Mercedes SLK World banner

1 - 19 of 19 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
Hi everybody, I have a 1999 R170 230k and I have some problems with my car, when the car is hot it makes a smooth misfiring, but you can feel ir from the seat. The CO emissions are high too.


I changed:
- MAF.
- Lambda sensor.
- Exhaust manifold.
- Catalysator.
- Intake manifold gaskets.
- Spark plugs, spark plug wires and spark coils.
- Rebuilded fuel Injectors.
- Camhaft magnets (with M271 engine wires)
- The ECU is OK



And it still fails, the car failed before changing all parts. So I've continued looking for the fault and I have doubts about the function of these two pieces: http://i68.tinypic.com/21c5pix.jpg





One is a valve that opens the passage of a tube that goes from the compressor to the engine block, under the exhaust manifold.



The other it seems to control the previous valve, but it have 2 more vacuum tubes and a 2 wire connector. But I don't know if my failure is due to this valves or not.


Thanks!
 

·
Registered
Joined
·
82 Posts
You changed over 20 parts that most likely did not need replacement. Maybe stop doing something that doesn't work and take your car to a proper shop that is known for good diagnostics? It would probably be cheaper at this point.

How do you know ECU is OK? Did you check if it always gives signal to the injectors (for which you would need an oscilloscope)?
Did you check if wiring is actually OK (like between MAF and ECU or between O2 sensor and ECU, ...)?
Did you use a good scan tool that can count misfires? Are they on one cylinder or more?
 

·
Premium Member
Joined
·
1,482 Posts
Hi everybody, I have a 1999 R170 230k and I have some problems with my car, when the car is hot it makes a smooth misfiring, but you can feel ir from the seat. The CO emissions are high too.


I changed:
- MAF.
- Lambda sensor.
- Exhaust manifold.
- Catalysator.
- Intake manifold gaskets.
- Spark plugs, spark plug wires and spark coils.
- Rebuilded fuel Injectors.
- Camhaft magnets (with M271 engine wires)
- The ECU is OK



And it still fails, the car failed before changing all parts. So I've continued looking for the fault and I have doubts about the function of these two pieces: http://i68.tinypic.com/21c5pix.jpg





One is a valve that opens the passage of a tube that goes from the compressor to the engine block, under the exhaust manifold.



The other it seems to control the previous valve, but it have 2 more vacuum tubes and a 2 wire connector. But I don't know if my failure is due to this valves or not.


Thanks!
No codes at all? :surprise:

You've done everything that I'd have thought of.
Have you read THIS ARTICLE? There is mention of fuel pump, fuel rail, burnt valve, head gasket and even the battery could all cause a misfire.
 

·
Premium Member
Joined
·
1,426 Posts
I'll be that guy (again). you might have low compression in a cylinder. have you done a compression check?
 

·
Registered
Joined
·
549 Posts
"- Rebuilded fuel Injectors." can you share any details? This is not a normal thing for petrol motor. I had a problem with the Green Beauty and I got a set of 4 used injectors from a low mileage car for 113 euro (shipping included). How does the car start when cold in the morning? Any tiny grey (grey, not white/blue) cloud of smoke from the exhaust?




Edit: videos of smoke from leaking injectors: https://www.slkworld.com/2967274-post25.html
 

·
Premium Member
Joined
·
1,482 Posts
High emissions and smooth misfire when it's hot .. you haven't mentioned the fuel economy, is that within "normal" parameters?

The fact that it only does this when it's hot suggests the lambda sensor or the cat to me but you've changed those.

AND you still have no codes at all?

Bit of a mystery, shot in the dark ... what make is the new lambda sensor?
 

·
Registered
Joined
·
14 Posts
Discussion Starter #14
"- Rebuilded fuel Injectors." can you share any details? This is not a normal thing for petrol motor. I had a problem with the Green Beauty and I got a set of 4 used injectors from a low mileage car for 113 euro (shipping included). How does the car start when cold in the morning? Any tiny grey (grey, not white/blue) cloud of smoke from the exhaust?




Edit: videos of smoke from leaking injectors: https://www.slkworld.com/2967274-post25.html

Due to the failure, I took the injectors to check and clean by ultrasounds, they told me that there were in perfect condition. The car starts perfectly and there aren't any grey clouds, and it smells normal. :S
 

·
Registered
Joined
·
14 Posts
Discussion Starter #15
High emissions and smooth misfire when it's hot .. you haven't mentioned the fuel economy, is that within "normal" parameters?

The fact that it only does this when it's hot suggests the lambda sensor or the cat to me but you've changed those.

AND you still have no codes at all?

Bit of a mystery, shot in the dark ... what make is the new lambda sensor?

Yes, the fuel consumption is a bit high. About 12-14L/100km Mixed fuel consumption. About 9-10L/100km in the highway (120Km/h max). Lambda make is Bosch, I've even tried another lambda sensor from another slk 230 (same OEM reference).
 

·
Premium Member
Joined
·
1,482 Posts
Yes, the fuel consumption is a bit high. About 12-14L/100km Mixed fuel consumption. About 9-10L/100km in the highway (120Km/h max). Lambda make is Bosch, I've even tried another lambda sensor from another slk 230 (same OEM reference).
In English that's about 20mpg (imperial) around town and about 30mpg on the highway which in itself isn't excessively low unless my maths fail me

.. and you say the cat is new also?

Personally I'd admit defeat at this point and take it to MB to get it on a Star system, that might work out cheaper in the long run.

:confused:
 
1 - 19 of 19 Posts
Top