francisco steve

My 95 E420 sters fine but after 5 to 10 mins it stars to run like its only firing on two cylinders? I assume its a sensor of some kind but where? Thanks for the help

komik

Hi,
There is no simple solution to your problem since it could have been caused by l many things. Believe me I have same problem and still have I have not solved it out completely. Here are first things I would check.
1: oxygen sensor
2. coolant temperature sensor (there is bunch of them you need to check one which ECU uses to get temperature)
3. check all rubber parts which have to do something with the air intake, also check vacuum lines
4. Everybody is going to throw at you to check OVP, many people on this forum think it is some kind of magic cure to replace this thing, well check it anyway, check the fuse on the top of it
Vlado

hartj

the ovp is only a magic cure if its the original one that came with the car. the was a design flaw in the original that cause's it to deteriorate( mb has a new one with upgraded design). this aslo only really apllies if you car wont start.(spark but no fuel, and is aonly the first place you should look). also i don't know if the v8 had a problem with ovp just the sixes i believe (i could be wrong).
with that said with an e420 the first thing i would check would be the 2x wiring harnes, upper and lower.

francisco steve

I am not a mechanic and I lost the job I had that would afford me taking this to one. I can wrench and I am not a total idiot so I am seeing if this can be repaired by me first. I am asking for more precise info on the upper and lower wiring harness,what am I looking for and so on. Your help is greatly appreciated believe me.
Thanks again
Steve

hartj

look at the condition of the wire insulation. the heat from the motor causes the insulation to deteriate faster than mb had anticapated. the wrotten insulation lets the wires inside touch other wires and causes shorts that will give you all kinds of headeaches if not replaced. as for the two harness i am not sure how they are routed(my car is a m104 inline six, and as such has only one harness). other members will need to chime in as i bought my car with the harness already replaced.

ebennz

francisco steve

welcome.

your wiring harness' are fried...

use the "search" feature-plenty of info. also go to mercedesshop.com and do a "search"

have you had it professionally tuned and the maint brought up to date?

how old are spark plugs and fuel filters?

Makahveli

How do you get the OVP out? Just grab the thing and pull up or shimmy it side to side?