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1999 S600 & 1999 S500
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849 Posts
Discussion Starter #1
My engine will surge on a hard take-off, especially when cold. If I take off normal it is not as noticeable.

Any ideas?
 

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600 coupe, one of the very first built
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134 Posts
These, IMO, are classic symptoms of un-metered air entering. Aka vacuum leaks.
Of course it could be that the MAFs are due for replacement.

Have you connected it to Star SDS scanner to read codes and live data?
Long- and short term fuel trims will be telling...
 

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1994 S600 Coupe, 1995 S600 Coupe
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1,862 Posts
My engine will surge on a hard take-off, especially when cold. If I take off normal it is not as noticeable.

Any ideas?
Check the boots between the mass air flow (MAF) sensors and throttle bodies for cracks/splits. They allow unmetered, unfiltered air in causing all sorts of issues. I was helping a new friend this week and both of his were cracked with splits so big, you could stick fingers through them. Sometimes they split on the bottom, so you may need to remove them if you don't see anything on top.

Jon
 

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W140 Moderator
"CHRIS" Merc 92 600SEL / Sold > 93 600SE / 93 S500 / 89 560SEL / 413CDI / B180-CDI /A170-CDI
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7,599 Posts
Also check all around the Manifold were the airhose are going into , 2 at the back ,facing engine right side . On transmission drivers side (my rhd ) ,2 air hoses go into it , 1 came of mine resulted bad shifting , check other .
Reset Throttle Body's : Key in pos 2,cluster lights up only ,dont start engine . Depress accelerator until you feel kickdown switch but dont activate it , keep foot like that for 90 seconds , ignition to position 0 , wait the 90 sec . Once time is up start engine ,if you done it correctly ,engine will rev to about 2000 rpm or more then settle . Reset procedure successfully done .
 

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96 sl600,97 s420(gone) 96 CL600
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618 Posts
I recently had the surge at idle, occasional miss at highway speed. One of the intake air temp sensors had come out of the maf, due to it having a missing tab.
 

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1994 s600 coupe
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456 Posts
surging it typically a lean condition. but anyway, try removing the air filters, and put the empty boxes back in, and close them. if you have access to scan tool, reset the diagnostic module, and both LH modules to base adaptations, disconnect battery, reconnect, and start over. my car always runs better with the air filters removed. they are exceedingly restrictive and small in size, for an engine this big. it is crucial to put the car on a scan tool with live data, and look at ALL the inputs. the last issue my car had, was multiple problems, one bad LH module, and one bad MAF sensor. the MAF was reading all over the place at idle, from 15-25 kg/hour up to 1000 kg/hour airflow. voltage was all over too. I changed it, problem went away. it required a scan tool to see that problem.
 

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Premium Member
1999 S600 & 1999 S500
Joined
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849 Posts
Discussion Starter #7
surging it typically a lean condition. but anyway, try removing the air filters, and put the empty boxes back in, and close them. if you have access to scan tool, reset the diagnostic module, and both LH modules to base adaptations, disconnect battery, reconnect, and start over. my car always runs better with the air filters removed. they are exceedingly restrictive and small in size, for an engine this big. it is crucial to put the car on a scan tool with live data, and look at ALL the inputs. the last issue my car had, was multiple problems, one bad LH module, and one bad MAF sensor. the MAF was reading all over the place at idle, from 15-25 kg/hour up to 1000 kg/hour airflow. voltage was all over too. I changed it, problem went away. it required a scan tool to see that problem.
Running without the air filters, other than for diagnostics, seems dangerous. It should run better w/o the filters as there is less differential pressure on the intake.
 

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1994 s600 coupe
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456 Posts
if the air is clean, i.e. country paved roads, no problem.
I would not recommend removing air cleaners in dusty conditions.
the screens in the MAF sensors will stop large pieces of debris,
from entering the engine.
actually a bigger screen can be cut and made to fit in the place of the filter.
you gain an increased ram effect of the air coming through the grill,
into the air filter inlet snorkel, and into the engine.
i.e. what they called "ram air" on the Pontiacs of the 1960's
 
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