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Occasional Hard Start/stall with no codes. Timing issue?
Vehicle is a 2013 E350 M276 with 120k miles
Recently, every now and then (1 in 20 starts?), when the vehicle is started, it occasionally dies immediately or has a rough idle for 10-30 seconds before it smooths out. It will start if you try again. There is no stalling once it warms up in 30 seconds. This issue can appear after being run less than an hour previously. I have no codes at all. No obvious chain noise at start up but that could be subjective.
This vehicle is subject to changing the secondary valve tensioners and adding check valves per the TSB. I have no evidence it was ever done by the previous owners (I acquired it with about 112k miles).
Should I just proactively change the 4 magnetic sensors, tensionsers, and add the oil check valve? Wait until codes appear? Or is this something else all together like an intake leak? The spark plugs were changed in the last 30k miles. Igntion coils are probably original.
Appreciate any guidance as I love the car but no happy about the stalling condition as it does not inspire confidence.
Recently, every now and then (1 in 20 starts?), when the vehicle is started, it occasionally dies immediately or has a rough idle for 10-30 seconds before it smooths out. It will start if you try again. There is no stalling once it warms up in 30 seconds. This issue can appear after being run less than an hour previously. I have no codes at all. No obvious chain noise at start up but that could be subjective.
This vehicle is subject to changing the secondary valve tensioners and adding check valves per the TSB. I have no evidence it was ever done by the previous owners (I acquired it with about 112k miles).
Should I just proactively change the 4 magnetic sensors, tensionsers, and add the oil check valve? Wait until codes appear? Or is this something else all together like an intake leak? The spark plugs were changed in the last 30k miles. Igntion coils are probably original.
Appreciate any guidance as I love the car but no happy about the stalling condition as it does not inspire confidence.
That's interesting... this sounds like HPFP not getting synchronized with jerky camshaft.
At 120kMi, there's a collection of parts you can throw at this issue.
+ Chain Tensioners (+ check-valves?)
+ HPFP + Roller + PCV
+ CPS + pigtails
+ better oiling than 10k thin oil
I stressed oil because thin oil is a direct contributor to VVT issues.
Ignition coils are not suspect until proven bad. They get damaged by over gapped plugs and cooked by extreme heatsoaks.
Furthermore I hate to throw parts at any issue without looking at what computers are doing. Scan your complete chassis for faults so you know what chaos is brewing (ECU timings are unfortunately linked to other CAN-C modules).
For good measure you can read idle fuel pressures:
low pressure: tank pump
high pressure: rail pump
Tank pump filter can sometimes starve HPFP.
Last edited by CaliBenzDriver; Mar 2, 2025 at 09:31 PM.
To be honest, the most important accessory these cars need is a MB aware scanner. It will save a lot of time, it will also help you provide objective information when asking on these forums.
Please before buying any parts, get an MB aware scanner, bidirectional best.
Then, fire as many questions as you want and you will find nearly infinite help in this forum.
Word of advice: these cars have stubborn electrical connectors. Learn how to pull/push them before disconnecting too many of them. Several people have found the hard way that a damaged connector triggered a long list of unnecessary parts.
To be honest, the most important accessory these cars need is a MB aware scanner. It will save a lot of time, it will also help you provide objective information when asking on these forums.
Please before buying any parts, get an MB aware scanner, bidirectional best.
Then, fire as many questions as you want and you will find nearly infinite help in this forum.
Word of advice: these cars have stubborn electrical connectors. Learn how to pull/push them before disconnecting too many of them. Several people have found the hard way that a damaged connector triggered a long list of unnecessary parts.
This also happened to my e350 4 matic 2013 around 180k miles maybe 2 year ago. I remember before that i switch oil from mobil one 0w40 to 5W40 Molygen New Generation Engine Oil (5 Liter). I also use injection cleaner from moly. After I switch back to mobil one problem disappear until now.
That's interesting... this sounds like HPFP not getting synchronized with jerky camshaft.
At 120kMi, there's a collection of parts you can throw at this issue.
