Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

Slow cranking

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  #1  
Old 07-11-2012, 08:28 PM
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Default Slow cranking

Hey all. I seem to have a serious problem that I can't seem to figure out on my own.

I have a 1986 Chevy 4x4 6.2L diesel auto. My problem is slow cranking. Over the last 5-6 days I have noticed the hood on my truck vibrating more and more at idle and it sounded like the engine was under a light load when stopped (you'd have to hear it to understand). I drove the truck like I always do and parked it and shut it off. About 5 minutes later when to start it and it would crank once every second or two. Usually I could get a ton of cranks. Now it struggles to rotate the engine. I noticed the alternator wasn't charging (lousy reman's) and now I have another one in. I charged both batteries but still the same thing. I have new wires and 2 dry cell 950cca batteries. Everytime I crank it after a few seconds the ground wires smoke from getting a bit hot so I stop. I have good connections everywhere and yes I have a new reman starter as well. I a bit baffled.

Any ideas?
 
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Old 07-12-2012, 01:18 AM
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I would load test the batteries just to be sure they are not failing, but it sounds like your starter is dragging. I have got bad reman starters before.

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You might want to make sure the engine rolls over like it should by hand before trying anything else just to bee sure that you don't have internal engine problems.
 

Last edited by Motor City Muscle; 07-12-2012 at 01:18 AM. Reason: Automerged Doublepost
  #3  
Old 07-12-2012, 05:46 AM
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If by dry cell batteries you do you mean Optima's ?I am no fan of these by any means as they dont seem to last very long after purchasing they tend to sit on the shelf at the part store alot longer than a lead acid Battery due to the higher price they ask for these,I would try a known ste of lead acid type batts in the truck and see if that dont make a difference.
 
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Old 07-12-2012, 08:38 PM
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I should be a little more specific. I meant sealed batteries. I am not a fan of optima batteries either. They always seem to discharge fast and a pain to get recharged when fully discharged. Since the starter is still under warranty I will put another one on. I was more concerned something might be wrong with the engine. I will have a new starter on today and give an update.

Also any ideas on why the engine would be running smooth at idle (sort of) and after some run time it starts to shake more then it did?

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Starter has to be ordered.

Now I noticed something incredibly strange that to me defys all logic and the laws of physics. I had my helper crank the truck over (after replacing the bad alternator and checking the batteries (totaling 1283CCA combined)) and still very slow cranking. Now here's the wierd part.

While I was under the truck and Matt was cranking it over the front driveshaft Yolk started to smoke and got insanely hot. Of all 4 yolk ends though only 1 was hot. Nothing else was even warm. The shaft itself was cold, 3 of the 4 yolk ends were cold and diff case and all were cold. But sure enough when Matt would crank the truck the one spot on the yolk would get hotter then a pastor at a Judas Priest concert. It makes no sense. Any ideas?
 

Last edited by ChristianKustomz; 07-12-2012 at 08:38 PM. Reason: Automerged Doublepost
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Old 07-12-2012, 08:51 PM
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I am not sure but it kinda sounds like a grounding issue or lack there of or maybe the starter is shorting out????
 
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Old 07-13-2012, 08:19 PM
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The yellow arrow is what is getting hot and smoking. The blue aroows show whats still ice cold. It doesnt make sense does it?....Like I said it defys all logic but after 7 tries and 7 different cranks and the same things happening its definately doing it. It makes no sense whatsoever and I am more confused now then I was when I first started.



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Ok. I installed the new starter today with no results. This time the cranking is even slower. I have checked all the terminals and all the connections and everything is good. I am thinking there might be something wrong with the engine. But I don't know. It was running perfectly fine and now won't crank for nothing. Am I missing something?
 

Last edited by ChristianKustomz; 07-13-2012 at 08:19 PM. Reason: Automerged Doublepost
  #7  
Old 07-13-2012, 08:34 PM
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Have you looked at the ground that is at the rear passenger side head to the body? and have you tried turning over the engine by hand with a half inch breaker bar or good rachet yet this may give you an idea as to wether or not you arehaving internal problems or not
 
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Old 07-13-2012, 09:46 PM
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I have checked all the grounds. I have 2 batteries. The drivers side battery ground is connected to the engine block and intake bolt. Another ground lead is from the passenger side battery to the fender, chassis and front grill. I do not recall a ground by the head. I know it never affected it though. I know with a solid ground on the block and intake the starter should not have a bad ground. The starter is bolted directly to the block.

I have tried to spin it with my hands by grabbing the TC and FW and turning it. It moved but then stopped. I think at that point I hit the compression stroke. But it seamed to be fine.

I do know that hooking a jumper box to the truck worked once but every time after that it was doing the same thing. 1 crank per second if that. Cranks like it has dead batteries. But I'm loading over 1200 CCA (tested) and volts are good. New alternator (reman went bad) and new starter (for good measure). New wires and everything has been scraped for good connections but still nothing. The one time I did get it restarted the truck engine was vibrating a lot more then usual. I just did an oil change a few days prior too. I am totally at a loss. Especially trying to figure out why the driveshaft yolk end is scorching hot when cranking.
 

Last edited by ChristianKustomz; 07-13-2012 at 09:50 PM. Reason: Grammatical error
  #9  
Old 07-14-2012, 03:07 AM
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have you tried cleaning between the starter and block? I did that on mine and it made a world of difference.
 
  #10  
Old 07-14-2012, 12:10 PM
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Thank you. That did the trick. I ran a ground wire from the back of the starter bolt to the battery and she fired right up. It's so hard to believe a tint little bit of rust could cause so much trouble.
 


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