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No Crank just one loud Click (LMM)

36K views 7 replies 4 participants last post by  mizterwizard 
#1 ·
Hey,

I went to start my 2008 2500HD Duramax after it sat for 2 days coming down from a fairly tame drive down the mountain, all I got was a distinct "click".

New batteries (under 1 month) each read 12.6V disconnected.

I tried swapping the big fuses (the numbers being the same)

I tried shorting the starter solenoid with a screwdriver, just made a few sparks.

I took a stab at a few voltages / drop test

From positive bat terminal to positive starter post 12.5V not turning key

From negative bat terminal to negative starter post 0 not turning key,

From negative bat terminal to negative starter post seen as high as 10.5V when turning key

From negative bat terminal post to negative bat terminal post clamp 0.00-0.01 when turning key

I followed the cable off the negative post on the starter (the smaller one). It is purple, and it goes all the way to the fuse box, i didn't see any crimps or mangled spots.

When trying to turn on the vehicle the lights DO dim

It won't crank in neutral or any gear, the security light is not on


I have a starter waiting in the nearby town, but would like to eliminate any possible electrical issues before i begin that particular struggle. What else can i do?

Thanks in advance;

Fred
 
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#3 ·
Okay! What is a good way to check if the motor turns over freely?

Also, if i run a wire from the negative battery terminal to the negative post, (given that i have full voltage on the red wire) will that kick in the starter? Im thinking i will be going to town to grab the new starter and some extensions for my ratchet shortly.
 
#4 ·
First, unless you have converted your truck to positive ground for some reason, the negative post on the battery goes to the block and chassis, not to the starter. I think you have the polarity thing backwards. Not that I think you actually have the cables wrong, just that I think you may be a little mixed up.

The block ground is G103 and it is located at the left rear of the block, just above the oil pan mating surface.

The chassis ground is G101. From the picture it appears to be located behind the right bumper mount, probably on the frame but it could be the lower core support.

There is no negative terminal on the starter itself. The purple wire is the start signal from the starter relay which is controlled by the ECM. That should give you a big idea. Pull the starter relay out and jumper past it. The starter should crank the engine. I suspect it won't but that you will get the loud clack you mentioned.

I tried swapping the big fuses (the numbers being the same)

The fuses should be 175 A and you need both of them. Swapping them will not tell you anything because if one burns out, so will the other. You would be just swapping two bad fuses. It would be better to measure the voltage drop across the fuses while trying to crank the engine. However, the fact that the solenoid throws means that the fuses are good.

I tried shorting the starter solenoid with a screwdriver, just made a few sparks.

If you shorted across the two large posts on the solenoid it would make a lot of sparks, especially if the engine is locked. You need to sort from the battery terminal on the starter to the purple wire terminal but bypassing the relay like I suggested above is a better test.

I took a stab at a few voltages / drop test

From positive bat terminal to positive starter post 12.5V not turning key


This is a good test with a bad result if you actually did what you think you did. The whole polarity thing adds a source of doubt. There should be nothing between the battery positive and the starter positive except a length of heavy copper wire. There should be no voltage drop. This could be where your problem is.

From negative bat terminal to negative starter post 0 not turning key,

From negative bat terminal to negative starter post seen as high as 10.5V when turning key

From negative bat terminal post to negative bat terminal post clamp 0.00-0.01 when turning key


This whole thing is kind of messed up because of the polarity thing and the fact that there is not negative post on the starter. If you were actually testing the positive cable then there is your problem. You have a bad battery cable or connection.

I followed the cable off the negative post on the starter (the smaller one). It is purple, and it goes all the way to the fuse box, i didn't see any crimps or mangled spots.

That is not a negative post or wire. It is a signal from the starter relay to the solenoid that energizes the solenoid.

When trying to turn on the vehicle the lights DO dim

It's a small thing and I think it is easy enough to understand what you are saying here but it would be clearer if you talked in terms of cranking the engine rather than turning it on.

What counts is how much the lights dim. It should be substantial. A slight dimming indicates only that the solenoid has energized. A big dimming indicates that the starter is trying to crank the engine but not being able to.

It won't crank in neutral or any gear, the security light is not on


I'm guessing, though you don't say, that your truck has an automatic trans but you didn't mention Park or the clutch so it could be an automatic or a manual. I presume that you have owned this truck for a while and know how to start it. The fact that it makes a noise when you try to crank it indicates that the park/neutral switch or clutch switch, as the case may be, is working properly.

As I see it the main suspect is the battery cable or terminal. The second most likely suspect is a bad starter. Third would be a locked engine.

