Diesel Won't Start

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Just Us

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Jan 14, 2006
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Hi all!

I have a class a with a 300HP Cummins Turbo diesel that won't start. I have replaced the chassis batteries which it seemed to need, but it still will not start. I think it might be the starter or solenoid, but I have no idea how to check these components to determine if they need replacing as I have never worked on a diesel engine. Any help would be greatly appreciated

 

Ned

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What happens when you turn the key?  The starter and starter solenoid on a diesel work just like they do on a gas engine.  I am assuming from your description that the engine doesn't turn over at all.
 

Ned

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Not usually.  We do get a preheat light, but it doesn't prevent cranking.  But then we have a Cat, not a Cummins.  The engine manual should describe any such lockout.

Just Us, do you get any warning lamps on the dash before or during a start attempt?
 

Just Us

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Everything seems normal except it won't crank.  When you turn the key the voltage drops on the dash meter and that is all that happens.
 

Ned

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If the voltage drops, then it's a good bet that the solenoid is working.  I would put a good voltmeter on the battery while trying to crank and see what the voltage actually is under load.  Check all the electrical connections from the battery to the solenoid to the starter.  Any corroded or loose connections could prevent the starter from turning.
 

TheDude

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Ned said:
If the voltage drops, then it's a good bet that the solenoid is working.? I would put a good voltmeter on the battery while trying to crank and see what the voltage actually is under load.? Check all the electrical connections from the battery to the solenoid to the starter.? Any corroded or loose connections could prevent the starter from turning.

+1
 

blueblood

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Just Us said:
Hi all!

I have a class a with a 300HP Cummins Turbo diesel that won't start. I have replaced the chassis batteries which it seemed to need, but it still will not start. I think it might be the starter or solenoid, but I have no idea how to check these components to determine if they need replacing as I have never worked on a diesel engine. Any help would be greatly appreciated

When you say won't start do you mean its cranking but doesn't start ? If so, then the control circuit wires (small elecronic size wire not the battery cables) which come off battery terminals are probably corroded in the terminals. 
 

Ned

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He did say it didn't crank.  It's looking more like either the battery or a bad connection, probably the former.
 

Chet18013

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I'd systematically clean all the battey terminals and then the connections at the other end of the cables.  I have seen a bad connection where the cable connects to the solenoid.  Also check the solenoid. If you don'tknow how to jump a selonid with a metal bar, get someone who does and try to crank the engine by bypassing the solenoid. It is also possible, but not to likely,that the starter is shot.

Seriously, unless you know what  you are doing, if it doesn't start after cleaning all the terminals, it's time to call a mechanic.

Chet18013
 

Hawkman

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Why don't people ever come back to state what it was, exactly, that was the cause of the problem?  

I've got this issue going on now with my 300hp Cummins.  I promise to provide an answer when I get it back running.  
 

Tom

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The original poster hasn't logged in since December, 2006. It's just the "grab and run" mentality of some folks getting information on the internet and/or forums.

 

Hawkman

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So I take my 8D battery to the battery place 30 miles away.  Guy runs two tests on it(voltage and load test using a big rolling unit) and it checks fine.  I'm thinking crap...on to the next thing with troubleshooting.  I'm messing around in the coach this afternoon after putting the battery back in, and things I'm checking just keep pointing in the direction of the battery.  I say what the heck, I'll call for a jump start.  Called Geico and 1st try some roadside company comes with a handheld jump box.  Please!  This is after I, and the Geico rep, specifically told their dispatcher what was being jumped.  2nd try, a different company responds.  International 4300 series shows up.  Yay.  Hooks up the cable...bam, starts right up.  It's the battery.
 

Jeff

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Hawkman said:
So I take my 8D battery to the battery place 30 miles away.  Guy runs two tests on it(voltage and load test using a big rolling unit) and it checks fine.  I'm thinking crap...on to the next thing with troubleshooting.  I'm messing around in the coach this afternoon after putting the battery back in, and things I'm checking just keep pointing in the direction of the battery.  I say what the heck, I'll call for a jump start.  Called Geico and 1st try some roadside company comes with a handheld jump box.  Please!  This is after I, and the Geico rep, specifically told their dispatcher what was being jumped.  2nd try, a different company responds.  International 4300 series shows up.  Yay.  Hooks up the cable...bam, starts right up.  It's the battery.

Hawkman:

Not a cable connection by chance?
 

Hawkman

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Ok...time for an amendment.

The coach seemed to want to start again when I installed a new battery, but later in the day it went back to doing what it was doing originally...not starting. 

Finally traced it to dirty terminals connected to one of the solenoids.  Took off all the connections, scraped the terminals clean, reconnected and now it's starting fine.

 

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