Mercedes-Benz Forum banner

1 - 16 of 16 Posts

·
Registered
99 SL500
Joined
·
122 Posts
Discussion Starter #1
MY99 SL500 starts on a dime, idles steady, runs perfectly, yet shakes/shudders like she has a cold when stopped. When in Neutral / Park, she 'shudders' (2-3 strong jerks/vibrations) every 3-5 seconds regardless of rpm, but this is felt more strongly below 750rpm. In Drive it is still felt, but MUCH less / barely noticeable.

I've searched multiple forums and the closest I've found is here: Need help 99 SL acting up - PeachParts Mercedes ShopForum
(I tried PMing the original poster but no reply)

I'm having the same experience at mentioned in that thread. I've replaced spark plugs and wires, resistance-tested the coil packs, thoroughly cleaned air filter assembly, MAF and elbow, and the throttle body. The engine mounts have been replaced, and the 'adaptations(?)' have been reset by an indy. No codes register on the computer, and each cylinder test shows no misfire when connected to the computer. I've also have run a tank through with Chevron Techron added to it. All of these actions listed have made NO CHANGE to the problem.

Any input is greatly appreciated, for this is driving me crazy!

TIA
 

·
Registered
1997 SL500
Joined
·
398 Posts
Double check your engine and tranny mounts, that is what it sounds like to me.
 

·
Registered
'01-E320 & 02-ST2
Joined
·
31,633 Posts
You didn't mention your injectors or your fuel filter or the transmission mount (noted by catterman).

That said it could also be carbon buildup in the combustion chamber, lazy O2 sensors (how many miles?) or a partially blocked cat, so those are some additional items to consider.

Take care and enjoy the ride,
Greg
 

·
Registered
1999 500sl sport - 2001 e430 4matic - 2000 bmw 528i sport - 1966 corvette
Joined
·
93 Posts
My wifes 1999 500sl had to have a new harmonic balancer installed by Benz, some sort of recall, no charge even though way out of warranty. I would call Benz dealer with vin # to determine if under recall.:)
 

·
Registered
SUPERCHARGED Silver Arrow
Joined
·
2,126 Posts
I agree with gregs210.
Check your injectors and possibly even your 02 sensors.
It sounds to me like an injector or two might be partially clogged.
 

·
Banned
Y2K SL500 Silver
Joined
·
8,660 Posts
I agree with gregs210.
Check your injectors and possibly even your 02 sensors.
It sounds to me like an injector or two might be partially clogged.
All the more reason to be running Chevron gas w/ Techron most of the time.
I have heard more than a handful of M-B Technicians suggest this gasoline.
 

·
Banned
Y2K SL500 Silver
Joined
·
8,660 Posts
MY99 SL500 starts on a dime, idles steady, runs perfectly, yet shakes/shudders like she has a cold when stopped. When in Neutral / Park, she 'shudders' (2-3 strong jerks/vibrations) every 3-5 seconds regardless of rpm, but this is felt more strongly below 750rpm. In Drive it is still felt, but MUCH less / barely noticeable.

I'm having the same experience at mentioned in that thread. I've replaced spark plugs and wires, resistance-tested the coil packs, thoroughly cleaned air filter assembly, MAF and elbow, and the throttle body. The engine mounts have been replaced, and the 'adaptations(?)' have been reset by an indy. No codes register on the computer, and each cylinder test shows no misfire when connected to the computer. I've also have run a tank through with Chevron Techron added to it. All of these actions listed have made NO CHANGE to the problem.

Any input is greatly appreciated, for this is driving me crazy!

TIA
Tia, FWIW please consider the following line items that might be the answer to your problem. And if one of these seems of interest try digging deeper through an Advanced Forum Search.

Check Overvoltage Protection Relay(OVP)
Check Crankshaft Position Sensor(CPS) for MY99-02 should be p/n 0031532828
 

·
Registered
MB SL600, MB 380SE, Suzuki Grand Vitara, 38' Chris-Craft, Volvo V70XC, and my own two feet...
Joined
·
4,131 Posts
Double check your engine and tranny mounts, that is what it sounds like to me.
+1 on the engine/tranny mount situation.

What you're describing sounds exactly like you have a bad mount. Although you said you replaced the motor mounts, what about the tranny mounts? Also, have the motor mounts double-checked, you could have gotten a defective one.

How many miles are on this car?
 

·
Registered
Joined
·
15 Posts
Mine did the same, but evened out after a few seconds. I did have a bad oil leak on the oil pressure switch, but ever since I repaired it, seems to have gone away. Seems MB engines are more electrics than vacuum hoses (from what I see)
What you can do to see if the mounts are bad is open the hood, put it in drive and give it a little gas (you should be able to peek inbetween the hood to see if the motor rises. Also look toward your shifter and notice any movement. When a mount is bad, it is very noticeable.
 

·
Registered
00 SL500 SOLD, 05 SL600 Sport, 09 Silverado 4x4 LTZ,SOLD '15Silverado LTZ 6.2 8Speed John Deere 318
Joined
·
1,781 Posts
How many miles are on the car??? The first thing I would change is the Crankshaft Position Sensor!!! If there is NO code in the car, its going to be a little tough to figure out. Were all of the parts changed, replaced with TOP QUALITY parts?
 

·
Registered
99 SL500
Joined
·
122 Posts
Discussion Starter #11
To add a little more info...

The motor mounts are new, genuine MB - but the trans mount needs to be inspected (I don't think its ever been replaced). The crankshaft position sensor has been replaced, and the harmonic balancer inspected.

