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Discussion Starter #1 (Edited)
I've got an intermittent cranking problem with my car. It doesn't happen every time I start up my car and I'm having a hard time figuring out what might be causing it. It seems like every time I try to get it on video, it won't do it for me. But this morning I FINALLY got it....and now it's done it the past 3 times I've cranked. Hoping someone can shed some light. First attempt at starting it up results in a grinding (ish) sound and it won't turn over. Second attept, starts up but really struggled to get there. Once it starts, it idles high for about 1 minute, then the RPMs drop (maybe this higher idle part is normal for this car?). Once the RPMs have leveled out, you can see the needle ever so slightly float up and down. When it floats, it feels like there's a slight miss in the engine. Up until today, the grinding(ish) sound only happened every once in a while. What happens more often is (see last video) the car doesn't grind, but will try and try to turn over (even after I let go of the key) and then it finally starts up. High idle, then drop, happens with or without the grind. Any ideas on what might cause these issues?





 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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How old is battery?
Has it been tested?
The slk loves a great battery, not a good battery
 

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Discussion Starter #3 (Edited)
I had the battery tested about two months ago and it tested fine. It is a MB battery, the indicator bubble is still clear, but I'm not sure how to tell how old it is.


Also, just for reference, it had a brand new Napa battery in it when I bought the car, but when these cranking issues first came up, one of the guys at the MB shop gave me this battery they had laying around for free to see if that helped my problem. And it seemed to for a little while, but now the cranking problem is becoming more frequent, so I guess all in all, the battery didn't solve my problem after all :|
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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mb usually puts a green sticker with the month/year on it
forgive me, but testing 'fine' is not 'great'. just sayin' :D
did they test cranking voltage, etc?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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new battery should be 12.7 at starting/crank
year old battery, charging weekly, 12.5
 

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Discussion Starter #6
mb usually puts a green sticker with the month/year on it
forgive me, but testing 'fine' is not 'great'. just sayin' :D
did they test cranking voltage, etc?


LOL! I understand :) He did not do a load test once the battery was I my car. Could a "fine" battery cause whatever that screech/grind/halting noise is when I try to crank in the first video? I cannot figure out what exactly is making that noise.
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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Our r170 experts will chime in on the grind. :D
i know the 230 likes to make about a few minutes worth of noise on cold start!
 

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The idle seems fine to me for now but the grinding of the starter is a little concerning.

When you start the car, do you hold the key in the start position until it is running or do you just tap it there? If you have an automatic you do not to hold it there and that could cause issues.
 

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Hello 2 Big Red Dogs,

Three things.... all basically parroting what Jeff and Chris have said:

1) Make sure your have a strong battery. It seems a little slow to start.
2) In the first video the grinding noise sounds like the key being held on after the engine is firing. As Chris mentioned, turn the key and let it go, unless you have a manual transmission.
3) High idle - upon cold start ours idles around 1200 RPM until it warms up. It also delays the shifting on an automatic transmission, to help get it warm more quickly.

Good luck and enjoy,
Tim
 

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Discussion Starter #11
El Toro and iChris, thanks for your replies! :)

First video and second video – I’ve been trying to figure out a way to describe the noise that’s made and you nailed it with saying that it sounds like the key is being held too long! I was holding the key in the start position, not just a tap, waiting for it to start, but then before it had a chance to turn over, it made that terrible sound so I quickly turned it off. I guess when I hear something alarming like that, I immediate want to make it stop because it sounds “damaging” LOL. But yes, I do typically hold the key until it is fully cranked (it is an automatic), and then let the key go. Not just a tap, and not so long that it would make the sound like trying to crank when your car is already cranked.

Third video was actually from a few weeks ago when I was trying to capture the high idle when I first start the car. During that crank, it did not make the grinding noise, but I held the key into the starting position and it was very slow to turn over. So I just let the key go to see what it would do (did not turn it to the off position, just simply let the key go) and it ended up finally turning over. I do not typically, however, let the key go before it fires up (unless of course I hear that grinding noise and in that case, I turn the key to off).
 

