Super Chevy
Click here to find out more!

Voltage issue on a 86 elco

Super Chevy
Item Posts    Sort Order

Voltage issue on a 86 elco

ELCaminos ELCaminos
I love my Chevy Chevette! | Posts: 2 | Joined: 08/13
Posted: 08/21/13
09:58 AM

Wanted to see if anyone had any expertise in this- my 86 elco 305 completely stock has been giving me voltage issues, i've replaced the harness on the alternator, the wiring between the battery to the alt, the battery to the starter, starter to the alternator....

The voltage still shows around 11.5 to 13.5...  Confused  When i use the headlights, turn signals or any power accessories it will go even lower, I belive my motor isn't burning the gas 100% (Tach shows 600something in DRIVE, 900 in Park) but it runs and drives normal (or so it seems)

When i'm at the stop sign or the stop light I Can smell the exhaust/gas reeking its got a new exhaust system, and it didnt do that the first 1.5 years, i am pretty sure its because of the low voltage my HEI isnt shooting enough voltage to burn off the gas (make sense?)

WHen i first bought it 2 years ago, it was in a good running condition i chose the 86 stock over 12 different el caminos (all 5th gen G bodies) every one of them had been molested or modified in one way or another, and i came across one that i felt was running as it should from the factory at somewhat over 100k mileage (odometer doesnt work)

After a year the car one day died on me on the highway after i picked my mother and sister up from the airport (of course it had to happen! Begin the nagging of why do i drive old cars) i was so dissappointed i wanted to prove it to her that OLDer CARS ARE JUST FINE!

Before i tear into the wiring harness or the wiring to the fusebox/gauge etc i just wanted to see if someone can chime in and give me a proximity of where to attack, its my personality to tear into something thats giving me problem and just remove it put in a new wiring set up and whatnot, but i've found this car to be pain in the butt since its a california smog car and the wiring, plastic pipings are just all over the place!!!!!!

Thanks in advance Smile  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 08/21/13
06:49 PM

first thing.. lets perform a voltage drop test.. takes just a few minutes..

copy and print these instructions...

engine running..  headlights on.. digital volt meter set to 20 volts DC..

1.  Negative battery post to the positive battery post.. 14.1 to 14.8 volts DC

2.  Negative battery post to the engine block.. 0.04 volts DC MAX.

3.  Negative battery post to the Body.. 0.02 volts DC MAX..

4.  Engine block to the Body.. 0.02 volts DC MAX.

please post results by number..





if you get more than the 0.04 or 0.02 volts on tests 2, 3, 4, fix the grounds between those parts..


additional places to check..

again.. engine running.. headlights on..

X. positive battery post to the alternator output terminal ..  post results should be less than 0.5 volts.. but i would like a lot less.

Y. positive battery post to the thick red wire into the SIDE connector on the alternator.. post results..

Z. alternator rear case to the negative battery post..  why.. because the alternator creates electrons and they flow from the rectifier bridge to the back of the alternator case then to the brace or thru to the front case and to the engine block.. if your alternator is not properly grounded to the engine.. you will have voltage issues...


now.. onto the fuel issue.. do you still have the feed back carb system installed. or is this one with the Throttle body fuel injection..

i am very familiar with the feed back carb systems used on GM cars and trucks..

take some pictures also. post them to photobucket its free.. then paste a link to them here..

and lastly.. when you got the new exhaust system.. did they reinstall the oxygen sensor ??? without an oxygen sensor.. the feedback system is blind...

this is complicated.. but i can walk you thru it..