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Throttle actuator rewire

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7.7K views 4 replies 3 participants last post by  davidwozei  
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#1 ·
I got tired of the hesitation on acceleration sometimes so finally decided to tackle the throttle actuator. I should have done it when I redid the engine/trans wiring harness last winter, but I didn't realize that this deteriorated too.
The throttle actuator comes out very easily. Take the air intake off, then the intake air splitter valve. Then the rubber intake tube, 4 allen head screws, remove the connector to the throttle linkage and it will come off.
The more I dug in, the more I was amazed that the car ran. I was trying to check continuity between the pin ands and the circuit board end and just stopped because they were all shorted together! I soldered in new wire and got it all wrapped up last night. Only thing left to do is use some silicone sealer at the throttle body hole and then put it back on and test.
I have all the old wires and was seriously thinking about sending them to Mercedes. I am impressed that the car ran with the deteriorated engine harness and throttle actuator harness. Mercedes must have done a lot of research on the control units to deal with intermittent shorts and bad values. Start to finish was about 5 hours for the rewiring part
 

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#2 ·
Finally got to put the rebuilt throttle actuator on. Everything seems to work a lot better now. There is a slight hesitation every once in awhile, but I think that's being caused by something else. I did the head gasket over the winter and replaced the valve cover gasket and the spark plug gaskets, but I noticed there was oil around the spark plugs when checked this evening. It's either because the spark plugs were not tight enough or the round seals just didn't seat right.
IT is nice to know that I have good wiring in the throttle actuator and I didn't have to pay Mercedes $1200-$1600 for a new throttle actuator because Hans and Franz used shitty insulation. I saved the wiring I took out and am going to send it to Mercedes with some pictures of my wiring harness too.
I still give a lot of credit to MErcedes for making control units which can deal with all the short circuits in that era of cars. The really troublesome part is that I don't know what era of Mercedes to look at next. After reading "Taken for a Ride" (great read btw), I think it would be wise to avoid the era when they "merged" with Chrysler. I almost tend to think that it's better to get something earlier and just restore the parts that wear instead of dealing with all of the newer electronic stuff that will break and will cost significant $$$ to repair/replace. If this wiring insulation is any kind of indicator, by the time anyone figures out there are major problems, the models will have moved on and noone will care.
 
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#3 ·
The car runs so much better now. I cleaned up the spark plug holes and made sure I torqued the spark plugs to spec (15-22 ft lbs.). I think I was not torquing the aprak plugs to the proper torque. I usually go finger tight + 1/4 turn. 15/22 ft. lbs is way more than that. I'll check in a week or so and see if any oil comes back.
Will send the old actuator wires to MErcedes next week. I'm curious to see if I get any response.
 
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