08 MB ML 320 CDI long cranking slow start
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
08 MB ML 320 CDI long cranking slow start
My car has got a challenge which I can’t get a sensible explanation to.
The challenge is related to long cranking/slow start after the car has been parked overnight. I visited a MB garage yesterday for a full diagnosis test - absolute everything was good!
However if I wait for 10 seconds before cranking after finished glowing the engine seems to start up normal.
Any ideas or experiences?
The challenge is related to long cranking/slow start after the car has been parked overnight. I visited a MB garage yesterday for a full diagnosis test - absolute everything was good!
However if I wait for 10 seconds before cranking after finished glowing the engine seems to start up normal.
Any ideas or experiences?
Junior Member
Joined: Apr 2024
Posts: 62
Likes: 22
ML350 Bluetec
I am looking at a "slow starting/long cranking" problem with my ML350 too. I narrowed it down to 4 possible culprits.
Bad glow torches
Bad Glow module
Bad starter motor
Bad battery > checked is ok
From all the articles online I found that it seems the starter engine is the most common problem. It turns the engine a fraction to slow resulting in a few seconds cranking.
Bad glow torches
Bad Glow module
Bad starter motor
Bad battery > checked is ok
From all the articles online I found that it seems the starter engine is the most common problem. It turns the engine a fraction to slow resulting in a few seconds cranking.
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
I am looking at a "slow starting/long cranking" problem with my ML350 too. I narrowed it down to 4 possible culprits.
Bad glow torches
Bad Glow module
Bad starter motor
Bad battery > checked is ok
From all the articles online I found that it seems the starter engine is the most common problem. It turns the engine a fraction to slow resulting in a few seconds cranking.
Bad glow torches
Bad Glow module
Bad starter motor
Bad battery > checked is ok
From all the articles online I found that it seems the starter engine is the most common problem. It turns the engine a fraction to slow resulting in a few seconds cranking.
Last edited by Olsyno; May 9, 2024 at 05:37 AM.
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
Thank you for your respond to my enquiry!
If one or several of the glow plugs and/or the glow module are gone it would have been found in the diagnostic test. A full diagnostic test was carried out on last Tuesday without any findings!
If one or several of the glow plugs and/or the glow module are gone it would have been found in the diagnostic test. A full diagnostic test was carried out on last Tuesday without any findings!
Junior Member
Joined: Apr 2024
Posts: 62
Likes: 22
ML350 Bluetec
"the starting of the engine seems OK if I wait with cranking for 10 seconds after the glowing is completed" This suggest the problem is in the glowing..
I found that diagnostic tests not always reveal the real problem.
For me it doesn't matter how long I pre-glow it still takes longer cranking to start, that leads me to believe my starter engine turns to slow. I'm replacing the starter engine one of these days
I found that diagnostic tests not always reveal the real problem.
For me it doesn't matter how long I pre-glow it still takes longer cranking to start, that leads me to believe my starter engine turns to slow. I'm replacing the starter engine one of these days
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
"the starting of the engine seems OK if I wait with cranking for 10 seconds after the glowing is completed" This suggest the problem is in the glowing..
I found that diagnostic tests not always reveal the real problem.
For me it doesn't matter how long I pre-glow it still takes longer cranking to start, that leads me to believe my starter engine turns to slow. I'm replacing the starter engine one of these days
I found that diagnostic tests not always reveal the real problem.
For me it doesn't matter how long I pre-glow it still takes longer cranking to start, that leads me to believe my starter engine turns to slow. I'm replacing the starter engine one of these days
Pls do me a favour and revert with the cranking/starting results when you’ve installed a new starter engine!
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Super Member
Joined: Jul 2016
Posts: 703
Likes: 129
From: NE OHIO
1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
slow crank
A couple of things I would check:
1 Complete test of the battery with a modern battery tester . Then after that I would charge the battery ( assuming AGM TYPE) with a good quality AGM charger for 24 hours. This has always help my slow starting issues on a couple of 550 gas motors .
2. There have been issues on the positive wiring from battery to starters .. do a search on the replacing of harness … it is either from battery to under engine hood or engine hood to starter .. don’t remember.
3. Starters.. make sure you read all the tips .. I changed my starter in under 2 hours without doing hardly any of the recommended install instructions.. I do remember doing a twisting motion on the starter for install and removal .. No motor mounts and that method
4. Being an old electrical guy I would really lean towards a battery. When voltage goes down ( after all the current is put to the glow plugs) the current has no choice but rise while trying to start the car… waiting 10 seconds after the glow plugs gives the battery a little time to recoup from the large current draw.
5. Another simple test would be to have a volt meter on the battery and watch while you activate the glows and see how bad the battery drops…A dc current clamp meter would also be helpful
6.If you have an OBDII reader like a IcarSoft it will also show voltage .
