please help....temp. gauge

Alright guys here's the deal. A while back...probably 6 months ago I started a thread on here about my temp gauge. First off it's a '91 hatchback with a Y8 mini-me swap. While I'm driving my temp gauge will go crazy and jump around or it will just go to the "H" and stay for a little bit then come back down. I have a brand new radiator so I don't thing that is it. I've check hoses and nothing is leaking. I put a new temp. sending unit it ( the little piece right below the distributor ) and that didn't work. I even put a whole new instrument cluster in because I thought maybe the cluster was bad. The T-Stat is new and the overfill bottle is full. Still, none of this worked. Does anybody have an idea what this may be? There is no check engine light coming on if that matters. Any help would be great. Thanks

I would check your grounds. There is one on the thermostat housing, one on the starter, one on the valve cover and one on the transmission. Then there are the ones inside the car, like the one behind the hood release..there are others but I cant remember where. Download a manual, itll detail each ground in the car.

i had that problem with my old 91 hatch, i had a short to ground, when i hit a bump, or sometimes just randomly it would spike like thattry running a jumper from your temp sensor directly to the ecm, might fix it, and a hell of alot easyer than trying to find a short

I've checked the grounds under the good...they all seem good and are tight. What are the ones inside the car?

its been 6 years since i have owned my hatchie......but, i'll see if i cant find you a ecu wiring schematic

There are two under the car, one under the dash on the right kick panel, near the main relay/fuse box, close to the hood release.
The other is under the steering column somewhere. black wire, white or red dots.