James911

Hi,

I have a couple of questions about the wiring of my SBC, because I do not know which cable is for which part at the engine.
I bought the car disassembled, therefore I have this problem.




It is a Chevy Impala year 1970 with a HEI-distributor vacuum , therefor I think it is one from 1975 to 1981 ??) and a Edelbrock carb 600 cfm, 4-Barrel with electro Joke

Here are some pics about, may be that helps:

http://s303.photobucket.com/albums/n...a-1970/Impala/

I think the following parts have to be connected:




alternator
starter
oil pressure sending unit
Hei
carb

How do I find out which cable is for what?

I found the following cables in under the hood, for which I measured the voltage and the resistance.
1. a single black cable, very long


Unfortunately formatting does not work for may tables, what I mean is I have three positions for the key OFF Run Start an then I write the result stuff I measured

Result from measuring

position of the key Off Run Starting
resistance to - Pol of Bat: no no connection no connection

resistance to + Pol of Bat: no connec no no

voltage + Pol of Bat: 17 V 0 0
voltage - Pol of Bat: 0 17 V 17 V

strange, depending on the key position its + or -


What is this cable for????



1. wiring harness contains three cables


longest cable, black



Result from measuring

position of the key Off Run Starting
resistance to - Pol of Bat: no connec no connec no connec

resistance to + Pol of Bat: no connec no connec no

voltage + Pol of Bat: 0 V 0 0
voltage - Pol of Bat: 0 0 V 17 V




--> should be the cable for the starter, to give the starting signal








middle cabel (green black)


Result from measuring

position of the key Off Run Starting
resistance to - Pol of Bat: no connec no connec no connec

resistance to + Pol of Bat: no connec no no connec

voltage + Pol of Bat: 0 V 0 0
voltage - Pol of Bat: 0 17 V 0 V




?????????????????


short cable (red)




Result from measuring

position of the key Off Run Starting
resistance to - Pol of Bat: no connec no connec no connec

resistance to + Pol of Bat: no connec no connec no connec

voltage + Pol of Bat: all three only leaking air current

voltage - Pol of Bat: all three only leaking air current



????????????



2. wiring harness:

red cable + and a connector that fits to the alternator ---> cable for alternator



Who can help me? all fuses are ok.

Thanks

James

trackbird

iTrader: (4)

Ok, the tube in the second photo is for the vacuum modularor on the transmission. Or it appears to be for that purpose.

The tube by the fender (third photo) could be for a transmission cooler hookup. It's on the wrong side to be a fuel line. Does it run back to the transmission?


On the starter, the heavy battery lead goes to the large nut at the top of the solenoid (opposite the copper spacer that has the copper bar out of the starter motor connected).

On the solenoid, you use the S terminal for starting (off the top of my head) and the "R" terminal was to bypass the ballast resistor on the ignition to allow the engine to start when the starter pulls the battery down to 10-ish volts while cranking.

The big nut on the back at the top of the starter "can" is to hook to a support bracket that should be bolted on the side of the engine. It's a black "hook" shaped bracket made from basically "L" shaped steel. You just hook it on the starter and put the nut on there.

The alternator wire you show. The black plug plugs into the alternator. The red ring terminal goes on the nut in the left of your photo. The nut on the right is for a ground strap.

The distributor should have a spade terminal (that's hot with the key on and in the crank position) that plugs into the Batt side to give ignition power. The other hook up is for a tachometer.

I can't see what your "3 cable" harness looks like or where it goes. It could be a hot and a tach hookup for the distributor, but it could be a lot of things (check it out before you take my word for that).

I hope that helps get you started.