1 Complete test of the battery with a modern battery tester . Then after that I would charge the battery ( assuming AGM TYPE) with a good quality AGM charger for 24 hours. This has always help my slow starting issues on a couple of 550 gas motors .
2. There have been issues on the positive wiring from battery to starters .. do a search on the replacing of harness … it is either from battery to under engine hood or engine hood to starter .. don’t remember.
3. Starters.. make sure you read all the tips .. I changed my starter in under 2 hours without doing hardly any of the recommended install instructions.. I do remember doing a twisting motion on the starter for install and removal .. No motor mounts and that method
4. Being an old electrical guy I would really lean towards a battery. When voltage goes down ( after all the current is put to the glow plugs) the current has no choice but rise while trying to start the car… waiting 10 seconds after the glow plugs gives the battery a little time to recoup from the large current draw.
5. Another simple test would be to have a volt meter on the battery and watch while you activate the glows and see how bad the battery drops…A dc current clamp meter would also be helpful
6.If you have an OBDII reader like a IcarSoft it will also show voltage .
Last edited by vesiadog; May 11, 2024 at 01:51 PM. Reason: wording
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Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
A couple of things I would check:
1 Complete test of the battery with a modern battery tester . Then after that I would charge the battery ( assuming AGM TYPE) with a good quality AGM charger for 24 hours. This has always help my slow starting issues on a couple of 550 gas motors .
2. There have been issues on the positive wiring from battery to starters .. do a search on the replacing of harness … it is either from battery to under engine hood or engine hood to starter .. don’t remember.
3. Starters.. make sure you read all the tips .. I changed my starter in under 2 hours without doing hardly any of the recommended install instructions.. I do remember doing a twisting motion on the starter for install and removal .. No motor mounts and that method
4. Being an old electrical guy I would really lean towards a battery. When voltage goes down ( after all the current is put to the glow plugs) the current has no choice but rise while trying to start the car… waiting 10 seconds after the glow plugs gives the battery a little time to recoup from the large current draw.
5. Another simple test would be to have a volt meter on the battery and watch while you activate the glows and see how bad the battery drops…A dc current clamp meter would also be helpful
6.If you have an OBDII reader like a IcarSoft it will also show voltage .
1 Complete test of the battery with a modern battery tester . Then after that I would charge the battery ( assuming AGM TYPE) with a good quality AGM charger for 24 hours. This has always help my slow starting issues on a couple of 550 gas motors .
2. There have been issues on the positive wiring from battery to starters .. do a search on the replacing of harness … it is either from battery to under engine hood or engine hood to starter .. don’t remember.
3. Starters.. make sure you read all the tips .. I changed my starter in under 2 hours without doing hardly any of the recommended install instructions.. I do remember doing a twisting motion on the starter for install and removal .. No motor mounts and that method
4. Being an old electrical guy I would really lean towards a battery. When voltage goes down ( after all the current is put to the glow plugs) the current has no choice but rise while trying to start the car… waiting 10 seconds after the glow plugs gives the battery a little time to recoup from the large current draw.
5. Another simple test would be to have a volt meter on the battery and watch while you activate the glows and see how bad the battery drops…A dc current clamp meter would also be helpful
6.If you have an OBDII reader like a IcarSoft it will also show voltage .
Your professional opinions related to the battery is very interesting, but…
The AGM battery in my car was renewed at 12th of April 2023 and I should think that it would last longer… I’ll of course get it tested particularly since the MB garage didn’t reveal anything during the full diagnostic scan on last Tuesday!
But since the start of the engine seems normal after a waiting time of ten seconds after completed glowing it might be an indication that the battery has “recovered”!
Super Member
Joined: Jul 2016
Posts: 703
Likes: 129
From: NE OHIO
1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
Thank you for your respond to my enquiry!
Your professional opinions related to the battery is very interesting, but…
The AGM battery in my car was renewed at 12th of April 2023 and I should think that it would last longer… I’ll of course get it tested particularly since the MB garage didn’t reveal anything during the full diagnostic scan on last Tuesday!
But since the start of the engine seems normal after a waiting time of ten seconds after completed glowing it might be an indication that the battery has “recovered”!
Your professional opinions related to the battery is very interesting, but…
The AGM battery in my car was renewed at 12th of April 2023 and I should think that it would last longer… I’ll of course get it tested particularly since the MB garage didn’t reveal anything during the full diagnostic scan on last Tuesday!
But since the start of the engine seems normal after a waiting time of ten seconds after completed glowing it might be an indication that the battery has “recovered”!
Member
Joined: Sep 2017
Posts: 173
Likes: 25
From: UK
Mercedes R320L CDI 4MATIC 2007
My car has got a challenge which I can’t get a sensible explanation to.
The challenge is related to long cranking/slow start after the car has been parked overnight. I visited a MB garage yesterday for a full diagnosis test - absolute everything was good!
