Wiring harness suspect on 400E? - PeachParts Mercedes-Benz Forum

amg280 · #1 06-09-2002, 03:25 AM

After reading many posts about bad wiring harness woes on the M104, was there any known issues on the M119 motors, specifically a 92 400E. Mine has some trouble starting (sometimes) when its warm, it cranks over a while before it starts. Another weird thing it does is when under full acceleration, a few seconds after it shifts into second gear, it will hesitate about twice, like someone is turning the ignition switch on and off.

The car only has 111,000 miles, under the 125,000 miles specified in this group for the harness. Could my wiring harness be suspect? If not, what could be? Should I clean any sensors? Should I even be worried?

Thanks to all that respond.

#2 06-09-2002, 01:32 PM

Yes, the M119's are affected with the poor grade engine wiring as well. What you need to do is remove the airbox and take a look around at some of the wiring, be gentle with the wiring you find.

Take a look at the insultation, usually it start to crumble to the touch leading to shorts, grounds, and generally false signals creating some of the conditions you mentioned.

If this is the case, you may be able to have a Dealer perform the replacement, but I believe it is up to the Dealer to say yes or no.

amg280 · #3 06-09-2002, 08:53 PM

I took the air cleaner housing off, and inspected some wires but didnt see really anything stick out. What exactly am I looking for? On the passenger side there is a big harness that goes to the computer in the firewall. Is that the harness that goes bad? It sprouts out all the little sensor wires and EFI wires too. They dont look bad, Do I have to cut open the insulation and peek in it? Where exactly do they go bad? Seems like where they are clamped down on the pass. cam cover mabye a potential spot. Let me know, I dont want to get stuck fronting this bill if I dont have to.

Thanks to all,

Andy

euro 287 · #4 06-09-2002, 09:39 PM

Remember not only the engine harness is a problem. The throttle valve harness on most mercedes produced from 92-95 are also bad. If you cut a small slit in the harness and look you will see the wires except for the black ones totally bare and touching every once and a while.

TimFreeh · #5 06-09-2002, 09:40 PM

My 1993 400e had a bad engine harness. I replaced it a couple of months ago. You should check the harness - I would say there is a good chance you have a problem.