+ Chain Tensioners (+ check-valves?)
+ HPFP + Roller + PCV
+ CPS + pigtails
+ better oiling than 10k thin oil
I stressed oil because thin oil is a direct contributor to VVT issues.
Ignition coils are not suspect until proven bad. They get damaged by over gapped plugs and cooked by extreme heatsoaks.
Furthermore I hate to throw parts at any issue without looking at what computers are doing. Scan your complete chassis for faults so you know what chaos is brewing (ECU timings are unfortunately linked to other CAN-C modules).
For good measure you can read idle fuel pressures:
low pressure: tank pump
high pressure: rail pump
Tank pump filter can sometimes starve HPFP.
CaliBenzDriver,
(looks like you are in the SF Bay Area - so am I!)
I had wondered about fuel delivery issues. I will check out your HPFP idea. Do you read the idle fuel pressures with a physical gauge or using a scanner?
What do you mean by "roller"?
By better oil, what do you mean? I am using 0w-40 Mobil 1 or Catrol Syntec (same weight). Change it every 5k.
I did borrow an icarsoft EUpro scanner and there were no codes on ECU, transmission, or anything else interesting (the multi contour seat had a code or two). This scanner is not intuitive to use however so maybe i am missing something as you have to hunt for problems.
Thanks for the reply. I replied to another post but I did use an Icarsoft EUpro scanner. To be honest, I find it cumbersome to use. Is there a good entry level (<$250) scanner to use or do I need the Xentry system?
(looks like you are in the SF Bay Area - so am I!)
I had wondered about fuel delivery issues. I will check out your HPFP idea.
Do you read the idle fuel pressures with a physical gauge or using a scanner?
What do you mean by "roller"?
By better oil, what do you mean? I am using 0w-40 Mobil 1 or Castrol Syntec (same weight). Change it every 5k.
I did borrow an icarsoft EUpro scanner and there were no codes on ECU, transmission, or anything else interesting (the multi contour seat had a code or two). This scanner is not intuitive to use however so maybe i am missing something as you have to hunt for problems.
The HPFP is actuated by a roller pin riding very sharp camshaft lobes. It's affected by getting the least lube in the whole engine.
Fuel pressure : use scanner to read both pressures data from pump/engine modules.
Better oiling is achieved with stable oil viscosity that does not shear into W30. These V6 rely on stable oil pressure to work VVT + HPFP timings.
Castrol may be ok and so are Group IV PAO and group V esters : Amsoil, Motul...
It appears your scan reports no big deal: good !
Overall everything appears normal yet its not....
you have no significant fault codes
you don't have misfires
you don't have VVT Rattles
you may not have "oil in ECU harness"
You do have hard starts.... FUEL!
> Do a good job at fuel pressure check.
-- We need to know why your rail pressure takes a while to build up.
-- Assess what your low pressure supply does under load when you step on it: drop/colapse or stable??
Last edited by CaliBenzDriver; Mar 3, 2025 at 01:02 PM.
I got 2 values of fuel pressure from my scanner at Idle (560 RPM) with a warmed up engine
Fuel pressure (from tank fuel pump "Kraftatoffdruck"): varies between 71-88 psi at idle. Is that much variation normal???
Fuel Rail Pressure at idle: 2176psi
Fuel temp seems very high to me 110F? Ambient temp outside is 60-70F.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by e350_W212
Thanks for the reply. I replied to another post but I did use an Icarsoft EUpro scanner. To be honest, I find it cumbersome to use. Is there a good entry level (<$250) scanner to use or do I need the Xentry system?
Ideally, you want (and eventually need) XENTRY, but it's not going to be <$250. So, the next best is the LAUNCH Creader Elite 2.0 BENZ. Compact and can be kept in the car. You can get it on Amazon, or KingBolenTool for a little less.
Just to follow up, I replaced all the coils, spark plugs, camshaft sensors and the problem has not returned. I did find oil in the harness and ECU which will be the topic of another thread.
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