howcome my tach when i first start up engine- hot or cold- and if i rev it when starting, sticks stuck at about 2k for a little while like 5 or 6 minutes of driving and then goes back to normal operation as if nothing ever happened? also what causes temp gauge ot peg all the time way past 225 or whatever ? i assume is grounded out on something somwhere ? or can something else affect this ? my alternator oragne fused wire at the back of alt has an arc when i connect it, does it have anything to do with that ? 84 H)305 7004r if i matters

i appreciate anything at all from all you third gen experts ! im slowly learnign these things i hope! learning new is always good and i make myself learn it

 

I had a similar problem, usually when the engine was cold the tach wouldn't read at all until the engine warmed up a bit... I took out the filter for the tach wire at the firewall right behind the distributor. This may not be your problem, but it was a 2 second fix that can easily be undone because it's only wire clips--you don't have to rewire anything. The only reason I say this might not be your problem is because this wire has nothing to do with your temp gauge.

 

Hey Chevy, i think the temp problem is a separate alone problem from the tach one, then i got the dome lamps that are stuck on when i replace fuse, and then the heater blower not working at all problem, the red wire and orange wire at the relay on the heater box under the hood are hot, and the black and brown arent grounded like they should be, and so the purple has no hot, whats the deal with that ? i assume that hot juice flows through the heater speed resistor springs, correct ? shouldnt the black and tan always be grounded ? how come they arent right now ? dome lamps and courtesy lamps all stuck on ? i checked the door switches, they seem fine i even pb blasted them in case..

the fuse was blown and when i replaced them they all came on and shut the doors and they dont go out and its not the headlamp switch turned all the way doing it either, so... hmmm...

i may make a new thread regarding this one and maybe the heater one, meanwhile im gonna do some wiring diagram tracing tonight and see what i can find out.. i have a white ground wire grounded out somewhere that aint supposed to be........ may have to snip til i break the circuit.. and replace that wire...

Ill check out the filter deal for the tach soon, may just replace it with a GM one soon, probably nereds it anyways, i noticed it on the firewall just above the dizzy, was kinda wondering about it,,,

thanks for the info !!

 

When I took out the filter for the tach I didn't bother to replace it, I just left it off. The tach still reads accurately. I think it was only there to avoid radio interference and to smooth out the tach so it doesn't seem jumpy... and I have neither of the problems after taking it out.