2005 E320 CDI seems underpowered
 

Good day folks

Got a 2005 E320 CDI 118k miles. It just seem sluggish and underpowered. Seems to be lacking the torque it should have.

This is my first CDI car in family. I have not driven any other CDI I6 to compare.

So its got new fuel and air filters, Clean EGR system and no check engine lights. New air intake temp sensor and new MAP sensor.

I still think the damn thing does not have the grunt it should provide. I had car scanned on MB star program and no faults found.

Would a clogged air intake make such a great difference. Would there not be some sort of fault code for it?

What about the injectors? Car starts up great and has no smoke under heavy acceleration.

Fuel milage in town is ok, not great 13l to 100km..

Thanks

Possibly........but I doubt it. I would guess that it depends on your perspective.

My CDI is like driving a leashed stallion. It always wants to pull and run like a scalded ape. Just a fraction of a steady kept push on the foot feed produces a 'kick' in each gear shift change propelling you forward.

What do the records you got with the car indicate?

Those cars have so many sensors that it's hard to imagine a problem that would not be flagged by one of them.

Just speculating, I would say look at the VGT actuator and possible cat flow problems. Just a "gut" feeling, I know nothing of these...

I agree. Lot of sensor. We got the car with a limp mode and went from there to fix it.

We did the sensor at back of fuel rail. We had issue with the HP pump where a internal valve did not return fuel properly to fuel tank.

We replaced the MAF sensor. We also replaced the LP pump in fuel tank and fuel sender unit.

A lot of work has gone into her. Right now runs great, no codes yet low on power.

So I am coming back to the cat converter issue. While at the shop few months ago. We did disconnect the exhaust just AFT of the turbo. Thus running it without the primary or secondary Cats..

The mistake we did perhaps was the way we tested it. Only went on a short run outside of shop. Did not notice a great difference so we bolted everything right up.

Seems like I shall revisit the CAts again.

I guess I'm a little confused but if you disconnected the exhaust system and nothing changed why would you have to re-visit the issues of the cat's being clogged?

Seems like you've already replaced a bunch of parts, was there any diagnosis done before they were replaced? If so did the replacement of the parts cure whatever issues were discovered in the diagnosis process?

I can second Skid-rows comments, my CDI comes off the line with real authority. Traction control can be activated at will with full-throttle applications on dry conditions up until around 20-30mph.

0-60 times are in the mid 6 second range and accompanied by lots of nice black smoke. If yours isn't acting like this something is amiss.

I'm wondering why people are having stopped up cats? I didn't know these cars' cats were so short lived, or that they even ever stopped up. Or do they?

Over the years I've only ever seen one plugged up cat, on my son-in-laws Dodge truck. It wasn't a very hard diagnosis as the truck had no power at higher revs and the cat glowed cherry red. I've made a test-bung that threads into the O2 sensor to check back pressure and it indicated something like 300 PSI of pressure at full-throttle. Typical good values are less only a couple of PSI so it wasn't a tough one. I've never seen an MB cat melt down and plug but I have seen them develop rattles when the ceramic structure inside cracks and this permits the ceramic matrix to rattle around inside the metal supporting structure.

Again its not clear to me that the converter is the problem here, if the original poster removed the exhaust system prior to the cat and nothing changed I don't see how the cat could be involved.

I do agree with the previous poster that given the level of computer management on the CDI's it seems unlikely that something could be really amiss and have nothing show up on the CE lights or SDS codes.

I'd like to know if the original poster ever did a 0-60 test and if so what were the numbers.

Is the trans set to winter or summer? May be as simple as being set to winter and reducing available torque.

I had the trap oxidiser plug up in my 87 300TD.

This was the replacement one that was included in the entire exhaust replacement recall of years ago.

Symptoms were low power and lots of black smoke.

I dropped the exhaust aft of the turbo, and it was clear almost immediately that the exhaust was plugged. Car obviously ran much better with the detached exhaust. It was noticable even running down the driveway (300').

A simple tool made from a piece of rebar sharpened like a flat blade screwdriver made short work of the plugged matrix w/o any outward signs of tampering.

Jim

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,

13l/100km=18 mpg (US). That's worse than my 300D. Something is wrong, but I'm not sure what. I'm having trouble thinking of a powertrain problem that would create those symptoms without throwing a code. Have you checked for dragging brakes?

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, although maybe there's a SBC brake failure going on? Worth questioning.

For reference, my 09 (OM642) gets ~25mpg in town lugging around at 1100-1200 rpm. Highway at 80mph it gets 38mpg; guessing at 65mph it would get in the low 40's. It does get up and roar whenever you put your foot down hard and challenge the traction control as another poster mentioned.

The Bio use concerns me, may be inj or pump issues still unresolved. I believe B5 is the max bio limit.

