Well I just got done rewiring my truck and getting it started after a few years. I installed my gauges that I had sent out to get refurbed from United Speedometer. They redid the gauges and converted them to electric. The problem is the temp gauge reads nothing with the key off and will do so for a minute after the engine is started. after that the needle goes to the very top of the scale and is obviously not reading the temp. What could be the problem here? -Casey http://picasaweb.google.com/caseywcochran/TruckPics
Is the temp guage electric also? If so, check the resistance from the sender and make shure it is putting out. Also make shure the paint is ground from the back of the guage bucket where the guage itself mounts to it, I have had problems with fuel guages when they weren't properly grounded. My mechanical temp guage has a little stick to it and doesn't show until the engine is almost to temp, I need to open it up and lube it a little and make shure it isn't dragging anywhere...
The sending unit isn't the right one for the gauge. Most likely a "switch" for an idiot light, not a variable sending unit you need for a gauge. This would account for the all or nothing operation of your gauge. I'd contact United Speedometer and get their recommendation.
Thanks guys for your help. I called United Speedometer and they schooled me. I was dumb and used teflon tape on the sender unit.
Ok... took the teflon off but still it was either on or off. I think it may be an idiot light sending unit. I will have to go and get a new sending unit. Thamks guys
Don't Forget To actually test the gauge ! it's simple : ignition on , ground the wire at the sender , gauge must go all the way to one extreme . Now , disconnect the sender wire and make sure it's not touching anything , gauge must go all the way to the other extreme . Pretty simple .
I never, EVER heard of teflon tape interfering with a temp sending unit. I use it all the time and have never had a problem with it. Andy
The Guy at United seemed to think teflon tape on the sender would make the gauge act screwy. Either way, I am going to go out there today and test the sending unit. May also stop by the local auto parts store and buy a sending unit in case this is the idiot light type.
Given that United Speedo converted the gauge to electric I think I'd get their advice as to which sending unit to use. I still bet the one you have is a switch for an idiot light.
Sounds like your on the right track Yeah sounds like you have a idiot light switch hooked up to your gage. We use one of those on our race car in conjunction with a mechanical gage. just to let us know if it is starting to overheat i think it is set at 220 degrees or so. Like others said you need the variable temp sensor......try ordering one for a 70's corvette because those cars didnt have any idiot lights but were electric gages and should bolt right into your head which is I believe 1/2 npt thread. Iv been having a issue with the temp gage on my 55 myself .....always reads around 200 even when the engine is 10 below zero.....after looking close I noticed that the previous owner made some modifications to it......The stock gages had the capillary bulb and tube that was filled with what I believe is ether ??.....well apparently the previous owner (ROCKET SCIENTIST)cut the tube or it broke and he repaired it by installing a electrical type sending unit and crimped a female blade electrical connector onto the old capillary tube...... kinda made me laugh for a good 5 minutes. Well OK good luck with it, Leon
Ground I had this problem once before and as strange as it seems, the engine wasn't grounded to the firewall. You would think with all the hardware involved it would have been grounded but it wasn't. Just a thought!
the gauge works as a variable ground the hotter the engine the more the "grounding" of the sender. you need to confirm the sending wire isn't shorting out on the frame. it would get you a false reading GT
