Very odd issue I haven't seen before, been having a lot of trouble with it and can't figure it out. temp gauge will dance with turn signals only after car is warm and only when car is moving. I've check all the grounds and replaced 3 grounds and ECT sensor and the other sensor on the head (its a B20B) and still problem persists. Battery and alternator are new and not one fuse is blown. Is it an ELD issue? Any help is much appreciated.

 

Has it been doi g this since you purchased car or recent mod p
Or tune up?

 

Well I've had the car for 4 years now and its never had any electrical issues until recently. I swapped a B20 and it ran fine with aboslute no problems then swapped out a p75 obd1 ecu and that only made it run better since it was on a stock p28. Oh my rad fan relay went out on me when I first swapped it so I ran a manual switch for the time being. I've done a cylinder leak down test to make sure its not the headgasket just as pre caution and bleed the cooling system as well so its not an air bubble

 

I replaced the Fuse box under the hood and checked all bulbs as well and now ran it without any bulbs, it started fine like it usually does as it reached optimal temp i started driving and as soon as i started to move it jumped up and started bouncing around. Only thing else i can think of would be the harness so im going to inspect it to see if any wires are showing.

 

dude Add an Extra ground or 2 in the engine bay im sure ull get rid of that problem.

 

added 2 grounds and it didnt fix the issue. i believe it maybe caused from a short in the light wiring because it seems to get worse when i use my highbeams or turn signals but doesnt seem to be caused by anything else and ive checked everything but its odd because the car has to be moving for the problem to start but after the problem starts and the car is at idle the problem doesnt go away.

 

Do you have a spare cluster to swap in just to rule out the gauge?