Mercedes-Benz Forum banner
1 - 6 of 6 Posts

·
BenzWorld W140 Host
W140 S 320 L & R129 500SL
Joined
·
1,918 Posts
Discussion Starter · #1 ·
Hello,

I need your opinion on this one. The SL started fine & went to the petrol station to fill her up & from there went to a restaurant.

15 Mins at the restaurant- I went back to the car
The problem
1) Engine shaking & sounded like a motor boat( RPM goes up & down violently)- I panicked & turn it off & restart the car- Same thing- Engine shaking sounded like a motor boat &
I just shift the gear to "R" the battery light come on & the car engines automatically shut off. I start it again & do the same- I move forward a bit "D" & Try to engage the "R" the engine shut off- Battery light comes on.

So I call my dad for help & waited for 15 minutes. We start the car again- Engine shakes a little & Try to engage to "R" bits of shaking & shift the gear to "D" the car is back to stable.

The car performs "OK"- No shaking, RPM is stable- Looks like nothing is happen.

So my dad & I test the car one hour later- The car starts fine with no problem. Car goes smoothly.

Cliff- Engine shaking + Sounded like a motor boat+ RPM goes high up & down + Battery light & car shut off. After 15 mins- Started Car: Engine a bit unstable but it didn't shut off & goes OK. Everything is fine after that.

Any Ideas?

I'm bring to a tech tomorrow to check & also will ask them to install the EHA valve that I ordered few weeks back.
 

·
Registered
1991 500SL - 162,000 miles, 1972 Camaro - 88,000 miles
Joined
·
6 Posts
Zeag: I'm chasing a similar problem as you what you described in this post. Sometimes the engine runs perfectly, then suddenly it is nearly impossible to start and it runs terribly when it does finally start. Did replacing the distributor cap rotors actually solve the problem for you? Thanks.
 

·
BenzWorld W140 Host
W140 S 320 L & R129 500SL
Joined
·
1,918 Posts
Discussion Starter · #4 ·
Hello,

Yes- The mechanic said the crack on the Cap allow moisture in & form some green fungus inside the cap that causes the car to perform like this. It does't happen often because once the moisture in the cap dry up- The car performs normally.

So changing the distributor Cap, Rotor did solve the problem for me. But ck other thing first like spark plugs etc..
 

·
Registered
1995 SL320 Roadster
Joined
·
34 Posts
I know that you solved your problem already but I would like to note that you said you filled it up with petrol right before you had the problem. The same exact thing happened to me. But it turns out that it was the gas that was causing the engine to become unstable and the battery lights to flicker on and off. Did you get your petrol from a reputable company? I didn't when my problem occurred as it turns out that the place I got petrol from diluted it with water. Mercedes engines don't like that. My car had the same symptoms as yours. Where it was unstable but after a while it would run smoothly. I ended up having to get about 15 gallons of Shell petrol to flush out the 3rd rate gas i had gotten in order to get the car to run normally.
 

·
BenzWorld W140 Host
W140 S 320 L & R129 500SL
Joined
·
1,918 Posts
Discussion Starter · #6 ·
I know that you solved your problem already but I would like to note that you said you filled it up with petrol right before you had the problem. The same exact thing happened to me. But it turns out that it was the gas that was causing the engine to become unstable and the battery lights to flicker on and off. Did you get your petrol from a reputable company? I didn't when my problem occurred as it turns out that the place I got petrol from diluted it with water. Mercedes engines don't like that. My car had the same symptoms as yours. Where it was unstable but after a while it would run smoothly. I ended up having to get about 15 gallons of Shell petrol to flush out the 3rd rate gas i had gotten in order to get the car to run normally.
Over here in brunei- There's no choice- Only shell petrol station are available. So i'm not too sure if the quality of the petrol is good or not- Lots of Euro cars owner here complain of hard start here- Dealer will put in Fuel cleaner & usually solve the problem. I remember our S class suddenly stalled when driving. So we were stuck on the highway- Called the 24 hrs Mercedes recovery team-& they came. When they ck why- They just took a bottle of fuel cleaner from their van & put it into our S class- After few attempts starting- The car runs perfectly fine. They claim the quality of fuel here is "not very clean" . The Mercedes dealer here recommends me to put fuel cleaner every few months. I did it for the first few months but got lazy :D So far it run OK...

As for the SL- before the Distributor cap & rotor change- What i notice is: If the car left untouch for few days(3 days)-I Will face this problem in the morning as stated in my first post. But if I use it everyday- The car will run fine.
When I bring to the mechanic to ck- They suspect the dist cap. ; when they ck it- It's has a small crack & found green fungus inside the cap which explains why I have the problem.

So I just change it for a peace of mind.
 
1 - 6 of 6 Posts
Top