1994 E320 Wagon - Several Electronic items
 

Greetings all,

Recently dove into the world of Benz with the purchase of a 1994 E320 Wagon (140K miles). I love the car but as a first time owner, I failed to adequately research the car prior to purchase. In spite of that, I feel I got a decent deal in spite of its problems.

I have been lurking for several months now and already tackled the Blower motor lubrication, and rewired the engine harness from scratch. I have other items yet to tackle but am trying to keep focused on getting the engine right first. I jumped into the Blower motor because I was freezing driving to work the 1st week of December.

I have the classic issues with the engine harness and after much research, obtaining the wiring diagrams, etc, tore into it over a Christmas vacation. I was mostly successfull. The 44 pin connector needs replacement (future junkyard acquisition) and I have several concerns on Polarity and some resistors.

Polarity first. The original harness had been partially modified (ignition and injector wires). I am concerned as to the proper polarity leading to the injectors. The wiring diagram shows a numbered post for the hot lead and the computer lead, but I cannot find a corresponding number on the plug. I used the numbering for all the other MB plug ends with great success but and skeptical for the injectors. I do have photos of the injector wiring before the replacement, however, that wiring was modified and do not trust it. Can anyone help me in the wiring arrangment for these injector plugs?

Resistors Second. I inspected the lead to the MAF sensor and found all the wires in the same state of decay. So I prompted noted my wire positions and began rewiring it. It was not till after I completed the job for the entire car that I noted there are two resistors in the plug leading to the MAF. The first resistor is on the #1 lead (i assume hot) on the MAF plug which connects to Pin 5 on the 44 pin connector behind the battery. The second resistor is at the end of this resistor and ties # 1 lead with #4 lead (ground wire) of the MAF plug (look at the inside of the plug for the numbers) Can any tell me the resistances of these? I hope to put in a small pcb with the resistors to fix my mistake.

Any help is appreciated

Brian

1994 E320 Wagon with some warts

I highly recommend a new harness if you have any plans on keeping that chassis for long term...patching a harness is a never ending process and if the right shorts start popping ECU circuitries, you will be in Hell,never mind the $$$$$$$$ you will cost yourself in the long run.
These harness were made with bio-degradable insulation and they will degrade with time, no matter what you do short of replacement to the new, modified harness.
I am starting to see these newer style harness pop up on ebay from time to time b/c junkers are aware when they have a partser come in if it has the up-graded harness already done ..they know there is a market for such and I see them in the $100 backet there...worth a check and inquire to the lister to see if they know for sure. [ in the event you do not want to go for a new one..they are not cheap]..

has the W210 also this issue?

Thanks for the reply Tex,

I was aware of the insulation issue and that was my reason for focusing on it first. My intention is to eventually replace the rebuilt harness. However, at this time funds are not available for the $900 item.

The rest of the wiring (leaving only a .5" stub to solder into the 44 pin connector) I triple checked for continuity and the proper pin locations on both ends of the harness. So except for the very short stub, the insulation is gone.

<<Thanks for the reply Tex,>>


You are Welcome..................

are the new wiring harnesses for the W124 made out of the SAME bio-degradable material as the original harness as my car in 1995, or M-B finally figured it out and opted for a more robust material?

The up-graded harness has solved the problem.
It was not just Benz..it was the harness supplier...Jag had the same problems.
Same goes for your original OVP relay..the replacement part solved the original faulty ones ..in that case , they changed to another manufacturer.
[ along with a new part #]

Both these parts should be changed on these chassis b/c both will cause a
" WHEN , not IF " failure condition.............

Back to original question
 

Anyone able to tell me the Ohms between Lead 1 and 4 on the MAF plug for the 1994 E320?

Also on the injectors. My hot lead is currently tapped into the forward most lead of the fuel injector. Do I have this right? Its that way now and I have been driving a week with no issues - Just trying to make sure.


Thanks in advance.

Brian

1994 E320 with warts

Partial answer
 

Injector Plug arrangements

Ordered replacement connectors and unlike the ones with the original wiring I had, the bosch replacements have numbered terminals corresponding to the schematics. Common hot lead is the terminal closest to windshield.

MAF Resistors in wiring

In an email to Bob weir regarding this issue, the thought that the resistors might be inside the the MAF side of the plug came to mind. SO this weekend, I will check MAF terminals 1-4 to see if there is continuity (hot to ground via resistor). That might explain why I see no problems to date with the idle now that the ETA is rewired.