W203 C270 loss of power and low boost

[SMP142]

Awhile ago the car went into limp mode and would not rev beyond 3k rpm or create any boost. Every once in awhile it would be normal in the morning and run seemingly fine. Then it went into limp mode for good. I checked the resistance of the intake sensor and it was bad so I went an got a new one.

The sensor fixed the rpm issue I was having, but it still feels like it is not creating boost. It did go into limp mode once with the new sensor which worried me, however the old one checked bad anyway, so it had to go.

I pulled everything apart to see if anything was bad. I leak checked the intercooler and piping. I put a new hose on the turbo actuator and it functions properly. My vacuum to all spots is good (dont think it would cause this issue.) My entire air filter and box are all good.

I installed all new fuel lines under in the engine compartment 8 months ago, but there is no fuel leaking.

I have a laptop program called OBDWiz that can check for codes and other diagnostics. I do not think it works with everything on the MB, but i can check manifold pressure while driving.

I do not know what stock numbers are, but it seems extremely low to me.

Idle = 14.7psi (1 bar) 0 pressure inside of the manifold
Full boost = 21psi (1.4 bar) subtract the 1 and it shows I am at 6psi or 0.4 bar.

I know this car used to push a lot more than this before. It just feels like it has no power anymore. I have no way of checking rail pressure, but maybe this could be the issue. But I have no check engine light or any codes that I can read.

I have heard of cats breaking apart and blocking the flow. I have also heard the flapper ports getting suck and making the car run this way. Does this sound plausible?

I know a guy that has the big bosch scanner, will it read the codes for this car? I am trying to keep from going to the dealer since I am in Italy and I am not fluent in italian.

Any help at this point would be appreciated. Thanks.

 

[Chrishazle]

Won't rev beyond 3k - does kickdown work? These were the 2 symptoms 3 months after I bought my 2001 C270 S203 - it was the MAF, had it changed under warranty, problem solved.

 

[SMP142]

Already replaced the maf and it fixed the rpm issue for the most part. Limp mode came back once since then. Car is a 6 spd standard trans so no kickdown. Just feels like no boost. So I think it's a fueling thing. I don't think I am getting enough fuel to the engine to get the turbo spinning. So something has to be holding it back.

 

[Erfan]

Hole in turbo pipe?

 

[SMP142]

Hole in turbo pipe?

Nope. Pressure check was good.

 

[SMP142]

P0100, P1403, P1470. About to look them up and see where to start.

 

[91dm]

Was it a replaced with a Mercedes MAF, I had similar symptoms Chrishazle had which turned out to be the MAF?

 

[SMP142]

MAF is good. I pulled out the intake pressure sensor and tried to clean it. It does run slightly better, but that might just be in my head. The store was closed yesterday when I tried to get a new one. I am going to try that out and see if it works. Hopefully this fixes it. This car is no fun to drive when it has no power.

 

[SMP142]

***Update***

Back in October I replaced both the MAF and intake pressure sensor. This cleared up my rev limit issue, but the loss of power is still there. Due to traveling over the holidays and my wife needing the car to get around, we have just dealt with the power issue.

I was able to bring it into my mechanic again this week to see if it was an old code that needed to be cleared since installing the new sensors. He told me that the EGR is stuck open and that is causing the lack of power.

He suggested I either clean the valve and see if that works, or block off the tube by cutting a small round piece of metal to block the gas.

Now... from what I have read, blocking it off will possibly cause a code to appear because it can tell if the EGR is blocked off. I would really like to remove the intake and do the complete delete of EGR, swirl flaps, and install the resistors but... I just do not have that sort of time and I will be moving and selling the car in a little over a year.

I plan to remove the EGR and clean it prior to doing any of the below items.

NOTE: I am not required to comply with emissions standards, so I am able to do whatever I want to the engine.

On to the next question/options:
1. Is it worth getting an ECU flash to turn off the EGR system?
2. If I do go that route, would I be better off paying a little extra to get it remapped to add a little extra power/fuel economy?
3. Is it best to avoid any of this unless I do a full delete?
4. Should I just go ahead and try blocking the tube and see what happens?
5. Last option is I just turn it into the mechanic and let him try to mess with it.

