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2003 SLK320
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Discussion Starter · #1 ·
2003 SLK 320, manual transmission. Has anyone gotten the combination of a stumbling/hesitating engine at low (1800–2200) rpm together with an over-enthusiastic ESP light? The stumble is only when under load, and the flashing light is unrelated to road conditions or steering wheel angle.

My car became afflicted with both these woes in the last few weeks, and is now on its third day at the local Benz dealer. The two maladies don’t often occur together, but they did start about the same time.

I have read a number of posts (both here and on BenzWorld) on these topics, but they seemed inconclusive. The plugs and wires are less than 10,000 miles old, though non-MBenz. I have replaced the crankshaft position sensor and cleaned the MAF sensor. Also took out the trunk light’s bulb, which I found to be perpetually on, but this fixed things for only a few days. I have suggested to the tech to check the alternator and voltage regulator; so far, I think he is just reading codes. Nice guy nevertheless, and he drove the car with me as passenger in order to be certain of my complaint. He says this is a “very subtle” problem!

Greg
 

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Discussion Starter · #4 ·
That is an interesting combination. Do you have a good scanner to read the ESP and ABS module?
Probably middling quality. It gave me the following:

B1040 — Fault in CAN communication with control unit MR engine control.
B1041 — Fault in CAN communication with control unit Traction systems
B1471-001 — Component outside temperature sensor has open circuit
B1010 — Vario roof, low supply voltage, less than 9-10 volts
N1140 — CAN Bus Error
N1243 — ? CD Player
N1100 — No signal is received from right side speed sensors for Telematic system
N1101 — No signal is received from left side speed sensors for Telematic system
 

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2003 SLK230
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You have 4 wheel sensors , check them , they will throw the ESP out , periodic pain in the ... Mine does this , yet not constantly , just periodic, my mechanic lost hair on this cos 'no code ' for wheel sensors showed up
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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Sad to say it but MB Dealerships are by and large clueless, more so on the older tech Cars :(

Sounds to me like errant Wheel Speeds which is likely to be Reluctors or Speed Sensors themselves, and the erroneous readings fed to ESP will cut Engine power as ESP will think the Car is skidding ;)

HTH ;)
 

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2003 SLK320
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Discussion Starter · #7 ·
You have 4 wheel sensors , check them , they will throw the ESP out , periodic pain in the ... Mine does this , yet not constantly , just periodic, my mechanic lost hair on this cos 'no code ' for wheel sensors showed up
Thank-you. I will definitely pass this along to the fellow. About the same time (July) I had the shocks switched over to Bilstein B6s. Let me sing their praises! Is it possible that the mechanics nudged the sensors and threw off their ability to communicate?
 

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2003 SLK200K
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I had a similar problem with my 2003 SLK200 R170, esp light flashing and hesitation felt on the rear, then ABS BAS light came on. Problem was the os speed sensor, no gap between the sensor and the reluctor ring caused by a buildup of rust, dirt etc. Fitted a washer under the sensor to provide a gap and problem solved. This will only work if the reluctor ring is round and not oval.
 

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Discussion Starter · #9 ·
The two problems turned out to be unrelated. Fried spark plugs and wiring (just a few thousand miles old, but not MB quality) caused the stumbling, and a faulty left rear wheel speed sensor caused the hyper-active ESP light. Tech said that the M112 engines run notoriously hot, thus the need for MB-spec wiring (and perhaps plugs).
 

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The two problems turned out to be unrelated. Fried spark plugs and wiring (just a few thousand miles old, but not MB quality) caused the stumbling, and a faulty left rear wheel speed sensor caused the hyper-active ESP light. Tech said that the M112 engines run notoriously hot, thus the need for MB-spec wiring (and perhaps plugs).
Have you considered whether a V8 radiator would fit , that is if it has a fatter core than the V6 ?
 

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Discussion Starter · #11 ·
Never thought of that! But sounds like it would be more $ than the plugs and wires. I do wonder why all the heat; is it simply being trapped by the enormous engine cover, and the plastic shield underneath? Or is it being generated by the cats, so close to the engine? Or is it just normal for aluminum blocks to generate a lot of heat?
 

