New problem

[Stepside Billy]

I drove my truck to Home Depot yesterday. Fired her up and it was running a little rough. Got my stuff and went to start her and she was cranking very slow and would not start. My daughter picked me up and I got a new battery since mine was old. Put the new battery in and the same thing. I took out the starter, benched tested it and it's fine, less than a year old. My buddy came by to help out. I had previously cleaned all the grounds but when I cleaned the negative ground at the block she started right up. Drove her home, turned her off and she did the same slow crank, no start. Any suggestions on where to look next? Could the neg battery cable have **** the bed? Figured I'd ask here before just replacing parts. Thanks!!

 

[1973c10]

How old are the Battery Cable ??

 

[74 Shortbed]

Sounds like corroded cables, if so battery won't get a good charge either..

 

[HotRodPC]

And this isn't a vapor lock issue? Hot or warm motor, slow crank. Cools off, starts up just fine?

 

[Stepside Billy]

I replaced both battery cables, new battery, new starter, and it still cranks over very slow like the battery is on it's last legs and won't start. It had been running fine before hand. Timing is set right. What else can I check?

 

[CSFJ]

How's the grounds between the engine and body?

 

[Stepside Billy]

All good. When I got the truck last year I went through them all and cleaned them.

 

[CRM]

If you detach the starter from the engine does it spin fast?

 

[CSFJ]

Have you checked them recently? Only reason I ask, I had an s-10 that the engine ground kept loosening up on. Eventually had to use thread lock.

 

[1987 GMC Jimmy]

I feel like you could verify that it's a starter wiring problem with a higher degree of certainty by using a remote starter switch if you have one or know someone who does. All you gotta do is hook one alligator to the positive battery terminal, the other one on the solenoid 'S' terminal, and pull the trigger. This will work assuming there aren't any grounding issues. I have one at home, and if it were me, I'd just play and see what it did. Even though grounding sounds like a likely culprit, I know you know your truck better than anyone. I'm wondering, though, about continuity from the ignition switch to the starter. I'm also wondering about why it was running rough.

 

[Stepside Billy]

If you detach the starter from the engine does it spin fast?

Yes. I tested it in the parking lot before I got it started. When the truck did start it spun nice a fast.

 

[Stepside Billy]

Have you checked them recently? Only reason I ask, I had an s-10 that the engine ground kept loosening up on. Eventually had to use thread lock.

Yes. Checked them all.

 

[Stepside Billy]

I feel like you could verify that it's a starter wiring problem with a higher degree of certainty by using a remote starter switch if you have one or know someone who does. All you gotta do is hook one alligator to the positive battery terminal, the other one on the solenoid 'S' terminal, and pull the trigger. This will work assuming there aren't any grounding issues. I have one at home, and if it were me, I'd just play and see what it did. Even though grounding sounds like a likely culprit, I know you know your truck better than anyone. I'm wondering, though, about continuity from the ignition switch to the starter. I'm also wondering about why it was running rough.

Good idea. I'll pick one up now. My Son-in-Law works at Autozone.

 

[1987 GMC Jimmy]

Good idea. I'll pick one up now. My Son-in-Law works at Autozone.

Cool. Let us know.

 

[theblindchicken]

My truck has a similar issue to this: hard start when hot. Slow crank, stalls, slow crank, stalls, then fires right up.

Read something on it, and remember one of the guys say that the battery cable itself to the starter is corroded inside or gets heat soaked. So that it's fine when it's cold, but as soon as it's hot, there's too much resistance in the cable to turn the starter and/or fire up the truck.

Just a thought, but throw a ohmmeter across the cables cold & warm to see if there's a noticeable increase in resistance.