300E / 3.OL - Engine Wiring Harness
 

I am upgrading my 1986 300E with a 3.0L engine. Just changed the fuel injectors & seals. Now comes the engine wiring harness... MB dealership told me that it should be changed due to it's age and for the engine not running smooth. My questions are... 1) Should I buy the wiring harness from MB? 2) Is it a long or hard job to change? 3) Once the harness has been changed are their anything to look for after changing it... like any adjustments? 4) The price from MB is $1230.00 - their sales leader gave me a break seeing I have been spending a ton with them over the past few weeks.

Thanks,
Bill

Pelo,

While your dealership might be good guys- they are generalizing later-model advice to an early model W124. The wiring harness problems came with a change in the wiring insulation w/ M104 engines I believe. I'm *not* familiar with generalized problems with a M013 engines.

You need to find the problem- throwing parts at it is expensive.
How many miles do you have on the car?
What have you replaced to cure the rough idle?

FYI- my dealership gave me wholesale for years... They don't use the matrix pricing either(may us dealerships charge MORE than factory suggested retail). There are a couple dealerships which will ship you parts at wholesale prices.

Michael

The engine wiring harness problem is confined to 93-95 model years. Your 86 should not have this problem.

Bill,
Your 86 dies nt have an engine wiring harness.
The later cars had electrically-fired injectors,
and this harness would decay.(same harness has plugs for temp sensors,etc.)

The harness on 86 cars has never caused us a problem.

I think your fault lies elsewhere.