73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Chase.Craddock on July 14, 2020, 04:22:50 pm

Title: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 14, 2020, 04:22:50 pm
Hey guys, I have a 1979 GMC c15 with a 1998 Chevy 5.7L 350 motor and I’m having trouble getting it started. When I turn the ignition on the solenoid engages but it does not turn over. I’ve replaced the starter motor and verified that the battery is good. I’ve checked by hand and the motor turns freely. Do y’all have any ideas of anything else I could have missed or anything I should look for?


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: VileZambonie on July 14, 2020, 05:51:03 pm
What happens if you try to jump start it? What happens when you hear the solenoid? Does it just click?
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 14, 2020, 06:03:51 pm
Yeas it just clicks. I’ve tried using different batteries but Same thing keeps happening


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: mikes78k20 on July 14, 2020, 06:13:27 pm
Check your ground connections.
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 14, 2020, 06:42:33 pm
I checked all those and cleaned up with a wire brush about a week ago


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 14, 2020, 11:05:46 pm
Did you change the solenoid too? or just the 'starter motor'?
Title: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 15, 2020, 12:47:14 am
They were both changed it’s and Ac Delco part from rockauto.com

Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: VileZambonie on July 15, 2020, 07:00:52 am
Sounds like a defective starter. I would avoid mail ordering things like this that will leave you disabled, awaiting shipments and cores or defects being mailed back and forth. Buy local and if there's a problem you can get it resolved same day. It's not worth the few extra dollars you might save because it's pay me now or pay me later with the gamble.
Title: Re: Starting problem on 79 GMC C15
Post by: mikes78k20 on July 15, 2020, 10:15:19 am
On the solenoid, there should be two small posts horizontally from each other...do you have the starter wire hooked up correctly? Looking at it from the back, there should be a pink wire going to the post with the 'S'.
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 15, 2020, 01:34:00 pm
Pretty sure he wired it correctly since he says it 'clicks'.
Title: Re: Starting problem on 79 GMC C15
Post by: MIKE S on July 15, 2020, 05:25:38 pm
You could have high resistance in one or both cables. It would be hard to check resistance without a load on it. If either cable looks suspicious, corroded  or you have "repair" ends on them then replace. Make sure ground cable is attached to block or intake manifold boss. Do not attach it to an exhaust component or piggy back it to another wire.
Title: Re: Starting problem on 79 GMC C15
Post by: mikes78k20 on July 15, 2020, 07:44:18 pm
Pretty sure he wired it correctly since he says it 'clicks'.

You'd be surprised at what I've seen in 30 years as a mechanic....just because it clicks doesn't mean it's wired correctly...or have full current going to the starter.

To the OP:
Remove it and take it to your parts house. They have equipment to check it for you.
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 15, 2020, 08:08:47 pm
I was referring to the solenoid being wired correctly. No offense intended.

I agree, DC is a strange and mysterious harnessing of the finger of God.
Title: Re: Starting problem on 79 GMC C15
Post by: Mike81K10 on July 15, 2020, 09:11:14 pm
Jump solenoid posts to see if it will start! As JP said, auto part stores will check it for free on their bench. If bad, buy a new one at the parts store and send yours back to Rock Auto for a refund.
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 16, 2020, 01:52:45 am
Pretty sure he wired it correctly since he says it 'clicks'.

You'd be surprised at what I've seen in 30 years as a mechanic....just because it clicks doesn't mean it's wired correctly...or have full current going to the starter.

