ISSPRO has let me down

[blowinsmoke7.3]

Having some issues with my tranny gauge, upon start up this afternoon the needle shot up to 160 180ish and continued to climb fast, almost pegged the gauge. Truck was in park idleing.
Shut the truck off and started it back up, gauge acted normal, started to drive home from school, made it out of the parking lot and gauge shot right up to 220 and eventaully pegged itself out on the way home.
Initally i thought my tranny was fixin to sh!% on me so i crawled underneath the truck and its barely hot to the touch so i know its a gauge issue. Checked all connections everything looks good.
Anyone got any ideas

[dmbrichie]

I don't know man... I have been having problems with my ISSPRO gauges since day 1. About a year and a half ago I installed my gauges and the pyrometer NEVER went passed about 400 or so... After a while I called ISSPRO and they sent me a new gauge and wiring harness, installed both new items, and still NEVER goes passed 400-500... And now in the past month or so my tranny temp gauge is somehow loose somewhere, so it will be at its normal 160, I hit a bump and it will bounce all over the place... 190...220...back down to 160...I am not very pleased to say the least...

[blowinsmoke7.3]

Originally Posted by dmbrichie

I don't know man... I have been having problems with my ISSPRO gauges since day 1. About a year and a half ago I installed my gauges and the pyrometer NEVER went passed about 400 or so... After a while I called ISSPRO and they sent me a new gauge and wiring harness, installed both new items, and still NEVER goes passed 400-500... And now in the past month or so my tranny temp gauge is somehow loose somewhere, so it will be at its normal 160, I hit a bump and it will bounce all over the place... 190...220...back down to 160...I am not very pleased to say the least...

Im not ready to jump all over ISSPRO's a$$ yet as it may be just a simple fix and untill now my gauges have been great. However after spending a good $300 im not gonna let it go unsolved

[CHUCK]

Check all your power leads. I'm running autometer gauges, and nicked a pwr wire, causing a short to ground. It would peg my gauges, and pop a fuse. You may have a similar thing happening. Wiring can be aggravating.

[2005F250]

Check your grounds. Get a volt meter and test the voltage at the back of the gauge.

[CSIPSD]

What style of gauge are you running? EV or EV2 or Performax?

[dhanna6powerstroke]

Could also be the sender itself not grounded good. I know most of them are a 1 wire sender and it grounds itself when installed.

[Jake]

Check all of your connections. I had a problem with my trans temp gauge almost exactly what you are describing, it would jump up real high and if i wiggled the wires it would drop back down. It was the butt connectors i used for the extension wire.

[CSIPSD]

Originally Posted by dhanna6powerstroke

Could also be the sender itself not grounded good. I know most of them are a 1 wire sender and it grounds itself when installed.

Isspro use two wire senders...

[MichaelP]

Blowinsmoke7.3's problem could either be an intermittent connection to the temperature sensor, or an intermittent connection between the amplifier box and the gauge head. Most likely culprit is the connection down near the temp sensor, pull it apart and check for corrosion on the contacts. Try scraping the contacts with a tiny screwdriver, then add some dielectric grease when reassembling. If that doesn't fix it, check the resistance of the sensor. Here are the nominal values:
Res Temp °F
1115 100
1293 140
1393 160
1609 200

If it is significantly off of this curve, then you have a bad sensor. If the values look good and the connection is cleaned up but you still have a problem, check the set screw connections on the wiring going into the amplifier box. Next check the connections going into the back of the gauge. If all these things check out and you still have a problem, then it likely has an intermittent connection within the amplifier box.

dmbrichie -
Your trans temp sounds like the same thing as above. The pyro sounds like a bad connection to the thermocouple. Check the connection between the amplifier box and the thermocouple. If you have a good multimeter which can measure down to the millivolt range, try disconnecting the thermocouple and measuring the voltage across its wires. At 290°F (idle for most trucks) you should see about 5.01 mV. If that checks out, along with the connections to the amplifier box, then you probably have an intermittent connection in the amplifier box.

Regards,
Michael Pliska