2005 E320 CDI seems underpowered - Page 2 - PeachParts Mercedes-Benz Forum

engatwork · #16 04-22-2014, 09:02 PM

Quote:

Its a lil low but in the realm of possibilities if you only drive in town and are VERY heavy footed......I'd probably look at the Cats too

I have seen plugged cats on a 98 E300 that was driven for a long time exactly as described above on 100% biod. Don't remember exact code.

Are you able to watch the boost pressure when turbo spools up? What is it coming up to?

65aircooled · #17 04-22-2014, 09:12 PM

I just read all the posts on this thread and I haven't yet seen this question asked: What are you comparing your car to? Have you driven/owned another CDI, have you had another CDI owner drive your car? I think my car has lots of pep, when compared to most diesels and even gassers but I wouldn't line it up against a Corvette... maybe you are expecting more than what the car has to offer?
I am only saying that because acording to SDS all systems check out and there are no codes, newish HP pump, clean EGR which by the way, can trow the car into limp with no hard codes. Sounds like intake and exhaust are doing what they are supposed to. What was the outcome of the injector test? Did you check fuel rail preasure? Although that should come up in the SDS test if faulty.
Again, the CDI is peppy but it all depends on your expectations.

EDIT: BTW, my car doesn't smoke even when floored, at least not what I would consider black smoke like my old (2006) Ram CTD. The exhaust stinks, but no black smoke.

grease lightnig · #18 04-22-2014, 09:44 PM

Make sure it actually has a cat. There is a problem with backpressure. PO could have removed the guts to the CAT and the Turbo is off because of lack of backpressure which sounds against all possibility but it creates a swirl in the cat without the ceramic material on the inside. Most people have to cut the cat to get the material out look for the re-weld lines.

My original CDI got better fuel mileage and had more power but not much. I always wondered if the first had a tune on it that I did not know about.

I run WVO in mine on a two tank system. It is a great car. It is even better when you use 3 gallons of veg oil for each gallon of diesel.

Good Luck.

grease lightnig · #19 04-22-2014, 09:45 PM

Make sure it actually has a cat. There is a problem with backpressure. PO could have removed the guts to the CAT and the Turbo is off because of lack of backpressure which sounds against all possibility but it creates a swirl in the cat without the ceramic material on the inside. Most people have to cut the cat to get the material out look for the re-weld lines.

My original CDI got better fuel mileage and had more power but not much. I always wondered if the first had a tune on it that I did not know about.

I run WVO in mine on a two tank system. It is a great car. It is even better when you use 3 gallons of veg oil for each gallon of diesel. Mine never smokes either. Neither did the last one.

Good Luck.

Skid Row Joe · #20 04-23-2014, 01:04 PM

Quote:

Originally Posted by engatwork

I have seen plugged cats on a 98 E300 that was driven for a long time exactly as described above on 100% biod. Don't remember exact code.

Are you able to watch the boost pressure when turbo spools up? What is it coming up to?

Biodiesel.......

Quote:

Originally Posted by E300D

We did replace a whole bunch of parts after a full diagnostics of the CDI

We had fuel pressure issues that threw the car into limp mode as well as noise LP pump.

What I also need to mention is that the P.O run the car for approx 50K miles on Biodiesel...

So what happened was that he got the limp mode and dealer assumed the whole car fuel system is dirty and needs to be replaced. I took a chance on the car and bought it.

The fuel pressure problem went away after we swapped out the fuel pressure sensor at back of the fuel rail.

The noise fuel pump aka lift pump aka low pressure pump was replaced with a new one along with a fuel sender unit.

Additionally the HP pump was replaced due to a stuck internal fuel return valve.

MAF was also replaced since we did not get any readings from it.

So right now the car runs good. No codes and and engine runs smooth. However the issue of low power remains.

Why I think I should revising the CAT is because we disconnected at the turbo but did not really drive the car at a good speed to notice a difference. Sure the turbo was spooling up louder and I did notice the electronic VNT actuator move as it should.

So I think I shall go back, unplug the CAT and go for a boot in the car.

