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1986 chevy silverado won't crank need help please

 
Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/06/13 06:51 PM

Ok I have a 1986 chevy silverado with a 350 it has been ported and polished and bored  runnin 504 cam and lifters and a 750 Holley sittin on 36 super swampers.  My brother was driving it when the alternator belt broke and he ran it out of battery. We replaced the belt and tried jumping it off wouldn't crank so we roll started well he stalled it 3 times after and it cranked back up. Got  it hOme and it won't crank. Replaced starter and solenoid and battery wires and battey still won't crank. We have lights and the dash lights come on but will not crank it does nothing but the voltage meter goes down. Please help  

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zman123
Everything in my driveway’s a Chevy
Posts: 537
Joined: 06/08
Posted: 09/07/13 08:10 AM

Check all of the connections to the solenoid,all the grounds.  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/07/13 08:56 AM

to explain farther... lets run a few tests.. this is a 2 part test..

first to check the charge left in the battery...

Voltagedroptesting

this is printable...  

you can also and i would like you to run the test.. while somebody attempts to crank the engine...

also.. take a 5/8 six point socket.. on a breaker bar.. .. either use a deep socket or a short extension to be able to get to the crank center bolt...

does the engine actually TURN for 2 complete turns when you attempt to turn the crank..  

could there be debris blocking the flywheel .. torque converter... or water inside the engine causing the pistons to come up solid against the closed valves.. water does not compress..  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/07/13 09:07 AM

this is how the battery cables are run in a MID 80s chevy truck...

do you have them all hooked up???


http://i1207.photobucket.com/albums/bb476/waynep712/80s_chevy_truck_battery_cables.jpg



did the wires get installed on the starter solenoid properly??

Starterwiring


now... actually before you do anything..

take your test light...    there are 3 wires on the alternator..

hook up the test light clip to ground...    probe the stud with the output wires on the back of the alternator... the light should come on...

now.. there are 2 wires in the side of the alternator...

probe the big red one...  you should have power there also...

those are connected at the starter or at the terminal studs on the firewall to different circuits... if you blew out a fusible link.. at the starter or firewall.. you will not have any charging output voltage..  you may also not have power going into the truck to operate the starter motor....


test and reply...

run the voltage drop test above also...

and tests 2, 3, 4 need to be done while somebody is attempting to crank the engine.. it only takes a few seconds for each test..  

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Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/07/13 05:30 PM

We did the test and they were reading weird like negative numbers and this truck has the positive cable from the battery to the big post on solenoid the wire from the alternator to the same spot and another wire that runs from the harness on the big post and on the smallest post on the solenoid it has a small wire coming from the harness we hooked the new starter and solenoid up the same way the old one came off and like I said in the post it was running till the alternator belt broke after that all these problems occurred.  

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Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/07/13 05:37 PM

Hey waynep the truck was running perfect till the alternator belt broke while driving then the truck ran out of juice and this problem started occurring. The truck won't do anything now when you turn the key the only thing that happens is the voltage gauge drops no noises from started or anything but I do have headlights and dash lights when the key is in the on position. And like I said the truck does nothing starter doesn't even turn . And we had the battery checked it is perfect  

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Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/07/13 05:41 PM

And just to give a hint the wiring from the alternator to starter are new no fuse links  

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Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/07/13 05:45 PM

Zman the connections at the solenoid seem to be fine but the truck doesn't appear to have the body ground from the negative post only the big cable that goes to the frame  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/07/13 10:44 PM

ok....

when doing the voltage drop test... if you start getting negative numbers.. its OK just swap the test leads the other way..

i will accept POSITIVE OR NEGATIVE numbers...

i have a few things i would like you to verify...

80S Chevy Truck Battery Cables

battery negative cable attached to the block..

battery negative smaller cable attached to the core support or inner fender..