To test for a locked engine you will need to get to the balancer/pulley bolt with a long flex handle or to the flywheel with a pry bar. You shouldn't have to turn the engine much to see if it is locked. A small amount either way will tell the story.

If the engine is locked you will need to pull all of the glow plugs and crank it over by hand, if you can, to blow out what ever fluid is hydrolocking the engine. If it is still locked with the glow plugs out then have it towed to a shop for disassembly and repair.
 
#5 · (Edited by Moderator)
I would edit my post but I can't so I'll make an addendum. The starter relay is located in the under hood fuse and relay box. There are three relays right smack in the middle of the box. The smaller one is for the a/c. The middle one is for the starter. The other large one is for the power train.

The relay will have symmetrical terminals on the bottom. You can install it two different ways and it doesn't matter. The terminals you want to jumper are the #30 to the #87. This numbering is pretty universal across almost all makes and models of cars, trucks and relays. The actual position and construction of the relay may change but the numbering is always the same.

#30 is battery power. #87 goes to the controlled device. In this case it is the starter solenoid. #85 and #86 are the two sides of the coil inside that throws the relay. #87 is a normally open contact. That means that when you are holding it in your hand the switch inside will be open. Some relays will have a normally closed contact and it will be #87a. Many relays and relay sockets will have provision for the 87a connection even if there isn't anything there. You could probably find a relay that had the #87a and no #87 but I don't recall ever seeing one.
 
#6 ·
Mizterwizard has you on the right path to diagnose the problem--

If the starter relay has a loud click, when you try to start, the relay sounds OK.

You should check the voltage at the large battery terminal at the starter, with the key on start. [negative meter lead grounded to the block or the starter] If very low, move the positive meter lead to the battery cable where it is connected to the battery- note the voltage with the key on start. Do the same at the other battery. It sounds like you may have a bad cable to the starter-- or a bad starter.

If you jump from the larger terminal to the small terminal at the starter, that bypasses ALL switches, relays and safety devices. the motor should crank, IF the batteries, cables and starter are ok
 
#7 ·
Solved - it was the starter

Thanks for all the help guys,

The "relay" post on the starter was really lose compared the the refurb i purchased, i wonder if a rock manged to bounce up in there when i was coming down a logging road.

It wasn't nearly as bad changing it out as i thought, just needed 10mm to move the exhaust, 15mm to take off the starter and the wires were easy. Only tricky part was using 2 extensions to bring the ratchet in front of the everything in the way.

Turned over the best i've ever seen.

Heres a photo of the starter if anyone was curious
Starter with loose solenoid relay connection - Album on Imgur
Close up of starter solenoid with loose relay - Album on Imgur

If i hadn't beat the heck out of it with a hammer, i might have considered trying to just replace the solenoid.

Thanks for the advice!
 
#8 ·
Good that you got it fixed and that the repair worked.

I am a professional mechanic so I have to balance diagnosis time, which may find a problem but will not fix it, against just doing what I think it needs, which may fix it but if it doesn't it can be a big waste. It's hard to convince people that replacing something with a good part is a legitimate diagnostic step.

As far as replacing just the solenoid, I think that is a bad idea so I'm glad you didn't try it. There are contacts inside the solenoid that can be the source of the problem and sometimes you can just take the end cap off, turn the battery stud and the motor stud around and put it back together. More often though the brushes are worn out too. If you go that far you might as well replace the armature bushings. And once you are there you might as well turn the commutator.

By that time you have pretty much rebuilt the starter. Unless you place no value on your time, you will have spent as much rebuilding it as it would have cost to replace it. You might have a good working start at that point but no warranty and the possibility that the armature or field windings are near failure too.

Unless the starter is particularly expensive or hard to find, I prefer to replace it. Puts the burden of future failure on someone else.

Congrats on your outcome. I recently replaced the starter on my diesel car. It had cranked the same way ever since I got it but the new starter cranks it twice as fast. The starter has been bad for years and I never new it until it failed completely. Sometimes bad news turns out to be good news.

Thanks for all the help guys,

The "relay" post on the starter was really lose compared the the refurb i purchased, i wonder if a rock manged to bounce up in there when i was coming down a logging road.

It wasn't nearly as bad changing it out as i thought, just needed 10mm to move the exhaust, 15mm to take off the starter and the wires were easy. Only tricky part was using 2 extensions to bring the ratchet in front of the everything in the way.

Turned over the best i've ever seen.

Heres a photo of the starter if anyone was curious
Starter with loose solenoid relay connection - Album on Imgur
Close up of starter solenoid with loose relay - Album on Imgur

If i hadn't beat the heck out of it with a hammer, i might have considered trying to just replace the solenoid.

Thanks for the advice!
 
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