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1999 SLK230
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Thank-you. I will definitely pass this along to the fellow. About the same time (July) I had the shocks switched over to Bilstein B6s. Let me sing their praises! Is it possible that the mechanics nudged the sensors and threw off their ability to communicate?
So looking to update our old shocks, our r170 hit the bumps hard. We looked at Sachs, Bilstein, kyb, and gabriel shocks on all 4 corners. I am thinking anyone of these brand would do better than the 22 year old one's currently, thoughts?
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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Have you considered whether a V8 radiator would fit , that is if it has a fatter core than the V6 ?
It doesn't, but a good V6 R170 Radiator will cool a V8 when it is being thrashed un mercifully ..............
Tech said that the M112 engines run notoriously hot,
85 - 95 c is not hot for any Engine that has CAT's, they can happily reach 100c some days when Idling in a hot climate, but if the Cooling Fan and Radiator is all working fine they never burp Coolant or overheat ;)
 

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Discussion Starter · #14 ·
So looking to update our old shocks, our r170 hit the bumps hard. We looked at Sachs, Bilstein, kyb, and gabriel shocks on all 4 corners. I am thinking anyone of these brand would do better than the 22 year old one's currently, thoughts?
The Bilsteins (B6) give you a harsher ride than stock, but provide much more stability at high (70+ mph) speed and less body roll in any sort of corner. Less of a “floating mattress” feeling, overall, and much more precision to the driving. I also switched my air pressure in the tires to 33 front, 30 rear (the opposite of the recommendation) and this has all but eliminated the car’s understeer.
 

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Interesting, I might give that a whirl and see what comes of it. But new shocks are a definite replacement candidate for the car, seems like the previous owner just didn't have the means to do it right. Seems that happens with every german car I buy, just because you bought it cheap, doesn't mean is still not a luxury car with higher maintenance needs and requirements.

Thank for the quick response.
 

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Discussion Starter · #16 ·
85 - 95 c is not hot for any Engine that has CAT's, they can happily reach 100c some days when Idling in a hot climate, but if the Cooling Fan and Radiator is all working fine they never burp Coolant or overheat ;)
[/QUOTE]
LoL “Thrashed unmercifully…”. But I think the tech meant the engine in terms of the heat it throws into the engine bay. I am always amazed at how hot that airbox is after the shortest of trips. Want to drill air holes in it! Next summer hope to put on the shorter one from the sedan, with a larger throttle body, etc.
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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I have B6 on the V8 R170, together with suitable front springs and stock rear springs, optimised ride height via different thickness spring pads, Stabilus Steering Damper (stock) and it's running Uniroyal Rain Sport 255 /35 x 18 Rears with 235 / 40 x18 Fronts, at 32psi. The Car has also benefitted from all new Arms Bushes and Ball Joints.

Yes it is a bit firmer than 20 year old shocks etc etc but superb, it's like it's on rails at silly mph, like this Car hits 170 very easily in very short time, and I have had it sideways at 100mph with no dramas ;)

Drilling holes in the Airbox will simply Engineer out a bunch of HP ;) Yes the larger V6 S Class Air Box and a decent pipework through from behind the front grille works wonders ;)

@M4rCu5 has done that to his V6, he may have some pics ;)

Here is the 76mm Intakes on my V8 R170 ....

 
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Drilling holes in the Airbox will simply Engineer out a bunch of HP ;) Yes the larger V6 S Class Air Box and a decent pipework through from behind the front grille works wonders ;)

@M4rCu5 has done that to his V6, he may have some pics ;)
My take on that is that the slightly bigger airboxes from the S, E, ML, CLK Classes etc give a much improved air intake due to the 76mm intakes and circa 40% bigger filters, ideal if you're on a budget / don't want to spend the silly money (y)

But ALL of the N/A M112 and M113's will get hot because they all have that big slab plastic cover that sits directly above the Exhaust Manifolds. Hot air rises, straight onto the filter houses, it's not great for under bonnet air circulation or the AIT's. Just the way it is - for ALL of the N/A's 🤷‍♂️

Maybe heat shields under the airboxes would work?
Maybe bonnet vents?
Maybe wrapping the exhaust manifolds? (bit dubious on that one)
Maybe a combo of all 3? :cool:


Two links to consider:

SRT-6.com - Chrysler Crossfire SRT-6

NeedsWings Performance Products. Intake SLK320
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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AIT's. Just the way it is
But, The IAT's are kept down by the flow of outside ambient temp air when the vehicle is moving, so long as the Intake Tubes are present and intact ;)

Ex Manifolds are double skinned, ceramic coating is expensive but works really well, also improves Exhaust Flow as it keeps the EGT's up ;)

Bonnet Vents don't work well on many Cars, tends to encourage the Airflow to go upwards which exacerbates the Exhaust Heat rising, rather than the positive pressure down and out under the moving Car, not fitting the undershields makes matters worse too ...............

It's all about air pressure and direction ;)

Also a lot of Bonnet Vents mean stuff gets wet when it rains ;)

What does help, if you can find room, is some ducting from behind the lower grille to the upper Engine Bay just near the slam panel behind the headlamps each side, it will increase a positive pressure downwards and rearwards so it comes out past exhausts and bell-housing under the Car ;)
 
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