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El Toro and iChris, thanks for your replies! :)

First video and second video – I’ve been trying to figure out a way to describe the noise that’s made and you nailed it with saying that it sounds like the key is being held too long! I was holding the key in the start position, not just a tap, waiting for it to start, but then before it had a chance to turn over, it made that terrible sound so I quickly turned it off. I guess when I hear something alarming like that, I immediate want to make it stop because it sounds “damaging” LOL. But yes, I do typically hold the key until it is fully cranked (it is an automatic), and then let the key go. Not just a tap, and not so long that it would make the sound like trying to crank when your car is already cranked.

Third video was actually from a few weeks ago when I was trying to capture the high idle when I first start the car. During that crank, it did not make the grinding noise, but I held the key into the starting position and it was very slow to turn over. So I just let the key go to see what it would do (did not turn it to the off position, just simply let the key go) and it ended up finally turning over. I do not typically, however, let the key go before it fires up (unless of course I hear that grinding noise and in that case, I turn the key to off).
You do not need to hold the key. Once is begins to engage, just let go. The car will take over and do the rest!!! I agree, it did seem to crank slow in the one video, that could be a battery voltage issue.

Tim
 

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Yup, no need to hold the key. See if that helps. I also agree with you, if you hear something bad, interrupt the starting process by turning the key to off.

It is definitely the starter and hopefully letting it start itself will fix it.
 

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Discussion Starter #14 (Edited)
Here's my typical crank (no grind this time). Who knew I've been doing it wrong my entire life LOL! (aahem, ignore my music, apparently I was jamming earlier haha! And my bare feet and the TERRIBLE black spray-paint (seriously) job that someone did to try to fix the peeling. That's my next big project. Back to the original gray!)


Also, I had NO idea that this car delayed shifting until warmed up. I know sometimes that if I put my car into drive a few seconds after I start it, that it almost feels like it's going into limp mode. Now I know why. Thanks guys!!! I swear I learn something new every single time I get on this site.


https://youtu.be/qVOxDKl-d2E
 

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Here's my typical crank (no grind this time). Who knew I've been doing it wrong my entire life LOL! (aahem, ignore my music, apparently I was jamming earlier haha! And my bare feet and the TERRIBLE black spray-paint (seriously) job that someone did to try to fix the peeling. That's my next big project. Back to the original gray!)


Also, I had NO idea that this car delayed shifting until warmed up. I know sometimes that if I put my car into drive a few seconds after I start it, that it almost feels like it's going into limp mode. Now I know why. Thanks guys!!! I swear I learn something new every single time I get on this site.


https://youtu.be/qVOxDKl-d2E
This was the first car we have ever had that you didn't need to hold the key on. Now we have a 2011 Ford Escape that operates in the same fashion. I like it now. Chris has a standard transmission and on that the key must be held until it starts. Maybe that has something to do with having to hold the clutch in to engage the starter?

Tim
 

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I think you have more than one issue going on. There's a plastic cover you can remove from the bottom of the bell housing to inspect the flywheel ring gear that the starter engages - take a look at the entire thing looking for issues there, and also consider removing and having your starter tested. Many parts places will do this for free.
 

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I think you have more than one issue going on. There's a plastic cover you can remove from the bottom of the bell housing to inspect the flywheel ring gear that the starter engages - take a look at the entire thing looking for issues there, and also consider removing and having your starter tested. Many parts places will do this for free.
If you go under the car to inspect the flywheel, check and make sure the starter is bolted on properly. (tight with no bolts missing)
 

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Discussion Starter #18
The flywheel crossed my mind as a second though. But now that you mentioned it I will definitely check it out now! And while I'm under there I'll make sure that the starter is properly attached. Thanks everyone for your comments!!! Now that I've learned how to crank, it hasn't done the squeal again, but it's such an intermittent thing that I cannot be sure, just yet, that that was the cause. I'll give it some time and hopefully that will be what the problem was! Could I have possibly burned up my starter by holding the key longer than necessary? I've only had the car since October of 2014, so not quite a year yet, but I have no idea how the person before me was starting the car. It's got approximately 85K miles on it. Maybe someone should create a sticky on "How to start your car for idiots like Ashley" haha!!! :D
 

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Nah, we don't teach by embarrassment.
better ways like 'Did you read the owner's manual?' :D
 

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The Bendix in the starter is going bad. The starter should either be rebuilt or replaced:


After the car starts, it should fast idle for a minute or two. As for the fluctuations, the engine is likely out of tune. It could also be a bad injector, coil, fuel problem, or just the >:D punishing you for past sins!
 
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