Air Leak without positive trims (p0171/p0174)
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clk 280
Air Leak without positive trims (p0171/p0174)
2007 CLK 280. 146,000 mls.
OBD2 codes p0171/p0174
Intermittent mis-fires (short to coil etc.)
Yes, it’s ‘those’ codes again. This time with a twist that I am hoping someone here will be able to help with.
I have had this engine smoked with no air leaks detected, but i have a persistent problem with lean codes across both banks. The problem has been going on for a year or so now and i cant shift those codes.
Original culprit for lean codes was a faulty evap valve. New one fitted. No more high STFT’s at idle.
Maintainence I’ve carried out this year includes:
- Both fuel pumps replaced (which includes fuel pressure regulator, filters etc.)
- Evap Valve
- intake manifold gaskets
- injector o-rings
- new spark plugs
- air-filters (these get changed every 6mths or so)
- oil cooler gasket
- vacuum pump o-rings
- PCv system
- 1x new coil pack
The MAF is well within tolerance and reads around 2.5 - 3.5mgs at idle consistently, and i have a spare to check it against.
I have recently checked the secondary air inlet valves on both sides and found the valve on bank 1 was not actuating well. On inspection I found that the reed was also bent in to the open position. Expensive part so if anyone can suggest a repair i would be most grateful. CATs are both heating up quickly on cold start, although the one on bank 1 is a bit quicker and remains at a degree or so higher than bank 2 at all times. To be expected?
Here are my fuel trims. PLEASE HELP. This is driving me nuts.
Idle: STFT. LTFT. (92deg c After cold start)
Bank 1. -0.8. 3.1
Bank 2. -0.8. 0.0
No real change in STFT @1500 or 2000rpm and fuel trims seem to return to normal after a little time o2 sensors might be getting a bit tired. They then bounce about a bit between -1.6 and 0.
After a long run at 60mph LTFT goes Bank 1= 2.6, Bank 2= -2.3
Your thoughts please?
OBD2 codes p0171/p0174
Intermittent mis-fires (short to coil etc.)
Yes, it’s ‘those’ codes again. This time with a twist that I am hoping someone here will be able to help with.
I have had this engine smoked with no air leaks detected, but i have a persistent problem with lean codes across both banks. The problem has been going on for a year or so now and i cant shift those codes.
Original culprit for lean codes was a faulty evap valve. New one fitted. No more high STFT’s at idle.
Maintainence I’ve carried out this year includes:
- Both fuel pumps replaced (which includes fuel pressure regulator, filters etc.)
- Evap Valve
- intake manifold gaskets
- injector o-rings
- new spark plugs
- air-filters (these get changed every 6mths or so)
- oil cooler gasket
- vacuum pump o-rings
- PCv system
- 1x new coil pack
The MAF is well within tolerance and reads around 2.5 - 3.5mgs at idle consistently, and i have a spare to check it against.
I have recently checked the secondary air inlet valves on both sides and found the valve on bank 1 was not actuating well. On inspection I found that the reed was also bent in to the open position. Expensive part so if anyone can suggest a repair i would be most grateful. CATs are both heating up quickly on cold start, although the one on bank 1 is a bit quicker and remains at a degree or so higher than bank 2 at all times. To be expected?
Here are my fuel trims. PLEASE HELP. This is driving me nuts.
Idle: STFT. LTFT. (92deg c After cold start)
Bank 1. -0.8. 3.1
Bank 2. -0.8. 0.0
No real change in STFT @1500 or 2000rpm and fuel trims seem to return to normal after a little time o2 sensors might be getting a bit tired. They then bounce about a bit between -1.6 and 0.
After a long run at 60mph LTFT goes Bank 1= 2.6, Bank 2= -2.3
Your thoughts please?