Gosh, my 2005 will fly; I try to stay off it because I don't like the smoke, but it will fly. It has 130K. I just made a trip out of state one day, averaged 40.7 mpg according to the on-board. I typically get circa 35 around town here (rural area).
BioDiesel? Uhoh...no telling what it could be. Injectors clogged? Turbo wheel dirty? Are you certain the trans is shifting into high gear? Is a brake caliper sticking/dragging?

thanks for all the replies. I am too scratching my head..

I think brakes are OK. I did several tests where I put car in N and it was moving without any binding on brakes. Unless the SBC system engages somehow during driving and impedes the wheels.

I bought diesel injector tester kit Lhttp://www.princessauto.com/pal/en/Testers/Fuel-Injection-Test-Kit/8504748.p

We will test the injectors in upcoming days.

Would it be safe to assume that the car would throw codes at me if CATs are blocked?

Update:

Had car at MB dealer and checked for all updates on software on ECU and Tranny..No changes after software reflash to latest.

Checked injectors and flow test them.

Checked Y values on High Press Pump


Cleaned out intake manifold from carbon build up. Wasnt bad at all, mild build up no blockage.

Replaced MAP sensor and air temp sensor on boost pipe leading into intake manifold of engine

Replaced MAF sensor at air intake filter with Bosch unit

Checked exhaust for blockage, nothing found,

The E320 CDI drives fine with no codes but still lacks that power it should have out it.

I am out of ideas of what to check next.:(

Is there a sensor that I might be missing, perhaps its giving wrong values to ECU?

I have absolutely no codes at all. Nothing stored. No limp mode. Revs to redline but aint got that punch it should.

Runs smooth, no black smoke,

I am about to give up. A car of this caliber with a whack load of sensors and nothing is showing up...

What am I missing?>

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?

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.

Cat
 

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.

Cat
 

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.

Biodiesel.......

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

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.

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...

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.

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.

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..

Leaky boost hoses will most definitely throw ck engine lite.

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:mad::mad:

Did you ever verify the VGT actuator was working properly?

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..,

Tire/rim diameter the same on both cars?

yes both 2005.

identical cars

You said you did the sensor on the back of the fuel rail. The one on the back of the fuel rail can not be changed it is set at the factory and the book says to change the whole rail if that is a problem. Mercedes does not change them at the dealerships just the rail. If you removed that sensor. I am willing to bet you got it in there good enough for it to run without an error code but not as good as the factory settings. It is adjustable maybe before you buy a new one for $325 you should micro adjust it. I think you should mark the rail in both directions and mount a pointer on the sensor. Adjust it left one notch and then test it. Adjust it right one notch. Until it runs really good. If it starts to throw code you know you did it wrong.

Good Luck with that.

I have purchased a new one and we actually swapped it out and it did not make a difference at initial diagnosis. It was a sensor at front of the hp pump.

From what I have heard, the press regulator is not adjustable.

Thanks

Do these cars have a fuel strainer in the tank that could be plugged?

Why do I ge the feeling that you guys are talking about two complete different things? HP pump and fuel rail...

The bio diesel has ruined your injectors I have seen this many times ... There is a tester for the leak quantity of the injectors if u want to confirm but pretty much garuntee they are ruined as well as the pressure regulator

After being away adventure travelling for almost a month, I returned home to Texas and once again have the pleasure of driving my 06 E320 CDI every day or so a few miles - it struck me that it is almost; overpowered, if anything. You have to watch that these massive-powered creatures don't get away from you when pushing the throttle on 'em. I am thinking that the foreign versions of the 05/06 E320 I6 CDI, the E270s, are probably a little more tame to handle and better mated for power, than these monster-powered 3.2 liter turbo sedans that we have here in the States.:)

Common Rail
 

Did you change the back of the Common Rail "We did the sensor at back of fuel rail." Because that would be bad. I was wrong I looked it up a new rail is $750. And Yes I have a spare in my garage that has an adjuster nut on it. It might not be adjustable but it can be adjusted.

Drove the car today. Running smooth and no smoke. Fuel pressure rail peaks at about 23000 psi..turbo peaking at 32 psi...

The dealer has flow tested the injectors before I bought the car..not sure if I can trust them or not..they also performed engine compression test. All seemed to be well

So if I am peaking at 23000 psi ..how could the pressure regulator at back of rail mis adjusted?

How can injectors be fried if car runs smooth and no smoke.


It seems like a software or sensor issue..but ..

If the injector spray pattern/atomization is messed up, I can see the results being low power and poor fuel economy due to poor combustion - it kinda makes sense. But then I would also expect there to be an observable difference in the way the engine runs - either idle noise, or perhaps additional black smoke under acceleration.

Unfortunately the piezo injectors are very expensive (~$500 each), so swapping them on speculation isn't feasible. I wonder if there are services which can test/evaluate/recondition them?

