ML270 2000mod, limp mode

[Larss1983]

Hi
Just got a ML270, that has past 350 000km.
I just fitted a new serpentine belt and a leaking diesel house. I disconnected the battery for some days. Starter the car and it seems like it is in the limping mode some sort. Runs like lack of power, max 2000rpm, if forced in 2gear the rpm goes to 3000rpm and slowly decreasing.
It does not seem to be any different if I unplug the MAF. Tried to measure the voltage at the MAF plug, when the engine idle it is 2,6V between pin 4-5. When hitting the gas throttle the voltage drops to 1,6-1,8v.
I tried to look at old treads… please help! Living in Norway

 

[mersum1es]

Car was ok before belt/hose repair?

Best start is read the codes, preferrably by SDS.

Meanwhile you could check is turbo control arm moving when starting and revving (also check there is vacuum in control lines).

 

[Larss1983]

Car was ok before belt repair. The batterie was disconnected for 2-3days also.

 

[Larss1983]

Dismounted the car today…the arm at turbo does not move…
I took a look at the EGR valve, it was stuck. So it’s now soaking in diesel. Hope this fix the limp mode.

 

[mersum1es]

Are you getting vacuum on turbo and EGR control lines? I think it is more than bad timing if EGR just happened to stuck after repairs.

 

[Larss1983]

Got vacuum at turbo and egr….
I also cleaned the sensors.
If the egr is stuck, wouldn’t that effect the turbo? It was also leaking exhaust in front of the egr….

 

[Larss1983]

Hope that’s just bad luck that EGR got stuck after belt change. Seems like this car is pretty tired all over, so just hoping this cleaning will help.

 

[oigle]

With that mileage, you'll be chasing your tail for quite a while to get everything working properly. Maybe best to exclude the egr from the system and even consider excluding the maf at the same time. Cheap fixes and removes them from the list of probable issues.

 

[mersum1es]

If there was a leak in exhaust/egr/boost it will effect to MAF calculation or pressure expection and may well trigger limp mode.

 

[mioba]

Id be working back on what you put back to make sure its all as should be.
You didnt spark the battery when putting it back did you - just thinking of the OVP relay if applicable.
This was one my first lessons with car maintenance on my w124 a long long time ago. Pulled the batt on my W124 (sparked) put all back together and ran like crap. My mecahnic at the time (head mecahnic at MB) said what have you done. I explained. He laughed and showed me how to connect and replace a battery and took out the relay for a few mins and put it back. Was right as rain.

 

[Larss1983]

Hi. We putted all together yesterday. Waited to sealed had hardened on EGR. Started it now, and it was like The engine runs fine and all the power is back!!
I had a old guy, boat mechanic, to help me out…he truly understands engines. Thanks for help people!!