gauge troubles

[Unionjackjim]

evening all , Having just finished a few little jobs , like new fuel tank / up graded drive shafts & seals / bush guard & under body protection + new generator & all the belts , I just fitted a new oil pressure gauge as the existing was perminately 120psi + , only to find that it reads 0 & when you rev it actually goes the wrong way ( sub zero ) any ideas ???? TM does not appear to detail this problem .

Also the fuel gauge works but will only show a max of 1/4 tank , the sender etc was all new when i changed the tank , other than that the truck is great & ready for some action.

 

[nattieleather]

Any chance you have the wires switched at the gauge?

 

[Unionjackjim]

tried that , but it was then just dead , will have to get the tester out & print the TM section

 

[papakb]

The HMMWV has a plastic dash panel and needs a good solid ground to work properly. Check to see that you have good continuity to the ground stud just in front of the heater controls on the firewall.

Kurt

 

[emmado22]

grounds ground grounds!

 

[Unionjackjim]

Point taken , I will do a temp ground directly from gauge to battery to check

 

[papakb]

Going all the way to the battery isn't necessary. Just use a clip lead and connect to the ground stud. That stud is known to give problems because of where it's located. Heating and cooling can cause it to loosen up over time and the result is gauge problems. You have to remove the panel to get to it and even then it's tucked in behind the heater controls. You want to make sure those connections are clean and tight. If you want to take the time putting some anti-oxidant grease on the terminals will help in the future. You can get a little tube of it at Home Depot or Lowes.