full on the bench. Possibly failing fuel gauge was causing the problem. Just a guess. I'll probably switch all gauges over to Datcon with the next failure!
Thanks, again, for all the help and suggestions! Steve

SOTVEN · Post by **SOTVEN** » Fri Nov 02, 2007 8:48 am

Hello friend, to my understanding, I will agree with those that said your problem must be bad ground in the dash panel. So I would take a look at that first. Regarding your fuel tank, I have the same problem with my motorcycle. Sludge comes out of it and clogs my in-line fuel filter. You said boiling, but is that all? any chemicals? is it clean enough now? I had cleaned my m37 tank long time ago with a tiresome proceedure and in the long run it got messy again, so I do not want to go through this ordeal all over. I wish there is an easier way.

sbreedlv · Post by **sbreedlv** » Tue Nov 06, 2007 1:29 pm

First of all, thanks for all the input on getting my fuel gauge problem resolved. 2+ 'heads" are definitely better than 1.....

I did purchase a NOS fuel gauge since mine had a needle that was sticking on empty. New gauge installed, same problem! Gauge pegged with or without sender wire on. Hum.....pulled sender out again. Test on bench with ohm meter and worked fine. EXCEPT I could not get a "ground" anywhere on the top edge of the sender where my additional ground wire was placed under a screw head. Worked fine with ground to underside of sender. SO, my added ground wire got layed out under the mounting surface edge and into a small depression near a mounting screw. Power on....gauge WORKED!!!
........what was that quote about "never trusting your ground"?
Thanks, again. Such a great place to keep these "dodgies roll'n" !
Steve

N1VSM · Post by **N1VSM** » Wed Nov 07, 2007 1:03 pm

Wow - I never thought I'd be quoted! To be honest, I swiped the line from my Electrical Engineer brother.

Gauge Problems

Gauge Problems

probably a bad ground

Thanks

Gauges

Posting Pics

Re: Gauge Problems

Guages

At Last!

Trusting your ground