Engine Harness blues

[Vetruck]

Had to finally bit the bullet and buy a damn $900 engine harness because mine is finally taking a shit. Nothing pisses me off more than finding out this piece of shit company Mercedes used this crap biodegradable wiring and never did a recall. I knew my days were numbered 4 years ago after replacing my throttle body for the same issue. It had a stumble intermittently about 3 months ago and has been idling rougher and rougher. Stumble went away thinking it was only spark plug wires (changed them and everything was fine- or at least I got lucky for a few months more). Car is acting up a lot that I had the Gf stop driving it last week. Harness should be here in a few more days. Until then it will sit and wait for repair.

BTW, in case anyone is curious- a 1994 C220. Best price I found on the harness was $843.01 through ECS tuning and free shipping.
https://www.ecstuning.com/b-genuine-mercedes-benz-parts/engine-wiring-harness/2025403832/

[Chisel86]

Do you know the span of years that have this issue? Mine is a '99. Should I start saving $$$?? Mine shows $1329!!

[John Jones Jr.]

Do you know the span of years that have this issue? Mine is a '99. Should I start saving $$$?? Mine shows $1329!!

No issues from around 1997 onwards. The really bad years here in Europe seem to be 1993/94/95 - usually W124/W202/W140's.

[John Jones Jr.]

Had to finally bit the bullet and buy a damn $900 engine harness because mine is finally taking a shit. Nothing pisses me off more than finding out this piece of shit company Mercedes used this crap biodegradable wiring and never did a recall. I knew my days were numbered 4 years ago after replacing my throttle body for the same issue. It had a stumble intermittently about 3 months ago and has been idling rougher and rougher. Stumble went away thinking it was only spark plug wires (changed them and everything was fine- or at least I got lucky for a few months more). Car is acting up a lot that I had the Gf stop driving it last week. Harness should be here in a few more days. Until then it will sit and wait for repair.

BTW, in case anyone is curious- a 1994 C220. Best price I found on the harness was $843.01 through ECS tuning and free shipping.
https://www.ecstuning.com/b-genuine-mercedes-benz-parts/engine-wiring-harness/2025403832/

Did you not know any auto elec shop that would build you a new loom? It's a common issue here in Europe and a lot of owner's use a specialist to build a new loom rather than buying off the shelf.

[Chisel86]

That's good to hear!

[Vetruck]

Did you not know any auto elec shop that would build you a new loom? It's a common issue here in Europe and a lot of owner's use a specialist to build a new loom rather than buying off the shelf.

I could build it myself but weighed the time it would take opposed to just buying it and figured it was close to a wash compared to what I make a day. Sometimes it's just not worth the hassle at my age...I am always busy.I even asked my NASCAR mechanic Larry if he would do it for he and his quote was hell no.(Larry smogs my cars for me and does little stuff here and there when I am lazy on my occasional off days). It it is not modifying a car, I don;t care to do routine maintinace crap like heater cores, water pumps etc. Done that too many times in life.

The bad years are 92-96

PS- funny thing is I don't even like doing oil changes on my street cars, yet last friday I replaced two complete rear ends on both race cars in about 4 hours at the race shop and was loaded up and heading to Vegas for a weekend race. The thought of changing this harness amongst all the crap in the engine bay of a street car? Im dreading it.

[Vetruck]

Okay guys I'm scratching my head on this one. Just finished replacing the engine harness and it's really not hard to do because everything is pretty simple when you disconnect one thing you plug it back in and it can really only go one way. The car was running before I took the old harness off. Now when I try to start it it cranks but once it starts to fire its like it's stopping the cylinders and it will not fire at all. It feels to me like the timing is off yet I have not touched anything do with timing. My guess possibly if I had a bad cam sensor that maybe with the old wiring loom was not activated properly. My guess now is with the new loom the cam sensor is activated and causing it not 2 time correctly

[Vetruck]

I just tried unplugging sensors one at a time and cranking it but no change. The timing is still off. I can definitely smell fuel but no start at all

[Vetruck]

Stepping away from this for an hour or two. I hope to hell this new harness was not built wrong. I've gone over the wiring 4 times now with the old harness then checking the new connections. Everything checks out. no start. Cranking but very very weak sort of firing or backfiring occasionally like something is off timing wise. Injectors are labeled 1,2,3,4 and are in order front to rear. Ive unplugged the cam sensor- tried to start, no change, plugged it back in. The same with MAF. Getting ready to spray some fuel into the TB in an hour and see if there is fire that way. Scratching head still.

What puzzles me is fuel and spark seem to be unrelated to the engine wiring harness other than the injector plugs and the few sensor plugs that relate to engine management function. Nothing can be adjusted wrong- just plug in things. Car was running prior so if something else is wrong it is completely coincidental.

[Vetruck]

This guy had the same exact problem I'm having to the letter.

