BenzHausNC

I had 2 instances where I would not get any power at half throttle or higher and no transmission kick down either. After driving for a while and shutting down, I would start the engine and it seemed just fine.

The first time it happened, I was not thinking and started the GL320 without running the glow plugs. I drove for 45 miles on the highway. It would keep highway speeds on flat ground. Fuel mileage seemed normal. I let it sit for 30 minutes and all was normal again.

The next time, I went up into the mountains. Was driving normal, but after drive down from the mountains, where I used some engine braking and coasting in gear, the half throttle/no kick down happened again. Stopped the truck for an hour and all seemed normal again.

I do get somewhat normal power up to half throttle and can pull away from an intersection just fine.

Any ideas whats going on here?

Thanks for any replies!

N_Jay

You went in to limp mode for some reason.


Search this forum and the ML forum for "limp" and you will find a number of threads.

BenzHausNC

Wouldn't I get a check engine light? Mine never came on.

Thank you!

alx

The car needs to be read and if no revealing errors were found your transmission adaptations need to be reset. If that doesn't help most likely your tranny valve body is in its way out.

N_Jay

Several errors that force limp mode do not throw a CEL.


Intermittent limp mode seems to reset usually on a restart. No waiting required.

N_Jay

You are guessing.


I put my money on the DPF differential pressure sensor, but I too am guessing.

alx

Dpf will not cause shifting malfunction. Also it will throw emission codes which will result in check engine light.

Engine tq management will limit engine output if tranny signals are found implausible.

Yes I am guessing the culprit which I have seen more than I care

BlownV8

I'm guessing turbine speed sensor and or trans valve body.

N_Jay

Funny, mine does exactly what he describes when it goes into limp. (Including no check engine light)


I am not sure it is my DPF differential pressure sensor because I have not replaced mine yet, but there have been MANY people here (and apparently on Sprinter forums and Jeep CRD forums) reporting the same thing, and reporting that replacing the DPF differential pressure sensor fixes it.


But we all could be wrong.


Remember, a diesel in limp mode does not build any boost and the RPMs are limited so it won't "kickdown".


https://mbworld.org/forums/gl-class-...d-weather.html


https://mbworld.org/forums/gl-class-...limp-mode.html


https://mbworld.org/forums/gl-class-...home-mode.html

BenzHausNC

Well today the engine threw a code P2015 'Intake Manifold Runner Position Sensor/Switch Circuit Range/Performance"

This does not sound like fun.

N_Jay

There are some reports of oil dripping from the turbo output seal on to the intake tumbler flap motor.
S

BenzHausNC

This I need to check out. I have seen a few small oil spots under one of the vehicles.

I did an "Italian Tuneup" today, and have not had any issues since. I am thinking that I have been driving REAL light for fuel mileage. I tried that once with a VW TDI and ended up with EGR clogging. A little running hard and it cleared up forever.

We shall see....

N_Jay

The oil from the intake in very little, doubt it makes it to the ground.


Most oil leaks are from the oil cooler seals. (Lots of threads on that also)

BlownV8

Don't muck around with diesel oil leaks on these engines. I've seen a few with blown engine's because the oh s hit light did not activate.

N_Jay

Has anyone traced a blown engine to an oil cooler seal leak, or have they all been bigger problems like an oil cooler failure?


Mine loses/burns about 1 to 2 quarts between changes (10K miles/1 year).
I check it before each major trip, so about 6 to 8 times a year.


So far I have never added more the 1/2 a quart at a time.

BlownV8

I guess they don't call for oil burners for nothing. Yes, I believe we have had an example where it caused a blown engine. It leaked oil and the owner did not catch because the low oil light failed to illuminate. Seized engine.

will_w204

I'm having the SAME issue on my 450, totally different motor, exact behavior you describe. 2 weeks in the shop, 2 techs and the foreman say it feels like every other GL450, he can't find anything wrong, there are no codes, no MILs, and they checked trans adaptation and claim it is in spec.

This aall happened suddenly a few weeks ago, and has not gotten better. I know my car. This thing has been a bullet for 15k and more than a year, having bought it at 74k, with 90 on it now.

Coinciding with this change has been a marked decrease in fuel economy. I typically get 17.1-18.5 on my normal loop, depending on temp, AC, etc. Lately, I have been getting between 15.6 and 16.5. The shop claims it's winter gas, but I've had it 2 winters, and I get gas from the same 2 places, and it ran fine on winter gas from Aug/whenever until a few weeks ago

IDEAS?

BlownV8

It's got to be your turbine speed sensor or valve body. Mine went out around 90 or 100k if my memory serves me correctly. It will get to where it will not downshift at all unless you shut it off and restart the car.

BenzHausNC

Turned out being the intake flaps. I think the linkage may have gotten mucked up with oil from a bad seal from the EGR pipe, leaking oil onto the linkage. I pulled the plug to the flaps and sensor and placed a 4.7k to 5k Ohm resistor, on the middle 2 terminals, imitating the position of the flaps. Ever since then all is good. Great fuel mileage, full power....carry on.

If anyone is interested I can take pictures.

BlownV8

Yes, do share.

N_Jay

Talked to a shop about doing the oil cooler and they suggested always doing the manifolds also, since the flaps get stuck and the linkage breaks.
$600 a side! Just for the parts. No labor since they are already off to do the cooler.
Anyone know where to get reman manifolds?

N_Jay

Yes please.


Were they stuck, or just sticky? Was the linkage broken?


How often were you having the problem, and how long has it been since you did the fix?

BenzHausNC

OK I will grab a picture tomorrow.

This is all related to error code P2015. Putting that in so that someone can search on that.

I never got to the linkage, so I dont know if they were broken. It started out happening infrequently and got worse and worse. There was oil all over the area from the EGR pipe being lose. The flaps and linkage are well hidden and buried. It is my guess that the oil built up then dirt got in there and gummed everything up so it could not move.

It all started about a month ago and got worse real fast. I could clear it once and a while but it would always come back and I would be in limp mode.

This fix is easy and does not seem to effect the performance. As a matter of fact, while driving real gently, I got over 30 MPG on the highway on the way into work one morning. I was drafting behind a semi too, so it is not normal, but dannnng!

N_Jay

So you got a code with your limp mode?


There are a bunch of us who get limp mode without any codes stored.

BenzHausNC

It would go into limp mode for quite a while then throw a code P2015.

Its worth trying. 4.7kOhm to 5kOhm resistor across terminals 2 and 3 on the plug to the flap mechanism. I will try to take pictures today, but having family over for Easter.