Another suspect I have is a blocked intake manifold. However when I pulled out EGR valve it was clean as a whistle.

Now back to the point where PO used Biodiesel in the car: The car had already approx 30-40K miles when he started using biodiesel.

I do not have sufficient knowledge of biodiesel but I know MB allows only something like a 20% blend with petrol diesel. Well from what I gathered the PO run B100 or 100% biodiesel.

From what I understand biodiesel burns clean and acts as a detergent, cleaning out crap and such from the engine. In theory, is there a possibility where a whole bunch of gunk and crap from the combustion process clogged up one of the cats over the last 60K miles?

I have not done any 0 to 60 times. The car seems fine but lacks that responsiveness.

I have switched bet Winter and Summer mode but not big difference in response.

If I hold the car against brakes and let turbo spool up it takes off, but I am unable to activate traction control. Also there is very little black some if any when I floor it.

Thanks guys,

From what I am hearing from some other diesel owners, biodiesel is a no-go.

shertex · #21 04-23-2014, 07:16 PM

I wonder if it would help to test drive another one....see if your subjective impression is any different.

And have you done the 0-60 test yet? That would seem to be in order.

E300D · #22 04-24-2014, 08:50 AM

Hi guys and thanks for the input

The car does have a OE CAT, we took off the clamp and looked inside of it to verify, we can see a mesh type honeycomb which is not blocked.

Looks like the OM 648 motor E320 in NA have one CAT right after the turbo and then 2 rear mufflers.

I do not believe the exhaust is the culprit.

Mass Airflow Sensor under load 900MG of flow.
Boost pressure 2300MBAR
Rail Pressure 1600 BAR
Removed clamp on downpipe and test drove, no changes

New fuel filter, new air intake temp sensor new pressure boost sensor, new MAF
New thermostat runs at proper eng temp.

I cleaned intake and checked intake port flaps and all ok. Also did the test on them on the car.

I have comparison to same car that has a much better perf.

0 - 60 is around 9 sec.

Like I said car runs well with no stored codes.

I do not hear any boost leaks, do not see any issues with that.

EGR is clean and was clean when I first removed it.

Seems like I have reached all the items I can check...

pimpernell · #23 04-24-2014, 08:58 AM

excerpt from Car and Driver test report:

Nevertheless, the diesel is quicker to 60 mph-7.1 seconds versus 7.4-and delivers more punch in low- and midrange sprints: 30 to 50 in 3.5 seconds, 50 to 70 in 4.8. The gas E320 recorded 3.8 and 5.4 seconds, respectively.

shertex · #24 04-24-2014, 09:06 AM

Since you're coming up empty, I might be tempted to have it chip tuned. Would set you back a few hundred dollars, but might enable the ECU to compensate for whatever's ailing it.

E300D · #25 04-24-2014, 09:24 AM

thought of chipping but it should run 100% stock before you chip..

I am going to explore the boost hoses and see if there is anything hiding in there..

engatwork · #26 04-24-2014, 11:21 AM

Leaky boost hoses will most definitely throw ck engine lite.

E300D · #27 04-24-2014, 12:46 PM

check all boost hoses , looks good.

This sounds like a electronics problem,

I need to find out more info and location of the electronic throttle position sensor

KarTek · #28 04-25-2014, 12:48 PM

Did you ever verify the VGT actuator was working properly?

E300D · #29 04-25-2014, 07:20 PM

Hi guys.

We checked visually the vnt actuator and it moved fine.

Today I tested the electronic gas pedal. Swapped w another one ..no change.

Car run smooth yet other car has better perf. Car a is a 2005 cdi w 30k miles on it.. Car b is the vehicle in my subject

Here is some numbers I pulled of today during a test drive;
Hard accel load 99%. MAP 224-240 kPa..MAF 213 -240 g/s.........car a

car b :hard accel load 99.2% ..MAP 210 -225 kPa...MAF 210 - 220 g /s....numbers look similar over a series of few runs...both coolant temp approx 85 C..,

TMAllison · #30 04-26-2014, 11:15 AM

Tire/rim diameter the same on both cars?