My car is going to my mechanic tomorrow due a rough idle and hard starting (yes, it is a 86 300E). I took it there a couple of weeks ago a he recommended to change the fuel injectors, after doing a few tests, including a compression test, which was high? around 180 across the board. I did get new brass injectors. The problem continues...Last night I did the water on the plug wires test and I saw "some" sparks before and after the water including the ignition coil. The fuel pump is noisy also. My question is: am I suppose to see ANY sparks? Wires are bosch and about 2-3 years old. I will do the resistance test later on tonigh but, I would like to have some ammunition tomorrow for the mechanic. I do not want to change all the parts in my car to find a problem...
Sorry for the lenght of this note but I though it was necessary. If this time it does not work I will make an appointment with Steve in Gainesville, Fl.
Thank you!

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J.H.
'86 300E

The Bosch wires are not as good as the OE ones. You should see NO sparks, if you do, there is an electrical leak.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Greetings,

Seeing as this problem is predominant with this year and model Benz, did you ever solve your problem. What parts did you end up changing out during your troubleshooting, and which one finally fixed your rough idle?

Thanks,

Charles

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"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Who is the OE manufacturer of MB spark plug wires? What is the best/ recommended manufacturer of plug wires for W126 cars, namely a 1989 420?

Thanks,

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1989 420 SEL

Thats a good question I assumed that Bosch was OE.
The wires on my 86 Euro SE are copper core and they look pretty old I know you can buy rolls of high quality copper core spark plug wire at speed shops to build your own.......
William Rogers.......

You could try Magnecor.com . They pride themselves as being specialists in this field. Their website has good info and competitive pricing for nearly every car.

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95 E320 Cabriolet, 159K

Best wires I've ever had.........on my truck.
Have not tried them on my M-B, but will, when the time comes.

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2007 C 230 Sport.

the noisy fuel pump could be due to a blocked fuel filter.

if you have replaced it ,then the next step would be a new fuel pump-i fitted a bosch one from the dealer and all the hissing/buzzing noise disappeared on my car.


just my experience on the 190e car