However if I wait for 10 seconds before cranking after finished glowing the engine seems to start up normal.
Any ideas or experiences?
The challenge is related to long cranking/slow start after the car has been parked overnight. I visited a MB garage yesterday for a full diagnosis test - absolute everything was good!
However if I wait for 10 seconds before cranking after finished glowing the engine seems to start up normal.
Any ideas or experiences?
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
Possible fuel system loses pressure ovee night. I mean low pressure side. When ignition is on, pump in tank preps the system again, builds enough pressure for start. Have same on mine. All was ok, could not find the issue. Till started doing this delayed start. Not ideal..
Your explanation seems plausible particularly since the challenge on my car didn’t trigger any findings during the full diagnostic test.
Is there any corrective actions to rectify the low pressure issue? Do you know if there is a non return valve between the pump in the tank and the engine which might be faulty? In my car this long cranking started for a couple of year ago and is getting worse…. I just recently was informed about the delayed start after finished glowing, but it would be great to get it dealt with!
Member
Joined: Sep 2017
Posts: 173
Likes: 25
From: UK
Mercedes R320L CDI 4MATIC 2007
Thanks for your respond to my enquiry!
Your explanation seems plausible particularly since the challenge on my car didn’t trigger any findings during the full diagnostic test.
Is there any corrective actions to rectify the low pressure issue? Do you know if there is a non return valve between the pump in the tank and the engine which might be faulty? In my car this long cranking started for a couple of year ago and is getting worse…. I just recently was informed about the delayed start after finished glowing, but it would be great to get it dealt with!
Your explanation seems plausible particularly since the challenge on my car didn’t trigger any findings during the full diagnostic test.
Is there any corrective actions to rectify the low pressure issue? Do you know if there is a non return valve between the pump in the tank and the engine which might be faulty? In my car this long cranking started for a couple of year ago and is getting worse…. I just recently was informed about the delayed start after finished glowing, but it would be great to get it dealt with!
so the issue is not solved. it does not get any worse so i am leaving it till later.
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
i have found out that there is a return valve in low pressure pump. I was suspecting this one could the root cause. Tried externally fitted return valve in forward line, just some generic valve. Did not solve the issue. Then I was assuming there could be issues with pressure getting lost in high pressure pump where fuel is fed. To what i recon the is some valve inside of it as well. replaced high pressure pump. no change. So started suspecting that it could be high pressure line valve possibly letting some fuel past when its not powered and fuel is let out through return line. Did not go for replacing this one. Its one of rails replacement, as valve is part of it. I left it as it is, i just keep running ignition for longer in the mornings and start up.
so the issue is not solved. it does not get any worse so i am leaving it till later.
so the issue is not solved. it does not get any worse so i am leaving it till later.
Just wonder… have you ever thought about the possibilities for uneven diesel return from the diesel injectors/nozzles…? I’ve heard that the MB engines are very “sensitive” to such challenges!
Member
Joined: Sep 2017
Posts: 173
Likes: 25
From: UK
Mercedes R320L CDI 4MATIC 2007
Yes i have done leak test on injectors as well. Forgot to mention. Two were showing a bit more than the rest but nothing abnormal. Not sure if that would relate to cold start issue. I would think all starts would be problematic if injectors would have issue?
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 27
Likes: 4
2008 MB ML 320CDI w164
The MB mechanic that carried out the full diagnostic test on my car a week ago told me that my engine was very sensitive to uneven diesel return from the injectors. He told that if this becomes too bad the engine will not start at all. Testing this on my car should be prioritised! Today I’ve planned to do a complete system test on my electrical system with a Exide battery & electrical system analyzer - model EBT900. Carry out the “cheapest” and easiest tests first and try to eliminate as much as possible before I get the diesel injectors return measured/tested.
Member
Joined: Sep 2017
Posts: 173
Likes: 25
From: UK
Mercedes R320L CDI 4MATIC 2007
Thanks for your feedback - much appreciated!
The MB mechanic that carried out the full diagnostic test on my car a week ago told me that my engine was very sensitive to uneven diesel return from the injectors. He told that if this becomes too bad the engine will not start at all. Testing this on my car should be prioritised! Today I’ve planned to do a complete system test on my electrical system with a Exide battery & electrical system analyzer - model EBT900. Carry out the “cheapest” and easiest tests first and try to eliminate as much as possible before I get the diesel injectors return measured/tested.
The MB mechanic that carried out the full diagnostic test on my car a week ago told me that my engine was very sensitive to uneven diesel return from the injectors. He told that if this becomes too bad the engine will not start at all. Testing this on my car should be prioritised! Today I’ve planned to do a complete system test on my electrical system with a Exide battery & electrical system analyzer - model EBT900. Carry out the “cheapest” and easiest tests first and try to eliminate as much as possible before I get the diesel injectors return measured/tested.
