BlueShadow

Hi guys,

I'm not sure how many of you remember me, but I used to hang around H-T's FI forum quite a bit. Since getting my RX7 I havent really been in the FI forums on H-T and preludeonline. Now I have some questions, but either no one on the RX7 boards know or they haven't gotten around to reading my post yet.

I am having some issues installing my Nordskog digital water temp gauge. Here is how the instructions say to wire in the gauge. Since it's a general type question, I thought I'd ask them on here.

RED wire = + 12V source
BLACK wire = ground
BLUE wire = temperature sender
PURPLE wire = dimmer switch

And here is how I wired things up:

RED = fuse tapped into ignition
BLACK = grounded in the engine bay (same loaction as grounding straps
BLUE = temp sender, sender is located on thermohousing...same place almost everyone else uses
PURPLE = for max illumination, this wire has to be grounded.

For the temp sender installation here is how I have everything attached onto the sender screw from top to bottom. Retaining nut, locking washer, BLUE wire coiled around sender screw, "cardboard-looking" washer. Normal operating temps for an FD is ~200-210 degrees F, 230 on up is when the engine overheats and when the engine fails.

Upon starting the car to warm it up, indicated temps are very erratic. Temps are bouncing back and forth between 330-340 F and 350-360F. If this was true my motor would be toast, but there is more. Out of nowhere the temps will drop down to 210-220/230-240 F (still behaving erratically. Then it will bounce up again to the 300 range. Quickly revved engine to 4-5K RPMs, temps went to max reading of 375 F.

Some tests I did, grounds checked out ok, power source is ok. Tested dimmer switch byt applying +12 V, gauge disply darkened (dimmed). Removed cardboard looking washer thingy temps shot up to indicated 375 F and stayed there. Possibly bad wiring from BLUE wire to temp sender. Unsure of where to put cardboard looking washer. Gauge will show a steady 375 F UNLESS the cardboard washer is on the bottom (washer a problem?). All wire connections were done by cutting off plastic sheath on end of wiring and winding the wires together (problem maybe). Wires used were also used speaker wiring for homw entertainment system Another problem maybe?)

tomorrow I will buy some good wire to wire connectors and a wire to ground connector. Will also buy some 18G electrical wiring and use that. So anyways what do you guys think my problem might be?

TIA