Hey guys, I really need your help. I've got a 87 Camaro 2.8L that isn't running right. The voltage on the gauge is super finicky. It never wants to sit still. It goes down when I hit the brakes, turn on lights or turn signals, ex. But always jumps right back up. It also runs somewhat rough, especially at idle. Sometimes it will stall when coming to a stop. Today I checked most the grounds I could find, and they all seem to be fine with the car off and on. I've cleaned most my connections at and near the battery and the ground on the block. I've done new O2 sensor, plugs, plug wires, MSD Street Fire ignition coil, and I've got a new fuel filter to put on too. I've tried carb/fuel injector cleaner, and that didn't make it run any better. I also had problems with spark arcing from my coil to the mounting bracket, but I just put the MSD on a few hours ago so I'm unsure if the arcing is still going on. Please help!

 

Forgot to mention - even when the gauge on the dash is reading low and bouncin all over the place, I will read correct and constant voltage on my multimeter on the battery and when checking the grounds. Installed a brand new alternator the other day too.

 

So what is the actual voltage that is reading? How low does the voltage dip?

 

Actual voltage is ~12.8 with the car off and ~14.4 with the car on. The gauge will go anywhere from 14 - 11, and it usually won't sit still for more than a few seconds. If I turn on AC, lights, turn signal, and put it in gear the voltage really dips on the gauge, but won't go below ~13.3 on my multimeter.

 

Mine rises and drops with load but never has any issues running. With everything running and engine fan on it shows under 12v at idle. 13.8 measured off the battery.
I always assumed this was a byproduct of using smaller wires than optimal and the resulting voltage drop over distance.

 

Hmmm. I've really been trying to pinpoint if my problem is electrical or fuel related. The only things left I can think of are my fuel filter or cat being clogged. I plan on changing the fuel filter in a few minutes. The cat does clank some at idle when the idle starts to drop and come back up. I just can't tell if it's because it's lose and smacking the car or if it's the inside of the cat. Also, I took it for a spin about an hour ago to really test out the new wires and coil. I was doing about 50, gave it some gas to speed up, and it tried to go for like a tenth of a second, my RMPs shot all the way up on the gauge, and it stalled. No clue why. After that it would crank but wouldn't start back up. Popped the hood and checked all my connections. Then I got back in my car and it started right back up.

 

Turns out the clips to the connectors for my ignition coil are bad and the connection came lose. That's why my RMPs shot up and I stalled. Today I cleaned up my IAC, found a vacuum leak and fixed it, and tightened up the connection to my coil. Unhooked the battery for a few minutes to reset the computer. Took it out for a spin and it's running somewhat better. The idle is a little smoother, and the RPMs will get a little low when coming to a stop, but not nearly as low as they were getting, and it hasn't tried stalling yet.

 

The gauge is likely just lieing to you, especially if you are reading a steady and much higher voltage with a DMM than the volt gauge is telling you.

I'm more concerned about actual voltage as read by a precision instrument than a mass produced somewhat indicative gauge placed on my dash.

 

I've noticed that some days the gauge will read 14.5v and my turn signals blink at a regular speed. Other days my voltage is lower and finicky, and the blinkers are probably twice as slow.