Hello,
I am new to this site and from what I've seen, looks pretty COOL.

I have a 1993 500 SL with 60,000 miles on it. At idle when in gear, ie stop light, the car has a intermitten skip or stumble. Once off idle, the car runs fine. I've had it to the dealership here in Atlanta (RBM) and an independent shop, and both of their suggestions was to run fuel injector cleaner through it. This helps a little, but does not cure the problem and once the fuel with the cleaner in it is gone, the car continues to idle rough.

Any sugestions, anyone?

Thank you for your time.
Robert Tanner

Welcome to the BEST MB support site in the internet.
I am not familiar with your car, but I am sure you will get responses with potential solutions soon.
I will suggest you do a search in the meantime, it will be very helpful.

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Thank you,

Robert

Try a 20oz bottle of Techron added to a half tank of fuel. That cured a similar problem with my M104. YMMV.

__________________
2002 500SL(Black/Black)
1992 300SE(Black/Black)
1992 190E 2.3(White/Navy)
1999 VW Jetta TDI(Pearl Green)
1986 SAAB 900 Base 3 door(White)
1983 Porsche 911SC(Chiffon)
1977 VW Scirocco(DiamondSilver)

Robert,

Welcome to the site. My 92 did much the same except upon accelleration it would skip for a couple of seconds as I started off. In my case it turned out to be a fuel injector. MINE WAS INTERMITTENT and the problem would go away while they were working on it...

My shop was patient and persistent in tracking down the problem and I highly recommend them. There is a thread here somewhere as I fought this and an intermittent ASR issue simultaneously over a period of time. If you are a DIY person you might just get a whole set of injectors and just change them all.

I think it took 2 or perhaps 3 tries to get the right one for me. In defence of the shop, remember it was intermittent. Try MBS Motors on Peasant Hill in Duluth.

Stan

__________________
02 S500
92 500SL
92 400E (Sold)
87 300E (Sold)
83 300D Turbo (Sold)
75 300D (Sold)
74 240D (Sold after 20 years)

speace,
That was kind of my thought as RBM said to try the injector cleaner "before" they start replacing injectors. I also thought it might be a bad plug wire that was giving insufficient spark at idle. Not sure where MBS is, but I'm somewhat familiar with Duluth. The independant shop that I carried the car to is Cummins Automotive on McFarland in north Alpharetta. I have not stuck my fingers into this car as I am better at simple engines like the ones in my boat, 622 cu. in., super charged, 950 hp. All this electronic stuff has so many areas for failure. Thanks for the advice. I like the blue color also. Mine is all white.

Robert

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If you wantto do a fuel injection cleaning, I have heard that this product is supposed to be top notch:

http://www.autobahnpower.com/products.asp?recnumber=92


Here it is from their homepage:
http://www.bgprod.com/bgprofessional/bgproducts/autofuel.html

__________________
1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz

lino,
That's the stuff the dealership gave me to try last year when I was going on a trip. I ran two cans back to back and it seemed to help a little, but once I got in stop and go traffic, the problem would reoccurr. I not beating on the dealership or the shop that worked on the car, I was trying to give some history on what I had already tried. I still use the same people to service the car when needed.

Is there a way to remove the fuel injector and test it, or is it hit and miss by just changing them. Thanks for the responses.

Robert

Robert,

Not officially being a mechanic, I'm not aware of a bench test for an injector. I think they could test the spray patterns for the old diesels I had.

I think your 93 will be like my 92 injection system with the individual fuel lines and the fuel distributor. The newer models went to electronic injectors and a fuel rail. I hear the electronic injectors are a good bit more expensive than the mechanical ones.

What my shop did as a test was to 'crack' the fuel lines loose one at a time at the fuel distributor to see which one had the least negative effect. That one would be the one that was already skipping...

I tried the Techron early on at the advice of my shop to no avail. I've never had a fuel additive to have a long-term positive effect on any of my cars, so I wouldn't hold much hope for it fixing the problem. It is a simple thing to try if you feel like investing in the stuff.

__________________
02 S500
92 500SL
92 400E (Sold)
87 300E (Sold)
83 300D Turbo (Sold)
75 300D (Sold)
74 240D (Sold after 20 years)

Robert, like you I found this site a great help and spent DAYS going thruogh it after spending over eight months & £2k trying to get my 93 sl300 going. Its a long story but mine would stumble all over the place and would'nt really follow a patton except when the engine was really hot or it was hot and raining.
My mech worked through every thing & and changed loads, it would run perfectly then get worse. I was driven to distraction and nearly bankrupted by the bills. I finally found out MYSELF and I really don't have a clue it was the plastic plate Behind the rotor arm. It had a small nick on the top of it and let all the damp air in and sent the cap green on the contacts.
£45.00 was all it cost to do!!!

I had a similiar problem with my 91...you may want to check the resistor ends on the end of the spark plug wires. They can be tested with an ohm meter.