temp guage zero'd out under WOT

[Migdhorse]

So I was enjoying my gvr4 after a recent tune and under wot the temp guage seemingly died and zero'd out. I noticed pretty much right away. Turned the car off and haven't touched it since. I've been at work all day haven't even had the chance to open the hood. I could imagine it could be several things: tstat, water pump, guage, or even a belt maybe but I don't think a pump or belt would make it zero out instantly and suddenly. Luckily my passenger was filming to watch the knock guage (converted boost guage) to see if it was consistent with readings on link. A clip of the video and guage zeroing out is linked below. nervous to even turn it on and that's why I posted here first before I even start to tear into things. Thanks ahead of time for any associated help.

[ame=http://youtu.be/RYP4Enxip9Q]4g63t WOT temp guage zero out - YouTube[/ame]

 

[NordicSaab]

Start with the easy stuff first. Make sure that all of you connections are clean especially the ground for the temp sender. I doubt this is a big problem.

Usually temp gauge going to zero is just a bad ground

 

[Migdhorse]

Thank you. If there's a bad ground, where should I look? The temp sensor? Sorry...there's a reason I posted this in the newb section.

Edit: oops I reread your post. Lol yes but of course I would look at the temp sensor ground.

 

[Migdhorse]

problem solved. discovered that someone did a poor job crimping the wire between the coolant temp send and the gauge. pulled it all out, cut it and soldered it. turns out the wire was pulled fairly tight so i assume the motor mounts being torqued under throttle caused it to pull the wire apart. I added some extra length and did an anal job soldering it up. next job is to rework all the wires in the engine bay that have been crimped seemingly with the gap in someone's front teeth.