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Hi all
I have recently noticed my exhaust becoming excessively black, to the point that even low load on flat road not much more than idle it leaves a haze behind.
When giving it a boot load it bellows with black smoke, and even when steadily increasing the throttle when stationary and giving it a gently rev it blows quite black.
The vehicle is otherwise well maintained, has ~160km on the clock, injectors are ~20k and 14 months old, air filter is fresh, manifold should be clean as it was cleaned completely after I added a catch can.
The engine also idles fine, and seems to run fine apart from a very intermittent low boost condition that goes away on restart which I believe is unrelated.
I performed some diagnostics today to try and assess the health of the MAF sensor, idea was to determine if the MAF readings increased in a linear fashion at 250rpm increments - and they do.
What I did discover though were a few peculiarities in the figures which I was hoping could start some discussion.
From a cold start the MAF reading at idle (802rpm cold engine) was 9.1 g/sec up to around 55 degrees coolant temp. I also noted that the MAP was 78kpa (ambient was 101kpa).
Then whilst the engine warmed up I noticed an audible change, hard to describe but like it was lower pitched. At the same time the MAF reading at idle (now 700rpm) went to ~18 g/sec and steady.
The at idle MAF did not change from there remaining between 16 and 18 g/sec.
I thought this was a bit high, and I am struggling to find a good reference for expected normal MAF readings.
What I did also notice was that the MAP (Manifold Pressure) was still low at ~80 kpa. So I shut the engine down to assess the MAP with no pressure, and it was still around 80 kpa. The Barometric Pressure readout was steady at 100 kpa and I am almost at sea level and the current actual atmospheric pressure is 101 kpa.
By my logic I would assume with the engine off the MAP should be close to or equal to the Barometric Pressure. Am I correct in this thinking?
For reference my MAF readings were, and when charted these are near linear:
So questions:
Cheers
Cam
I have recently noticed my exhaust becoming excessively black, to the point that even low load on flat road not much more than idle it leaves a haze behind.
When giving it a boot load it bellows with black smoke, and even when steadily increasing the throttle when stationary and giving it a gently rev it blows quite black.
The vehicle is otherwise well maintained, has ~160km on the clock, injectors are ~20k and 14 months old, air filter is fresh, manifold should be clean as it was cleaned completely after I added a catch can.
The engine also idles fine, and seems to run fine apart from a very intermittent low boost condition that goes away on restart which I believe is unrelated.
I performed some diagnostics today to try and assess the health of the MAF sensor, idea was to determine if the MAF readings increased in a linear fashion at 250rpm increments - and they do.
What I did discover though were a few peculiarities in the figures which I was hoping could start some discussion.
From a cold start the MAF reading at idle (802rpm cold engine) was 9.1 g/sec up to around 55 degrees coolant temp. I also noted that the MAP was 78kpa (ambient was 101kpa).
Then whilst the engine warmed up I noticed an audible change, hard to describe but like it was lower pitched. At the same time the MAF reading at idle (now 700rpm) went to ~18 g/sec and steady.
The at idle MAF did not change from there remaining between 16 and 18 g/sec.
I thought this was a bit high, and I am struggling to find a good reference for expected normal MAF readings.
What I did also notice was that the MAP (Manifold Pressure) was still low at ~80 kpa. So I shut the engine down to assess the MAP with no pressure, and it was still around 80 kpa. The Barometric Pressure readout was steady at 100 kpa and I am almost at sea level and the current actual atmospheric pressure is 101 kpa.
By my logic I would assume with the engine off the MAP should be close to or equal to the Barometric Pressure. Am I correct in this thinking?
For reference my MAF readings were, and when charted these are near linear:
| RPM | MAF g/sec |
| 913 | 24 |
| 1250 | 36 |
| 1480 | 43 |
| 1750 | 52 |
| 2000 | 59 |
| 2250 | 66 |
| 2500 | 77 |
So questions:
- Could this cause the engine to run rich?
- Does anyone have a reference MAF reading chart for the 1 KD FTV?
- What is a normal MAF reading at idle
Cheers
Cam
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