'00 ML320 Engine Control Unit / Hesitation
 

Hello everyone,

I've done quite a bit of reading on the board about this issue. I have the exact same problems that have been described here before. (Cold engine will hesitate as you pull away from a stop sign and stumble for a few seconds, but never stall) My MAF has been replaced, my plugs have been changed, my O2 sensors have been changed, updated fuel pump, no crank position sensor problems. Car starts up cold every time without question, just be careful pulling into traffic and needing to go faster than 10mph. The only Check Engine Code it's given me is a misfire on cylinder 1.

I've explained the post Gilly made referencing a bulletin for that engine in the E class getting a ME update. My service technician looked at me like I was speaking a different language so I went to the MB Master Tech and told him. He didn't think the update applied to the ML320 and suggested it's a transmission problem. I know good and well it's not a transmission problem when the engine is running rough, misfiring and not turning any RPM's.

Can anyone please point me in a direction I can relay to my dealer to identify this problem? Gilly do you know more specifics on the bulletin/info for the ML? I've complained about this problem since I bought the truck from the dealer. Hopefully if there is a fix MB will help me out since I was under the 80,000 mile emission warranty when I first documented this problem.

2000 ML320
106,000 Miles

Thanks everyone.

Matthew

Check your plug wires. They should have their resistance value stamped on them.

I had almost the same problem before, to the extent the truck stalled once. The dealer replaced an ignition module and 2 wires attached to it and cured the problem.

Will check.
 

Q & ML320Truck,

I'll check all the wires and replace the ignition module for cylinder 1 since thats the hole I've had throw a check engine light.

It would be nice if it was just that simple. If it was the wire or the ignition module wouldn't I have problems at other times than just the first 1-5 min of running time?

ML320Truck, did your check engine light ever come on to clue the dealer what hole to go after?

Thanks,
Matthew

Just a thought...If ignition module is the same as the coil, try swapping coils with another cylinder. I think those coils are around $100 each. You could also switch wires as well with another cylinder with the same length wires. If cylinder 1 is the front passenger, then I think you could switch with cylinder 4 (if that is the front driver's side).

The check engine light did come on and that's why the dealer can pin point the problem.

I thought the same that it should always misfire if a module is bad, but from what I have learned from the board, it looks like it only happens under certain conditions and only after a period of time, the light will finaly come on, in my case, about 2 months after I first noticed the viberation.

Hesitation After Cold Start/Rough Idle
 

The technical service bulletin for all M-Class models up to MY2000 is "23M/00-2 Group 07". It is covered under warranty (8 years/80,000 miles). This is for the ME 2.0 Injection System (M112 and M113).

Great. Here it is. :thumbsup:


SUBJECT: LIGHT TRUCK DEALER TECHNICAL BULLETIN 23M/00

23M/00-2 GROUP 07 - All M-CLASS MODELS UP TO MY 2000(EXCEPT AMG) WITH ME 2.0 INJECTION SYSTEM (M112 AND M113): This includes the following models: ML430, ML320.

If you receive complaints of rough idle and, or hesitation after cold start, they may be caused by the engine control module (ME-SFI) running very lean after the cold start.

To resolve, please install an updated ME 2.0 engine control module, part number as follows:

Engine M112 (V6): 112 153 0479

Engine M113 (V8): 113 153 0379

Note: Before an updated ECU is installed, ensure that all engine related systems are within specification. This software update will not compensate for any system malfunction.

Version codes have not changed, therefore use the version code from the old ECU. Parts can be ordered from Retailer Parts Services.

For warranty, please use Damage Code: 54575 52

Service Engineering

HHcm

8-31-00

My problem was eventually fixed with replacement of all the wires about a year ago. Now, the light viberation comes back and I think it is going to get worse sooner or later and I gonna to replace the wires again!

rough idle lean accelerating
 

Mat Did you ever find a Cure ?
Ive been replacing parts for 2 months now.

1030pm update. took a flashlight and mirror and looked all around the firewall and found a 3/4" vacuum hose disconnected. Hooked it up , it seemed to idle smoother and the check engine light immediately was off. Tomorrows test drive will tell the story.

Steve

Top Tier Gas
 

My 2000 ML320 had the same problem of hesitating after about a mile of driving after a cold start. I started using a top tier high detergent gas (Chevron) and it completely cleared up. I had been using FINA before. You can check out www.toptiergas.com to find which companies have the recommended high detergent gas.