just got a voltmeter, now what

[chocolatelab]

I just bought a voltmeter at ace hardware. I'm ready to test.

Can you please review issue below and help me solve new and nagging issue

The tach bounces sporatically. Drove from Murrieta to Ventura yesterday and back with no bouncing. Tach bounced during 50% of my driving today. It appears that a good pothole can start it. But after a bit it will settle down. Also the tach will bounce when I turn the lights on or the blinkers.

The second problem just came up today. This morning the blinkers worked fine. 20 minutes of driving and then they would not work. Later they started working again and now they dont work.

Fuses all seem to be fine.

Please help I'll post results quickly.

Thank you.

[1990C4S]

Do you want to fix it or just use your meter?

Do a search of the tach issue. I think it is generally related to worn points. But you could also measure the alternator voltage while driving. Set your meter to DC volts, connect the black to ground, the red to the cigarette lighter and see what voltages you get.

Check the ground wires on your turn signals, and the bulb sockets.

[WPOZZZ]

Tach - Remove from dash and make sure all connections are tight.

blinkers - maybe your turn signal switch is on its way out.

[chocolatelab]

I am terrible with electricity but convinced i can get it.

The tool is a multimeter.

at idle i get 13.9 at the cig lighter
car off at the battery i get 12
cig lighter holds steady at 13.9 with 2-3k rpm

[80-911SC]

new to the volt meter , just a guess that you got a multimeter ??

if so set to DC (if it has a range option the lowest option that is above 12v)

start off with testing your battery should be in the 12 +/- 1 with engine off

check from battery + terminal to - terminal and from battery + term to body ground to check your ground strap ...

then you can double check your grounds at the dash , take gauge thru the dash turn meter to continuity and test from ground wire at gauge to body ground , there are multiple spots to ground under the dash ...

have fun with the new toy Chris , i have three or four , one in the car , one in the pickup, the good one in the tool box and the spare in the kitchen drawer ...

[chocolatelab]

i knew youd chime in steve

thanks

tip for removing the tach?

[80-911SC]

harbor freight they have a "dash tool" set its 4 pieces of nylon like plastic in shapes to help with interior trim removal with out gougeing and cutting ... place at six a clock and start the gauge out under the lip but watch the dash, then 9 o clock then 3 O'Clock be patient and work slow i wouldnt use metal some say a screwdriver but that scares me here are links to tech center that describe it a bit more , or give me a call or ??

check first part of this

Pelican Technical Article: Gauge Face Replacement

or here

http://www.pelican parts.com/techarticles/bob_tindel/brighter_instruments.htm

glad you got the car back from the Doctor's have fun with it i still owe you those pics

[chocolatelab]

i checked the continuity from the tach ground to ground spot in car. measured 0 ohms.

They need to figure out a better way to pull that tach.

Engine appears to be running terrific by the way.

almost 500 miles since friday

[1990C4S]

Originally Posted by chocolatelab

I am terrible with electricity but convinced i can get it.

The tool is a multimeter.

at idle i get 13.9 at the cig lighter
car off at the battery i get 12
cig lighter holds steady at 13.9 with 2-3k rpm

Seems just right to me. Not the issue. Points is my guess....

[80-911SC]

agree points , you get to learn a new word dwell meter ...

[madmmac]

Buy one of those cheap digital voltmeters that plug into your cigarette lighter. Keep an eye on it while driving around. The voltage should be 12.9 to 13.3 or so. Take a good look at it when the tach starts bouncing.

Guessing the alternator is going.

[80-911SC]

that plug in voltmeter is available at H-frieght for about 6 bucks you have to adjust the ground out a bit as the early Porsche lighters are a bit larger than the standard (the metal bump on the side)

have a good night Chris , check in on you tomorrow ...

[chocolatelab]

good deal

heading to get a mobile meter tomorrow.

that seems like a good idea as it happens randomly

[chocolatelab]

the harbor freight i went to didnt have the mobile volt meter.

try again tomorrow

this sucker has been bouncing on and off for 3k miles

maybe im pressing my luck.

[theiceman]

okay a couple of "points "

a 78 sc doesn't have any ...

The regulator could be going bad or the alternator .. if it is original the regulator is in the left rear engine bay and can be swapped independantly of the alternator. If the car has been updated the regulator is part of the alternator and should just be rebuilt as a unit.

if you swap the regulator and it still does it, it could be the alternator .
Before doing all this check your connections to the battery and all the ground in the car. also check the connections around the ignition module.

Good luck

[theiceman]

BTW pulling the tach is easy , pull the clock put your hand through the hole and push out the next guage over etc. usually the clock pulls out easiest.

if I remember I think you have to pull the wheel however to get the tach out if it is a stock wheel with no extention

[gsmith660]

Originally Posted by chocolatelab

I just bought a voltmeter at ace hardware. I'm ready to test.

Can you please review issue below and help me solve new and nagging issue

The tach bounces sporatically. Drove from Murrieta to Ventura yesterday and back with no bouncing. Tach bounced during 50% of my driving today. It appears that a good pothole can start it. But after a bit it will settle down. Also the tach will bounce when I turn the lights on or the blinkers.

The second problem just came up today. This morning the blinkers worked fine. 20 minutes of driving and then they would not work. Later they started working again and now they dont work.

Fuses all seem to be fine.

Please help I'll post results quickly.

Thank you.

bouncing tach is a usually a bad signal ie dirty connector or worn points next time blinkers dont work try to move stack switch around and the emer. flashers if you get them to work that way probably your switch is going bad a common thing.

[Gogar]

I was going to say you're going to have a hard time buying POINTS for an SC, but the iceman beat me to it.

[gsmith660]

oops I have a 77 motor never paid any att. to an SC ignition no wait a min. I dont have any points either.....now. Im so confused!

[chocolatelab]

gsmith

you nailed the blinker issue

i played with the emergency blinker then the regular blinkers started working properly.

what is the component i would want to replace to avoid that in the future?