To the OP:
Remove it and take it to your parts house. They have equipment to check it for you.
Alright I’ll do that next time I get the chance thanks


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 16, 2020, 01:54:32 am
On the solenoid, there should be two small posts horizontally from each other...do you have the starter wire hooked up correctly? Looking at it from the back, there should be a pink wire going to the post with the 'S'.
The solenoid I got only had two post on it one for the ground and one going to the battery


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 16, 2020, 02:01:39 am
You could have high resistance in one or both cables. It would be hard to check resistance without a load on it. If either cable looks suspicious, corroded  or you have "repair" ends on them then replace. Make sure ground cable is attached to block or intake manifold boss. Do not attach it to an exhaust component or piggy back it to another wire.
I have a ground cable going from the battery to the Solenoid and they way the guy before me wired it is was against the header so it was burnt up a little bit, I ordered a new one, but I figured as long and it wasn’t completely ruined it would still be getting a good enough connection, then I have a ground cable that’s coming from the battery connecting to the block. Is that wired correctly?


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: VileZambonie on July 16, 2020, 05:21:27 am
 :o

Your solenoid is case grounded. You should have the Posititve B+ cable going to the solenoid as well as the fusible links. The S terminal should have the signal wire from the ignition switch Purple. Sounds like you've got something a miss
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 16, 2020, 05:47:07 am
 :o right?

Wonder what is clicking...
Title: Re: Starting problem on 79 GMC C15
Post by: VileZambonie on July 16, 2020, 05:56:18 am
Fusible links popping like popcorn?  ;D
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 16, 2020, 06:00:05 am
Best guess  ;D
Title: Re: Starting problem on 79 GMC C15
Post by: bd on July 16, 2020, 07:43:03 am
Post a pic of the starter clearly showing its connected cabling.
Title: Re: Starting problem on 79 GMC C15
Post by: mikes78k20 on July 16, 2020, 12:54:57 pm
Post a pic of the starter clearly showing its connected cabling.

I second that.
Clearly something is wrong with the way you described the connections. There should NOT be a ground connection on the starter motor itself, only the heavy gauge positive battery cable and the smaller gauge start wire....and both on the solenoid.
The ground connection should be on the alternator adjustment slotted thing and then a cable from the engine block to the frame and another from the frame or engine to the body.
No such thing as too many grounds.
Title: Re: Starting problem on 79 GMC C15
Post by: Chase.Craddock on July 16, 2020, 08:00:43 pm
(https://uploads.tapatalk-cdn.com/20200717/11e437d62d9475c7763e0b3e170e580f.jpg)

black is ground wire to battery
red is to ignition switch
when you turn the key
solenoid engages flywheel but does not turn

When I bought the truck this is how it was wired and I replaced the ground wire to the battery today


Sent from my iPhone using Tapatalk
Title: Re: Starting problem on 79 GMC C15
Post by: MIKE S on July 16, 2020, 08:53:08 pm
That is a very odd looking starter. Can you give us the part number of the starter you ordered from rock auto. Also if that is the ground wire on your starter post which it shouldn’t be, were is your positive cable attached too. Although I see your using a 1998 motor so I believe that’s probably a later model starter. Possibly a gear reduction starter. To be clear does it just click or does it click and make a wirr noise without turning the engine?
Title: Re: Starting problem on 79 GMC C15
Post by: bd on July 16, 2020, 09:23:54 pm
(https://uploads.tapatalk-cdn.com/20200717/11e437d62d9475c7763e0b3e170e580f.jpg)

black is ground wire to battery

So, the black cable pictured connects to the negative terminal of the battery?  I concur with MIKE S.  Where is the battery's positive cable connected?
Title: Re: Starting problem on 79 GMC C15
Post by: JohnnyPopper on July 16, 2020, 09:35:45 pm
Chase,

Please get your nomenclature right  :o

Battery 12v + positive (RED) or B+
Battery 12v - negative (GROUND-BLACK) or B-

Where is the "yellow wire" going to? It's probably the fusible link that runs the electrical system.

I forgot what year your truck is, but usually the upper 12+ is linked to the starter winding.

"how did it ever work before?"
 
Title: Re: Starting problem on 79 GMC C15
Post by: VileZambonie on July 17, 2020, 10:46:24 am
I highly suggest you disconnect the battery and correct the wiring. On the B+ stud at the solenoid, you should have the POSITIVE battery cable along with your fusible links. The small stud should be live during cranking only.