ground strap from the back of the heads to the firewall...

~~~~~~~~~~~~~~

positive battery cable to the top of the starter solenoid..

wire from the top post on the starter to the output terminal on the back of the alternator...

wire from the other small wire on the top of the starter solenoid to the SIDE terminal #2 on the alternator.. this wire continues over and usually up to a terminal stud on the firewall  then over to the bulk head connector...


lets look at the 1980 wiring diagram...

this requires printing several copies.. and following with a pen on the lines..

77 80 Chevytruck Fusible Links

the picture above is BIGGER than you can see.. there is a slider below to shift it.. or better drag it to your computer and print a copy...

do you see the 2 circuits that go toward the bottom right of the image above.. one goes several places.. the Ignition switch BAT 1  and the other one goes to BAT 3..

all the wires i colored in RED are HOT all the time...

do you see the junction block on the right side of the image.. do you have something like that on your firewall.. sort of behind and slightly above the passenger side cylinder head..


do me a favor.. test from that terminal block to the battery positive...

have somebody attempt to crank the engine.. if you get a volt reading there.. then you have a loose connection somewhere ...

you can narrow it down by testing various connection with your volt meter.. while somebody attempts to crank the engine.. if you are connected to the same side.. if the connection is good.. you will get NO DIFFERENCE in voltage.. if the connection is bad.. you will get a voltage reading..


let me go at this a DIFFERENT direction...

volt meters display differences in voltage between the places you touch the probe at..

so lets say.. you have a dirty battery terminal...

you touch the center of the battery post.. and the terminal around the post.. meter set at 20 volts.. if everything is off.. you get 0.00 volts.. turn something on..  or try to crank the engine..  if you get voltage between the post and the terminal attached to it... you have found a bad connection..   if you turn something on or try to crank the engine.. and you get 0.00 then that part is properly connected..

what happens.. when you have a loose or dirty connection.. when you drag power thru it.. there will be less voltage passing across the dirty connection.. so you can measure it with a digital volt meter..

the test way up.. is 0.04 and 0.02 volts... is the actual resistance in the copper wire in a properly designed circuit..  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/07/13 11:10 PM

a HUGE WARNING..


fusible links are REALLY IMPORTANT..  

when the fusible links do their job and burn out.. they PROTECT not just your wiring harness.. but your entire truck..

why.. if you have a short... and there is no fusible link to burn out.. the electrical fire it going to get into the main harness under the hood and usually under the dashboard...  because the plastic insulation burns.. the tape and zip tubing burn.. the plastic bulk head connectors burn.. the insulation on the inside of the firewall burns.. the carpet in your truck burns..   you will have a FIRE that you cannot putout easily.  electrical fires have to be put out but also have the power disconnected...

i have a trick that i used with the many catering trucks i used to service..  as they were forever burning out fusible links...

i would go to radio shack and keep some various sizes of European style terminal blocks in my tool box.. along with various sizes of fusible link..   12, 14, 16, 18 gauge.. i had small rolls.. but individual short pieces are available...

i took a 3/8" yellow ring crimp terminal and 2 inches of 10 gauge wire...  added a single section of european style terminal block to that..  then a 4 inch section of 14 gauge fusible link.. and another european style terminal block


3/8 yellow ring------10 gauge x2" long---E term block----14 gauge fusible link-- E term block..   this goes to the 10 gauge wire up to the junction block on the firewall

i usually made a special with  another 12 gauge wire x 2" long  terminal block and 16 gauge fusible link.. then the european style terminal block.. to 2 wires


what..

3/8 yellow ring.. 12 gauge  E term block.. 16 gauge fusible link.. e term block.. 2 12 gauge wires sort of wedged into the european style terminal block. i keep various sizes of these things..  one of these go to terminal 2 on the side of the alternator when its equipped with a big wire on the side.. the other goes into the bulk head connector on the other circuit..


you will see that there is a third fusible link feeding the inside of the cap from the terminal block..

protect your harness and your truck.. screw this up and you might loose both.. it has happened WAY too many times..  save a few bucks.. cost you thousands..

i know that your 86 is wired slightly different that the 77 to 80 diagram i posted..

i will have to look around for a better 86 diagram..  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/08/13 12:17 AM

i went hunting.. found this

Mid80s Gm Starter Wiring Zpscd5fb12d  

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Redneck59250
I love my Chevy Chevette!
Posts: 6
Joined: 09/13
Posted: 09/08/13 10:05 AM

The body ground is broke off will that cause this  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/08/13 11:20 AM

fix that ground connection ... might take 5 minutes..

get under the truck... do you have a remote starter button that can clip to the starter solenoid.??


or jump from the TOP post on the solenoid to the S terminal on the solenoid at 3 o clock...

does the starter crank the engine????? that proves the negative cable from the engine to the battery negative is hooked up properly.. it also shows that the positive cable from the starter to the battery positive is hooked up properly...

got a test light???  hook it up to the wire to the back of the alternator.. and shove the probe into a good ground...   turn the key to crank the engine... does the light stay on.. or does it go dark..

do the same test at the terminal block on the firewall..  clip end on the stud.. probe into something grounded... the light should stay bright while attempting to crank...

now.. under the dash board... this is reversed... clip the test light to one of the bolts under the dash to ground it... stick the probe end into a fuse end.. where it will light the probe..   turn the key.. does the light stay bright or does it dim or go out...

???????

you have an open someplace...

a loose connection..

a burned connection...

got pictures of your truck .. under the hood.. showing the various sections of the wiring harness so i can point out places to check...

use photobucket.. its free...  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/08/13 11:20 AM

give me a call.. log in.. click the private messages link to the left of where you log out at.. there is a message waiting for you...  

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