Let me know what you guys think. I really do not want to keep driving the car like this forever. I have family flying in this summer, and I know the car will have very poor performance with 4 people riding around.

Thanks-
Brian

 

[SMP142]

I took off the EGR valve and cleaned it today. It was not that dirty, but it was kind of stuck closed. I hooked up my vacuum pump and got it to pop open. This led me to go down the path of checking the vacuum again.

I checked the vacuum at the brake booster port and I am getting 20 inches. When I check it at each vacuum solenoid (EGR and Turbo) I get right around 5. This does not seem normal to me, as it should still be 20, and the solenoid regulates what the diaphragm sees from there.

I have tried to find a vacuum line diagram to no avail. I plan to dig into it rather soon. Does anyone know where the lines go to and from?

 

[estate-agent]

If you're not 100% sure if your able to check all fault codes then i'd suggest getting someone with a reliable code reader or Star. Is your EML light lighting up on your dash?

If MAF is fine and you can't hear boost pressure escaping when driving then I would suggest checking the swirl flaps are working. If you can hear boost leak then obviously check boost hoses / intercooler etc.

Mine swirl flaps had got stuck closed so had no boost. I tackled the dreaded job of inlet manifold off and removed flaps and plugged holes - Job done, full power again.

I still have the EML light on as I have yet to add the resister to wiring loom (which I'm going to do at ECU end of loom). The light has no effect on how it drives, I get full boost and 30+mpg around town and same stonking 55+ mpg on long runs.

If you can get under your car with under shields removed you should be able to see motor and its connecting rod to flaps.


.

 

[SMP142]

I havent checked my flaps. I want to removed them, but I heard its quite the job. I have no EML either. I checked the vacuum lines and they hold pressure. The solenoids leak air when I tried to pull a vacuum on them. I assume that is normal until the ECU tells them to do otherwise.

I have an OBDII reader that hooks to my laptop and I can log "some" information. I am going to drive it around tomorrow and see what I can figure out. Maybe I can see what the issue is by reading the logs.

 

[SMP142]

got some logs today. now the car only shows a max boost of about 2-3 psi. or less than .2 bar.

I am not sure why the car is doing this. Still no check engine light or anything. I think I am going to have to take it to the mercedes dealership and see if they can see whats up. I can only do so many things without the high priced equipment.

 

[a111r]

An easy thing you can do is unplug the flap motor and bridge the connector with a 4.7K ohm resistor.
The flaps should default open.

 

[SMP142]

I will check that out. I also read about the cats being clogged. Same symptoms. I am going to pull the exhaust today.

 

[SMP142]

Cats were clean. Unplugged the flapper motor and drove it without the resistor. No change. No even a fault light. Is that normal?

 

[SMP142]

Its went back into full limp mode today with 3k rpm limit. It was fine until I unhooked the MAF plug to check the cat. I think I might have a bad MAF plug. going to check those wires tomorrow. The saga continues...

 

[SMP142]

Fixed! i think?

So I took the car back to my mechanic friend and got the codes read again. These showed up:

P1403
P1470
P1189

The 1189 is because I had the flapper motor unplugged.

So... I decided to do the EGR bypass/delete by dieselman utilizing the resistors and diode. Long story short, I installed everything and took it back to him to wipe the codes and both 1400 codes are gone. 1189 was still there since I didnt plug it back in yet.

Now I have boost again. It still feels a little slower than I remember, but I have been daily driving my supra for a few months.

Hopefully this fixed everything. Only time will tell.

 

[SMP142]

another update....

Plugged the flapper motor back in and 1189 went away. Still have the 1470 though...

I decided to check into a few things since it still felt slow. After returning to the vacuum leak I thought I had, it turns out the wastegate actuator is bad. I tried several variations with different hoses and bypassing the solenoid and nothing seemed to change it. So I took a brand new hose and check it with my hand pump. I can only build up to 5hg before it would leak down, which isn't even enough to move the actuator.

Just ordered a new one on ebay, so I hope this is the final thing I have to deal with on this car.

As always, I will update once I get the new part installed.

 

[Snoop108]

any joy?
I have a c270, swirl flaps removed and motor delete, along with the EGR resistor delete. Ran fine for a while, but now its got low boost from turbo. I can hear it still trying to work, but down on power. 2nd cat was also removed but was not blocked