Author Topic: flickering gauges (Read 3628 times)

78w72 · « **on:** November 12, 2006, 11:55:42 AM »

got a weird one for you all. just completed a subframe & engine rebuild & putting some miles on the motor. i notice that my oil press & other gauges seem to "flicker" at random. i didnt hook up a ground strap from the eng to frame/firewall, could that be the problem?
heres a really weird thing too, when i push the clutch pedal down it stops the flickering & makes the headlights & interior lights get brighter. right when the throwout bearing makes contach with the press plate "fingers" it stops the flickering, kind of like it is making a ground when it engages the pressure plate & stoping the flickering. nothing is connected to the clutch, i removed reverse light switch etc.
i will try to hook up another ground, but cant figure out what is causing the flickering & why the clutch effects it. where should the ground be hooked to from the eng??

PLEASE HELP!!!

ta78w72 · « **Reply #1 on:** November 12, 2006, 07:48:46 PM »

There is a braided ground strap that goes from the engine to the firewall...I think it's slightly towards the passenger side.

Under the steering column is a brace (you see it when you take off the under column trim piece). The brace is held to the dash frame by four bolts....is that piece installed? If not, your IP harness won't be properly grounded.

78w72 · « **Reply #2 on:** November 12, 2006, 11:20:32 PM »

all the dash seems to be original & the frame you mention is intact, i also see what seem to be ground wires in 1 or 2 places & they are hooked up as original.

the car runs great & the lights are ok but you can notice a very slight change when i depress the clutch pedal. & at the same time the gauges steady out. i will try a ground real soon. going to be pulling the carb & sending it to cliff for a rebuild in about a week so the problem may need to wait until spring.

also the tach bounces around a bit or is unsteady as well. but seems to calm down after the mysterious clutch ehgaugement....any ideas would be helpfull. thanks.

shooby · « **Reply #3 on:** November 19, 2006, 05:32:47 PM »

Hook up all your ground straps. I had one gauge that bounced. Found a broken firewall strap. Braided from block to firewall. From the block to the frame, and from the block to the neg side of the battery.

78w72 · « **Reply #4 on:** November 20, 2006, 12:17:55 PM »

thanks for the reply. i was hoping to get a few other replies from here, but i guess this one has em all baffled!

i will try getting the grounds hooked up very soon. where does the ground for the frame go? i can see the firewall strap but cant locate where a frame ground would be.

thanks again.

shooby · « **Reply #5 on:** November 21, 2006, 09:34:13 PM »

There is a ground strap from the Unibody to the Transmission housing

78w72 · « **Reply #6 on:** November 21, 2006, 10:58:50 PM »

great!!! i do have a bolt there in the floor but where does it attach to the tranny? i would guess on the bellhousing somewhere. i have a 4 speed.

also where does the strap from the firewall go on the block? head bolt or manifold bolt???

thanks again.

shooby · « **Reply #7 on:** November 22, 2006, 04:31:04 PM »

I have an automatic. It is attatched to one of the bolts connecting the transmission to the block. The firewall strap is connected to the end of the head.

78w72 · « **Reply #8 on:** November 22, 2006, 04:43:21 PM »

i imagine mine would be the same. does the firewall strap go to the end head bolt, or in an accsy hole on the back of the head??

78w72 · « **Reply #9 on:** November 26, 2006, 11:54:26 AM »

i fixed the problem. just hookedup the ground to the firewall & the flickering stopped & the lights are alot brighter.

the clutch was creating some sort of ground path when it engaged the throwout bearing, pretty weird.

works great now, thanks for the help.