For not too much money you could dyno the car and have hard evidence of lack of power.

Rgds,
Chris W.
'95 E300D, 418K, not too much power, but enough

No Piezo injectors in the CDI, still won't be cheap tho

I am having a similar issue. When I first bought the car I was getting 32MPG in town. Over the last year or so the fuel economy has been slipping to the point now where I'm at around 26MPG for the same type driving. No codes in the computer according to ScanGage. Power has always been lower than it should be as indicated by the 9 plus second 0-60 time.

I keep track of the fuel economy on Fuelly.com so that helps in comparisons. Air, fuel filters, Glowplugs, thermostat(with temp sensor) have been changed. I cleaned the EGR valve, the MAF sensor, MAP sensor, and dielectrically greased most all electrical connectors under the hood in an attempt to maintain the vehicle and also to regain lost power & fuel economy. I even removed and reseated the fuses in the fuse box to ensure I didn't have any high resistance contacts there.

After reviewing the information online about how this injection control scheme works and the various sensor inputs I am wondering if I have a fuel temp sensor problem or perhaps an O2 sensor issue. Both those inputs help the vehicle decide how much fuel to use by way of adjusting fuel rail pressure and fuel injection duration. I am currently testing my fuel temp sensor which according to CDI literature should be a NTC(negative temp coefficient) type. Not sure what the resistance per temp spec on it is however.


I wonder if the OP has considered checking or replacing the fuel temp sensor or perhaps the O2(Lambda) sensor?

That's interesting. I have not had the car for long, in fact I have put less than 3K miles on it. My in town mpg's have always been around 26.5 to 28 and no more than 35 for highway, though I like to keep the go pedal on check to keep the EGR clean :P
I always thought the power was very good, but now I am starting to wonder if my car is suffering from the same and I just don't know better :confused:
I have no hard or soft codes either and the car runs as smooth as butter. I have read at least one member's comments about his car feeling like a "rocketship" and a "wild horse" that could easily slip out of control.
The only two cars I ever drove that gave me that particular feeling was a V10 Dodge Viper and a Porsche 911 turbo, and my CDI, although a very peppy car, doesn't even come close to that.
I hope my low mpg's are more related to my right foot rather than a motor related issue.
I'll be getting the bag of popcorn for this one...

Just a data point.... I purchased my 05 in 2010 with 130k on the clock. It now has 229k and 99% of those 99k miles were on homemade BD.

Mine still accelerates like a bat out of he** just like it did the day I got it. I won't even let my 16yr old son drive it because of the acceleration.

I recently had some shifting issues, so I sprung for the aftermarket tranny dipstick and did fluid and filter change. Back to normal health now.

During some of my shifting issues, it was evident that the tranny seems to have the ability to restrain the engine. You may want to look at the tranny as a contributor to your problem.

On BD, I will get 32mpg all day long. The very rare occasions of pump diesel, it will get 37.

Your car is behaving like mine did when a pack rat chewed through the wires (3) that went to an air control flow valve, I'm really sorry I don't remember the proper name, but it's located under the intake on the left side of the engine about at #2/#3 cylinder back from the front. It's an electrically operated valve.

I'm sure DAS tests function, via voltages, but if it was stuck, I wonder if DAS would know it's not working correctly. My OM642 has been throwing a P1101 code that turned out to be the air inlet temp sensors, but was flagging the HFMAFs on the left tube.

Point being, DAS doesn't necessarily catch everything correctly?

Again, the lifeless behavior is exactly what mine was doing.

Quick question, what setting is your tranny on? C or S?
On my 05 and I'm sure other models selecting "C" on the little button at the left front of the shifter on consul will start you off in 2nd gear. There is a Huge acceleration difference between "C" & "S" IMO, be sure it's in "S" for the fun factor! Also look for the "S" illuminated on the dash when picked.

DD

josh my mpg drops off a lot if i have any injector seals leaking, and i had some leaking that evidently did not leak long enough or bad enough to build up carbon around them

could not tell my looking at them

but put some gas leak tester on them and found 2 leaking

changed those and mpg back up by 4-5mpg

my plan is to change out the injector seals every 75,000 miles now or earlier if i get any leaks , and i will do them all at once instead of one or two at a time

Thanks for the info. Can you expand more on your method of testing?
Thanks

Great information there! Funny because I just looked under the hood a few days ago to see very early start of "Black Death" on cylinder #1 injector. I used BrakeKleen, and STP carb/choke cleaner and it all cleaned up really nicely. I'm waiting for the tools now to get that injector out and new seal and new bolt installed. It looks like it happened in the last 500 miles since my fuel economy went from 26 to 21 MPG over that time. My question to you is you mention gas leak tester....Would soapy water work just as well? Maybe Snoop?