The fuel filter may have been replaced (I say may because I have invoices from the PO stating work done that I later discovered wasn't done)

The car has 70K on the clock but has only been driven 6K in the last 3 years. I've searched everywhere and the general consensus I've been hearing is fuel / injector related, for fuel seems to be notorious for creating problems without throwing any codes, and the fact that its been sitting a lot over the last few years. I found a guy on ebay who does ultrasonic injector cleaning for $80, and was planning on sending mine in as the next step of diagnosis, along with swapping out the fuel filter at that time.

(lynns - TIA = Thanks In Advance)
 

·
Registered
MB SL600, MB 380SE, Suzuki Grand Vitara, 38' Chris-Craft, Volvo V70XC, and my own two feet...
Joined
·
4,131 Posts
To add a little more info...

The motor mounts are new, genuine MB - but the trans mount needs to be inspected (I don't think its ever been replaced). The crankshaft position sensor has been replaced, and the harmonic balancer inspected.

The fuel filter may have been replaced (I say may because I have invoices from the PO stating work done that I later discovered wasn't done)

The car has 70K on the clock but has only been driven 6K in the last 3 years. I've searched everywhere and the general consensus I've been hearing is fuel / injector related, for fuel seems to be notorious for creating problems without throwing any codes, and the fact that its been sitting a lot over the last few years. I found a guy on ebay who does ultrasonic injector cleaning for $80, and was planning on sending mine in as the next step of diagnosis, along with swapping out the fuel filter at that time.

(lynns - TIA = Thanks In Advance)
I doubt your injectors are shot with 70k on the clock. They usually last 100k or more.
 

·
Banned
Y2K SL500 Silver
Joined
·
8,660 Posts
The car has 70K on the clock but has only been driven 6K in the last 3 years. I've searched everywhere and the general consensus I've been hearing is fuel / injector related, for fuel seems to be notorious for creating problems without throwing any codes, and the fact that its been sitting a lot over the last few years.

I found a guy on ebay who does ultrasonic injector cleaning for $80, and was planning on sending mine in as the next step of diagnosis, along with swapping out the fuel filter at that time.
Well TIA anyway for joining us this Saturday! You can talk to several of the guys about your car at that time.

Yes, it's my understanding that gas can go bad and the best way to store a car is to fill the gas to the top and throw an additive in the tank. I guess you should be glad that the car didn't pick up a tire flat spots in any one or all of the tires as well.

I personally don't believe in one bottle of the Techron additive. I think you should start running your car on nothing but Chevron w/ Techron. Especially after you get your problem solved. And I can't wait to hear more about the $80.00 ultrasonic injector cleaning.

I just replaced my fuel filter after buying a Bosch 71058 from Auto Parts at AutohausAZ - OEM Auto Parts for about $33.27 plus the INDY labor. (The Flexible Service System -FSS calls out for a new filter every 4 years or 60K miles.) This DIY can be a little messy unless you have the right temp. hose clamps for the gas lines in order to remove the OE hose clamps. After that it's easy to put it back together but you will need at least 4 small hose clamps because the OE factory clamps get thrown away.

This is an example of where my Indy already had the car up while replacing my rear pads, I had him R&R the fuel filter, torque the 3 bolts holding the sterring box.
 

·
Registered
1991 500SL
Joined
·
140 Posts
Is it possible that the key here is that it "has only been driven 6K in the last 3 years". If it has had a lot of sitting time, I'm thinking it may have had stagnant fuel at times, leaving gum deposits throughout the fuel system, which could include the injectors. Also, possibly some condensation causing water to foul the fuel filter, etc. Twenty bucks will get you a good quality fuel system conditioner and drier such as a BG kit, and if you are unsure that it has been done, less than $50 would change the fuel filter with an OEM filter if you install it yourself. Mine has ran a lot better at idle since the fuel treatment. I was at about 66K miles. It may be a fairly easy and inexpensive place to start?
 

·
Registered
Joined
·
21 Posts
i had the same problem with my 1999 sl. the car had very very low mileage in five years use. took on a trip 16oo miles each way and used injector cleaner JECTRON and the car is fine now. i would give this a try.
 

·
Registered
'01 R129 SL500 & '08 W204 C300
Joined
·
94 Posts
In the last two years prior to purchasing my '01 SL 500 I test drove 3-4 Different SL 500's all '98+. One car the (Worst) of all tested had 71K obvious body work and a well worn interior but was cheap. I passed on this car for two reasons, A/C didn't work, had really noticeable "bounce" from the motor at start/up and warm idle and didn't quit doing it after a spirited 20 minute test drive. Also that car was slow to down-shift and accelerate for some reason??? The other cars I drove all had a similar "bounce" after cold-start and cold-warm idle but were smooth as glass after a quick drive. My pristine one owner 40K mile '01 Has a soft "bounce" following ever cold start, but once the engine warms up and you drive off it completely goes away until you start it up again cold from sitting over night. My car had a lot rougher idle though after I bought it (used) from my local MB retailer. I suspect they filled the empty tank with 87 octane fuel. The car ran like a new car after I completely went through that tank and filled up with 91 octane + a qt of Chevron Techron "Concentrate" there is a difference from the regular Techron bottle. Still have a soft bounce at idle but it's not nearly as bad as when I brought the car home from the dealer, also my acceleration is now explosive and not sluggish like it was. Also I think the "Bouncy" idle is an MB inherent characteristic, My wife's 2008 C300 V6 does the exact same thing every cold start and is smooth as glass after the temps come up and a quick drive.
 
1 - 16 of 16 Posts
Top