Wondering what the coincidence is of "94 faulty wiring harnesses allowing a faulty CPS(crank positioning sensor) to run the car until a good harness is put into place then the CPS kills the engine function.

http://www.benzworld.org/forums/general-mercedes-benz/1734529-94-c220-new-engine-wiring-harness.html

[Chisel86]

That's pretty strange... Hope you get it sorted soon.

[Vetruck]

Thank you. I ordered a new cps that shipped today. Starting with that first.

[turbochris]

How did you go, did you figure out what the problem was?

[Vetruck]

Actually I have not touched this car for 2 months. I put it up on jackstands, pulled the starter and realized what a pain in the arse it is to get to this sensor....knowing I also need to put a transmission into this car (reverse is bad- forwards gears all fine though) so the wife and I went out the next morning and bought her a new Mini Cooper S to drive daily. I "re inherited" this car from her daily use back to just another play car. Currently acquiring all the parts for a 6sp manual swap so I pushed the car over to my other garage where it is awaiting a full tear down to fix a few oil leaks - one that appears to be coming from up near the head. Car will be down for a few months more but I am very certain it is this CPS that is the culprit. My original harness was in very bad shape after removing it and inspecting( cutting various sections of the looms open) Exposed wires everywhere. I traced the harness 4 times and everything was hooked up properly. Only sensor that made an effect/change in starting response was unplugging this CPS so I am very confident this is the problem. This is why I am moving on to do lots of other works while I tear into this car to replace this sensor. Might as well pull the trans to make life easier. full exhaust build (All ready have a JicCross catback system so I will build custom headers for it, port the heads, and a few other goodies/parts I have lying around (electric fan setup) I have 3 other cars plus race cars I mess around with so this is now a play car
3097

[turbochris]

Sounds good Vetruck

My C220 is also a hand me down - have just been in the process of fixing a blown headgasket when I discovered the crappy disintegrating wiring harness.

Interesting that you are considering mods - I'm an engineer and also have a few other cars and do some club motorsport. But this thing is so sluggish I think it would take a lot to generate any excitement hehe. I think a lot of the poor performance is due to the lazy transmission. I just want to get it going to be a reliable runaround car.

[Vetruck]

Sounds good Vetruck

My C220 is also a hand me down - have just been in the process of fixing a blown headgasket when I discovered the crappy disintegrating wiring harness.

Interesting that you are considering mods - I'm an engineer and also have a few other cars and do some club motorsport. But this thing is so sluggish I think it would take a lot to generate any excitement hehe. I think a lot of the poor performance is due to the lazy transmission. I just want to get it going to be a reliable runaround car.

Lol, Not really a hand me down. Its a car I bought from an older friend and started to build. During this few months my girlfriend/wife's car was totaled in an accident (2011 Toyota- 0% her fault) so I just told her to take that car as a daily driver. I just got it back after she purchased a new car. She used this car full time for about 4 years. It has a full Brabus body kit which is extremely rare. I have owned and or driven many many fast cars in my life, enough to know I like a simple well handling little engine car for daily street use that is mediocre fast and most importantly handles and stops very well. This car has plenty of power for street use, I am not racing anyone- if they think I am then they are an idiot and can meet me at the track with my racecars. I just like good solid reliable cars...albeit unique cars, but older, different, and modernized reliable. I do not like pulling up to a stop light in something that anyone else can buy that looks the same- hence her Mini CooperS. I have driven that once in the two months since she bought it- her car...chick car in my opinion, but she likes it and its a commuter that saves my other cars.

Why build it? Wouldn't waste my time on things unless I have to do maintenance. Since I have oil leaks and I need to pull this thing down? I always build my cars better at that point. I will not work on anything unless I "hot rod" it . Would rather pull and build a motor then simply replace a waterpump (boring and just same results as before)Its a motivating factor otherwise I hate working on these new cars(meaning modern computer cars. The truck you see next to the Merc is "Vetruck" (as in Corvette truck) It is a 155 mph top speed road race street truck that will carry 4000lb in the bed and run a 13.7 1/4 mile. it is extremely unique. I bought it new in 1989 and it ended up this way from stock parts breaking- I modify things to be more bullet proof once they break so I hopefully will never have to fix them again in a long time- In other words, I do things the correct/best way I possibly can.

I also have my old "68 Corvette racecar (stored elsewhere- full race car), just sold my motorhome, and what you do not see is my 1967 Cooper S that is sideways up in front of her new Mini cooper in that same right side garage with the S10 truck (yes 3 cars in a 2 car garage). I have been building the Vintage Mini with a mid engine 4cyl RWD Dodge neon motor that will be turbo charged when the build is complete.
Beside the NASCAR team(two trucks I am in charge of and manage a professional race team) I am very busy with cars in life besides my other hobby's.

My Mercedes is also just simply a run around car for days I want a car, not a truck. Yes I totally agree the trans is a joke in these things- hence why I am building the drivetrain. Like stated, might as well do a few other little goodies while in there.