E320 Idle Issue
 

I got my 320 Back on the road, Runs Beautifully, however at idle, there's what I'd call a Lope, The rpms drop, then recover etc I was told my fuel Tubes were filthy which I'll clean them out, but should I look at more? I was thinking about doing a tuneup now that it's working again etc. Open to suggestions

MAF

or....ETA

how would I go about checking them?

Or the rubber elbow (crank vent tube or other) that comes off of the bottom of the intake, ... crack and leak.

M104 engine has a non-OBD2 code system. You can make a code reader following some of the info on the forum here. MAF sensor usually goes around 130K or so and eventually throws a code, although you may get spurious other codes too.
Don't worry about your EGR tube, that just causes you to fail CA emissions, and doesn't give you bad idle.

well, if it makes any difference, the head was just off... and it idled fine before that..

How's the wiring harness? The insulation crumbles off on the W124 engine harness. Maybe you disturbed it.

I used MAF cleaner,and idle is fine.

Wiring harness is ok. but it's getting replaced as its about the age to do it, But I'm thinking it's the MAF or something.. I dont think it's a wiring issue

crc maf cleaner is only about 6 bucks at the auto shops

where's the MAF so I can check it?

I should describe this a little better, when I start the car, the car runs fine, then as it warms up, the RPMS drop to 3-500 then revive to 1,000 and stay there for awhile, then repeat the process. I'll grab a video of it etc soon

back to the top.

181K miles on the original wire harness must be some kinda record. I replaced the harness on my '95 E320 about 4 years ago when it had 64K miles on it. I had all sorts of idle and perforance problems that only got worse as I changed plugs, cleaned the MAF etc. I opened the old harnes and the wire insulation was a dry powder. I consider myself lucky that a short circuit didn't damage any electronics or start a fire.

I'll worm a new harness into this thing soon. It's on my list of things. if I dont, this is gonna get a new engine. Diesel. Have not decided yet though...

Where is the MAF so I can clean the bugger.

The MAF is in the black intake tube just downstream of the air filter. You will need to disturb the wiring harness -see how that works?-to remove it from the car.

Oh fun, thats what that is.... i'll clean it, report back,

on a side note, is the sedan/coupe/Wagon harness the same one? I have one from a sedan and after a little reading there's some that say they are different

I b'lieve there is an early harness for engines with a ignition distributor and a later harness for engines without a distributor.

All of the E320s are distributorless, the 300E 2.8 and 300CE had the distributor M104 IIRC.

However, there was a wire harness change mid-year in '95, you can tell by VIN, I believe that the above ^^ sellers have the harness listed by VIN.

If you have the later-style belt tensioner (not the M103-style), you might also have the later harness. Best to check.

No Idea. I know I need a harness now... eesh.. touch one little thing and it all goes plotz. on a side note, I think I figured out some of the problem. On the front of the engine there's a round thing I assume has to do with timing, there was one of 2 wires that was almost completely sheared off, also the MAF is clean.

anyone care to tell me if I need an early or late harness WDBEA92E6RF288812

Looks like that VIN takes the early version (up to F302891), p/n 124-440-56-32.

The front of the engine thing is the cam timing adjustment mechanism. It should also have one or two vacuum hoses going to it. That reminds me that there is at least one vacuum hose that connect to the underside of the intake manifold and, and it is an acrobatic feat to make sure it is connected. Reach in from the front and snake your arm in.
The idle thing could also be a vacuum leak.

I know one of them is missing now too. weee. this should be fun

Red- Where does this connect to, and how. Pictures would be lovely (borrowed the pic from the wiki)

Yellow. Wires that broke now

It's been a while since I've had a 104, but I believe that connects to the EGR.

EGR is hooked up

final update, I got a new harness in. Idle issues and hesitation are gone. It was the control harness.

97 E320 WONT STAY ON
 

I HAVE A 97 E320 I JUST REPLACED THE UPSTREAM AND DOWN STREAM SENSORS FUEL FILTER AND AIR FILTER DID A OIL CHANGE AND TRANNY FLUID SCREEN CHANGE ON THE CAR TODAY IT JUST CUT OFF AND WILL NOT CRANK UNLESS I PRESS THE GAS PEDAL TO THE FLOOR BEFORE I TRY TO CRANK IT AND IT WILL CRANK OH ALSO I CHNAGED THE CAMSHAFT SENSOR ALSO ANYONE HAVE A IDEA ON WHAT THE ISSUE COULD BE AND WHY THE CAR WILL NOT STAY ON

WE WALK BY FAITH AND NOT BY SIGHT

Not sure if the 97's had the issue. what's your harness condition?

reply
 

the harness im not sure but i was tol it could be possibly the maf

thats also a possibility

OK ALSO THE ETS LIGHT CAME ON AND CHECK ENGINE LIGHT WAS OFF BUT ITS NOW BACK ON