Benz'ers,

I just finished replacement of the upper engine wiring harness and the ETA on my 1993 300e (3.2l). Now I am getting a large number of DTC's off of pin 8. Before I stopped checking, I read:

2, 3, 4, 5, 8, 9, 13, 16, 45, 46, (then I stopped, it's freezing outside).

It will start and idle, but only with the MAF disconnected. If I have the MAF connected it will start briefly but then either die right away or BARELY idle and stumble.

I replaced the harness with a used harness that was from a 1994, but the date code on the harness was 1999. The replacement wires are in great shape and passed a basic continuity test before I installed it. The installation went well, the only tricky part was the bit under the plastic front cover on the engine. I have giant hand but I managed.

Any thoughts or anyone solve a similar issue?

make sure all the connections are good from the MAF/ECU/upper harness

i remember my maf did that because the harness was dirty, but i checked my maf for continuity as well


hold button down for 8 seconds with engine off, accessory on and make sure you put your seat belts in.. (serious)
engine off,led light should flash once,the codes clear


if not unplug the negative for 45 mins

then try reading the codes again

please make sure you didn't mix up the wires for smog pump, and the cps

also, make sure your pump is starting if you have to bypass it via relay.. but you can kind of do a "preglow" turn the key to the one right before ignition, wait 5 - 10 seconds so your fuel pumps to the engine, and fire it up.

if you might need any parts, then i have a stock of m104 3.2 parts sitting in storage (i have a 1993 that i never fixed) hence brand new parts are sitting in storage
(i have tuneup parts)

also, please check your ETA cable and connections, it is right below the plenum, right under the CPS

try waiting 5 - 10 seconds, push the gas in and start the car.

btw check all the things the other guys told you on the other forum you posted in